JPH06101947A - Heater cooling device - Google Patents

Abstract

PURPOSE:To rapidly cool a semiconductor wafer acting as a heater the temperature of which is increased after being supplied with electrical power to a specified temperature when a characteristic evaluation test of many integrated circuits formed on the semiconductor wafer is carried out. CONSTITUTION:A contact surface of a cooling block contacted with a heater 1 in a face-to-face relation is provided with a plurality of supplying ports 7 for supplying helium gas and a plurality of recovering ports 10 for recovering helium gas fed from the supplying port 7 and filled in a fine gap formed between the contacted surfaces. The helium gas supplied from a tank 8 is supplied to a specified supplying port 7 by adjusting a valve 9 and then an integrated circuit to be inspected is effectively cooled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating element cooling device for cooling a heating element and holding it at a predetermined temperature with high accuracy, and particularly when inspecting the electrical characteristics of an integrated circuit formed on a semiconductor wafer. The present invention relates to a heating element cooling device suitable for cooling a heating element such as a semiconductor wafer which is supplied with power and generates heat.

[0002]

2. Description of the Related Art Conventionally, in this type of semiconductor wafer cooling apparatus, as shown in FIG. 8, on a cooling block 4 having a cooling pipe 6 in which a low-temperature cooling fluid supplied from a refrigerator 5 circulates, A semiconductor wafer 1 which is a heating element is placed, and this semiconductor wafer is vacuum-chucked by a vacuum pump 8 through a vacuum exhaust port 15 provided in the cooling block 4, and contact conduction with the cooling block 4 causes the semiconductor wafer 1 to move. It was cooling. At this time, the temperature of the semiconductor wafer may change significantly due to the contact thermal resistance between the cooling block and the semiconductor wafer, and the temperature distribution may become non-uniform. Therefore, a method for stabilizing the contact thermal resistance to be small has been proposed. As one of them, Nikkei Electronics June 17, 1985 issue (NO. 371) describes a structure in which a high thermal conductive grease called a thermal compound is applied to the contact surface between a semiconductor package and a thermal conductor. .

[0003]

When cooling a semiconductor wafer which is a heating element, even if the surface accuracy of the contact surface of the cooling element is finished with high accuracy and the surface roughness and the warp are about several μm, the distance between the contact surfaces is reduced. There is no fluid near the vacuum chuck,
Air is present on the outer periphery of the semiconductor wafer. In the area where no fluid is present, heat conduction becomes extremely poor,
Although the portion where air is interposed is not as high as in a vacuum, the thermal resistance between objects is large because the thermal conductivity of air is small. Further, if dust of about several μm adheres between the contact surfaces, the contact thermal resistance fluctuates greatly. Therefore, it is difficult to cool the semiconductor wafer that generates a large amount of heat with high accuracy.

The above-mentioned conventional technique has been proposed to solve this problem, but this method also has the following problems. In other words, when a structure for applying and cooling high thermal conductive grease is used for cooling semiconductor wafers, the amount of grease applied should be kept constant in order to control the temperature of semiconductor wafers that are frequently attached and detached with high accuracy. I have to keep it. That is, since the contact thermal resistance is governed by the thickness of the grease interposed between the contact surfaces, it is essential to keep the amount of grease constant. However, it is difficult to make the grease thickness constant for a large number of semiconductor wafers in a short time. Further, after the semiconductor wafer is cooled, it is necessary to wash the grease applied to the contact surface, which increases the labor in the process. Further, incomplete cleaning has a great influence on the subsequent process.

Another known method for stabilizing the contact thermal resistance is to supply helium gas having high thermal conductivity between the contact surfaces of the semiconductor wafer and the cooling body in a semiconductor CVD apparatus. However, when the helium gas is jetted, the semiconductor wafer is slightly pushed up by the supply pressure of the helium gas, and the desired adsorption action with the semiconductor wafer cannot be obtained. Further, if the pressure of the helium gas is reduced to a low pressure in a narrow space, the thermal conductivity is lowered, so if the pressure is reduced to adsorb the wafer, the cooling performance is lowered. Then, the gas that has been supplied to the cooling surface and has contributed to heat transfer diffuses to the surroundings, affecting the process in the surroundings.

An object of the present invention is to cool a heating element such as an LSI chip having a large heating value, which can efficiently cool the heating element and the surface flatness with high accuracy without polluting in a short time. To provide a device.

Another object of the present invention is to cool the area including the heat generating chip with high performance and to reduce the cooling performance of the other non-heat generating chip area as compared with the area including the heat generating chip, thereby improving the inspection area. It is to make the temperature distribution of the chip uniform.

Still another object of the present invention is to provide a control device for effectively supplying a highly heat-conductive fluid to the gap between the heating element and the cooling element for high performance cooling.

[0009]

In order to achieve the above object, the present invention provides a heating element in contact with a cooling element, and a mechanism for supplying and recovering a heat conductive fluid is provided between the heating element and the cooling element contact surface. The high thermal conductive fluid is jetted and filled, and the contact thermal resistance is reduced by conduction of the high thermal conductive fluid.

Another feature of the present invention is to add a structure for controlling the supply pressure and the recovery pressure of the high thermal conductive fluid, set the supply pressure lower than the ambient pressure of the heating element, and further lower the recovery pressure. By doing so, a pressure difference is generated, contact heat resistance is reduced, and at the same time, a mechanism for adsorbing and fixing the heating element on the surface of the cooling element is provided.

Still another feature of the present invention is that when a high thermal conductive fluid supplied from a minute gap between contact surfaces is guided to a recovery port having a relatively large opening area, a rapid pressure drop occurs near the recovery port. , When the high thermal conductivity fluid is a gas, the temperature of the fluid becomes low due to adiabatic expansion, and when the high thermal conductivity fluid is a liquid, due to the added cooling effect such as heat of vaporization when vaporizing by evaporation. The performance is improved.

Still another feature of the present invention is that when the heating element is divided into a plurality of partial areas and the partial areas generate heat independently, the thermal conductivity is independent for each partial area of the heating element. A fluid supply / recovery mechanism is provided, and control is performed so that the high thermal conductive fluid is supplied / recovered only in a partial area where heat is generated.

Still another feature of the present invention is that when the heat-generating portion of the heat-generating body is subjected to weighting and is pressed against the cooling body, the supply pressure is lower than the weighting pressure and the recovery pressure is lower than ambient pressure. By setting and controlling the weighting mechanism and the supply mechanism of the high thermal conductive fluid in synchronization, a mechanism for increasing the pressure of the high thermal conductive fluid while adsorbing the heating element to the cooling body compared to the case without weighting Be prepared.

[0014]

According to the present invention, a highly heat-conductive fluid is supplied to and brought into contact with a minute gap between a heating element and a cooling element, and at the same time, air which has been present on this contact surface is recovered. By recovering from the hole, the gap is filled with the high thermal conductive fluid, and the contact thermal resistance between the heating element and the cooling element can be reduced. At this time, dust attached to the contact surface of the heating element is removed by jetting of the fluid, and it is possible to avoid deterioration of performance due to the dust being caught between the contact surfaces.

Further, according to the present invention, by setting the supply pressure of the high thermal conductive fluid to be lower than the ambient pressure of the heating element and the recovery pressure to be lower than the supply pressure thereof, a pressure difference is generated and the cooling body is caused. It is possible to avoid a decrease in cooling performance due to the heating element being adsorbed on the surface and warping the heating element to widen the gap between the heating element and the cooling element.

Further, according to the present invention, with respect to the heating element divided into the partial regions, the high thermal conductive fluid is supplied only to the region including the heating portion to perform the high performance cooling, and the cooling performance of the surroundings. By keeping the temperature low, it is possible to reduce the escape of heat from the heat generating portion to the surroundings and to make the temperature distribution of the heating element uniform.

Further, according to the present invention, when the heating element is under load, the supply pressure of the high thermal conductive fluid is increased in a range lower than the load pressure, and is high only in the loaded area. By supplying high thermal conductivity fluid at pressure,
It is possible to use a highly heat-conductive gas, which does not float the heating element from the cooling body, and has a property of lowering the thermal conductivity at a low pressure under advantageous conditions.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a vertical sectional view of a heating device cooling apparatus according to a first embodiment of the present invention. In this figure, a semiconductor wafer 1 is a target for evaluation of electrical characteristics, and a silicon wafer is often used. The semiconductor wafer 1 becomes a heating element by supplying power to the power supply circuit and the signal circuit in the integrated circuit each time when evaluating a large number of integrated circuits formed on the upper surface of the semiconductor wafer 1.
When the electrical characteristics of the integrated circuit are evaluated, the semiconductor wafer 1 needs to be cooled because power is supplied at a constant temperature in order to remove the influence of temperature changes on the characteristics.

Above the semiconductor wafer 1, the semiconductor wafer 1
A contact probe pin 2 for supplying power and taking out a test signal, and a probe card 3 for holding the probe pin 2 are installed in the integrated circuit formed in 1. The semiconductor wafer 1 is placed on the upper surface of the cooling block. In FIG. 1, the contact state between the cooling block 4 and the semiconductor wafer 1 is illustrated as if they were in contact with each other through an equivalent gap, but the cooling block 4 and the semiconductor wafer 1 are Both of them have surface roughness and warpage of several μm, so in actuality, when they contact each other, microscopically, uneven portions of the surface collide with each other, and minute gaps exist in the concave portions. Since it is difficult to illustrate such a microscopic situation, in order to show the existence of a minute gap in this concave portion, it is shown by a simulated equivalent gap as described above.

The heating device cooling apparatus of this embodiment is arranged in the cooling block 4 through the cooling block 4 on which the semiconductor wafer 1 is mounted and the cooling pipe 6 which is partially formed in the cooling block 4. A refrigerator 5 for supplying a coolant, and a tank 8 for supplying helium gas as a highly heat-conductive fluid from a supply port 7 to a contact surface between the semiconductor wafer 1 and the cooling block 4 through an upstream passage provided in the cooling block 4. The recovery device 11 recovers the high thermal conductive fluid from the recovery port 10 provided in the cooling block 4 through the return flow path. More specifically, the cooling block 4 is cooled by the cooling pipe 6 contained therein by the refrigerant sent from the refrigerator 5, and the refrigerant is returned to the refrigerator 5 again to form a circulation flow path. In addition, in the cooling block 4,
A plurality of supply ports 7 are provided so as to face the central portion and the outer diameter side of the semiconductor wafer 1, and the supply ports 7 have high thermal conductivity via a flow rate control valve 9 for controlling a constant flow rate from a tank 8. Fluid is supplied. Further, the cooling block 4 is provided with a plurality of recovery ports 10 that are open on the outer diameter side of each supply port 7 so as to face the semiconductor wafer 1. Supply port 7
The high thermal conductive fluid flowing out of the cooling block 4 is interposed between the high thermal conductive fluid and the cooling block 4 to form the high thermal conductive fluid layer 12, and is recovered by the recovery device 11 via the recovery port 10. The layer referred to as the high thermal conductive fluid layer here has a surface roughness of about several μm and minute irregularities due to warpage on the contact surface between the semiconductor wafer 1 and the cooling block 4, so that this contact surface It includes a portion in solid contact with each other and a minute gap in which a highly heat-conductive fluid exists.

Here, the integrated circuit formed on the semiconductor wafer 1 is inspected step by step. Since only the integrated circuit under inspection generates heat, the flow path of the portion corresponding to the integrated circuit 13 under inspection is provided. Only the provided flow control valve is opened to supply the high thermal conductive fluid to the integrated circuit portion which is generating heat. Since the supplied high thermal conductive fluid is recovered from the recovery port 10, only the back side portion of the integrated circuit 13 to be inspected is filled with the high thermal conductive fluid, and the thermal resistance can be partially reduced.

The load of the contact probe pin 2 is applied to the front surface side of the semiconductor wafer 1. On the other hand, on the back surface of the semiconductor wafer 1, the pressure of the high thermal conductivity fluid acts on the contact surface of the high thermal conductivity fluid. Therefore, the average pressure of the high thermal conductive fluid is smaller than the pressure due to the load of the contact probe pin 2, and the pressure of the high thermal conductive fluid at the recovery port 10 is equal to or lower than the atmospheric pressure. By setting, effective cooling can be performed.

Further, the flow is controlled in synchronization with the movement of the contact probe pin 2 so that the contact probe pin 2 supplies the high thermal conductive fluid only while the load is applied to the semiconductor wafer. As a result, the semiconductor wafer 1 can be brought into close contact with the cooling block 4, and the high thermal conductivity fluid can be supplied to the gap between the semiconductor wafer and the cooling block without lowering the thermal conductivity of the high thermal conductivity fluid.

Next, the operation method of this embodiment having the above-mentioned configuration will be described. At the time of inspection, first, the contact probe pin 2 is pressed against a certain integrated circuit on the semiconductor wafer 1. Next, the control valve 9 is opened to supply the high thermal conductive fluid. Then, when the high thermal conductive fluid spreads in the gap and the thermal resistance is reduced, power is supplied to the integrated circuit and the inspection is started. When the inspection is completed, the supply of the high thermal conductive fluid is stopped and the contact probe pin 2 is lifted. Next, the contact probe pin 2 is moved to the position of the integrated circuit to be inspected. As a result, the integrated circuit which is first generating heat can always be cooled with high performance. Second, the pressure in the gap between the semiconductor wafer 1 and the cooling block 4 is made smaller than the pressing pressure between the semiconductor wafer 1 and the contact probe pin 2,
Can always be adsorbed on the cooling block 4.

FIG. 2 is a surface view of the contact surface side of the cooling block 4 in FIG. A high thermal conductive fluid supply port 7 is provided at the center of a region where each integrated circuit is in contact, and a fluid recovery port 10 is provided at each of four corners of the region to independently supply and recover the high thermal conductive fluid to each integrated circuit. It is configured to be able to.

Further, FIG. 3 shows a second embodiment of the present invention. In the embodiment of FIG. 2, grooves 14 are provided on the surface of the cooling block 4 corresponding to the boundary of each integrated circuit and are adjacent to each other. The high thermal conductive fluid recovery ports 10 that fit together are connected. As a result, first, the fluid pressure near the recovery port for recovering the fluid can be made uniform in the peripheral direction of each integrated circuit,
Next, it is possible to ensure that the pressure in the area outside the integrated circuit under load is equal to or lower than the recovery pressure of the high thermal conductive fluid, and further, by supplying the high thermal conductive fluid only to the heat generating integrated circuit, There is an effect that it can be made uniform. Moreover, since the recovery pressure of the fluid is made uniform in the groove 14, the number of the fluid recovery ports 10 can be reduced.

FIG. 4 shows a third embodiment of the present invention.
In this embodiment, the grooves 14 between the integrated circuits arranged in a line in the center are removed, and the high thermal conductive fluid supply ports are integrated into one for the integrated circuits in this line.
By doing this, it becomes possible to divide the integrated circuit into groups and supply and recover the high thermal conductive fluid for each group, reducing the number of high thermal conductive fluid supply ports and flow control valves. You can

FIG. 5 shows still another embodiment of the present invention. Below the cooling block 4, the cooling block 4
A table 16 on which the table is placed is provided, and a supply pipe 18 for a highly heat-conductive fluid is formed in a substantially central portion of the table 16. An O-ring 17 is arranged on the surfaces of the cooling block 4 and the base 16 which are opposed to each other in order to prevent the high thermal conductive fluid from leaking from the supply pipe 18. Similar to the embodiment of FIG. 4, the cooling block 4 is provided with a groove 14 corresponding to the periphery of each integrated circuit, and a fluid recovery port 10 is provided at the bottom of the groove 14. The contact probe pin 2 is provided above the cooling block 4 so as to correspond to the center of the table 16. The cooling block 4 is provided with a plurality of supply ports for the high thermal conductive fluid, and the supply ports used can be changed according to the integrated circuit to be inspected. That is, the cooling block 4 is floated from the base 16 while the wafer 1 is adsorbed to the cooling block 4, and the cooling block 4 is horizontally moved so that the integrated circuit to be inspected is directly below the contact probe pin 2 and the high thermal conductivity fluid. The supply port 18 and the supply port 7 are connected to form one flow path. The connection part of this flow path is O
Since it is sealed by the ring 17, it is possible to prevent the high heat conductive fluid from leaking to the outside. This ensures a high thermal conductivity fluid supply path to the integrated circuit under test. As a result, it is possible to supply the high thermal conductivity fluid to the integrated circuit under test without providing the control valve 9 for each integrated circuit. Further, although the O-ring 17 is arranged between the cooling block 4 and the base 18 in this embodiment, a groove may be provided in the base 18 or the cooling block 4 and the O-ring may be held in the groove. . In this case, the platform 4 can be moved more quickly.

FIG. 6 shows a fourth embodiment of the present invention, in which valves 9 are provided below the supply port 7 for the high thermal conductive fluid. After adjusting the position of the cooling block 4 to the position of the integrated circuit to be inspected, the valve controller 19 is pushed up to supply the high thermal conductive fluid to the chip to be inspected. As a result, the valve control mechanism can be simplified.

FIG. 7 shows a method of manufacturing the cooling block 4. The plates 20, 21, 22, and 23 are sequentially laminated to form a cooling block. The high thermal conductive fluid supplied from the outside is sent to the fluid supply port 7 from the flow path formed by the grooves provided in the plates 21 and 22 and the plates 22 and 23, and is recovered from the recovery port 10. After the plate 20
The gas is formed in a flow path formed by a groove provided between the plate 21 and the plate 21, and is exhausted. If manufactured in this way,
Even if the number of fluid supply ports and the number of fluid recovery ports increases, it is possible to deal with them by simply increasing the number of plates, and the cooling block can be easily configured.

Further, the present invention is within the scope of the invention and does not deviate from the above.
It can be applied to an apparatus, an etching apparatus and the like.

[0032]

As described above, according to the present invention, the heating element can be held in close contact with the cooling element in the air, and the contact thermal resistance between the heating element and the cooling element can be reduced to maintain a uniform temperature condition. An integrated circuit formed on a semiconductor wafer can be inspected.

[0033]

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of the present invention.

2 is a view of the contact surface of the cooling block of FIG.

FIG. 3 is a surface view of a cooling block according to another embodiment of the present invention.

FIG. 4 is a surface view of a cooling block according to another embodiment of the present invention.

FIG. 5 is a perspective view of another embodiment of the present invention.

FIG. 6 is a vertical cross-sectional view of another embodiment of the present invention.

FIG. 7 is a diagram showing a method of manufacturing the cooling block in FIG. 1.

FIG. 8 is a vertical cross-sectional view of a conventional semiconductor wafer cooling device.

[Explanation of symbols]

1 ... Heating semiconductor wafer, 2 ... Contact probe pins, 3 ... Probe card, 4 ... Cooling block,
5 ... Refrigerator, 6 ... Coolant circulation pipe, 7 ... High thermal conductive fluid supply port, 8 ... High thermal conductive fluid tank, 9
High thermal conductive fluid flow rate control valve, 10 High thermal conductive fluid recovery port, 11 Fluid recovery device, 12 High thermal conductive fluid layer, 13 High thermal conductive fluid recovery groove, 14 High thermal conductive fluid supply groove, Reference numeral 15 ... Integrated circuit, 16 ... Cooling block support, 17 ... O-ring, 18 ... High thermal conductivity fluid supply pipe, 19 ... Valve controller, 20 ... Grooved plate, 2
4 ... Vacuum exhaust port

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shoichiro Harada 2326 Imai, Ome-shi, Tokyo Hitachi, Ltd. Device Development Center

Claims (6)

[Claims] 1. A cooling device for a heating element, comprising a cooling element for mounting a heating element and cooling the heating element through a contact surface with the heating element, wherein a high thermal conductive fluid is supplied to the contact surface of the cooling element. A port, a recovery port for recovering a high thermal conductive fluid flowing from the supply port through a minute gap formed by the unevenness of the contact surfaces of the heating element and the cooling element, and a flow formed in the cooling body at the supply port. A fluid supply means for supplying a high thermal conductive fluid through a passage, a fluid recovery means for sucking the high thermal conductive fluid from the recovery port through another flow path formed in the cooling body, and the heating element A heating element cooling device comprising: a load mechanism that presses against a cooling body; and a pressure adjusting unit that makes the supply pressure of the high thermal conductive fluid to the supply port lower than the load pressure of the heating element. 2. The cooling device for a heating element according to claim 1, wherein the fluid supply means supplies the fluid having high thermal conductivity when the heating element is under load. 3. The heat generating element is divided into a plurality of partial regions, each of the partial regions is capable of generating heat, and a high thermal conductive fluid is provided between the contact surfaces of the heat generating element and the cooling element for each of the partial regions. The heating device cooling apparatus according to claim 1, further comprising: a fluid supply unit that supplies the fluid and a fluid recovery unit that sucks the high thermal conductive fluid. 4. The heat generating device according to claim 3, wherein the fluid supply means provided for each of the partial regions supplies the high thermal conductive fluid only to the partial regions in the partial region where heat is being generated. Body cooling system. 5. The heat generator cooling device according to claim 1, wherein the heat generator is a semiconductor wafer. 6. The cooling body is formed by laminating a plurality of plates having grooves and through holes on a surface thereof.
5. The cooling device for a heating element according to any one of items 1 to 5.