KR100789699B1 - Wafer prober station being capable of testing in low and high temperature - Google Patents

Abstract

A wafer prober station for performing a test process at low and high temperature is provided to perform a correct test process under low temperature environment by suppressing generation of frost. A cooling unit(250) is installed in an inside of a wafer prober station in order to supply a cool coolant. An air dry unit(260) dehumidifies air and supplies the dehumidified air to an inside of a wafer prober station. A wafer is loaded on a chuck(222). A cooling chuck(230) is installed at a lower part of the chuck in order to receive the coolant from the cooling unit. A heater(226) is installed at a lower part of the cooling chuck and is formed with a heating plate. A power supply unit(282) supplies power to the heater. A control unit(270) controls the cooling unit, the air dry unit, and the power supply unit in order to maintain the predetermined temperature of the chuck. The temperature of the chuck is determined according to the temperature of the cooling chuck and the heater.

Description

Wafer prober station being capable of testing in low and high temperature}

1 is a cross-sectional view schematically showing a wafer prober apparatus according to the prior art.

2 is a schematic block diagram of a low temperature testable wafer prober apparatus according to a preferred embodiment of the present invention.

3 is a cross-sectional view of a cooling chuck used in a wafer prober device according to a preferred embodiment of the present invention in a horizontal direction.

<Explanation of symbols for the main parts of the drawings>

20: wafer prober device

250: cooling unit

260: air dry unit

270 control unit

280 temperature sensor

290: Dew Point Sensor

222: Chuck

230: cooling chuck

226: heater

232: circulation passage

234: inlet

236: outlet

The present invention relates to a wafer prober device that can be tested at high temperature, room temperature, and low temperature. More specifically, the present invention relates to a wafer prober device that can further adjust the temperature of the chuck to a test temperature by further including a cooling chuck and a heater under the chuck. will be.

In general, a wafer prober station is an in-process semiconductor manufacturing process in which wafer dies are electrically tested to determine whether they are operating normally before packaging semiconductor chips made on a semiconductor wafer. As one of the EDS inspection equipment, it is a process equipment to save the material, time and other damage to be used in the subsequent packaging and packaging test process by early contacting and testing the pads of the wafer die to eliminate the defective die early.

1 is a schematic cross-sectional view of a typical wafer prober station. Referring to Figure 1, the above-described wafer prober station (1) stages (100, 110, 120, 130) for moving and fixing the wafer to be inspected on the chuck, (2) electrical inspection with the wafer to inspect the wafer A prober card that provides a connection and transmits and receives electrical signals, and (3) a program that checks whether or not various wafers are manufactured according to a specified specification using the electrical signals transmitted and received from the prober card. Tester 140 for performing the inspection, (4) prober station and computer 150 for controlling the tester, and (5) a loader for moving the wafer from the cassette into which the plurality of wafers are inserted onto the stage of the stage. And 180.

Here, the stage unit is a mechanism consisting of a chuck and four axes, the four axes are composed of the X, Y, Z axis and the rotation axis, the X, Y axis (100, 110) to move the respective plane The Z axis 120 is installed on the X, Y axis and moves up and down, and the rotation axis is rotated on the Z axis. On the other hand, the chuck 130 is installed on the rotating shaft, and to fix the wafer to be tested on the upper surface.

Generally, when electrically testing chips in a wafer die state, they are tested at high or low temperatures as well as at room temperature. Therefore, the wafer prober station must be able to maintain the temperature of the wafer at the temperature to be tested. That is, the wafer prober station must be able to test the wafer at low temperature (eg, -10 ° C to -40 ° C) as well as at room or high temperature.

Therefore, the present applicant is to propose a wafer prober device that can be tested even at low temperatures.

An object of the present invention for solving the above problems is to provide a wafer prober device that can provide a testable environment at high temperature and room temperature as well as low temperature.

Features of the present invention for achieving the above technical problem relates to a wafer prober device that can be tested at high and low temperatures,

A cooling unit mounted in the wafer prober device and providing a cooled coolant,

An air dry unit which introduces air in the wafer prober device to dehumidify and provides the inside of the wafer prober device again,

The chuck on which the wafer to be inspected is placed on the top surface,

A cooling chuck disposed below the chuck, the coolant flowing from the cooling unit and discharged back to the cooling unit through an internal circulation passage;

A heater disposed below the cooling chuck and formed of a heating plate;

A power supply for a heater for providing power to the heater, and

Control unit for controlling the driving of the cooling unit, the air dry unit and the power supply for the heater to maintain the predetermined test temperature

The temperature of the chuck is determined according to the temperature of the cooling chuck and the heater.

 A wafer prober device having the above-described features includes at least one temperature sensor and a dew point sensor in adjacent regions of the chuck and / or on the surface of the chuck,

The controller detects the temperature of the chuck using the temperature sensor, compares the detected temperature with the test temperature,

If the detected temperature is higher than the test temperature, after driving the cooling unit to lower the temperature of the cooling chuck, the temperature of the chuck is adjusted to the test temperature by precisely controlling the heater power supply unit and heating the heater. ,

In addition, the controller detects the temperature of the chuck using the temperature sensor, and detects the dew point of the adjacent region of the chuck using the dew point sensor, and compares the detected temperature of the chuck with the dew point,

If the sensing temperature of the chuck is lower than the dew point, the air dryer is driven to dehumidify and convert the air inside the wafer prober device into dry air so that the dew point inside the apparatus is always lower than the sensing temperature of the chuck. It is preferable.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and operation of the wafer prober device that can provide a low-temperature test environment according to a preferred embodiment of the present invention.

2 is a block diagram schematically showing the configuration of a wafer prober apparatus 20 according to a preferred embodiment of the present invention. Referring to FIG. 2, the wafer prober device 20 according to the present invention may include a stage unit (not shown), a cooling unit 250, an air dry unit 260, a control unit 270, and at least one temperature sensing sensor. 280 and at least one dew point detection sensor 290, wherein the stage portion includes a chuck 222, a cooling chuck 230, a heater 226 and four axes (not shown) on which the wafer to be tested is placed. ).

The four axes of the stage portion consist of X and Y axes moving in the X and Y directions, a Z axis for moving the X and Y axes in the up and down direction, and a rotation axis for rotating the Z axis, and these are general wafer prober devices. Since the same as the four axes of the detailed description thereof will be omitted.

The stage unit is disposed on the heater 226, the cooling chuck 230 and the chuck 222 sequentially on the rotation axis, the wafer to be tested is placed on the chuck 222.

The heater 226 generates heat by the power supplied from the heater power supply 282, and the heater power supply is operated according to a control signal from the controller 270 to supply power to the heater. To be heated.

Figure 3 shows a cross-sectional view in the horizontal direction of the cooling chuck according to a preferred embodiment of the present invention. Referring to FIG. 3, the cooling chuck 230 according to the present invention has a circulation passage 232 through which coolant can be circulated, and an inlet 234 and circulation in which the coolant flows into the circulation passage. And a discharge port 236 through which the refrigerant is discharged.

The outlet and inlet of the cooling unit 250 are connected to the inlet 234 and the outlet 236 of the cooling chuck 230 using a double silicon blade hose, respectively. The cooling unit reduces the temperature of the coolant to sub-zero temperature by using the heat of the refrigerant after making the refrigerant to a sub-zero temperature, and then provides the cooling chuck. The coolant provided to the cooling chuck circulates through the circulation passage of the cooling chuck, and then flows back into the cooling unit to be recooled and circulated.

When the surface temperature of the chuck cooled by the cooling chuck of the wafer prober device according to the present invention becomes lower than the dew point of the ambient air, frost occurs on the surface of the chuck, so that the wafer on the chuck cannot be properly tested. The problem arises. In order to solve this problem, the wafer prober device according to the present invention further includes an air dry unit 260 therein, and has an outer housing that seals the wafer prober device entirely with external air. In the low temperature test, the wafer prober device according to the present invention is to be filled with air (for example, air having a humidity of 0.1% or less), which is always dried by the air-dryer, by the outer housing. Minimize the change in the dew point inside.

The air dry unit 260 introduces air in a normal state in the prober apparatus, dehumidifies and dries using an adsorbent, and provides the same to the prober apparatus. In this way, by providing the air dried by the air dry unit 260 into the prober device, the dew point of the air in the prober device becomes lower than the surface temperature of the chuck, and as a result, frost does not occur on the surface of the chuck. In addition, the air dry unit 260 injects the dried air not only to the stage portion but also to the loader portion for moving the finished wafer to the cassette, thereby testing the wafer at a sub-zero temperature. This prevents frost on the wafer during transfer.

As such, the air dry unit 260 dries the air in the prober device sealed by the outer housing, thereby preventing frost on the chuck and / or the wafer on the chuck even when the temperature of the chuck drops below zero.

The temperature sensor 280 is a sensor that detects a temperature of the chuck 222 of the wafer prober device and is inserted and mounted in the chuck. More specifically, by drilling a long circle in the interior of the chuck and inserting a stick-shaped temperature sensor therein, it is possible to measure the actual temperature of the chuck.

The dew point sensor 290 detects the humidity of the air inside the wafer prober device and converts the humidity into a dew point. The dew point sensor 290 checks the dew point of the dried air provided in the wafer prober device and provides the dew point to the controller. The dew point sensor is placed in a position adjacent to the chuck to measure the dew point of dry air on the surface of the chuck, particularly preferably at a similar height as near the chuck as possible.

The controller 270 controls all the equipments to match the temperature at which the chuck of the wafer prober device is to be tested, and includes a temperature control module and a humidity control module. First, the operation of the temperature control module of the controller 270 will be described.

If the test temperature preset by the administrator is below zero, the cooling unit is driven to provide a cooled coolant to the circulation passage of the cooling chuck to reduce the temperature of the cooling chuck to zero. By reducing the temperature of the cooling chuck, the temperature of the chuck is also reduced. Next, the temperature sensor detects the temperature of the chuck placed on the cooling chuck. When the temperature of the chuck falls below a predetermined temperature, the heater is controlled to heat the heater. Next, after confirming the temperature of the chuck disposed on the cooling chuck by using the temperature sensor, by controlling the heater power supply device to change the temperature of the heater, the chuck by the cooling chuck and the heater to maintain the test temperature continuously.

If the test temperature is above room temperature (25 ~ 35 ℃), the temperature control module of the control unit controls the power supply for the heater to heat the heater so that the chuck maintains the test temperature.

Hereinafter, the operation of the humidity control module of the control unit 270 will be described. As the temperature of the chuck drops below room temperature, the dew point around the chuck becomes higher than the temperature of the chuck. In this case, frost forms on the surface of the chuck, making it impossible to accurately test the wafer. Therefore, the humidity control module of the control unit controls the humidity in the wafer prober device to prevent frost on the surface of the chuck.

Simultaneously with maintaining the temperature of the chuck at the test temperature, the humidity control module measures the dew point using a dew point sensor disposed around the chuck and measures the temperature of the chuck using a temperature sensor mounted on the chuck. If the dew point around the chuck is higher than the temperature of the chuck, the heater is heated to remove the frost already generated on the surface of the chuck, and at the same time, the air dryer is driven to remove air from the inside of the wafer prober device to remove moisture, and then the wafer prober. Spray the dehumidified air back into the device. As a result, as the dehumidified dry air is provided into the wafer prober device, the dew point inside the prober becomes lower than the temperature of the chuck, allowing safe testing without frost on the surface of the chuck. .

On the other hand, the wafer prober device according to the present invention is placed in an outer and hermetically sealed outer housing so that the door opens only when the wafer is loaded or unloaded on the chuck, thereby minimizing the dew point change inside the stage portion.

Although the present invention has been described above with reference to preferred embodiments thereof, this is merely an example and is not intended to limit the present invention, and those skilled in the art do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications which are not illustrated above in the scope are possible. And differences relating to such modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

The wafer prober device according to the present invention can test the wafer in a low temperature environment having a sub-zero temperature as well as an ambient temperature or a high temperature environment.

In addition, according to the present invention, no frost occurs on the wafer even when the temperature of the chuck remains below zero, so that accurate testing can be performed even in a low temperature environment.

Claims (6)

In the wafer prober apparatus, A cooling unit mounted in the wafer prober device and providing a cooled coolant; An air dry unit configured to supply air in the wafer prober device to dehumidify and provide the dehumidified air to the inside of the wafer prober device; A chuck on which the wafer to be inspected is placed; A cooling chuck disposed below the chuck, the coolant flowing from the cooling unit and discharged back to the cooling unit through an internal circulation passage; A heater disposed below the cooling chuck and formed of a heating plate; A heater power supply for providing power to the heater; And Control unit for controlling the driving of the cooling unit, the air dry unit and the power supply for the heater to maintain the predetermined test temperature And a temperature of the chuck is determined according to temperatures of the cooling chuck and the heater. The wafer prober device of claim 1, wherein the wafer prober device is disposed in an outer housing sealed to the outside. The apparatus of claim 1, wherein the wafer prober device comprises at least one temperature sensing sensor in an adjacent region of the chuck, in the chuck, and / or on the surface of the chuck, The controller detects the temperature of the chuck using the temperature sensor, compares the detected temperature and the test temperature, If the detected temperature is higher than the test temperature, after driving the cooling unit to lower the temperature of the cooling chuck, the temperature of the chuck is adjusted to the test temperature by precisely controlling the heater power supply unit and heating the heater. Wafer prober device. The apparatus of claim 1, wherein the wafer prober device comprises at least one temperature sensor and a dew point sensor in adjacent areas of the chuck and / or on the surface of the chuck, The controller detects the temperature of the chuck using the temperature sensor and detects the dew point of an adjacent region of the chuck using the dew point sensor, and compares the detected temperature of the chuck with the dew point, If the sensing temperature of the chuck is lower than the dew point, the air dryer is driven to dehumidify and convert the air inside the wafer prober device into dry air so that the dew point inside the apparatus is always lower than the sensing temperature of the chuck. Wafer prober device, characterized in that. The cooling chuck of claim 1, wherein the cooling chuck includes an inlet through which coolant flows from a cooling unit, a circulation passage through which coolant introduced into the inlet is circulated, and an outlet through which coolant circulated through the circulation passage is discharged. And a discharge port and the inlet port are connected to the cooling unit so that the coolant repeatedly circulates the cooling chuck and the cooling unit. The apparatus of claim 1, wherein the wafer prober device comprises at least one temperature sensor and a dew point sensor in adjacent areas of the chuck and / or on the surface of the chuck, The controller detects the temperature of the chuck using the temperature sensor and detects the dew point of an adjacent region of the chuck using the dew point sensor, and compares the detected temperature of the chuck with the dew point, If the sensing temperature of the chuck is lower than the dew point, the heater is heated to remove frost generated on the surface of the wafer, and the air dryer is driven to dehumidify the air inside the wafer prober device to convert it to dry air. Thereby keeping the dew point inside the device always below the sensing temperature of the chuck.

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