JP6322083B2 - Semiconductor wafer cooling method and semiconductor wafer cooling apparatus - Google Patents

Description

  The present invention relates to a semiconductor wafer cooling method and a semiconductor wafer cooling apparatus for cooling a semiconductor wafer covered with a sealing sheet or an adhesive tape having a sealing layer made of a resin composition in a heated state.

  After the dicing process, only non-defective bare chips are selected, and a desired processing is performed on a semiconductor wafer (hereinafter referred to as “wafer” as appropriate) formed by coating a plurality of the bare chips with resin. For example, the semiconductor wafer on which the carrier support plate is bonded with a double-sided pressure-sensitive adhesive tape is ground and thinned. Thereafter, by heating or heating the semiconductor wafer, the adhesive force of the double-sided pressure-sensitive adhesive tape is reduced or eliminated to separate the support plate from the wafer.

  The wafer in a heated state after separating the support plate is cooled. In other words, in order to improve the throughput of the cooling process, in the transfer process until the transfer to the cooling stage, the heated wafer is lifted in a non-contact manner and air is blown while being transferred to the cooling stage to perform preliminary cooling. (See Patent Document 1).

JP 2012-119439 A

  However, the above conventional method has the following problems.

  That is, as the size of the wafer increases, it becomes difficult to lift and transfer the wafer in a non-contact manner. That is, since the support plate is removed and the rigidity is lowered, and the resin is softened by heating, the wafer is easily warped and bent by its own weight. The occurrence of the warp causes a handling error of the wafer, resulting in a problem that the wafer is damaged due to the handling error.

  In addition, the pre-cooling transfer apparatus for transferring a large wafer to the cooling stage has a disadvantage that the installation area is increased.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a semiconductor wafer cooling method and a semiconductor wafer cooling apparatus capable of accurately cooling a semiconductor wafer with a simple configuration. And

  In order to achieve such an object, the present invention has the following configuration.

That is, a semiconductor wafer cooling method for cooling a semiconductor wafer covered with a resin sheet or an adhesive tape,
A placing process of placing the semiconductor wafer in a heated state on a heated holding table;
A separating process to a predetermined position Ru raising and lowering movement of the semiconductor wafer to separate the semiconductor wafer, the radiation heat of the holding table is transferred from the holding table,
A cooling process for cooling the semiconductor wafer while adjusting the temperature and time in a state of being held in the allowed Rutotomoni the predetermined position separating the semiconductor wafer from the holding table,
Equipped with a,
The cooling process is characterized in that the temperature of the semiconductor wafer is adjusted while indirectly heating the semiconductor wafer with the radiant heat .

(Operation and Effect) According to the above method, the wafer is gradually cooled by the heat radiated from the holding table by separating the heated wafer from the heated holding table. At this time, by adjusting the distance from the holding table to the wafer and the temperature due to radiant heat, the warpage of the wafer that occurs when it is rapidly cooled is suppressed.
Can do.

  In the above method, the temperature is adjusted by changing at least one of the distance from the holding table to the semiconductor wafer or the heating temperature of the holding table, for example.

  In the above method, the temperature may be adjusted by changing the distance and the heating temperature and blowing a cooling gas onto the semiconductor wafer. Alternatively, the gas flow rate and speed may be adjusted with a constant distance from the holding table to the semiconductor wafer.

  In each method described above, the temperature of the surface of the semiconductor wafer may be detected by a detector, and the temperature may be adjusted according to the detection result.

  According to this method, the temperature drop of the wafer can be accurately controlled according to the detection result of the detector.

Furthermore, in the above method, a detection process of detecting warpage of the semiconductor wafer by a detector is provided,
In the separation process, a plurality of locations on the outer periphery of the semiconductor wafer are supported by a plurality of support members, and the center of the semiconductor wafer is suction-held by a suction member,
In the cooling process, the semiconductor wafer is flattened while the support member and the suction member are moved relatively apart or moved in accordance with the reaction amount of the semiconductor wafer detected by the detector during cooling.

  According to this method, when the wafer is warped during the cooling process, the gap between the wafer center and the outer edge caused by the warp can be corrected to be small by separating or approaching the support member and the suction member. That is, the wafer can be cooled in a flat state.

  In order to achieve such an object, the present invention has the following configuration.

That is, a semiconductor wafer cooling device for cooling a semiconductor wafer covered with a resin sheet or adhesive tape,
A holding table for holding the semiconductor wafer in a heated state while heating;
And then separating the semiconductor wafer, separating the radiation heat of the holding table Ru by vertical movement of the semiconductor wafer to a predetermined position which is the transmission mechanism from the holding table,
A control unit for cooling the semiconductor wafer while adjusting the temperature and time in a state of being held in the allowed Rutotomoni the predetermined position separating the semiconductor wafer from the holding table,
Equipped with a,
The controller is configured to adjust the temperature of the semiconductor wafer while indirectly heating the semiconductor wafer with the radiant heat .

  (Operation / Effect) According to this configuration, the wafer placed on the holding table by the separation mechanism can be held in a state of being separated from the holding table. Therefore, the wafer is gradually cooled by the heat radiated from the holding table by adjusting the distance from the holding table to the semiconductor wafer and the separation time. That is, the above method can be suitably performed.

  In this configuration, for example, the control unit controls the temperature by adjusting at least one of the distance from the holding table to the semiconductor wafer or the heating temperature of the holding table.

  Moreover, the structure provided with the gas supply part which sprays the gas for cooling toward a semiconductor wafer may be sufficient.

  According to this configuration, the wafer can be actively cooled. For example, when the variation in the temperature distribution on the wafer is large, a cooling gas can be locally blown to a part having a high temperature.

Further, in the above configuration, a detector for detecting the temperature of the surface of the semiconductor wafer is provided,
The control unit may adjust the temperature according to the detection result of the detector.

  According to this configuration, since the temperature change of the wafer is sequentially detected, the speed at which the temperature of the wafer is lowered can be adjusted with high accuracy.

Furthermore, in the above configuration, a detector for detecting warpage of the semiconductor wafer is provided,
The separation mechanism includes a plurality of support members that support the outer periphery of the semiconductor wafer at a plurality of locations,
An adsorbing member for adsorbing and holding the central portion of the semiconductor wafer;
A drive mechanism for moving the support member and the suction member relatively apart and approach each other,
The control unit flattens the semiconductor wafer while relatively moving the support member and the adsorption member toward or away from each other according to the amount of the semiconductor wafer.

  According to this configuration, when warpage occurs in the wafer, the warpage is corrected and the wafer is cooled in a flat state by separating or approaching the support member and the adsorption member in accordance with the change in the amount of the warpage. Can do.

  According to the semiconductor wafer cooling method and the semiconductor wafer cooling apparatus of the present invention, the semiconductor wafer covered with the sealing sheet or the adhesive tape in the heated state can be accurately cooled without causing warpage.

It is a side view of the workpiece | work formed by bonding a support plate to a semiconductor wafer. It is sectional drawing of a semiconductor wafer. It is a front view of a cooling device. It is a top view explaining operation | movement of a cooling device. It is a top view of a cooling device. It is a top view of the cooling device of a modification. It is a top view explaining operation | movement of the cooling device of a modification. It is a top view explaining operation | movement of the cooling device of a modification.

  Embodiments of the present invention will be described below with reference to the drawings.

  For semiconductor wafers used in this embodiment (hereinafter referred to as “wafers” where appropriate), bare chips that have been diced after circuit formation on the wafer surface are inspected, and only good bare chips are selected. With the bare chip 1a facing down, as shown in FIG. 1, it is aligned and fixed in a two-dimensional array on a double-sided adhesive tape 3 affixed to a carrier support plate 2. Further, a resin 1b is deposited on the bare chip 1a and regenerated into the shape of the wafer 1.

  Further, in this embodiment, as shown in FIG. 2, the heat treatment is performed after the back grinding process of the wafer 1 bonded through the double-sided adhesive tape 3 concentrically with the support plate 2 made of stainless steel, glass substrate or silicon substrate. Is a device for handling the wafer 1 from which the support has been removed.

  That is, the double-sided pressure-sensitive adhesive tape 3 has a heat-releasable pressure-sensitive adhesive layer 3b that loses its adhesive strength when heated on both sides of the tape substrate 3a, and an ultraviolet ray that is cured by irradiation with ultraviolet rays and has reduced adhesive strength The pressure sensitive adhesive layer 3c of curable type or non-ultraviolet curable type is provided. That is, the support plate 2 is attached to the adhesive layer 3b of the double-sided adhesive tape 3, and the wafer 1 is attached to the adhesive layer 3c.

  FIG. 3 is a front view of the cooling device according to the present invention, and FIG. 4 is a plan view of the cooling device.

  The cooling device includes a holding table 5 and a wafer support mechanism 6.

  The holding table 5 includes a table body and a chuck plate 5a. A heater 6 for heating the wafer 1 via a chuck plate 5a is embedded in the table body.

  The chuck plate 5 a is made of a metal or porous ceramic that is smaller than the outer shape of the wafer 1. The chuck plate 5a is connected to an external vacuum device 7 through a flow path. That is, the chuck plate 5a sucks and holds the mounted wafer 1. Further, the chuck plate 5 a is configured to be moved up and down by a cylinder 9.

  The wafer support mechanism 6 includes an annular member 10 that is larger than the outer shape of the wafer 1. The annular member 10 includes a plurality of support pins 11 that support the outer periphery of the wafer. The support pins 11 are horizontally arranged with their tips directed toward the center of the holding table 5. The annular member 10 is configured to be moved up and down by a cylinder 12.

  Further, the annular member 10 is provided with a temperature sensor 13. The temperature sensor 13 detects the temperature of the upper surface of the wafer 1 and transmits the detection signal to the control unit 14. The function of the control unit 14 will be described in detail in the operation description of the device described later.

  Next, the operation of the cooling device will be described with reference to FIGS.

  As shown in FIG. 3, the wafer 1 from which the support plate 2 has been removed is placed on the chuck plate 5 a and the support pins 11 that are stored in the holding table 5 and are flush with each other by a transfer robot (not shown). The

  Since the temperature distribution on the entire wafer surface varies before the wafer 1 is transferred to the holding table 5, the wafer 1 is kept at a predetermined temperature over a predetermined time in order to make the temperature distribution of the wafer 1 uniform. Heat. At this point, the resin 3b is in an uncured state.

  In this heating process, the temperature sensor 13 detects the temperature of the front surface or the back surface of the wafer 1 and transmits the detection signal to the control unit 14. The control unit 14 compares a predetermined reference temperature with an actually measured temperature (actually measured value). When the measured value reaches a predetermined temperature, the control unit 14 raises the chuck plate 5a and the annular member 10 to the same predetermined height as shown in FIG. That is, the wafer 1 is separated from the table body in which the heater 8 is embedded to a predetermined height and is held horizontally.

  Here, the separation height is appropriately set according to the shrinkage characteristics of the resin 1b and the bare chip 1a when the wafer 1 is cooled. That is, it is determined by the correlation between temperature and time at which the wafer 1 is hard to warp by experiment or simulation. The correlation is held in the control unit 14 as a recipe.

  For example, it is cooled to a predetermined temperature (for example, room temperature) at a constant distance. In this cooling process, the heater 8 of the table main body is operated so that the wafer 1 is not cooled sharply, and the cooling rate is adjusted by radiating the heat from the table main body to the back surface of the wafer 1. ing.

  Even during this cooling process, the temperature of the wafer 1 is detected by the temperature sensor 13, and the detection signal is transmitted to the control unit 14. When the temperature of the wafer 1 reaches a predetermined temperature, the control unit 14 is received by the transfer robot while being separated from the table body.

  Thereafter, the chuck plate 5a and the annular member 10 are lowered to the wafer receiving position of the table body. The one-round operation is completed as described above, and the cooling process for a predetermined number of wafers 1 is repeatedly executed thereafter.

  According to this configuration, in the process of cooling the wafer 1 in which the resin 1b is softened by heating, the wafer 1 is separated from the table body, and the temperature of the wafer 1 is adjusted while indirectly heating the wafer 1 by radiant heat. Therefore, the occurrence of warping of the wafer 1 can be suppressed. Therefore, it is possible to prevent the handling error due to the warpage of the wafer 1 and to avoid the damage of the wafer 1 caused by the handling error.

  The present invention can also be implemented in the following forms.

  (1) In the above embodiment, the case where no warpage occurs in the cooling process has been described. However, when warpage occurs, the following may be performed.

  As shown in FIG. 6, two sets of detectors 15 such as optical sensors or ultrasonic sensors are arranged on the annular member 10 so as to face each other with the wafer 1 interposed therebetween, and the warpage of the wafer 1 is monitored.

  In this configuration, for example, when the center of the wafer 1 is warped so as to be raised, the light from the one projector 15a is blocked as shown in FIG. At this time, the control unit 14 is adjusted downward by a cutoff signal transmitted from the light receiver 15b, as in the chuck plate 5a indicated by a one-dot chain line in FIG. In the downward adjustment process, as shown in FIG. 6, when the control unit 14 receives the light reception signal from the light receiver 15 b again, the control unit 14 eliminates the warp of the wafer 1 and is in a flat state. Judging and stopping the descent operation. Thereafter, until the temperature of the wafer 1 reaches a predetermined temperature, the process of monitoring the warpage and correcting the warpage in a timely manner is repeatedly executed.

  When the warping direction of the wafer 1 is specified by the characteristics of the resin 1b or the like, the moving direction of the chuck plate 5a may be one direction, and the detector 15 can be a set. Therefore, the number of detectors 15 is not limited to two sets.

  According to this configuration, it is possible to reliably eliminate the warpage of the wafer 1 during cooling.

  (2) In the above embodiment, the distance for separating the wafer 1 from the table main body may be changed over time.

  (3) In each of the above embodiments, in the process of cooling the wafer 1, cooling air may be blown continuously or intermittently from the nozzle toward the wafer 1. For example, in the process in which the surface of the wafer 1 is monitored by the temperature sensor 13, the cooling air may be locally blown when a temperature of one part is higher than the other part.

According to this configuration, since the entire surface of the wafer 1 is cooled in a uniform state, the occurrence of warpage can be suppressed.
(4) In the above embodiment, if the correlation between the temperature, cooling time, distance, and warpage of the heater for radiant heat is determined in advance in the characteristics of the resin, the wafer 1 is used according to the parameters without using the temperature sensor. May be cooled.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer 1a ... Bare chip 1b ... Resin 2 ... Support plate 3 ... Double-sided adhesive tape 5 ... Holding table 5a ... Chuck plate 6 ... Heater 7 ... Vacuum apparatus 9 ... Cylinder 10 ... Annular member 11 ... Support pin 12 ... Cylinder 13 ... Temperature sensor 14 ... Control unit 15 ... Sensor

Claims (10)

A semiconductor wafer cooling method for cooling a semiconductor wafer covered with a resin sheet or adhesive tape,
A placing process of placing the semiconductor wafer in a heated state on a heated holding table;
A separating process to a predetermined position Ru raising and lowering movement of the semiconductor wafer to separate the semiconductor wafer, the radiation heat of the holding table is transferred from the holding table,
A cooling process for cooling the semiconductor wafer while adjusting the temperature and time in a state of being held in the allowed Rutotomoni the predetermined position separating the semiconductor wafer from the holding table,
Equipped with a,
In the cooling process, the temperature of the semiconductor wafer is adjusted while indirectly heating the semiconductor wafer with the radiant heat . The method for cooling a semiconductor wafer according to claim 1,
The temperature adjustment is performed by changing at least one of a distance from the holding table to the semiconductor wafer and a heating temperature of the holding table. In the cooling method of the semiconductor wafer of Claim 1 or Claim 2,
The temperature adjustment is performed by blowing a cooling gas onto the semiconductor wafer. In the cooling method of the semiconductor wafer in any one of Claim 1 thru | or 3,
A method for cooling a semiconductor wafer, wherein the temperature of the surface of the semiconductor wafer is detected by a detector, and the temperature is adjusted according to the detection result. In the cooling method of the semiconductor wafer in any one of Claim 1 thru | or 4,
A detection process for detecting warpage of a semiconductor wafer by a detector is provided.
While supporting a plurality of locations on the outer periphery of the semiconductor wafer with a plurality of support members, and holding the center of the semiconductor wafer by suction with an adsorption member
In the cooling process, the semiconductor wafer is flattened while the support member and the adsorption member are relatively separated from each other or moved in accordance with the reaction amount of the semiconductor wafer detected by the detector during cooling. Cooling method. A semiconductor wafer cooling device for cooling a semiconductor wafer covered with a resin sheet or adhesive tape,
A holding table for holding the semiconductor wafer in a heated state while heating;
And then separating the semiconductor wafer, separating the radiation heat of the holding table Ru by vertical movement of the semiconductor wafer to a predetermined position which is the transmission mechanism from the holding table,
A control unit for cooling the semiconductor wafer while adjusting the temperature and time in a state of being held in the allowed Rutotomoni the predetermined position separating the semiconductor wafer from the holding table,
Equipped with a,
The said control part adjusts the temperature of the said semiconductor wafer, heating the said semiconductor wafer indirectly with the said radiant heat, The cooling device of the semiconductor wafer characterized by the above-mentioned . The semiconductor wafer cooling device according to claim 6,
The control unit includes: a temperature of the semiconductor wafer by adjusting at least one of a distance from the holding table to the semiconductor wafer or a heating temperature of the holding table. In the semiconductor wafer cooling device according to claim 6 or 7,
A semiconductor wafer cooling apparatus, comprising: a gas supply unit that blows a cooling gas toward the semiconductor wafer. The semiconductor wafer cooling device according to any one of claims 6 to 8,
A detector for detecting the temperature of the surface of the semiconductor wafer;
The said control part adjusts temperature according to the detection result of a detector. The semiconductor wafer cooling device characterized by the above-mentioned. The semiconductor wafer cooling device according to any one of claims 6 to 8,
A detector for detecting warpage of the semiconductor wafer;
The separation mechanism includes a plurality of support members that support the outer periphery of the semiconductor wafer at a plurality of locations,
An adsorbing member for adsorbing and holding a central portion of the semiconductor wafer;
A drive mechanism for moving the support member and the suction member relatively apart and approaching each other;
The control unit flattens the semiconductor wafer while relatively moving the support member and the adsorbing member closer to or away from each other according to the amount of reaction of the semiconductor wafer.

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