CN116759347A - Control method and control device of epitaxial process and semiconductor processing equipment - Google Patents

Control method and control device of epitaxial process and semiconductor processing equipment Download PDF

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CN116759347A
CN116759347A CN202311034993.XA CN202311034993A CN116759347A CN 116759347 A CN116759347 A CN 116759347A CN 202311034993 A CN202311034993 A CN 202311034993A CN 116759347 A CN116759347 A CN 116759347A
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heating
heating region
region
change rate
difference
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CN116759347B (en
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曹建伟
沈文杰
张文浩
朱凌锋
段智方
傅加兴
李月洲
汤承伟
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Zhejiang Qiushi Chuangxin Semiconductor Equipment Co ltd
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Zhejiang Qiushi Chuangxin Semiconductor Equipment Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67248—Temperature monitoring
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/02104—Forming layers
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
    • H01L21/67005—Apparatus not specifically provided for elsewhere
    • H01L21/67242—Apparatus for monitoring, sorting or marking
    • H01L21/67253—Process monitoring, e.g. flow or thickness monitoring

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  • Physics & Mathematics (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)

Abstract

The present invention relates to the field of semiconductor processing technologies, and in particular, to a control method and a control device for an epitaxial process, and a semiconductor processing apparatus. The control method of the epitaxial process comprises the following steps: in the epitaxial deposition process of the reference wafer, respectively controlling the heating power of each heating area of the reaction cavity based on a PID algorithm by adopting a preset control model; adjusting control parameters of a preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model; and in the epitaxial deposition process of the target wafer, adopting a target control model to respectively control the heating power of each heating area. According to the technical scheme, the temperature compensation between the adjacent heating areas is reduced by reducing the heating power difference of the adjacent heating areas of the reaction cavity, so that the temperature field uniformity of the reaction cavity is improved, and the generation of slip lines is reduced.

Description

Control method and control device of epitaxial process and semiconductor processing equipment
Technical Field
The embodiment of the invention relates to the technical field of semiconductor processes, in particular to a control method and a control device of an epitaxial process and semiconductor processing equipment.
Background
Epitaxy (epi) refers to a process of depositing a thin monocrystalline layer on a monocrystalline substrate to form an epitaxial layer. In the silicon epitaxial process, the uniformity of the temperature field has an important effect on the generation of slip lines during epitaxial growth. Prior studies have considered that, for wafers, the temperature difference between the center temperature and the edge temperature of the wafer needs to be controlled within a certain range to achieve slip line-free epitaxial growth.
In the prior art, temperature field control is generally performed in a reaction cavity by adopting a mode of temperature control of multiple temperature areas, however, the temperatures of all the temperature areas in the temperature control system of the multiple temperature areas can be mutually influenced to form a strong coupling system. By adopting the mode of independent temperature control of each temperature zone, the power among the temperature zones has compensation phenomenon, so that the temperature and the energy actually obtained by each zone on the surface of the wafer have larger difference, and finally, a sliding line is formed on the surface of the wafer.
Disclosure of Invention
The embodiment of the invention provides a control method and a control device for an epitaxial process and semiconductor processing equipment, which are used for weakening temperature compensation between adjacent heating areas of a reaction cavity, so that the temperature field uniformity of the reaction cavity is improved, and the generation of slip lines is reduced.
In a first aspect, an embodiment of the present invention provides a method for controlling an epitaxial process, including:
In the epitaxial deposition process of the reference wafer, respectively controlling the heating power of each heating area of the reaction cavity based on a PID algorithm by adopting a preset control model;
adjusting control parameters of the preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model; wherein the first heating region is any one of the heating regions, the second heating region is adjacent to the first heating region, and the control parameter includes at least one of a proportional parameter, an integral parameter, and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region;
and in the epitaxial deposition process of the target wafer, adopting the target control model to respectively control the heating power of each heating area.
Optionally, the adjusting the control parameter of the preset control model to reduce the difference of the heating power of the first heating area and the second heating area includes:
and continuously adjusting at least one of proportional parameters, integral parameters and derivative parameters in the PID algorithm applied to the first heating region and/or the second heating region when the difference degree of the heating power change rate of the first heating region and the heating power change rate of the second heating region is larger than the preset difference degree, until the difference degree of the heating power change rate of the first heating region and the heating power change rate of the second heating region is smaller than or equal to the preset difference degree, and obtaining the adjusted preset control model.
Optionally, the difference degree between the heating power change rate of the first heating area and the heating power change rate of the second heating area is greater than a preset difference degree, including:
one of the heating power change rate of the first heating region and the heating power change rate of the second heating region is a positive number, and the other is a negative number; and/or the absolute value of the difference value between the heating power change rate of the first heating area and the heating power change rate of the second heating area is larger than or equal to a preset difference value.
Optionally, when the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than a preset degree of difference, continuously adjusting at least one of a proportional parameter, an integral parameter, and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region until the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than or equal to the preset degree of difference, including:
continuously increasing the proportional parameter in the PID algorithm applied to the first heating region and decreasing the proportional parameter in the PID algorithm applied to the second heating region when the heating power change rate of the first heating region is positive and the heating power change rate of the second heating region is negative until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than a preset difference or until the proportional parameter in the PID algorithm applied to both the first heating region and the second heating region has been adjusted to a corresponding limit;
If the proportional parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to a preset difference value, continuously adjusting the integral parameters in the PID algorithm applied to the first heating region and/or the second heating region until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than the preset difference value, or until the integral parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values;
if the integral parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to a preset difference value, the differential parameters in the PID algorithm applied to the first heating region and/or the second heating region are continuously adjusted until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than the preset difference value, or until the differential parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values.
Optionally, the controlling the heating power of each heating area by using the target control model includes:
and controlling the heating power of each heating area based on the PID algorithm by adopting the target control model based on the proportional parameter, the integral parameter or the differential parameter after each heating area is adjusted.
Optionally, the control method of the epitaxial process further includes:
respectively controlling the heating power of each heating area based on a PID algorithm by adopting a preset control model so as to enable the temperature of each heating area to reach a corresponding target temperature, wherein the target temperature is the sum of a set temperature and a preset offset value;
after the epitaxial deposition of the reference wafer is finished, if a slip line exists in the epitaxial layer of the reference wafer, adjusting the preset offset value corresponding to at least one heating area, and controlling the epitaxial deposition processes of other reference wafers based on the adjusted preset offset value until the slip line does not exist in the epitaxial layer of the reference wafer;
and taking the preset offset value of each heating area corresponding to the reference wafer without the sliding line as a target offset value, and controlling epitaxial deposition of the target wafer based on the target offset value.
Optionally, the heating region includes a central heating region and at least two edge heating regions, the position of the central heating region corresponds to the position of the center of the wafer, the edge heating region corresponds to the position of the edge of the wafer, and the first heating region is any one of the central heating region and the edge heating region.
Optionally, each heating area is heated by a heating device, and the heating power of the heating area is the output power of the heating device of the heating area.
In a second aspect, an embodiment of the present invention provides a control device for an epitaxial process, including:
the reference wafer control module is used for respectively controlling the heating power of each heating area of the reaction cavity based on a PID algorithm by adopting a preset control model in the epitaxial deposition process of the reference wafer;
the control model adjusting module is used for adjusting control parameters of the preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model; wherein the first heating region is any one of the heating regions, the second heating region is adjacent to the first heating region, and the control parameter includes at least one of a proportional parameter, an integral parameter, and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region;
And the target wafer control module is used for respectively controlling the heating power of each heating area by adopting the target control model in the epitaxial deposition process of the target wafer.
In a third aspect, an embodiment of the present invention provides a semiconductor processing apparatus controlled by the control method of the epitaxial process described in the first aspect, where the semiconductor processing apparatus includes:
the reaction cavity is used for carrying out epitaxial deposition on the wafer and is provided with at least two heating areas;
and the heating device is arranged corresponding to the heating area and is used for heating the heating area.
According to the control method and the control device for the epitaxial process and the semiconductor processing equipment, in the epitaxial deposition process of the reference wafer, the preset control model is adopted to respectively control the heating power of each heating area of the reaction cavity based on the PID algorithm, the control parameters of the preset control model are adjusted to reduce the difference of the heating powers of the first heating area and the second heating area, the adjusted preset control model is used as the target control model, in the epitaxial deposition process of the target wafer, the target control model is adopted to respectively control the heating powers of each heating area, so that the heating powers of each heating area tend to be consistent in the epitaxial deposition process of the wafer, the temperature compensation between adjacent heating areas is reduced, the uniformity of the temperature field of the reaction cavity is improved, the generation of slip lines is reduced, and the process window of epitaxial growth without the slip lines is enlarged.
It should be understood that the description in this section is not intended to identify key or critical features of the embodiments of the invention or to delineate the scope of the invention. Other features of the present invention will become apparent from the description that follows.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of a control method of an epitaxial process according to an embodiment of the present invention;
FIG. 2 is a schematic structural view of a reaction chamber according to an embodiment of the present invention;
FIG. 3 is a schematic structural view of a heating device for a reaction chamber according to an embodiment of the present invention;
fig. 4 is a flow chart of another method for controlling an epitaxial process according to an embodiment of the present invention;
fig. 5 is a flow chart of another method for controlling an epitaxial process according to an embodiment of the present invention;
FIG. 6 is a graph of the results of a first set of comparative experiments;
FIG. 7 is a graph of the results of a second set of comparative experiments;
fig. 8 is a partial top view of an epitaxial wafer from a first set of comparative experiments;
fig. 9 is a partial top view of an epitaxial wafer from a second set of comparative experiments;
fig. 10 is a schematic structural diagram of a control device for an epitaxial process according to an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The embodiment of the invention provides a control method of an epitaxial process. Fig. 1 is a flow chart of a control method of an epitaxial process according to an embodiment of the present invention. The embodiment may be applicable to a case of controlling an epitaxial process, where the method may be performed by a control device of the epitaxial process, where the control device of the epitaxial process may be implemented in hardware and/or software, and where the control device of the epitaxial process may be configured in an electronic device. Referring to fig. 1, the method specifically includes the steps of:
s110, in the epitaxial deposition process of the reference wafer, heating power of each heating area of the reaction cavity is controlled by adopting a preset control model based on a PID algorithm.
The preset control model may be a control model based on a PID algorithm. In the epitaxial deposition process, heating power of each heating area is controlled by adopting a preset control model based on a PID algorithm, so that the temperature of each heating area reaches a corresponding target temperature. The PID algorithm is an algorithm for calculating according to the functional relation of the proportion (P), the integral (I) and the derivative (D) based on the input deviation value to obtain an operation result for controlling the output so as to correct the deviation of the control object and enable the deviation to reach a steady state. The effect of the proportional control is, among other things, that as soon as the deviation value is generated, control is performed immediately to reduce the deviation value. The effect of the integral control is to eliminate the static difference and improve the no-difference degree of the system. The differential control can reflect the variation trend of the deviation signal, and can introduce an effective early correction signal into the system before the value of the deviation signal becomes too large, thereby accelerating the action speed of the system and reducing the adjustment time. In this embodiment, according to the difference between the actual temperature and the target temperature of each heating area, the heating power of each heating area may be controlled by using a preset control model based on a PID algorithm, so that the temperature of each heating area reaches the corresponding target temperature.
FIG. 2 is a schematic structural view of a reaction chamber according to an embodiment of the present invention; fig. 3 is a schematic structural diagram of a heating device for a reaction chamber according to an embodiment of the present invention. Referring to fig. 2 and 3, the reaction chamber is used for epitaxial deposition of a wafer, and has at least two heating areas, and the heating device 14 is disposed corresponding to the heating areas of the reaction chamber and is used for heating the corresponding heating areas. The reaction chamber may be a quartz chamber, for example, and specifically includes a susceptor 1, a susceptor ring 2, a chamber upper layer 3, an intake flange 4, and an exhaust flange 5. The susceptor 1 may be a graphite susceptor for carrying wafers. The respective heating areas of the reaction chamber correspond to different positions of the wafer, i.e. to different positions of the susceptor 1.
In the epitaxial deposition stage of the reference wafer, the susceptor 1 is used for carrying the reference wafer, meanwhile, the heating device 14 is controlled to heat each heating area of the reaction cavity, the output power of the heating device 14 is the heating power of the corresponding heating area, and the output power of the heating device 14 corresponding to each heating area is respectively controlled based on a PID algorithm by adopting a preset control model.
S120, adjusting control parameters of a preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model.
The first heating area is any heating area, the second heating area is adjacent to the first heating area, and the control parameters comprise at least one of proportional parameters, integral parameters and differential parameters in a PID algorithm applied to the first heating area and/or the second heating area.
Specifically, when the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than the preset degree of difference, at least one of a proportional parameter, an integral parameter, and a derivative parameter in a PID algorithm applied to the first heating region, and/or at least one of a proportional parameter, an integral parameter, and a derivative parameter in a PID algorithm applied to the second heating region may be adjusted to reduce the heating power difference of the first heating region and the second heating region. The heating power change rate is the ratio of the change amount of the heating power in the set time length to the set time length, and can reflect the change trend and the change speed of the heating power. Because the temperature of each heating area of the reaction cavity can be mutually influenced to generate a coupling effect, the heating power of each heating area has a phenomenon of mutual compensation, so that the heating power of each heating area can be obtained in real time, and whether each heating area can be mutually influenced or not can be judged according to the heating power change rate of each heating area. When the difference degree of the heating power change rate of the first heating area and the heating power change rate of the second heating area is larger than the preset difference degree, the fact that the heating power difference of the first heating area and the heating power difference of the second heating area are larger is indicated, in order to avoid mutual compensation of the heating power of the first heating area and the heating power of the second heating area, at least one of a proportion parameter, an integral parameter and a differential parameter in a PID algorithm applied to the first heating area and/or the second heating area can be adjusted so as to reduce the heating power difference of the first heating area and the second heating area, so that mutual compensation between the first heating area and the second heating area is weakened, and the temperature field uniformity of each heating area is improved.
And adjusting at least one of the proportional parameter, the integral parameter and the derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region, so that after the heating power difference of the first heating region and the second heating region is reduced, an adjusted preset control model is obtained, wherein the adjusted preset control model comprises the adjusted control parameter, and the adjusted preset control model can be used as a target control model.
And S130, respectively controlling the heating power of each heating area by adopting a target control model in the epitaxial deposition process of the target wafer.
Specifically, the target wafer and the reference wafer have the same size, and the difference between the two wafers is that the reference wafer is used as a test wafer, and the target wafer is a wafer to be processed. Before performing epitaxial deposition on the target wafer, the heating devices 14 corresponding to the heating areas are controlled based on the PID algorithm by using the target control model, if the proportional parameter, the integral parameter or the derivative parameter in the PID algorithm applied to a certain heating area in step S120 is adjusted, the output power of the heating device 14 of the heating area is controlled based on the adjusted parameter, and if the heating power of a part of the heating area is not adjusted, the output power of the heating device 14 of the heating area is controlled based on the original parameter, so that the heating devices 14 of the heating areas are controlled to perform heating during epitaxial deposition of the target wafer.
According to the technical scheme, in the epitaxial deposition process of the reference wafer, the preset control model is adopted to control the heating power of each heating area of the reaction cavity based on a PID algorithm, the control parameters of the preset control model are adjusted to reduce the heating power difference of the first heating area and the second heating area, the adjusted preset control model is used as a target control model, in the epitaxial deposition process of the target wafer, the target control model is adopted to control the heating power of each heating area respectively, so that the heating power of each heating area tends to be consistent in the epitaxial deposition process of the wafer, the temperature compensation between adjacent heating areas is facilitated to be weakened, the temperature field uniformity of the reaction cavity is improved, the generation of slip lines is reduced, and the process window of epitaxial growth without the slip lines is enlarged.
On the basis of the above embodiment, optionally, in step S120, adjusting the control parameters of the preset control model to reduce the difference in heating power between the first heating region and the second heating region includes:
and continuously adjusting at least one of the proportional parameter, the integral parameter and the derivative parameter in the PID algorithm applied to the first heating area and/or the second heating area when the difference degree of the heating power change rate of the first heating area and the heating power change rate of the second heating area is larger than the preset difference degree, until the difference degree of the heating power change rate of the first heating area and the heating power change rate of the second heating area is smaller than or equal to the preset difference degree, and obtaining the adjusted preset control model.
Specifically, when the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than the preset degree of difference, at least one of a proportional parameter (P value), an integral parameter (I value), and a derivative parameter (D value) in a PID algorithm applied to the first heating region in the preset control model, and/or at least one of a proportional parameter, an integral parameter, and a derivative parameter in a PID algorithm applied to the second heating region may be continuously adjusted to continuously reduce the difference between the heating powers of the first heating region and the second heating region, and whether the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than or equal to the preset degree of difference may be determined in real time during the adjustment. If the difference degree between the heating power change rate of the first heating area and the heating power change rate of the second heating area is still larger than the preset difference degree, continuing to adjust at least one of the proportional parameter, the integral parameter and the differential parameter in the PID algorithm applied to the first heating area in the preset control model and/or at least one of the proportional parameter, the integral parameter and the differential parameter in the PID algorithm applied to the second heating area. If the difference degree of the heating power change rate of the first heating area and the heating power change rate of the second heating area is smaller than or equal to the preset difference degree, stopping adjusting the proportional parameter, the integral parameter and the differential parameter in the PID algorithm applied to the first heating area and the second heating area in the preset control model to obtain the adjusted preset control model. In practical applications, at least one of the proportional, integral and derivative parameters may be selected for adjustment to reduce the difference in heating power of the first and second heating regions according to the effects of the proportional, integral and derivative controls in the PID algorithm.
Optionally, in an embodiment, the degree of difference between the rate of change of heating power of the first heating region and the rate of change of heating power of the second heating region is greater than a preset degree of difference, including:
one of the heating power change rate of the first heating region and the heating power change rate of the second heating region is positive, and the other is negative; and/or the absolute value of the difference between the heating power change rate of the first heating area and the heating power change rate of the second heating area is greater than or equal to a preset difference.
For example, in the case where the heating power change rate of the first heating region is positive and the heating power change rate of the second heating region is negative, it is indicated that the heating power of the first heating region is continuously increasing and the heating power of the second heating region is continuously decreasing, so that the variation trend difference of the two is large, at least one of the heating power of the first heating region and the heating power of the second heating region needs to be adjusted, for example, at least one of a proportional parameter, an integral parameter, and a derivative parameter in a PID algorithm applied to the first heating region in a preset control model may be adjusted to slow down the increasing speed of the heating power of the first heating region, while at least one of a proportional parameter, an integral parameter, and a derivative parameter in a PID algorithm applied to the second heating region in a preset control model is adjusted to slow down the decreasing speed of the heating power of the second heating region, so as to reduce the heating power difference of the first heating region and the second heating region.
When the heating power change rates of the first heating region and the second heating region are positive (or negative) and the absolute value of the difference between the two is greater than or equal to the preset difference, it is indicated that the heating power change rates of the first heating region and the second heating region are relatively large, and at least one of the proportional parameter, the integral parameter and the derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region in the preset control model needs to be adjusted, for example, when the heating power change rates of the first heating region and the second heating region are positive, the heating power change rate of the first heating region is greater than the heating power of the second heating region and the absolute value of the difference between the two is greater than or equal to the preset difference, the heating power of the first heating region and the heating power of the second heating region are continuously increased, and the increasing rate of the heating power of the first heating region is relatively large, at least one of the proportional parameter, the integral parameter and the derivative parameter in the PID algorithm applied to the first heating region in the preset control model can be adjusted, so that the heating power of the first heating region and the heating power of the second heating region is increased.
Optionally, in another embodiment, the degree of difference between the rate of change of heating power of the first heating region and the rate of change of heating power of the second heating region is greater than a preset degree of difference, including:
obtaining a curve of the heating power of each heating region over time (hereinafter referred to as a heating power curve for convenience of description) from the heating powers of the respective heating regions; and within the set time period, if one of the heating power curve corresponding to the first heating area and the heating power curve corresponding to the second heating area is in an ascending trend and the other one is in a descending trend, determining that the difference degree of the heating power change rate of the first heating area and the heating power change rate of the second heating area is larger than the preset difference degree.
In an example, when the heating power curve corresponding to the first heating region is in an ascending trend and the heating power curve corresponding to the second heating region is in a descending trend, the heating power change rate of the first heating region is a positive number, the heating power change rate of the second heating region is a negative number, the heating power of the first heating region is continuously increasing, and the heating power of the second heating region is continuously decreasing, so that it can be determined that the change trend of the heating powers of the first heating region and the second heating region is greatly different, and at least one of a proportional parameter, an integral parameter and a derivative parameter in a PID algorithm applied to the first heating region and/or the second heating region in a preset control model needs to be adjusted, so that the heating power difference of the first heating region and/or the second heating region is reduced. According to the technical scheme, the degree of difference between the heating powers of the different heating areas is determined based on the heating power curves, and under the condition that the heating power curves of the different heating areas are increased and decreased and are mutually compensated, the heating powers of the corresponding heating areas are adjusted, so that the heating power curves of the heating areas tend to be consistent, and the mutual coupling effect among the different heating areas is reduced.
Optionally, when the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than the preset degree of difference, continuously adjusting at least one of the proportional parameter, the integral parameter and the derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region until the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than or equal to the preset degree of difference, including:
continuously increasing the proportion parameter in the PID algorithm applied to the first heating area and decreasing the proportion parameter in the PID algorithm applied to the second heating area under the condition that the heating power change rate of the first heating area is positive and the heating power change rate of the second heating area is negative until the absolute value of the difference value of the heating power change rate of the first heating area and the heating power change rate of the second heating area is smaller than a preset difference value or until the proportion parameter in the PID algorithm applied to the first heating area and the second heating area is regulated to the corresponding limit value;
if the proportional parameters in the PID algorithm applied to the first heating region and the second heating region are adjusted to the corresponding limit values, and the absolute value of the difference value between the heating power change rate of the first heating region and the heating power change rate of the second heating region is larger than or equal to the preset difference value, continuously adjusting the integral parameters in the PID algorithm applied to the first heating region and/or the second heating region until the absolute value of the difference value between the heating power change rate of the first heating region and the heating power change rate of the second heating region is smaller than the preset difference value, or until the integral parameters in the PID algorithm applied to the first heating region and the second heating region are adjusted to the corresponding limit values;
If the integral parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to the preset difference value, continuously adjusting the differential parameters in the PID algorithm applied to the first heating region and/or the second heating region until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than the preset difference value, or until the differential parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values.
In an exemplary embodiment, when the heating power change rate of the first heating area is positive and the heating power change rate of the second heating area is negative, the heating power curve corresponding to the first heating area is in an ascending trend, the heating power curve corresponding to the second heating area is in a descending trend, the heating power of the first heating area is continuously increasing, and the heating power of the second heating area is continuously decreasing, so that the variation trend difference of the two is larger. Under the condition, firstly, the proportion parameter in the PID algorithm applied to the first heating area in the preset control model is continuously increased, namely the P value is increased, so that the response speed of proportion control of the first heating area is increased, the response time is shortened, meanwhile, the proportion parameter in the PID algorithm applied to the second heating area in the preset control model is continuously reduced, namely the P value is reduced, so that the response speed of proportion control of the second heating area is reduced, the response time is prolonged, the heating power difference between the first heating area and the second heating area is reduced, the heating power of each heating area tends to be consistent, the temperature compensation between adjacent heating areas is reduced, the temperature field uniformity of a reaction cavity is improved, and the generation of a slip line is reduced. For example, the P value in the PID algorithm applied to the first heating region may be increased by the set step size, and the P value in the PID algorithm applied to the second heating region may be decreased by the set step size, while the heating power change rates of the first heating region and the second heating region are calculated, the trend of the heating power curves corresponding to the first heating region and the second heating region is observed until the absolute value of the difference between the heating power change rates of the first heating region and the second heating power change rate is smaller than the preset difference, so that the P values in the PID algorithm applied to the first heating region and the second heating region tend to be consistent, the adjusted preset control model is obtained, or the P values in the PID algorithm applied to the first heating region and the second heating region are stopped to be adjusted until the P values in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values.
If the P values in the PID algorithm applied to the first heating region and the second heating region are adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to the preset difference, so that the variation trend difference of the heating power curves corresponding to the first heating region and the second heating region is still greater, the integral parameters, i.e. the I values, in the PID algorithm applied to the first heating region and/or the second heating region in the preset control model are continuously adjusted, so that the heating power difference of the first heating region and the second heating region is reduced, the heating power of each heating region tends to be consistent, and the oscillation condition of the heating power curves corresponding to the first heating region and/or the second heating region is relieved. For example, the I value in the PID algorithm applied to the first heating region and/or the second heating region in the preset control model may be adjusted by a set step size, while calculating the heating power change rates of the first heating region and the second heating region, observing the trend of the heating power curves corresponding to the first heating region and the second heating region until the absolute value of the difference between the heating power change rates of the first heating region and the second heating power change rate of the second heating region is smaller than the preset difference, so that the I value in the PID algorithm applied to the first heating region and the second heating region is stopped from being adjusted when the heating power curves corresponding to the first heating region and the second heating region tend to be consistent, and the adjusted preset control model is obtained, or the I value in the PID algorithm applied to the first heating region and the second heating region is stopped from being adjusted until the I value in the PID algorithm applied to the first heating region and the second heating region has been adjusted to the corresponding limit value.
If the D values in the PID algorithms applied to the first heating region and the second heating region are adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to the preset difference, so that the variation trend difference of the heating power curves corresponding to the first heating region and the second heating region is still greater, the differential parameters in the PID algorithms applied to the first heating region and/or the second heating region in the preset control model, that is, the D values are continuously adjusted, so that the heating power difference of the first heating region and the second heating region is reduced, the heating power of each heating region tends to be consistent, and the stability of the heating power curves corresponding to the first heating region and/or the second heating region is improved. For example, the D value in the PID algorithm applied to the first heating region and/or the second heating region in the preset control model may be adjusted by a set step size, while calculating the heating power change rates of the first heating region and the second heating region, observing the trend of the heating power curves corresponding to the first heating region and the second heating region until the absolute value of the difference between the heating power change rates of the first heating region and the second heating power change rate of the second heating region is smaller than the preset difference, so that the D value in the PID algorithm applied to the first heating region and the second heating region tends to be consistent, and the adjusted preset control model is obtained, or until the D value in the PID algorithm applied to the first heating region and the second heating region has been adjusted to the corresponding limit value, the D value in the PID algorithm applied to the first heating region and the second heating region is stopped.
Based on the above embodiments, step S130 specifically includes: in the epitaxial deposition process of the target wafer, the heating power of each heating area is controlled by adopting a target control model based on a PID algorithm based on the proportional parameter, the integral parameter or the differential parameter of each heating area after adjustment.
After the epitaxial deposition process based on the reference wafer, the target control model is obtained, before the epitaxial deposition is performed on the target wafer, the heating power of each heating area is controlled by adopting the target control model based on the PID algorithm, and before the step S130 is performed, if the proportional parameter, the integral parameter or the derivative parameter in the PID algorithm applied to a certain heating area is adjusted, the adjusted parameter is used as the parameter applied by the PID algorithm adopted by the heating area, and if the parameter in the PID algorithm adopted by a part of the heating area is not adjusted, the original parameter is used as the parameter applied by the PID algorithm adopted by the heating area, so that the heating device of each heating area is controlled to heat in the epitaxial deposition process of the target wafer.
Fig. 4 is a flow chart of another method for controlling an epitaxial process according to an embodiment of the present invention. On the basis of the above embodiment, the present embodiment optimizes the control method of the external process. Referring to fig. 4, the method specifically includes the steps of:
S210, in the epitaxial deposition process of the reference wafer, heating power of each heating area of the reaction cavity is controlled by adopting a preset control model based on a PID algorithm, so that the temperature of each heating area reaches a corresponding target temperature.
The target temperature of each heating area is the sum of the set temperature and the preset offset value.
Optionally, the heating area of the reaction chamber includes a central heating area and at least two edge heating areas, the position of the central heating area corresponds to the position of the center of the wafer, the edge heating area corresponds to the position of the edge of the wafer, and the first heating area is any one of the central heating area and the edge heating area.
In one embodiment, the heating region of the reaction chamber includes a central heating region, a first edge heating region, a second edge heating region, a third edge heating region, and a fourth edge heating region, the first edge heating region being disposed opposite the second edge heating region, the third edge heating region being disposed opposite the fourth edge heating region. Illustratively, in conjunction with fig. 2 and 3, the reaction chamber includes a first temperature measurement point 6, a second temperature measurement point 7, a third temperature measurement point 8, a fourth temperature measurement point 9, and a fifth temperature measurement point 10, where the positions of the center and the edge of the wafer carried by the susceptor 1 correspond to the positions of the center and the side edges of the susceptor 1. The first temperature measurement point 6 is located in the center of the susceptor 1, corresponding to the position of the central heating zone. The second temperature measurement point 7 is located at the front of the susceptor 1, corresponding to the position of the first edge heating region. The third temperature measuring point 8 is located at the rear of the susceptor 1, corresponding to the position of the second edge heating area. The fourth temperature measurement point 9 is located on the left side of the susceptor 1, corresponding to the position of the third edge heating area. The fifth temperature measurement point 10 is located on the right side of the susceptor 1, corresponding to the position of the fourth edge heating region. The reaction chamber further comprises a first thermocouple 11, a second thermocouple 12, a third thermocouple 13 and a fourth thermocouple (not shown in the figure), the temperatures of the second temperature measuring point 7 and the fifth temperature measuring point 10 are measured through the first thermocouple 11, the temperatures of the first edge heating area and the fourth edge heating area are obtained, the temperature of the third temperature measuring point 8 is measured through the second thermocouple 12, the temperature of the second edge heating area is obtained, the temperature of the fourth temperature measuring point 9 is measured through the third thermocouple 13, the temperature of the third edge heating area is obtained, the temperature of the first temperature measuring point 6 is measured through the fourth thermocouple, and the temperature of the central heating area is obtained.
In one embodiment, the preset offset value of the central heating zone may be 0, i.e. the target temperature of the central heating zone is equal to the corresponding set temperature. The set temperatures of the first to fourth edge heating regions are all the target temperatures of the center heating region, and the preset offset values of the first to fourth edge heating regions may be the same or different. By setting the target temperature of the central heating region and the preset offset value of each edge heating region, uniformity of the wafer surface temperature field can be achieved. Optionally, during epitaxial deposition of the reference wafer, a PID algorithm is used to control the heating power of each heating region, so that the temperature of each heating region reaches a corresponding target temperature.
S220, obtaining the heating power of each heating area of the reaction cavity.
S230, adjusting control parameters of a preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model.
The first heating area is any heating area, the second heating area is adjacent to the first heating area, and the control parameters comprise at least one of proportional parameters, integral parameters and differential parameters in a PID algorithm applied to the first heating area and/or the second heating area.
And S240, after the epitaxial deposition of the reference wafer is finished, if the epitaxial layer of the reference wafer has a slip line, adjusting a preset offset value corresponding to at least one heating area, and controlling the epitaxial deposition processes of other reference wafers based on the adjusted preset offset value until the epitaxial layer of the reference wafer has no slip line.
S250, taking preset offset values of heating areas corresponding to the reference wafers without slip lines as target offset values, and controlling epitaxial deposition of the target wafers based on the target offset values and a target control model.
Specifically, after the epitaxial deposition of the reference wafer is completed, if the epitaxial layer of the reference wafer has a slip line, the preset offset value corresponding to at least one heating region may be adjusted to be the sum of the original preset offset value and the preset adjustment value, and the steps S210 to S240 are repeatedly executed based on the adjusted preset offset value to perform multiple tests, so as to control the epitaxial deposition process of other reference wafers, until the epitaxial layer of the reference wafer does not have a slip line, the current preset offset value of each heating region is used as a target offset value, and epitaxial deposition of the target wafer is controlled based on the target offset value, i.e., the target temperature of each heating region is the sum of the set temperature and the target offset value.
According to the technical scheme provided by the embodiment of the invention, the preset offset value of each heating area is adjusted based on whether the sliding line exists in the epitaxial layer of the reference wafer, so that the epitaxial deposition of the target wafer is controlled, the generation of the sliding line is reduced, and the process window of epitaxial growth without the sliding line is enlarged.
Fig. 5 is a flow chart of another method for controlling an epitaxial process according to an embodiment of the present invention. On the basis of the above embodiments, the present embodiment optimizes the control method of the external process. Referring to fig. 5, the method specifically includes the steps of:
s310, acquiring temperature values of all heating areas of the reaction cavity.
Illustratively, with reference to fig. 2 and 3, the temperatures of the second temperature measurement point 7 and the fifth temperature measurement point 10 are measured by the first thermocouple 11, the temperatures of the first edge heating region and the fourth edge heating region are obtained, the temperature of the third temperature measurement point 8 is measured by the second thermocouple 12, the temperature of the second edge heating region is obtained, the temperature of the fourth temperature measurement point 9 is measured by the third thermocouple 13, the temperature of the third edge heating region is obtained, and the temperature of the first temperature measurement point 6 is measured by the fourth thermocouple, and the temperature of the center heating region is obtained.
And S320, in the epitaxial deposition process of the reference wafer, controlling the output power of the heating device corresponding to each heating area by adopting a PID algorithm so as to enable the temperature of each heating area to reach the corresponding target temperature.
The target temperature of each heating area is the sum of the set temperature and the preset offset value.
Optionally, the central heating zone is provided with a first heating device group 21, the first edge heating zone is provided with a second heating device group 22, the second edge heating zone is provided with a third heating device group 23, the third edge heating zone is provided with a fourth heating device group 24, and the fourth edge heating zone is provided with a fifth heating device group 25. Each heating device group comprises at least one heating device 14, the heating device 14 may be a lamp 15.
S330, judging the uniformity of the surface temperature of the reference wafer based on the resistivity of the baked ion implantation sheet, and adjusting the preset offset value of each heating area accordingly.
In the implementation process, the ion implantation sheet is baked at high temperature, the temperature uniformity of the surface of the wafer is judged through the resistivity on the ion implantation sheet, and the preset offset value of each edge heating zone is given through an empirical formula, so that the temperature field of the surface of the wafer is as uniform as possible.
S340, controlling epitaxial deposition processes of other reference wafers based on the adjusted preset offset value, and obtaining temperature values of all heating areas of the reaction cavity.
Specifically, the preset offset value of each heating region is changed to a value obtained by adjusting according to step S330, so that the epitaxial deposition process of other reference wafers is controlled, and the temperature value of each heating region of the reaction chamber is obtained, so as to determine whether the temperature of each heating region reaches the corresponding target temperature and the temperature fluctuation range of each heating region.
S350, acquiring heating power curves of all heating areas of the reaction cavity, and adjusting parameters in a PID algorithm adopted by all the heating areas based on the heating power curves so as to reduce heating power differences of all the heating areas.
And S360, after the epitaxial deposition of the reference wafer is finished, if the epitaxial layer of the reference wafer has a slip line, adjusting a preset offset value corresponding to at least one heating area, and controlling the epitaxial deposition processes of other reference wafers based on the adjusted preset offset value until the epitaxial layer of the reference wafer has no slip line.
And S370, taking preset offset values of the heating areas corresponding to the reference wafers without the slip lines as target offset values, and controlling epitaxial deposition of the target wafers based on the target offset values.
According to the technical scheme, the temperature compensation between adjacent heating areas is reduced, so that the temperature field uniformity of the reaction cavity is improved, the generation of slip lines is reduced, and the process window of epitaxial growth without the slip lines is enlarged.
In order to verify the beneficial effects of the technical scheme of the invention, two groups of comparison experiments can be performed.
In a first set of comparative experiments, epitaxial deposition of wafers was performed using the following procedure:
setting parameters of a PID algorithm adopted by each heating area as default values, setting the temperature of a reaction cavity of an epitaxial furnace to 1170 ℃, and adopting high-flow 20 SLM HCl and 5 SLM H 2 After etching and cleaning the graphite component of the reaction cavity for 40 seconds, H is removed 2 The flow is increased to 60 SLM processing for 25 seconds, residual reactants in the cavity are removed, and the cleaning of the environment in the cavity is ensured;
step two, cooling the temperature of the reaction cavity to 850 ℃, and loading a 525um heavily-doped As polishing sheet into the reaction cavity;
step three, the temperature of the reaction cavity is raised to 1135 ℃, the preset offset value of the first edge heating area is set to 22 ℃, the preset offset value of the second edge heating area is set to 14 ℃, the preset offset values of the third edge heating area and the fourth edge heating area are set to 17 ℃, and the temperature of the reaction cavity is set to 60 SLM H 2 Depositing Si and extending for 120 seconds in the atmosphere of the substrate, and setting the rotating speed of the substrate to be 35r/min;
step four, after the deposition is completed, cooling the temperature of the reaction cavity to 850 ℃, and unloading the epitaxial wafer;
and fifthly, observing whether a sliding line exists on the surface of the wafer by adopting a metallographic microscope.
In a second set of comparative experiments, epitaxial deposition of wafers was performed using the following procedure:
step one, based on a heating power curve obtained by a first group of comparison experiments, the technical scheme of the invention is adopted to adjust the parameters of a PID algorithm adopted by each heating area;
setting the temperature of the reaction cavity of the epitaxial furnace to 1170 ℃, and adopting high-flow 20 SLM HCl and 5 SLM H 2 After etching and cleaning the graphite component of the reaction cavity for 40 seconds, H is removed 2 The flow is increased to 60 SLM processing for 25 seconds, residual reactants in the cavity are removed, and the cleaning of the environment in the cavity is ensured;
step three, cooling the temperature of the reaction cavity to 850 ℃, and loading a 525um heavily As-doped polishing sheet into the reaction cavity;
step four, the temperature of the reaction cavity is raised to 1135 ℃, the preset offset value of the first edge heating area is set to 22 ℃, the preset offset value of the second edge heating area is set to 14 ℃, the preset offset values of the third edge heating area and the fourth edge heating area are set to 17 ℃, and the temperature of the reaction cavity is set to 60 SLM H 2 Depositing Si and extending for 120 seconds in the atmosphere of the substrate, and setting the rotating speed of the substrate to be 35r/min;
step five, after the deposition is completed, cooling the temperature of the reaction cavity to 850 ℃, and unloading the epitaxial wafer;
and step six, observing whether a sliding line exists on the surface of the wafer by adopting a metallographic microscope.
Table 1 is a table of parameters of the PID algorithm employed for each heating zone. The parameters before optimization are parameters adopted by the first group of comparison experiments, and the parameters after optimization are parameters adopted by the second group of comparison experiments.
TABLE 1
FIG. 6 is a graph of the results of a first set of comparative experiments; fig. 7 is a graph of the results of a second set of comparative experiments. Wherein, the abscissa is time, the ordinate on the left side represents temperature, the ordinate on the right side represents power, t1 to t20 represent each process flow in the epitaxial deposition process, L1 represents a heating power curve of the central heating region, L2 represents a heating power curve of the first edge heating region, L3 represents a heating power curve of the second edge heating region, L4 represents a heating power curve of the third/fourth edge heating region, L5 represents a target temperature curve of the central heating region, L6 represents an actual temperature curve of the central heating region, and L7 represents a time curve of each process flow. As can be seen from fig. 6 and fig. 7, after the parameters of the PID algorithm adopted by each heating region are adjusted by adopting the technical scheme of the present invention, the heating power curves of each heating region tend to be consistent, which is favorable for weakening the mutual coupling action between different heating regions, so as to weaken the temperature compensation between adjacent heating regions, promote the uniformity of the temperature field of the reaction chamber, reduce the generation of slip lines, and further enlarge the process window of epitaxial growth without slip lines.
Fig. 8 is a partial top view of an epitaxial wafer from a first set of comparative experiments; fig. 9 is a partial top view of an epitaxial wafer from a second set of comparative experiments. By contrast, in the first group of comparison experiments, a plurality of sliding lines with different depths exist around the epitaxial wafer. In the second group of experiments, under the condition of the same preset offset value after heating power monitoring and PID parameter optimization, no slip line exists around the epitaxial wafer, and a process temperature window without slip line is more than 10 ℃.
Based on the same inventive concept, the embodiment of the invention also provides a control device of the epitaxial process. Fig. 10 is a schematic structural diagram of a control device for an epitaxial process according to an embodiment of the present invention. Referring to fig. 10, the apparatus includes: a reference wafer control module 410, a control model adjustment module 420, and a target wafer control module 430.
The reference wafer control module 410 is configured to respectively control heating power of each heating region of the reaction chamber based on a PID algorithm by using a preset control model during epitaxial deposition of the reference wafer.
The control model adjustment module 420 is configured to adjust control parameters of a preset control model to reduce a heating power difference between the first heating area and the second heating area, and take the adjusted preset control model as a target control model; the first heating area is any heating area, the second heating area is adjacent to the first heating area, and the control parameters comprise at least one of proportional parameters, integral parameters and differential parameters in a PID algorithm applied to the first heating area and/or the second heating area.
The target wafer control module 430 is configured to control the heating power of each heating region during epitaxial deposition of the target wafer by using a target control model.
The control device for the epitaxial process provided by the embodiment of the invention can execute the control method for the epitaxial process provided by any embodiment of the invention, has corresponding functional modules and beneficial effects of the execution method, and is not repeated here.
Optionally, the control device of the epitaxial process further comprises:
the heating power control module is used for respectively controlling the heating power of each heating area based on a PID algorithm by adopting a preset control model so as to enable the temperature of each heating area to reach a corresponding target temperature, wherein the target temperature is the sum of the set temperature and a preset offset value;
the preset offset value adjusting module is used for adjusting the preset offset value corresponding to at least one heating area if the epitaxial layer of the reference wafer has a slip line after the epitaxial deposition of the reference wafer is completed, and controlling the epitaxial deposition process of other reference wafers based on the adjusted preset offset value until the epitaxial layer of the reference wafer has no slip line;
the epitaxial deposition control module is further used for taking preset offset values of the heating areas corresponding to the reference wafers without the sliding lines as target offset values and controlling epitaxial deposition of the target wafers based on the target offset values.
Based on the same inventive concept, the embodiment of the present invention further provides a semiconductor processing apparatus, which may be controlled by using the control method of the epitaxial process provided by any embodiment of the present invention, and in combination with fig. 2 and 3, the semiconductor processing apparatus includes:
the reaction cavity is used for carrying out epitaxial deposition on the wafer and is provided with at least two heating areas;
the heating device 14 is provided corresponding to the heating region, and heats the heating region.
According to the technical scheme, in the epitaxial deposition process of the reference wafer, the preset control model is adopted to control the heating power of each heating area of the reaction cavity based on a PID algorithm, the control parameters of the preset control model are adjusted to reduce the heating power difference of the first heating area and the second heating area, the adjusted preset control model is used as a target control model, in the epitaxial deposition process of the target wafer, the target control model is adopted to control the heating power of each heating area respectively, so that the heating power of each heating area tends to be consistent in the epitaxial deposition process of the wafer, the temperature compensation between adjacent heating areas is facilitated to be weakened, the temperature field uniformity of the reaction cavity is improved, the generation of slip lines is reduced, and the process window of epitaxial growth without the slip lines is enlarged.
It should be appreciated that various forms of the flows shown above may be used to reorder, add, or delete steps. For example, the steps described in the present invention may be performed in parallel, sequentially, or in a different order, so long as the desired results of the technical solution of the present invention are achieved, and the present invention is not limited herein.
The above embodiments do not limit the scope of the present invention. It will be apparent to those skilled in the art that various modifications, combinations, sub-combinations and alternatives are possible, depending on design requirements and other factors. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of the present invention.

Claims (10)

1. A method for controlling an epitaxial process, comprising:
in the epitaxial deposition process of the reference wafer, respectively controlling the heating power of each heating area of the reaction cavity based on a PID algorithm by adopting a preset control model;
adjusting control parameters of the preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model; wherein the first heating region is any one of the heating regions, the second heating region is adjacent to the first heating region, and the control parameter includes at least one of a proportional parameter, an integral parameter, and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region;
And in the epitaxial deposition process of the target wafer, adopting the target control model to respectively control the heating power of each heating area.
2. The method of claim 1, wherein adjusting the control parameters of the preset control model to reduce the difference in heating power between the first heating region and the second heating region comprises:
and continuously adjusting at least one of proportional parameters, integral parameters and derivative parameters in the PID algorithm applied to the first heating region and/or the second heating region when the difference degree of the heating power change rate of the first heating region and the heating power change rate of the second heating region is larger than the preset difference degree, until the difference degree of the heating power change rate of the first heating region and the heating power change rate of the second heating region is smaller than or equal to the preset difference degree, and obtaining the adjusted preset control model.
3. The method of claim 2, wherein the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than a predetermined difference, comprising:
One of the heating power change rate of the first heating region and the heating power change rate of the second heating region is a positive number, and the other is a negative number; and/or the absolute value of the difference value between the heating power change rate of the first heating area and the heating power change rate of the second heating area is larger than or equal to a preset difference value.
4. A control method of an epitaxial process according to claim 3, wherein when the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than a preset degree of difference, continuously adjusting at least one of a proportional parameter, an integral parameter and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region until the degree of difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than or equal to the preset degree of difference, comprising:
continuously increasing the proportional parameter in the PID algorithm applied to the first heating region and decreasing the proportional parameter in the PID algorithm applied to the second heating region when the heating power change rate of the first heating region is positive and the heating power change rate of the second heating region is negative until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than a preset difference or until the proportional parameter in the PID algorithm applied to both the first heating region and the second heating region has been adjusted to a corresponding limit;
If the proportional parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to a preset difference value, continuously adjusting the integral parameters in the PID algorithm applied to the first heating region and/or the second heating region until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than the preset difference value, or until the integral parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values;
if the integral parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values, and the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is greater than or equal to a preset difference value, the differential parameters in the PID algorithm applied to the first heating region and/or the second heating region are continuously adjusted until the absolute value of the difference between the heating power change rate of the first heating region and the heating power change rate of the second heating region is less than the preset difference value, or until the differential parameters in the PID algorithm applied to the first heating region and the second heating region have been adjusted to the corresponding limit values.
5. The method according to claim 1, wherein the controlling the heating power of each of the heating regions using the target control model, respectively, comprises:
and controlling the heating power of each heating area based on the PID algorithm by adopting the target control model based on the proportional parameter, the integral parameter or the differential parameter after each heating area is adjusted.
6. The method of claim 1, further comprising:
respectively controlling the heating power of each heating area based on a PID algorithm by adopting a preset control model so as to enable the temperature of each heating area to reach a corresponding target temperature, wherein the target temperature is the sum of a set temperature and a preset offset value;
after the epitaxial deposition of the reference wafer is finished, if a slip line exists in the epitaxial layer of the reference wafer, adjusting the preset offset value corresponding to at least one heating area, and controlling the epitaxial deposition processes of other reference wafers based on the adjusted preset offset value until the slip line does not exist in the epitaxial layer of the reference wafer;
and taking the preset offset value of each heating area corresponding to the reference wafer without the sliding line as a target offset value, and controlling epitaxial deposition of the target wafer based on the target offset value.
7. The method of claim 1-6, wherein the heating region comprises a central heating region and at least two edge heating regions, the central heating region corresponding in position to a center of the wafer, the edge heating region corresponding in position to an edge of the wafer, the first heating region being any one of the central heating region and the edge heating region.
8. The method according to any one of claims 1 to 6, wherein each of the heating regions is heated by a heating device, and a heating power of the heating region is an output power of the heating device of the heating region.
9. A control device for an epitaxial process, comprising:
the reference wafer control module is used for respectively controlling the heating power of each heating area of the reaction cavity based on a PID algorithm by adopting a preset control model in the epitaxial deposition process of the reference wafer;
the control model adjusting module is used for adjusting control parameters of the preset control model to reduce heating power difference of the first heating area and the second heating area, and taking the adjusted preset control model as a target control model; wherein the first heating region is any one of the heating regions, the second heating region is adjacent to the first heating region, and the control parameter includes at least one of a proportional parameter, an integral parameter, and a derivative parameter in the PID algorithm applied to the first heating region and/or the second heating region;
And the target wafer control module is used for respectively controlling the heating power of each heating area by adopting the target control model in the epitaxial deposition process of the target wafer.
10. A semiconductor processing apparatus controlled by the control method of the epitaxial process according to any one of claims 1 to 8, comprising:
the reaction cavity is used for carrying out epitaxial deposition on the wafer and is provided with at least two heating areas;
and the heating device is arranged corresponding to the heating area and is used for heating the heating area.
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