CN115101441A

CN115101441A - Substrate processing equipment and method for improving signal-to-noise ratio of lower temperature detector

Info

Publication number: CN115101441A
Application number: CN202210640627.8A
Authority: CN
Inventors: 秦志坚
Original assignee: Jiangsu Tianxin Micro Semiconductor Equipment Co ltd
Current assignee: Jiangsu Tianxin Micro Semiconductor Equipment Co ltd
Priority date: 2022-06-07
Filing date: 2022-06-07
Publication date: 2022-09-23

Abstract

The present invention provides a substrate processing apparatus comprising: the device comprises a reaction cavity, a base supporting device, a lower heating device, a lower reflecting plate and a lower thermometer, wherein the base supporting device comprises a shaft and a plurality of arms, one end of each arm is connected with the shaft, and the other end of each arm is connected with the base; the lower heating device is arranged below the reaction cavity; the lower temperature detector is arranged below the lower reflecting plate, and a detection signal transmitted by the lower temperature detector reaches a detection point on the back surface of the base and is used for measuring the temperature below the base; the detection signal that lower thermoscope transmitted forms an contained angle with the vertical axis on the base radial plane, the contained angle is [ -15 °, 30 ° ]. The substrate processing apparatus of the present invention reduces the influence of the rotation of the arm on the pyrometer, and improves the signal-to-noise ratio.

Description

Substrate processing equipment and method for improving signal-to-noise ratio of lower temperature detector

Technical Field

The invention relates to the technical field of semiconductor equipment, in particular to substrate processing equipment and a method for improving the signal-to-noise ratio of a lower temperature detector.

Background

The existing semiconductor thin film equipment, such as epitaxial equipment, CVD equipment, etc., needs high temperature to realize process treatment, and during the process treatment, a temperature detector (such as a pyrometer) is needed to monitor the temperature of a heated substrate (or called a wafer) in real time and feed back the temperature to a temperature control system, and the temperature control system outputs corresponding temperature to heat the substrate and a pedestal to the required process treatment temperature. The thermometers need to have extremely high measurement accuracy and repeatability, and in the measurement process, the thermometers need to have a high signal-to-noise ratio to ensure the effectiveness and real-time performance of the measurement of the pyrometers.

In addition, the uniformity of the existing film deposition has a great relationship with the temperature and the distribution of the process gas flow field, and in order to ensure the uniformity of the film deposition, the existing technology is usually realized by adopting a rotary base mode.

However, as shown in FIG. 1, the rotation of the susceptor 108 is driven by the susceptor support device 104, and the susceptor support device 104 has a plurality of arms, and the rotation of the plurality of arms shields the thermometers 105, reducing the signal-to-noise ratio of the thermometers 105.

Disclosure of Invention

The invention aims to provide a substrate processing device and a method for improving the signal-to-noise ratio of a lower temperature detector, which are used for solving the problem of low signal-to-noise ratio of the lower temperature detector.

In order to realize the purpose, the invention is realized by the following technical scheme:

a substrate processing apparatus, comprising:

the reaction chamber is used for carrying out process treatment on the substrate;

the base is arranged in the reaction cavity and used for bearing the substrate;

the base supporting device is used for supporting the base and comprises a shaft and a plurality of arms, one end of each arm is connected with the shaft, and the other end of each arm is connected with the base;

a lower heating device disposed below the reaction chamber for providing thermal radiation to the reaction chamber during a process;

the lower reflecting plate is used for reflecting the heat radiation of the lower heating device into the reaction cavity;

the lower temperature detector is arranged below the lower reflecting plate, and a detection signal transmitted by the lower temperature detector reaches a detection point on the back surface of the base and is used for measuring the temperature below the base; the detection signal transmitted by the lower temperature detector forms an included angle with the vertical shaft on the plane where the base is located in the radial direction, and the included angle is [ -15 degrees, and 30 degrees ].

Optionally, the lower reflection plate includes an annular plate having an opening through which the detection signal passes to the back surface of the base.

Optionally, the lower reflection plate further includes an annular side wall, one end of the annular side wall is connected with one end of the annular plate, and the annular side wall is a complete ring.

Optionally, the included angle is [ -10 °, 20 ° ].

Optionally, the included angle is 0 °.

Optionally, the distance from the detection point to the center of the base is [50mm, 150mm ].

Optionally, the distance is [70mm, 135mm ].

Optionally, the distance is [80mm, 125mm ].

Optionally, the lower heating device comprises a plurality of heating lamps.

Optionally, the lower heating device includes a lower outer ring heating lamp set and a lower inner ring heating lamp set, the lower outer ring heating lamp set and the lower inner ring heating lamp set are both arranged annularly, the lower outer ring heating lamp set is used for heating the outer ring of the base, and the lower inner ring heating lamp set is used for heating the inner ring of the base.

Optionally, the lower reflection plate includes a lower inner ring reflection plate and a lower outer ring reflection plate, the lower inner ring reflection plate is used for reflecting the thermal radiation of the lower inner ring heating lamp group, and the lower outer ring reflection plate is used for reflecting the thermal radiation of the lower outer ring heating lamp group.

Optionally, the lower thermometer is arranged below the lower inner ring reflection plate.

Optionally, the lower inner ring reflection plate includes an annular plate and an annular side wall, the annular plate has an opening, one end of the annular side wall is connected to one end of the annular plate, and the annular side wall is a complete ring.

Optionally, the opening is circular.

Optionally, the lower thermometer is a pyrometer.

The invention also discloses a method for improving the signal-to-noise ratio of the lower temperature detector, which comprises the following steps:

step one, providing the substrate processing equipment;

and step two, forming an included angle between a detection signal emitted by the lower thermometer and the vertical axis on a plane where the radial direction of the base is located, wherein the included angle is [ -15 degrees ], and the included angle is 30 degrees ].

Optionally, the method further includes: step three, enabling the distance from a detection point of the detection signal reaching the back of the base to the center of the base to be [50mm, 150mm ]; the third step is executed before the second step, or executed simultaneously with the second step, or executed after the second step.

Optionally, the included angle is [ -10 °, 20 ° ].

Optionally, the included angle is 0 °.

Optionally, the distance is [80mm, 125mm ].

Compared with the prior art, the invention has the following advantages:

through the special setting of included angle theta and distance S, be different from the setting that tends the check point to the center among the prior art, make the check point keep away from the center, reduced the influence of the rotation of arm to the pyrometer, improved the SNR, especially need not to set up the breach on lower reflecting plate, avoided the heating inhomogeneous that the heat radiation leaked and leads to, simultaneously, when included angle theta is at [ -5 °, 5 ° ], the degree of accuracy greatly increased of temperature measurement, especially when included angle theta is at 0 °, the advantage is more obvious.

Drawings

In order to more clearly illustrate the technical solution of the present invention, the drawings used in the description will be briefly introduced, and obviously, the drawings in the following description are an embodiment of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts according to the drawings:

FIG. 1 is a schematic view showing a structure of a substrate processing apparatus in the prior art;

FIG. 2 is a diagram illustrating a detection signal path in the prior art;

FIG. 3 is a graph of prior art lower thermometer test data;

FIG. 4 is a schematic structural diagram of a lower reflector in the prior art;

FIG. 5 is a schematic view of the structure of a substrate processing apparatus of the present invention;

FIG. 6 is a schematic view showing the relationship between the thermometer and the included angle θ;

FIG. 7 is a schematic structural diagram of a lower reflection plate according to the present invention;

FIG. 8 is a graph of lower thermometer test data for the present invention.

Detailed Description

The invention is described in further detail below with reference to the figures and the detailed description. The advantages and features of the present invention will become more apparent from the following description. It is to be noted that the drawings are in a very simplified form and are all used in non-exact scale for the purpose of facilitating and distinctly facilitating the description of the embodiments of the present invention. To make the objects, features and advantages of the present invention comprehensible, reference is made to the accompanying drawings. It should be understood that the structures, ratios, sizes, and the like shown in the drawings and described in the specification are only used for matching with the disclosure of the specification, so as to be understood and read by those skilled in the art, and are not used to limit the implementation of the present invention, so that the present invention has no technical significance, and any structural modifications, ratio changes or size adjustments should fall within the scope of the present invention without affecting the efficacy and the achievable purpose of the present invention.

Fig. 1 is a schematic view showing a structure of a substrate processing apparatus in the related art. As shown in fig. 1, the substrate processing apparatus includes a reaction chamber including an upper dome 103, a lower dome 107, and a flange sealing and fixing the upper and lower domes 103, a susceptor 108, a susceptor supporting device 104, a heating device 102, a reflecting plate 106, and a thermometer, the reaction chamber being used for performing a process on a substrate; the base 108 is arranged in the reaction chamber and used for bearing the substrate; the base supporting device 104 is used for supporting the base 108, the base supporting device 104 comprises a shaft and a plurality of arms, one end of each arm is connected with the shaft, the other end of each arm is connected with the base, and the rotation of the shaft drives the plurality of arms to rotate so as to drive the base 108 to rotate; the heating device 102 is used for providing heat radiation to the reaction chamber during the process treatment, and comprises an upper heating device and a lower heating device, wherein the upper heating device is arranged above the reaction chamber, and the lower heating device is arranged below the reaction chamber; the reflecting plate 106 is used for reflecting the heat radiation of the heating device into the reaction cavity, the reflecting plate 106 comprises an upper reflecting plate and a lower reflecting plate, the upper reflecting plate is used for reflecting the heat radiation of the upper heating device into the reaction cavity, and the lower reflecting plate is used for reflecting the heat radiation of the lower heating device into the reaction cavity; alternatively, the lower reflection plate may include only the lower reflection plate, or the lower reflection plate may include the lower inner ring reflection plate and the lower outer ring reflection plate, according to different settings of the lower heating device. One side of the reaction cavity is provided with an air inlet, the other side of the reaction cavity is provided with an air outlet, process gas enters the reaction cavity from the air inlet, and the process gas is decomposed and reacted under the heat radiation of the heating device to grow a film on the substrate. The upper temperature detector 101 arranged at the center above the reaction cavity is used for monitoring the temperature of the center of the upper surface of the substrate, the lower temperature detector 105 is used for monitoring the temperature of the position, about 20mm away from the center, of the lower surface of the base 108, the upper temperature detector 101 is mainly applied during temperature calibration, because the upper surface of the substrate is a light sheet during temperature calibration, the surface emissivity of the substrate is constant, the reading of the upper temperature detector 101 is stable at the moment, the shapes of the upper surfaces of the substrates corresponding to different process products are different, the emissivity of the upper surface of the substrate can change according to different products, the reading of the upper temperature detector 101 is influenced, the lower surface of the base measured by the lower temperature detector 105 is a silicon carbide coating with constant emissivity, and therefore, the data of the lower temperature detector 105 is generally adopted as the temperature feedback of the process. Referring to fig. 2, the upper portion of the susceptor support 104 is provided with a plurality of arms, when the susceptor support 104 rotates, the arms operate to the detection signal P of the pyrometer, which periodically has a large influence on the measurement value of the lower thermometer 105, and particularly to fig. 3, which shows the data measured by the lower thermometer 105 in the prior art, and shows the reading of the lower thermometer 105 after one rotation, in which the horizontal value is the effective signal, the triangular value is the interference signal, the effective signal accounts for about 38%, and the signal-to-noise ratio is too low. The signals acquired during the process processing need to be processed, that is, the interference signals are filtered, when the temperature of the base 108 is stable, the interference signals are filtered, and then the temperature control is not greatly affected, but when the base 108 is in the process of temperature rise or temperature drop, because the interference signals have a large proportion, if the interference signals are filtered, the temperature feedback received by the temperature control system will be distorted and delayed, so that the temperature control system cannot timely and accurately output proper power to heat the base 108 to the required temperature.

Furthermore, as shown in FIG. 1, the lower thermometer 105 of the prior art forms an angle θ with the vertical axis yy' on the plane of the radial direction of the base, the angle θ being large enough to allow the detection signal P to reach the detection point on the back of the base 108 at a distance of about 10-20mm from the center of the base. Since the detection point is near the center of the base 108, the detection signal P is also close to the center (i.e., axis) of the base support 104, and therefore the time that the detection signal P is blocked by the arm is long and the signal-to-noise ratio is low. And due to the existence of a large included angle, the lower reflecting plate needs to be provided with an independent notch 1065 to avoid the detection signal P and prevent the detection signal P from being shielded, as can be seen from fig. 4: the lower reflection plate comprises an annular plate 1061 and an annular side wall 1063, one end of the annular side wall is connected with one end of the annular plate, notches 1065 are arranged on the annular plate 1061 and the annular side wall 1063 to avoid the detection signal P, and the notches cause the heat radiation of the lower heating device to leak from the notches, so that uneven heat distribution is caused, and finally, uneven film deposition is caused.

Fig. 5 is a schematic structural view of a substrate processing apparatus according to the present invention. The lower thermo detector 105 is disposed under the lower reflector, the detection signal P emitted from the lower thermo detector reaches the detection point O2 on the back of the base 108 for measuring the temperature under the base 108, the detection signal P emitted from the lower thermo detector forms an angle θ with the vertical axis yy 'on the plane of the base 108 in the radial direction, when the detection signal P is parallel to the vertical axis yy', the angle θ is 0 ° (as shown in fig. 5), when the detection signal P deflects from 0 ° to approach to the center O1 of the base 108, the angle θ is negative (as shown in fig. 1), when the detection signal P deflects from 0 ° to approach to the edge of the base 108, the angle θ is positive (not shown), the angle θ of the present invention deflects to the center O1 very little, even not to the center O1 (i.e., θ is 0 °), and even to the edge of the base 108, optionally, the angle θ is [ -15 °, 30 degrees ], such an included angle θ can make the detection point O2, at which the detection signal P reaches the back of the base 108, far away from the base center O1, so that the distance from the detection signal P to the center (i.e. the axis) of the base supporting device 104 also becomes longer, and therefore, compared with the prior art, at the same rotation speed of the base supporting device 104, the time for the detection signal P to be shielded by the arm becomes shorter, and finally, the signal-to-noise ratio is improved; alternatively, the angle is [ -10 °, 20 ° ], which allows the detection signal P to be further away from the center (i.e., axis) of the susceptor support apparatus 104, improving the signal-to-noise ratio.

According to the above principle, when the detection point O2 where the detection signal P reaches the back surface of the base 108 is at the edge of the base 108, the time that the detection signal P is blocked by the arm is shortest and the signal-to-noise ratio is highest. But according to the experimental findings: as shown in fig. 6, when the temperature detector is vertically placed to measure the temperature of a horizontal plate, the temperature accuracy of the detection signal is highest when the detection signal is parallel to the vertical axis yy' (i.e., when the included angle θ is 0 °, as shown in S1 in fig. 6), and is next to that when the included angle is 5 ° or less, and when the included angle θ is (5 °, 30 °) (as shown in S2 in fig. 6), the temperature accuracy of the detection signal is also higher, but when the included angle θ is greater than 30 ° (as shown in S3 in fig. 6), the temperature accuracy of the detection signal cannot be guaranteed, and therefore, it is further preferable that the included angle θ is [ -5 °, 20 ° ], and when the temperature accuracy is further considered, it is preferable that the included angle θ is [ -5 °, 5 ° ], and it is further preferable that the included angle θ is [0 °, 20 ° ], and when the temperature accuracy is further considered, preferably, the included angle θ is [0 °, 5 ° ]; preferably, the included angle theta is 0 DEG, and the temperature accuracy is highest.

As shown in fig. 5, the value of the included angle θ is set to ensure that the detecting point O2 is far from the base center O1, the distance S from the detecting point O2 to the base center O1 is [50mm, 150mm ], in order to improve the signal-to-noise ratio, the detecting signal P needs to be further far from the center O1 of the base supporting device 104, and optionally, the distance S is [70mm, 135mm ]; however, the detection signal P hardly reaches the vicinity of the edge of the susceptor due to the shielding of the lower outer ring reflection plate, and therefore, it is preferable that the distance S be [80mm, 125mm ].

The invention avoids forming a notch on the annular side wall of the lower reflector, and as shown in fig. 7, the lower reflector of the invention is shown, the lower reflector comprises an annular plate 1061 and an annular side wall 1063, the annular plate has an opening 1067, the detection signal passes through the opening to reach the back of the base, one end of the annular side wall is connected with one end of the annular plate, and the annular side wall is in a complete ring shape. Therefore, the lower reflecting plate only has the openings on the annular plate, and the influence on heat radiation leakage and temperature non-uniformity distribution is reduced to the minimum.

Specifically, the upper and lower heating devices each include a plurality of heating lamps, and optionally, the heating lamps are halogen lamps. The lower heating device comprises a lower outer ring heating lamp group and a lower inner ring heating lamp group, the lower outer ring heating lamp group and the lower inner ring heating lamp group are arranged annularly, the lower outer ring heating lamp group is used for heating the outer ring of the base, the lower inner ring heating lamp group is used for heating the inner ring of the base, the lower inner ring reflecting plate is used for reflecting the heat radiation of the lower inner ring heating lamp group, and the lower outer ring reflecting plate is used for reflecting the heat radiation of the lower outer ring heating lamp group; specifically, the lower inner ring reflection plate and the lower outer ring reflection plate both comprise annular plates and annular side walls, and one ends of the annular side walls are connected with one ends of the annular plates. Optionally, the lower thermometer is disposed below the lower inner ring reflector, the annular plate of the lower inner ring reflector has an opening, the annular sidewall of the lower inner ring reflector is a complete ring shape, and optionally, the opening is circular. Optionally, the lower thermometer is a pyrometer.

For a method of improving the signal-to-noise ratio of a lower thermometer, comprising:

step one, providing the substrate processing equipment;

The method further comprises the following steps: step three, enabling the distance from a detection point of the detection signal reaching the back surface of the base to the center of the base to be [50mm, 150mm ]; optionally, the third step is performed before the second step, or performed simultaneously with the second step, or performed after the second step. Specifically, in the third step, the distance S can be adjusted by adjusting the included angle θ; or the included angle theta is fixed, and the distance S is adjusted by moving the lower temperature detector along the radial direction of the base; alternatively, the angles and distances in the method may all be in the ranges described above.

Fig. 8 is a graph of the data from the lower thermometer test of the present invention, which was measured at an angle θ of 0 ° and a distance S of 98mm, showing that the effective signal ratio increased from 38% to 71%. When the base is in the process of temperature rise or temperature drop, effective signals fed back by the lower temperature detector 105 are greatly improved, the timeliness and the accuracy of the output power of the temperature control system are improved, the base 108 can be accurately and efficiently heated to the required temperature, and the stability of related epitaxial process products is improved.

In summary, the substrate processing apparatus and the method for improving the signal-to-noise ratio of the lower thermometer provided by the present invention are different from the prior art in that the detection point is arranged toward the center by arranging the special included angle θ and the special distance S, so that the detection point is far away from the center, the influence of the rotation of the arm on the pyrometer is reduced, the signal-to-noise ratio is improved, particularly, a notch is not required to be arranged on the lower reflection plate, the uneven heating caused by the leakage of the thermal radiation is avoided, and meanwhile, when the included angle θ is [ -5 °, 5 ° ], the accuracy of the temperature measurement is greatly increased, particularly, when the included angle θ is 0 °, the advantage is more obvious.

It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

While the present invention has been described in detail with reference to the preferred embodiments, it should be understood that the above description should not be taken as limiting the invention. Various modifications and alterations to this invention will become apparent to those skilled in the art upon reading the foregoing description. Accordingly, the scope of the invention should be determined from the following claims.

Claims

1. A substrate processing apparatus, comprising:

the base is arranged in the reaction cavity and used for bearing the substrate;

2. The substrate processing apparatus of claim 1, wherein the lower reflection plate comprises an annular plate having an opening through which the detection signal passes to a back surface of the susceptor.

3. The substrate processing apparatus of claim 2, wherein the lower reflection plate further comprises an annular sidewall, one end of the annular sidewall being connected to one end of the annular plate, the annular sidewall being a complete ring.

4. The substrate processing apparatus of claim 1, wherein the included angle is [ -10 °, 20 ° ].

5. The substrate processing apparatus of claim 1, wherein the included angle is 0 °.

6. The substrate processing apparatus of claim 1, wherein the distance from the detection point to the center of the susceptor is [50mm, 150mm ].

7. The substrate processing apparatus of claim 6, wherein the distance is [70mm, 135mm ].

8. The substrate processing apparatus of claim 6, wherein the distance is [80mm, 125mm ].

9. The substrate processing apparatus of claim 1, wherein the lower heating means comprises a plurality of heating lamps.

10. The substrate processing apparatus of claim 9, wherein the lower heating device comprises a lower outer ring heating lamp group and a lower inner ring heating lamp group, the lower outer ring heating lamp group and the lower inner ring heating lamp group are arranged in a ring, the lower outer ring heating lamp group is used for heating an outer ring of the susceptor, and the lower inner ring heating lamp group is used for heating an inner ring of the susceptor.

11. The substrate processing apparatus of claim 10, wherein the lower reflection plate comprises a lower inner-ring reflection plate for reflecting heat radiation of the lower inner-ring heating lamp group and a lower outer-ring reflection plate for reflecting heat radiation of the lower outer-ring heating lamp group.

12. The substrate processing apparatus of claim 11, wherein the lower thermometer is disposed below the lower inner ring reflector.

13. The substrate processing apparatus of claim 12, wherein the lower inner-ring reflection plate includes an annular plate having an opening and an annular sidewall having one end connected to one end of the annular plate, the annular sidewall having a complete ring shape.

14. The substrate processing apparatus of claim 2 or 13, wherein the opening is circular.

15. The substrate processing apparatus of any of claims 1-13, wherein the lower temperature probe is a pyrometer.

16. A method of improving the signal-to-noise ratio of a lower thermometer, said method comprising:

a step of providing a substrate processing apparatus according to any one of claims 1 to 15;

and step two, forming an included angle between a detection signal emitted by the lower temperature detector and the vertical shaft on a plane where the radial direction of the base is located, wherein the included angle is [ -15 degrees, and 30 degrees ].

17. The method of claim 16, wherein the method further comprises: step three, enabling the distance from a detection point of the detection signal reaching the back of the base to the center of the base to be [50mm, 150mm ]; the third step is executed before the second step, or executed simultaneously with the second step, or executed after the second step.

18. The method of claim 16, wherein said included angle is [ -10 °, 20 ° ].

19. The method of claim 16, wherein the included angle is 0 °.

20. The method of claim 17, wherein the distance is [80mm, 125mm ].