JPH11145227A - Temperature adjusting device of tester for semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a temperature adjusting plate, for keeping a semiconductor wafer accurately at a constant temperature during a burn-in test. SOLUTION: A wafer 50 is held constant at a given temperature by a temperature adjusting plate 1 through electrical continuity. The temperature adjusting plate 1 includes a cooling liquid path 6 which becomes larger from the center to the circumferential part thereof in a good thermal conductive disk plate 2, an electrical heater 7 with heating wires put more densely from the center to the circumferential part, temperature sensors 5a to 5c, and a temperature controller (C). Then, according to the difference in the temperatures of the wafer, the temperature of the central part is made lower than that of circumferential part of the wafer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screening test apparatus for detecting potential defects by applying a high temperature to an integrated circuit formed on a semiconductor wafer, and more particularly to a screening test apparatus for maintaining the semiconductor wafer at a predetermined temperature. And a temperature control plate for performing the temperature control.

[0002]

2. Description of the Related Art The above-described screening test apparatus, which is generally called a burn-in apparatus, packages an IC chip obtained by dividing a semiconductor wafer, and then conducts a conduction test in a hot atmosphere at a predetermined temperature to obtain a latent test. The defects are revealed and screening is performed.

[0003] Such a conventional apparatus requires a large constant temperature apparatus and generates a large amount of heat. Therefore, it needs to be performed separately from other manufacturing lines and in a separate room. It is necessary to perform a burn-in test at the stage of a wafer before being formed into chips, because it takes time and effort, and a defective product is found after packaging, causing waste. .

[0004] A burn-in apparatus for meeting such a demand needs to maintain a uniform temperature of the semiconductor wafer when applying a thermal load to the semiconductor wafer. As a temperature control plate for the wafer used for this purpose, a series of coolant channels and heaters are built in a plate made of a heat conductive material such as copper or aluminum, and the coolant channels have a temperature higher than the target temperature. A coolant for cooling the wafer to a low temperature is caused to flow, and the heater is heated to finely adjust the temperature of the plate-like body so that the semiconductor wafer brought into contact with the plate-like body is maintained at a predetermined target temperature. A temperature control plate is disclosed. (See JP-A-8-340030).

Most of the heat generated by energizing the semiconductor wafer is removed by contact with the temperature control plate, but a part of the heat is released as radiant heat or through the surrounding atmosphere or electric contacts. Is released. Therefore, there is a difference in the amount of heat dissipation between the peripheral portion of the wafer having a low ambient temperature and the central portion of the wafer surrounded by the heat generating portion. For example, when the calorific value of the entire wafer having a diameter of about 20 cm is 1.2 kW, a temperature difference of about 10 ° C. occurs between the central part and the peripheral part, so that the accuracy of the burn-in test may be significantly reduced. There was.

[0006]

SUMMARY OF THE INVENTION A first object of the present invention is to disclose a wafer temperature control apparatus capable of performing a screening test with high accuracy by maintaining a semiconductor wafer at a target temperature uniformly. A second object of the present invention is to disclose a wafer temperature adjusting device capable of quickly and accurately maintaining a semiconductor wafer at a predetermined temperature. A third object of the present invention is to disclose a wafer temperature control apparatus which has a simple configuration, is easy to maintain, and requires low running cost.

[0007]

A first gist of the present invention is a wafer temperature adjusting means in a burn-in apparatus for predicting a potential defect by energizing a semiconductor wafer on which an integrated circuit is formed at a predetermined temperature while maintaining a predetermined temperature. A coolant flow path is provided in the thermally conductive plate having a smooth surface, and an electric heater is provided between the coolant flow path and the smooth surface; The flow path has a coolant inlet near the center of the plate-shaped body and a coolant outlet near the periphery of the thermally conductive plate-shaped body, respectively. Wherein the flow path is formed so as to reach the coolant outlet while orbiting around the coolant inlet with the coolant inlet as the center, wherein the temperature control plate for the semiconductor wafer in the burn-in apparatus is provided. It is in.

[0008] In the temperature control plate according to the first aspect, an example of a flow path that goes around the coolant inlet and reaches the coolant outlet is a spirally formed flow centering around the coolant inlet. Examples include a path and a series of flow paths formed so as to turn concentrically. In the temperature control plate having such a configuration, the coolant flows in from the vicinity of the center of the temperature control plate, and gradually moves to the periphery of the temperature control plate while circling around the center of the temperature control plate. Finally, it is configured to exit from a coolant outlet provided in a peripheral portion. Representative examples of the thermally conductive plate-like body constituting the temperature control plate include aluminum, copper, and alloys thereof.

In the above process, the coolant absorbs heat from the wafer and rises in temperature. Therefore, near the coolant inlet, the temperature difference (temperature gradient) between the coolant and the wafer is largest, and Near the exit, the temperature difference is minimal.
In other words, the cooling liquid absorbs the largest amount of heat per unit time in the vicinity of the central portion of the wafer where the temperature is likely to be higher than the target temperature, cools the wafer, and the cooling efficiency decreases as it moves to the peripheral portion of the wafer. In this way,
In the wafer, unevenness of the temperature distribution during the burn-in test is eliminated. As one method to further enhance the effect, the distribution of the coolant flow path is made dense near the center of the temperature control plate and sparse near the center, so that the heat transfer between the center and the periphery is achieved. A difference may be provided in the area.

According to a second aspect of the present invention, there is provided means for enhancing the effect of the temperature control plate defined by the first aspect. Is characterized in that the cross-sectional area of the cooling liquid outlet side is larger than that of the cooling liquid inlet side. Assuming that the ceiling of the flow path faces the wafer surface, the expansion of the flow path cross-sectional area may increase the horizontal width of the flow path, or may increase the vertical width, or reduce both elements. May be included. By configuring the coolant passage in this manner, the flow velocity near the center of the temperature control plate is high, and the flow velocity near the periphery is low. As a result, the coolant having a low temperature flows rapidly in the vicinity of the center, and in the vicinity of the periphery,
As the coolant temperature rises, the flow velocity becomes slower. As a result, the cooling capacity is kept high near the center, and the cooling capacity around the plate is reduced. Thus,
The temperature difference between the central part and the peripheral part of the wafer temperature can be largely eliminated.

According to a third aspect of the present invention, in the temperature control plate defined by the first aspect or the second aspect, the amount of the cooling fluid flowing through the cooling fluid flow path is controlled by the cooling fluid flow rate of the cooling fluid flow path. A temperature control plate, characterized in that it is defined by a control means. This is a means for further enhancing the effect of the above-mentioned temperature control plate. By setting the flow rate to a predetermined speed, the temperature difference between the central part and the peripheral part in the burn-in test of the semiconductor wafer can be reduced. Can respond. For example, in relation to the cross-sectional area of the coolant flow path as defined in the second aspect, the flow velocity becomes high near the center of the plate where the flow path is narrow, and becomes slow at the periphery. Therefore, the heat transfer coefficient near the center is large, and in a gentle flow region where the fluid film is thick, the heat transfer coefficient is significantly small. Further, the flow of the cooling liquid can be turbulent near the center of the plate, and can be a slow laminar flow at the periphery.

According to a fourth aspect of the present invention, in the temperature adjustment plate defined in the first aspect to the third aspect, the amount of heat generated by the electric heater is such that, in the vicinity of the central portion of the thermally conductive plate, A temperature control plate for a semiconductor wafer, wherein the temperature control plate is set so as to be completely absent or smaller than a peripheral portion.

In the above, the electric heater may be constituted by one circuit so that the calorific value decreases in the central region of the plate-like body and increases in the peripheral region. Further, a heater may be provided in the peripheral area without any heater at the center, and heating may be performed in accordance with a temperature difference between the central part and the peripheral part of the wafer during energization. Further, electric heaters of a plurality of circuits are provided concentrically around the central part of the temperature control plate, and a controller is individually provided for each electric heater, and a temperature detection signal of the heating area of each heater is provided. Also, an electric heater for adjusting the amount of heat generated can be employed. In short, it is sufficient that a temperature rise gradient corresponding to the wafer temperature difference is formed from the center to the periphery. In this case, it is needless to say that the temperature of the heat medium is set to such a level that the wafer can be maintained at the target test temperature in a state where the heat generated by these heaters is added.

By distributing the calorific value of the electric heater as described above, the uniformity of the temperature distribution of the wafer can be further improved. As described above, the heater is divided into a plurality of parts, and each is controlled by a separate control system so that the amount of heat generation is small in the central portion and large in the peripheral portion. There is an advantage that it can handle a wafer having a pattern, but on the other hand, this leads to an increase in cost and complexity of the apparatus. When the temperature control plate according to the present invention is used, one system of electric heater
The intended purpose can be sufficiently achieved even by appropriately changing the wiring position and the wiring density and adjusting the amount of heat generated in the central portion and the peripheral portion of the plate.

A fifth aspect of the present invention is a wafer temperature adjusting means in a burn-in apparatus for predicting a potential defect by energizing a semiconductor wafer on which an integrated circuit is formed at a predetermined temperature and for predicting a latent defect. A temperature control plate in which a coolant flow path is provided in the thermally conductive plate-like body having an electric heater provided between the coolant flow path and the smooth surface; A temperature control device for a semiconductor wafer, comprising: a heat transfer sheet capable of closely contacting the smooth surface of the adjustment plate so as to be able to transfer heat, and a heat transfer plate closely contacting the heat transfer sheet so as to be able to transfer heat. is there.

In the first to fourth aspects, the temperature control plate is used for directly contacting the wafer with a smooth surface, or further, for the purpose of eliminating nonuniform heat transfer on the smooth surface of the temperature control plate or for wafers. The temperature is adjusted by interposing a heat transfer plate made of a heat-conductive smooth plate-shaped member in a close contact state by the convenience of mounting the current applying means. The fifth aspect of the present invention relates to an improvement in a structure in which a temperature adjusting plate and the heat transfer plate are combined. The heat transfer sheet is used for the purpose of improving the heat conduction between the temperature control plate and the heat transfer plate, and controlling the amount of heat transfer between the peripheral portion and the central portion. Therefore, the material of the heat transfer sheet may be a thin metal plate or the like, but preferably has flexibility and elasticity. Such a heat transfer sheet is made of a very thin sheet material having rubber elasticity and heat conductivity, which is obtained by uniformly dispersing powder made of a heat conductive material in a rubber sheet. Can be exemplified.

According to a sixth aspect of the present invention, there is provided a temperature control plate defined by any one of the first to fourth aspects, and a heat transfer sheet which is in close contact with a smooth surface of the temperature control plate so as to be able to exchange heat. And a heat transfer plate closely contacting the heat transfer sheet so that heat can be transferred.

According to a seventh aspect of the present invention, there is provided a temperature control apparatus for a wafer as defined in the fifth or sixth aspect, wherein the contact area between the heat transfer sheet and the central portion of the temperature control plate is reduced. The temperature control device for a semiconductor wafer is characterized in that the shape is determined so as to be larger than the contact area between the temperature control plate and the peripheral portion of the temperature control plate.

The adjustment of the contact area can be performed by distributing the cut-out portion or the cut-off portion in the peripheral portion of the heat transfer sheet. The portion of the heat transfer sheet having a large contact area has a greater amount of heat transfer than the portion having a small heat transfer sheet. It is possible to prevent the temperature from rising, and to prevent the test temperature from being uneven depending on the location of the wafer.

[0020]

FIG. 1 is a plan view showing a first embodiment of the temperature control plate of the present invention. Temperature control plate 1
Consists of an aluminum disk 2 whose surface 2a
Has a mirror-like smooth surface, and surrounds the center of the disk, and has concentric ring-shaped vacuum suction grooves 3a to 3d,
They are drilled at approximately equal intervals. 3f is a vacuum supply groove for interconnecting these vacuum suction grooves 3a to 3d.
Inside, one end of a vacuum supply path 3 penetrating through the disk 2 in the axial direction is open. The other end of the vacuum supply path 3 is connected to a vacuum supply tube 3g.

Temperature sensor storage holes 4a to 4c are formed through the disc 2 from the back surface 2b to the front surface 2a in the same manner as the vacuum supply path 3 in the axial direction. Temperature sensors 5a to 5c are housed therein so as to be vertically movable. The temperature sensors 5a to 5c are lightly urged upward by coil springs 5s, 5s,... In the storage holes 4a to 4c, and the temperature measuring units 5h, 5h,. Slightly projecting upward from As shown in FIG. 3, the coolant flow path 6 penetrates through the inside of the disk 2 near the back side and is defined by substantially concentric partition walls 2c, 2c,.
Are provided so as to form a series of flow paths from the center of the disk 2 toward the periphery by being inverted at the partition wall 2d. A coolant inlet 6a is opened at an end near the center of the disc of the flow path 6, and a coolant outlet 6b is opened at an end of the peripheral portion. 2 is connected to the coolant conduit on the back side.

In FIG. 2, the coolant flow path 6 has a constant depth in the vertical direction, but its width in the horizontal direction gradually increases from the center of the disk 2 to the periphery. Therefore,
The coolant that has entered through the coolant inlet 6a flows into the coolant outlet 6b.
, The cross-sectional area of the flow path increases, so that the flow rate of the coolant gradually decreases.
The cross-sectional area of the coolant flow path may gradually increase gradually toward the periphery of the disk, or may increase stepwise. The shape of the flow path may be such that the width facing the surface 2 is not changed, and the depth increases as it goes to the peripheral portion. Further, the two types may be combined.
Further, the cross-sectional shape is not limited to a square, but may be a circle, a trapezoid, or the like.

The cooling liquid has a small specific heat, a small change in viscosity (fluidity) depending on temperature, a boiling point higher than the operating temperature range and is chemically stable, has no corrosiveness, and has a low electric insulation. Conditions such as being high are required. Further, since the wafer screening inspection apparatus has an extremely high-precision mechanism, if the cooling liquid leaks from the temperature control plate or the piping, serious damage may be caused. For this purpose, it is particularly important that the coolant has no corrosiveness and is a substance having excellent electrical insulation properties. Examples of such a coolant include silicone oil and hydrogen represented by the chemical structural formula of polyether. Fluorinert (trade name, manufactured by Sumitomo 3M Limited) or Galden (trade name, manufactured by Montefuluos, Inc.) having a structural formula in which all atoms are substituted with fluorine atoms can be given.

The partition wall 2d is provided so as to cross in the radial direction from the peripheral portion to the center portion of the disk 2, and penetrates the partition wall 2d to form the temperature sensor housing hole 4a.
To c are provided. The cooling liquid passage 6 is formed by the partition wall 2.
It is configured to wrap at d, which is
It may be formed in a spiral shape, and the sensor housing hole may be provided so as to penetrate the partition wall 2c like the vacuum supply path 3.

On the other hand, an electric heater 7 composed of a sheathed heater is buried inside the disk 2 at an intermediate portion between the disk surface 2a and the coolant flow path. The arrangement density of the heaters 7 is arranged and accommodated such that the peripheral portion of the disk 2 becomes denser and becomes sparser toward the central portion. Reference numeral 8 denotes a take-out hole for taking out the heater power supply wiring below the disc in the peripheral portion of the disc 2. The electric heater 7 is constituted by a single circuit. Of course, a plurality of electrically independent heaters are arranged around the center of the disk concentrically with a predetermined interval between the arrangement of the heating wires. It may be arranged so that each heat generating circuit is independently controlled. The electric heater 7 is cast when the disk 2 is formed from an aluminum casting,
It can be easily embedded in a disk. Temperature sensor 5a ~
The detection signals c are input to the temperature controller C, respectively, are compared with the set values of the temperature controller C, and the correction power is output to the electric heater 7.

Next, an apparatus for supplying and circulating a cooling liquid to the temperature adjusting plate will be described. The elimination of the temperature difference in the temperature control region is achieved by fine adjustment of the temperature by a responsive electric heater, but in order to increase the efficiency of such a burn-in test, a large number of the above-mentioned temperature control plates are required. Maintaining a large number of temperature control plates efficiently and accurately near a predetermined temperature requires a large amount of heat transfer. This is performed via a cooling liquid flowing through a cooling liquid flow path of the plate, and a device for centrally managing the large amount of the circulating cooling liquid to adjust it to a predetermined temperature and supply it to each temperature control plate has a constant temperature. It is a cooling liquid supply device.

As shown in FIG. 4, such a constant-temperature cooling liquid supply device includes a constant-temperature tank 111 connected to each of the temperature control plates 1 via a first circulation channel 115 for the cooling liquid.
A heat exchanger R connected to the constant temperature bath via a second circulation channel 121 for coolant; and a coolant supply channel 127 connected to the heat exchanger and supplying coolant to the heat exchanger. A heat exchanger flow control means 1 provided in a second circulation flow path in accordance with a signal from a temperature detector provided in the temperature control plate and the thermostatic bath.
It is effective to have a controller for controlling the controller 26. Constant temperature coolant supply device 10 described below
This has an excellent effect as a temperature control means for a semiconductor wafer in which zero and a large number of the temperature control plates are connected by a series of coolant flow paths.

FIG. 4 schematically shows an example of the device, in which each of the coolant flow paths 6 of the temperature control plates 1, 1,.
The first circulation channel 115 through which the coolant circulates and flows between the thermostat 111 and the inlet 6a and the outlet 6b of 6,.
Are linked. The first circulation channel 115 includes a coolant supply pipe 116 and a return pipe 117, and a bypass pipe 118 that short-circuits the return pipe and the supply pipe.
The circulation pump 119 and the bypass pipe 118 have a bypass valve 120 for setting the flow rate of the bypass pipe.
Each is interposed. The supply pipe 116 branches by the number of the temperature control plates 1 to form branch pipes 116 a,..., And is connected to the inlet 6 a of the plate 1, while the return pipe 117 is connected to the coolant outlet 6 b of the plate 1. Tube 117a, ...
Are connected, and each of the branch pipes 117a is connected to the bypass pipe 11a.
On the upstream side of the connecting portion 118a between the return pipe 8 and the return pipe 117, it joins the return pipe.

In each of the branch pipes 116a, the flow rate of the cooling liquid flowing through the cooling liquid flow path 6 of the temperature control plate 1 per unit time is made uniform, and in order to eliminate temperature unevenness due to a difference in flow rate for each plate. The flow control valves 116b, ... are interposed. Instead of the flow control valve 116b, the branch pipe 1
A coolant distribution chamber may be provided at the branch of 16a, and a temperature control plate may be provided at a position radially equidistant from the distribution chamber via a branch pipe having an equal length.

The constant temperature bath 111 is filled with silicone oil as a cooling liquid. In the cooling liquid, a temperature detector 112 for detecting the temperature of the cooling liquid and a heater 113 comprising an electric heater are housed. Have been. The constant temperature bath 111 is also provided with a second circulation channel 121 for the coolant, so that the coolant circulates between the coolant and the heat exchanger R for cooling the coolant. The second circulation flow path 121 has a forward pipe 122, a return pipe 123, a forward pipe 122 and a short-circuit pipe 124 that bypasses the return pipe 123, and a circulation pump 125 is provided in the forward pipe 122, A three-way valve 126 capable of electric flow control is interposed at the connection between the short-circuit pipe 124 and the return pipe 123. Temperature detector 109
Detects the temperature in the vicinity of the coolant flow path 6,
0 continuously controls the three-way valve 126 based on the detection signal. In place of a three-way valve, return pipe 123, short-circuit pipe 1
24 may be provided with a flow control valve.

The three-way valve 126 reduces or increases the flow rate of the coolant passing through the heat exchanger by increasing or decreasing the flow rate of the short-circuit pipe 124 and the return pipe 123 in response to a signal from the temperature controller 110. The flow rate of the coolant passing through R
The temperature is changed from 0 to the capacity limit of the circulation pump 125 to adjust the temperature of the coolant in the thermostat 111.
Therefore, instead of the short-circuit pipe 124 and the three-way valve for adjusting the flow rate thereof, the heat exchanger flow rate adjusting means determines the rotation speed of the circulation pump (rotation speed of the pump drive motor) based on the detection signal of the temperature detector 109. The temperature may be controlled continuously by the temperature controller 110 to change the flow rate of the heat exchanger continuously. In the other flow path adjacent to the cooling liquid flow path of the heat exchanger R, a cooling water supply pipe 127 and a cooling water return pipe 128 that are drawn in as cooling water for equipment in a clean room are provided as a cooling liquid. Connected.
The cooling water return pipe 128 is provided with a temperature type water control valve 129 that detects the temperature of the cooling water and increases or decreases the flow rate in the pipe.

[0032]

A method of performing a high-temperature screening test using the above apparatus will be described. When the temperature of the coolant in the thermostat 111 is equal to or less than a set constant value at the time of startup of the temperature controller, the temperature sensor 112 detects the temperature, and the heater 113 operates to set the coolant temperature to a predetermined value. To a temperature of At this time, the flow rate of the coolant in the heat exchanger R is kept at the minimum. When the temperature of the temperature control plate 1 reaches a predetermined temperature, the heater 113 stops, and the temperature controller 11
0 opens and closes the three-way valve 126 to maintain the temperature control plate at a predetermined temperature. Bypass valve 120, flow regulating valve 11
The adjustment of 6b is not necessary if it is set once according to the target temperature.

As an example of mounting the wafer 50 on the temperature control plate, as shown in FIG. 2, a heat transfer plate 60 made of an aluminum plate is previously attached to the temperature control plate 1.
Up and down so that it can move up and down.
0 and the electrode plate 70 provided with a number of current-carrying contacts are positioned and fixed, and then lowered toward the temperature control plate 1. The protruding edge 61 projecting downward around the heat transfer plate 60 can abut a step 1a provided by lowering the peripheral edge of the temperature control plate 1 by one step. Since the O-ring 15 is provided around the step portion 1a, when the protruding edge portion 61 comes into contact with the O-ring 15, the heat transfer plate 60 is moved by the vacuum pressure from the vacuum supply passage 3 to the temperature control plate 1. It adheres to the surface 2a.

At this time, the through holes 6 provided in the heat transfer plate 60
In 2a to 2c, temperature measuring units 5h, 5h,.
And enters the rear surface of the wafer 50. 16, 1
Reference numerals 6 and 16 denote O-rings provided so as to surround the upper end openings of the temperature sensor housing holes 4a to 4c. The airtightness between the heat transfer plate and the rear surface is maintained together with the O-ring 16. Reference numeral 20 denotes support means for the electrode plates 70 erected at a plurality of locations around the temperature control plate 1, which is elastically held upward and holds the electrode plates 70 and the heat transfer plate 60. As the plate 80 descends,
It abuts around the holding plate and bears most of its load. Therefore, the contact pressure between the wafer and the electrode plate is maintained at such a level that electrically secure conduction can be obtained.

When the wafer generates heat in the energization test, the temperature of the plate 1 rises, and the coolant receives the calorific value. Accordingly, the temperature of the coolant in the thermostat 111 also starts to rise. The temperature detector 109 detects this immediately,
The flow rate through the heat exchanger R is increased, so that the temperature of the thermostat decreases and the temperature of the coolant supplied to the temperature control plate 1 is maintained at a predetermined temperature. The temperature of the cooling liquid is set so that the temperature of the cooling liquid is lower than the test temperature even when the wafer 50 is generating heat by the power-on test.

The coolant entering the coolant passage 6 from the coolant inlet 6a passes through the passage near the center, which is relatively narrow, at a high speed to take a relatively large amount of heat. As the temperature approaches the periphery, the coolant temperature gradually increases, and the flow velocity decreases, so that the cooling capacity decreases. Further, the amount of heat generated by the electric heater 7 in the central region where the temperature tends to be high is small in accordance with the temperature difference depending on the location of the wafer that is generating heat by energization. In other words, the amount of heat generated by the heater in the peripheral portion, which becomes lower than that in the central portion due to heat radiation to the surroundings, is an amount corresponding to the temperature difference,
The size is adjusted by increasing the density of the heating wires so as to increase the size.

In this way, a symmetrical temperature distribution, which is opposite to the temperature distribution of the semiconductor wafer during the energization test,
It will be created on the surface of the temperature control plate. The semiconductor wafer is brought into contact with the temperature control plate, thereby eliminating the non-uniformity of the temperature distribution, and for a predetermined target temperature, within an accuracy of ± 1 ° C. over the entire surface of the wafer.
An energization test can be performed.

FIG. 5 shows a main part of the second embodiment of the present invention. As shown in FIG. 2, the wafer 50 is set in advance on the heat transfer plate 60 to perform accurate positioning, and is connected to the means for supplying current to the wafer.
It is convenient on operation to perform the heat transfer by bringing the heat transfer plate 60 into close contact. In the first embodiment, a temperature distribution of a pattern substantially opposite (symmetric) to the temperature distribution of the wafer is completed on the surface 2a of the temperature control plate 1, and this is brought into contact with the wafer via the heat transfer plate 60. Thus, the wafer temperature distribution is made uniform. The second embodiment is a temperature distribution pattern opposite to the wafer temperature distribution pattern,
A heat transfer sheet for controlling heat conduction is interposed between the heat transfer plate 60 and the surface 2a of the temperature control plate 1 so as to appear on the heat transfer plate 60. Other configurations are not substantially different from the first embodiment.

The heat transfer sheet 30 shown in FIG. 5 is a thin sheet (for example, Shin-Etsu Chemical Co., Ltd.) in which metal oxide or nitride powder having excellent heat conductivity such as alumina or boron nitride is dispersed in silicon rubber. Rubber sheet for heat radiation manufactured by Kogyo Co., Ltd.
TC-20BG, having a thickness of 0.2 mm). The heat transfer sheet 30 has a large number of V-shaped notches 31 extending from the outer periphery to the center of the circular sheet having substantially the same size as the wafer in accordance with the temperature distribution pattern at the time of the burn-in test of the wafer to be inspected. It has a shape provided. By interposing such a heat transfer sheet 30 between the heat transfer plate 60 and the temperature control plate 1, the amount of heat transfer between the heat transfer plate and the temperature control plate is reduced according to the contact area of the sheet. The vicinity of the center without the portion can be made to decrease at the maximum as it goes to the peripheral portion.

The heat generated during the energization test is easier to dissipate to the periphery at the peripheral portion of the wafer than at the central portion of the wafer.
Since the temperature becomes lower, the contact area with the temperature control plate is reduced by the notches 31,..., The heat transfer of the temperature control plate becomes smaller than in the vicinity of the central portion, and the heat transfer plate closely contacts the heat transfer sheet. A temperature distribution opposite to the temperature distribution of the wafer is formed on 60, and therefore, when the steady state is reached after the start of the test, the temperature distribution of the wafer is kept uniform. The heat transfer sheet is extremely effective in increasing the accuracy of the temperature control plate. In the above-described embodiment, the heat transfer plate and the heat transfer sheet are configured to be in close contact with and detachable from each other, but this may be a structure in which the heat transfer plate, the heat transfer sheet, and the temperature control plate are integrated.

FIG. 6 shows a third embodiment of the present invention, in which a heat transfer sheet 35 having a structure different from that of the heat transfer sheet 30 is closely attached to the temperature control plate 1. is there. The circular heat transfer sheet 35 is formed by scattered circular cutouts 36, whose diameter gradually decreases from the peripheral portion to the vicinity of the central portion, so that the peripheral portion becomes denser and becomes sparser toward the central portion. It has a configuration provided. The operation is the same as that of the heat transfer sheet 30 described above.

These heat transfer sheets are advantageous in that they can be used for burn-in tests of various wafers by preparing heat transfer sheets having different thicknesses and notches (non-contact area) in accordance with the heat generation pattern of the wafer. is there. It is also advantageous that the temperature adjustment plate does not necessarily need a highly accurate plate capable of independently adjusting the temperature of the wafer as described above.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a first embodiment of a temperature control plate according to the present invention as viewed from a plane direction.

FIG. 2 is an explanatory sectional view taken along the line AA of FIG. 1;

FIG. 3 is an explanatory view taken along the line BB of FIG. 2;

FIG. 4 is an explanatory view showing an example in which a temperature adjusting plate of the present application is connected to a cooling liquid supply device.

FIG. 5 is an explanatory view of a main part of the second embodiment of the present invention viewed from a plane direction.

FIG. 6 is an explanatory view of a main part of a third embodiment of the present invention viewed from a plane direction.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Temperature control plate 2 Disk 3 Vacuum supply path 3a-d Vacuum suction groove 4a-c Temperature sensor storage hole 5a-c Temperature sensor 5h Temperature measuring section 6 Coolant flow path 6a Coolant inlet 6b Coolant outlet 7 Electric heater 8 Heater terminal outlet 30, 35 Heat transfer sheet 31, 36 Cutout 50 Semiconductor wafer 60 Heat transfer plate 70 Electrode plate 109 Temperature detector 110 Temperature controller 111 Constant temperature bath 112 Temperature sensor 113 Heater 115 First circulation channel 116b Flow rate Control valve 119, 125 Circulation pump 126 Three-way flow control valve 127 Cooling water supply pipe 128 Cooling water return pipe 129 Temperature type water control valve R Heat exchanger

Claims (8)

[Claims] A wafer temperature adjusting means in a burn-in apparatus for predicting a latent defect by energizing a semiconductor wafer on which an integrated circuit is formed at a predetermined temperature and predicting a latent defect, wherein the thermal conductive plate has a smooth surface. A coolant passage is provided in the body, and an electric heater is provided between the coolant passage and the smooth surface, and the coolant passage is provided at a center of the plate-like body. And a coolant outlet near the periphery of the thermally conductive plate-like body, and a series of flow paths from the coolant inlet to the coolant outlet are centered around the coolant inlet. A temperature adjustment plate for a semiconductor wafer in a burn-in apparatus, wherein the temperature adjustment plate is formed so as to go around the coolant inlet and reach the coolant outlet. 2. The temperature control plate for a semiconductor wafer according to claim 1, wherein the cross-sectional area of the coolant passage is larger on the coolant outlet side than on the coolant inlet side. 3. The temperature control plate for a semiconductor wafer according to claim 1, wherein the flow rate of the coolant in the coolant flow path is defined by a coolant flow rate adjusting means. 4. The heat generating device according to claim 1, wherein the amount of heat generated by the electric heater is set so as to be absent or smaller near the center of the thermally conductive plate-like body than at the periphery. Temperature control plate for semiconductor wafer. 5. A wafer temperature adjusting means in a burn-in apparatus for predicting a latent defect by energizing a semiconductor wafer on which an integrated circuit is formed at a predetermined temperature and predicting a latent defect, wherein the thermal conductive plate has a smooth surface. A temperature control plate in which a cooling liquid flow path is provided in the shape body and an electric heater is provided between the cooling liquid flow path and the smooth surface; A temperature control device for a semiconductor wafer, comprising: a heat transfer sheet capable of closely contacting heat transfer and a heat transfer plate closely contacting heat transfer with the heat transfer sheet. 6. A temperature control plate according to claim 1, a heat transfer sheet which is in close contact with a smooth surface of said temperature control plate so as to be able to exchange heat, and is in close contact with said heat transfer sheet in such a manner that heat can be exchanged. A temperature control device for a semiconductor wafer, comprising: 7. The shape of the heat transfer sheet is determined so that the contact area between the heat transfer sheet and the central portion of the temperature control plate is larger than the contact area between the heat transfer sheet and the peripheral portion of the temperature control plate. 5. The temperature control device for a semiconductor wafer according to 5 or 6. 8. The heat transfer sheet is made of a sheet material having rubber elasticity and heat conductivity formed by uniformly dispersing a powder made of a heat conductive material in a rubber sheet.
The semiconductor wafer temperature control device according to claim 5.