JP2019169548A - Cooling system of prober - Google Patents

Abstract

A prober having an effective cooling capacity in a wide temperature range from a low temperature range to a high temperature range. A bypass channel connecting a supply side channel and a recovery side channel, a temperature setting section for setting a temperature of a wafer chuck, a first state via a refrigerator, and the refrigerator. The first state and the second state based on the set temperatures of the refrigerator selection valve 38 and the air-cooling system valve 40 and the wafer chuck 22 that can be selectively switched between the second state using the bypass flow path 30 that does not pass through. And a switching unit 48 for selectively switching between. [Selection diagram] Fig. 1

Description

  The present invention relates to a prober for performing electrical inspection of a plurality of chips formed on a semiconductor wafer, and more particularly to a cooling system for cooling a wafer chuck.

  In a semiconductor manufacturing process, a semiconductor wafer is subjected to various processes to form a plurality of chips having devices. Each chip is inspected for electrical characteristics and then divided by a dicer, and then fixed to a lead frame or the like and assembled. The inspection of the electrical characteristics is performed by a prober equipped with a tester. The prober holds the wafer on the wafer chuck and brings the probe into contact with the electrode pad of each chip. The tester supplies power and various test signals from the terminal connected to the probe to the chip, and analyzes the signals output to the electrodes of the chip to confirm whether or not it operates normally.

  The commercialized device is used for a wide range of applications, for example, in a low temperature environment of −55 ° C. or lower, or in a high temperature environment of 200 ° C. or higher. For this reason, the prober is required to be able to inspect under such a high and low temperature environment. Therefore, a cooling system such as a chiller mechanism or a heating system such as a heater mechanism is mounted on the prober, and by cooling or heating the wafer chuck to a set temperature by these cooling systems or heating systems, (For example, refer to Patent Document 1).

JP 2008-311483 A

  In recent wafer inspection by a prober, the number of chips to be measured simultaneously is increasing in order to shorten the measurement time and reduce the test cost. At that time, even in a device such as a DRAM (Dynamic Random Access Memory) or a flash memory with a small amount of heat generated by one chip, the amount of heat generated increases as the number of simultaneous measurements increases. In this case, the wafer chuck is heated by the device heat generated during the wafer inspection and the temperature is raised.

  A refrigerator designed for low temperature is used in a cooling system that requires, for example, −40 ° C. as an inspection temperature in the low temperature region of the device (set temperature of the wafer chuck by the cooling system). However, if a coolant heated to, for example, 40 ° C. or more by the wafer chuck is passed through the refrigerator, the refrigerator oil is adversely affected (eg, deteriorated), or the refrigerator is subjected to a heat cycle with a large temperature difference from high temperature to low temperature. Take damage. For this reason, in the conventional cooling system, the cooling liquid cannot be used in a high temperature range where the cooling liquid is heated to, for example, 40 ° C. or more by the wafer chuck.

  Due to such circumstances, the cooling capacity of the wafer chuck in the conventional cooling system is lowered in a high temperature range where the coolant cannot be used. For this reason, there is a problem that the temperature of the wafer chuck exceeds the inspection temperature required for the inspection, particularly when inspecting a device having a large calorific value.

  On the other hand, it is conceivable to control the temperature of the wafer chuck in a wide temperature range with air instead of the coolant. However, since air has a small heat capacity, it has a disadvantage that its cooling ability in a low temperature region is inferior to a cooling system using a cooling liquid.

  That is, no conventional prober has an effective cooling capacity in a wide temperature range from a low temperature range to a high temperature range.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a prober cooling system having an effective cooling capability in a wide temperature range from a low temperature range to a high temperature range.

  In order to achieve the object of the present invention, a prober of the present invention includes a wafer chuck that holds a wafer, a refrigerator that cools a cooling liquid, a supply-side flow path that connects the refrigerator and the wafer chuck, and a wafer chuck. A recovery-side channel connecting the refrigerator and the refrigerator, a bypass channel connecting the supply-side channel and the recovery-side channel, and a connection between the supply-side channel and the bypass channel provided in the supply-side channel A heater provided closer to the wafer chuck than the position, a temperature setting unit for setting the temperature of the wafer chuck, a first state in which the recovery-side channel is connected to the supply-side channel via the refrigerator, and the refrigerator. The preset temperature of the wafer chuck set by the temperature setting unit and the valve member that selectively switches between the second state in which the recovery-side flow path is connected to the supply-side flow path via the bypass flow path are preset. Below the reference temperature Expediently, switching the valve member in a first state, when the set temperature is higher than the reference temperature, and a switching unit for switching the valve member to the second state.

  One aspect of the present invention includes a temperature detection unit that detects the temperature of the coolant heated by the heater, and a heater control unit that controls the heater based on the temperature detected by the temperature detection unit and the set temperature. It is preferable.

  In one embodiment of the present invention, the bypass channel preferably includes an air-cooling cooling unit that air-cools the coolant.

  According to the present invention, the cooling capacity is effective in a wide temperature range from a low temperature range to a high temperature range.

The block diagram which shows the structure of the prober to which the cooling system of embodiment was applied Functional block diagram of a control device for controlling the operation of the cooling system of the embodiment The flowchart which showed operation of the cooling system of an embodiment

  Hereinafter, a preferred embodiment of a cooling system for a prober according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a block diagram illustrating a configuration of a prober 10 to which the cooling system of the embodiment is applied.

  First, the prober 10 will be described. The prober 10 includes a probe card 14 having a probe 12 that is brought into contact with an electrode of a chip to be inspected, and a tester 16. The tester 16 includes a tester body 18 and an interface 20 that electrically connects the terminals of the tester body 18 and the terminals of the probe card 14. The tester 16 supplies power and various test signals from a terminal connected to the probe 12 to the chip, and analyzes signals output to the electrodes of the chip to confirm whether the chip operates normally.

Next, the cooling system of the prober 10 will be described. The cooling system of the embodiment includes a wafer chuck 22 that holds a wafer W, a refrigerator 24 that cools a coolant,
A supply-side flow path 26 connecting the refrigerator 24 and the wafer chuck 22, a recovery-side flow path 28 connecting the wafer chuck 22 and the refrigerator 24, and a supply-side flow path 26 and a recovery-side flow path 28 are connected. And a bypass flow path 30.

  The wafer chuck 22 is made of a material such as a metal such as aluminum or copper, or a ceramic having good thermal conductivity. A coolant channel 23 is provided inside the wafer chuck 22, and the supply side channel 26 and the recovery side channel 28 are communicated with each other through the coolant channel 23.

  In addition, the supply side flow path 26 is provided with a heater 32, a pump 34, and a temperature detection unit 36. The heater 32 is provided closer to the wafer chuck 22 than the connection position P <b> 1 between the supply-side flow path 26 and the bypass flow path 30. The pump 34 is provided between the connection position P1 and the heater 32. The temperature detection unit 36 is constituted by, for example, a temperature sensor, and is provided on the wafer chuck side with respect to the heater 32. A tank 37 in which the coolant is stored is connected to the supply-side flow path 26 between the refrigerator 24 and the connection position P1.

  In addition, the cooling system of the embodiment includes a refrigerator selection valve 38 and an air cooling system valve 40. The refrigerator selection valve 38 is provided in the recovery side flow path 28 and is provided closer to the refrigerator 24 than the connection position P <b> 2 between the recovery side flow path 28 and the bypass flow path 30. The air cooling system valve 40 is provided in the bypass channel 30. The refrigerator selection valve 38 and the air cooling system valve 40 are components of the valve member of the present invention.

  The bypass flow path 30 is provided with a natural air cooling type air cooling cooler 42 having a plurality of cooling fins. The high-temperature coolant flowing through the bypass channel 30 is air-cooled while passing through the air-cooled cooler 42.

  Further, the cooling system of the embodiment includes a control device 44 that controls the operation of each part of the cooling system. FIG. 2 is a functional block diagram of the control device 44.

  2 includes an arithmetic processing circuit including a CPU (central processing unit) (not shown), a memory such as a ROM (Read Only Memory) or a RAM (Random Access Memory), and an input device such as a keyboard. And an output device such as a monitor. In the control device 44, the functions of the respective units of the control device 44 are realized by the CPU executing a program stored in the memory. As shown in FIG. 2, the control device 44 functions as a temperature setting unit 46, a switching unit 48, and a heater control unit 50.

  The temperature setting unit 46 sets the set temperature of the wafer chuck 22 in accordance with information input via an input device such as a keyboard. This set temperature is output from the temperature setting unit 46 to the switching unit 48 and the heater control unit 50.

  The switching unit 48 controls the opening / closing of the refrigerator selection valve 38 and the air cooling system valve 40 based on the set temperature of the wafer chuck 22 set by the temperature setting unit 46. Specifically, when the set temperature is lower than the preset reference temperature, the switching unit 48 controls the refrigerator selection valve 38 to open and controls the air cooling system valve 40 to close. . As a result, the refrigerator selection valve 38 and the air cooling system valve 40 are switched to the first state in which the recovery side flow path 28 is connected to the supply side flow path 26 via the refrigerator 24. In this first state, the cooling liquid cooled by the refrigerator 24 of FIG. 1 can be supplied to the refrigerant flow path 23 via the supply side flow path 26, so that the surface of the wafer chuck 22 is cooled to a low temperature region. (For example, -40 degreeC or more and less than 40 degreeC) It becomes cooling possible.

  2 switches the refrigerator selection valve 38 to the closed side and the air cooling system valve 40 to the open side when the set temperature is equal to or higher than the preset reference temperature. To do. As a result, the refrigerator selection valve 38 and the air cooling system valve 40 are switched to the second state in which the recovery side passage 28 is connected to the supply side passage 26 via the bypass passage 30 without passing through the refrigerator 24. In this second state, since the high-temperature coolant heated by the heater 32 in FIG. 1 can be supplied to the coolant channel 23 via the supply-side channel 26, the surface of the wafer chuck 22 is placed in a high-temperature region (for example, , 40 ° C. or more and less than 125 ° C.).

  2 controls the temperature of the high-temperature coolant supplied to the wafer chuck 22 in FIG. 1 based on the set temperature of the wafer chuck 22. Specifically, the heater output of the heater 32 is controlled so that the temperature detected by the temperature detector 36 becomes a temperature corresponding to the set temperature of the wafer chuck 22. The storage unit 54 stores in advance data on the temperature of the high-temperature coolant corresponding to the set temperature of the wafer chuck 22 for each set temperature. That is, the storage unit 54 has a conversion map in which the relationship between the set temperature of the wafer chuck 22 and the temperature of the high-temperature coolant is associated.

  When the set temperature (for example, 100 ° C.) of the wafer chuck 22 is set by the temperature setting unit 46, the heater control unit 50 sets the temperature of the high-temperature coolant (for example, 97 ° C.) according to the set temperature. Read with reference to the conversion map of the storage unit 54. Then, the heater controller 50 controls the heater output of the heater 32 so that the temperature of the high-temperature coolant detected by the temperature detector 36 becomes a temperature (for example, 97 ° C.) corresponding to the set temperature. Thereby, according to the cooling system of the embodiment, the temperature of the high-temperature coolant supplied to the wafer chuck 22 in the operation in the high-temperature region can be adjusted to a temperature according to the set temperature of the wafer chuck 22.

  Next, an example of the operation of the cooling system configured as described above will be described. In the following description, 40 ° C. is exemplified as the switching temperature set for switching the flow path between the first state and the second state. This switching temperature corresponds to the reference temperature of the present invention. Although the reference temperature is not limited to 40 ° C., it is preferably 40 ° C. or less in consideration of damage given to the refrigerator 24 from the coolant.

  FIG. 3 is a flowchart illustrating an example of the operation of the cooling system according to the embodiment.

  According to the flowchart of FIG. 3, first, the temperature setting unit 46 sets the set temperature of the wafer chuck 22 in accordance with information input via an input device such as a keyboard (S10). The set temperature set by the temperature setting unit 46 is output from the temperature setting unit 46 to the switching unit 48 and the heater control unit 50. The switching unit 48 determines whether the set temperature set by the temperature setting unit 46 is equal to or higher than the reference temperature or lower than the reference temperature (S20). If the set temperature is lower than the reference temperature (S20: YES), the first setting is performed. The state is selected (S30), the refrigerator selection valve 38 is switched to the open side, and the air cooling system valve 40 is switched to the closed side.

  Next, the refrigerator 24 and the pump 34 are activated to start cooling the wafer chuck 22 (S40). Thereafter, the refrigerator 24 controls the temperature of the cooling liquid to a temperature corresponding to the set temperature of the wafer chuck 22, supplies the cooling liquid to the wafer chuck 22, and cools the wafer chuck 22 in a low temperature region. The cooling temperature of the coolant can be controlled, for example, by controlling the motor speed of a compressor (not shown) of the refrigerator 24 with an inverter.

  Thereafter, when the inspection of the wafer W by the prober 10 is finished (S50: YES), the refrigerator 24 and the pump 34 are stopped, and the cooling of the wafer chuck 22 is finished. When the inspection of the wafer W by the prober 10 is continuously performed (S50: NO) and the set temperature is not changed (S60: NO), the cooling system returns to S40 described above, and the wafer chuck Continue cooling in 22 low temperature range.

  On the other hand, when changing preset temperature (S60: YES), a cooling system returns to above-mentioned S20. Then, when the new set temperature set by the temperature setting unit 46 is lower than the reference temperature (S20: YES), the cooling system executes the operations from S30 to S60 described above.

  Next, the case where the new set temperature set by the temperature setting unit 46 is equal to or higher than the reference temperature (S20: NO) will be described.

  In this case, the switching unit 48 selects the second state based on the set temperature set by the temperature setting unit 46 (S70), switches the refrigerator selection valve 38 to the closed side, and sets the air cooling system valve 40 to the open side. Switch.

  Next, the heater 32 and the pump 34 are activated to start cooling the wafer chuck 22 (S80). Thereafter, the heater controller 50 controls the heater 32 based on the temperature detected by the temperature detector 36 and the set temperature, and controls the temperature of the coolant to a temperature corresponding to the set temperature of the wafer chuck 22. . This coolant is supplied to the wafer chuck 22 to cool the wafer chuck 22 in a high temperature range. At this time, the refrigerator 24 is preferably stopped.

  Thereafter, when the inspection of the wafer W by the prober 10 is completed (S90: YES), the heater 32 and the pump 34 are stopped and the cooling of the wafer chuck 22 is completed. When the inspection of the wafer W by the prober 10 is continued (S90: NO) and the set temperature is not changed (S100: NO), the cooling system returns to S80 described above, and the wafer chuck Continue cooling in the 22 hot zone.

  On the other hand, when changing preset temperature (S100: YES), a cooling system returns to above-mentioned S20. Then, when the new set temperature set by the temperature setting unit 46 is lower than the reference temperature (S20: YES), the cooling system executes the above-described operations from S30 to S60, and when it is equal to or higher than the reference temperature (S20). : NO), the operations from S70 to S100 described above are executed.

  As described above, according to the cooling system of the embodiment, the bypass flow path 30 is provided in the circulation flow path (the supply side flow path 26 and the recovery side flow path 28) for circulating the cooling system between the wafer chuck 22 and the refrigerator 24. A first state in which the coolant is circulated through the refrigerator 24 by the valve members (the refrigerator selection valve 38 and the air cooling system valve 40) according to the set temperature set by the temperature setting unit 46, and the refrigerator Since it is configured to be selectively switched between the second state in which the coolant is circulated through the bypass flow path 30 without using the air, it is difficult to obtain a sufficient cooling capacity with air. The wafer chuck 22 can be satisfactorily cooled even at a temperature or at a set temperature in a high temperature range where it is difficult to use the refrigerator 24.

  Further, according to the cooling system of the embodiment configured as described above, it is possible to apply a coolant having a fluidity at, for example, about −60 ° C. and a boiling point of 150 ° C. or more. Even if the set temperature is a wide temperature range of −40 ° C. or higher and 150 ° C. or lower, sufficient cooling capacity can be exhibited.

  Therefore, according to the cooling system of the embodiment, it has an effective cooling capacity in a wide temperature range from a low temperature range to a high temperature range.

  In the cooling system of the embodiment, the temperature of the coolant heated by the heater 32 is detected by the temperature detection unit 36, and the heater control unit 50 controls the heater 32 based on the detected temperature and the set temperature. The temperature of the wafer chuck 22 can be controlled to the set temperature.

  Furthermore, the cooling system of the embodiment is configured such that the air cooling unit 42 is provided in the bypass channel 30 and the high-temperature coolant flowing through the bypass channel 30 is cooled by the air cooling unit 42 and then returned to the heater 32. The temperature control of the coolant by the heater 32 can be effectively executed.

  In the cooling system of the embodiment, the refrigerator selection valve 38 and the air cooling system valve 40 are illustrated as the valve members of the present invention. However, a known three-way connection position P2 between the recovery side flow path 28 and the bypass flow path 30 is illustrated. By providing a valve (not shown), the valve member of the present invention can be configured.

  Moreover, in the cooling system of the embodiment, the natural air cooling type air cooling cooler 42 is exemplified as the air cooling unit, but it can be applied to a forced air cooling type air cooling unit using a fan.

  DESCRIPTION OF SYMBOLS 10 ... Prober, 12 ... Probe, 14 ... Probe card, 16 ... Tester, 18 ... Tester main body, 20 ... Interface, 22 ... Wafer chuck, 24 ... Refrigerator, 26 ... Supply side flow path, 28 ... Recovery side flow path, DESCRIPTION OF SYMBOLS 30 ... Bypass flow path, 32 ... Heater, 34 ... Pump, 36 ... Temperature detection part, 38 ... Refrigerator selection valve, 40 ... Air cooling system valve, 42 ... Air cooling cooler, 44 ... Control apparatus, 46 ... Temperature setting part, 48 ... Switching unit, 50 ... Heater control unit, 54 ... Storage unit

Claims (3)

A wafer chuck for holding the wafer;
A refrigerator that cools the coolant;
A supply-side flow path connecting the refrigerator and the wafer chuck;
A collection-side flow path connecting the wafer chuck and the refrigerator;
A bypass channel connecting the supply side channel and the recovery side channel;
A heater provided on the supply side flow path, on the wafer chuck side than a connection position of the supply side flow path and the bypass flow path;
A temperature setting unit for setting the temperature of the wafer chuck;
A first state in which the recovery-side flow path is connected to the supply-side flow path via the refrigerator, and the recovery-side flow path to the supply-side flow path via the bypass flow path without passing through the refrigerator A valve member that selectively switches between the connected second states;
When the set temperature of the wafer chuck set by the temperature setting unit is lower than a preset reference temperature, the valve member is switched to the first state, and when the set temperature is equal to or higher than the reference temperature, A switching unit for switching the valve member to the second state;
Prober cooling system. A temperature detector for detecting the temperature of the coolant heated by the heater;
A heater control unit that controls the heater based on the temperature detected by the temperature detection unit and the set temperature;
The prober cooling system according to claim 1, comprising: 3. The prober cooling system according to claim 1, wherein the bypass channel includes an air-cooling cooling unit that air-cools the coolant. 4.

Images