JP2007142246A - Prober and wafer test method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a prober capable of accurately setting the temperature of a device to be examined with simple configuration. <P>SOLUTION: In a prober, terminals of testers 21, 22 are connected to electrodes of a plurality of semiconductor devices formed on a wafer W in order to examine the semiconductor devices using the testers. The prober comprises a probe card 18 including a probe 19 for connecting the electrodes to the terminals of the testers in contact with the electrodes of the semiconductor devices, a wafer chuck 11 for holding the wafer, and a dipping liquid source 34 for supplying a dipping liquid DL with electric insulation property and high heat conductivity onto the wafer held by the wafer chuck. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wafer test method for electrically inspecting a plurality of semiconductor chips (dies) formed on a semiconductor wafer, and a prober for connecting the electrodes of the die to a tester.

  In the semiconductor manufacturing process, various processes are performed on a thin disk-shaped semiconductor wafer to form a plurality of chips (dies) each having a semiconductor device (device). Each chip is inspected for electrical characteristics, then separated by a dicer, and then fixed to a lead frame and assembled. The inspection of the electrical characteristics is performed by a wafer test system composed of a prober and a tester. The prober fixes the wafer to the stage and brings the probe into contact with the electrode pad of each chip. The tester supplies power and various test signals from the terminals connected to the probe, and analyzes the signals output to the electrodes of the chip with the tester to check whether it operates normally.

  Semiconductor devices are used in a wide range of applications and are used in a wide temperature range. Therefore, when a semiconductor device is inspected, it is necessary to inspect at a room temperature (normal temperature), a high temperature such as 200 ° C., and a low temperature such as −55 ° C. It is required that the inspection can be performed. Therefore, a wafer temperature adjusting mechanism for changing the surface temperature of the wafer chuck, such as a heater mechanism, a chiller mechanism, and a heat pump mechanism, is provided below the wafer mounting surface of the wafer chuck for holding the wafer in the prober. The wafer held on is overheated or cooled.

  FIG. 1 is a diagram showing a schematic configuration of a wafer test system including a prober having a wafer temperature adjusting mechanism. The prober includes a wafer chuck 11 that holds the wafer W, a coolant path 12 and a heater 13 provided in the wafer chuck 11, and a coolant source 14 that circulates coolant to the coolant path 12 via the path 15. And a heater power supply 16 for supplying power to the heater 13, a controller 17, and a probe card 18 having a probe 19 made in accordance with the electrode arrangement of the semiconductor chip to be inspected. By flowing the cooling liquid through the cooling liquid path 12, the surface of the wafer chuck 11 holding the wafer W is cooled, and the temperature of the held wafer W is lowered. Similarly, by supplying electric power to the heater 13 to generate heat, the surface of the wafer chuck 11 is heated, and the held wafer W becomes high temperature. The controller 17 controls the coolant source 14 and the heater power supply 16 based on the temperature detected by the temperature sensor 20 provided near the surface of the wafer chuck 11, so that the surface of the wafer chuck 11 reaches a desired temperature. To be. In addition to this, the prober detects a position of the probe, and a triaxial movement / rotation mechanism of the wafer chuck 11 in the X, Y, and Z directions, an alignment camera that detects the arrangement direction of the dies formed on the wafer, and the probe. A needle position detection camera and a housing for housing them are provided, and the probe card 17 is attached to a card holder provided in the housing. Since such components are not directly related to the present invention, illustration is omitted here.

  The tester includes a tester body 21 and a connection portion 22 that electrically connects the terminals of the tester body 21 and the terminals of the probe card 17. The connection part 22 has a connection terminal mechanism using a spring, a so-called spring pin structure. The prober performs measurement in cooperation with the tester in the wafer test, but its power supply system and mechanism are independent from the tester body and the test head.

  In addition, a vacuum path for vacuum-sucking the wafer W, a lift mechanism for the wafer W, and the like are provided in the wafer chuck 11. Regarding the arrangement of the coolant path 12, the heater 13, and the vacuum path in the wafer chuck 11. There are various modifications. In the following description, the coolant path 12, the coolant source 14, and the path 15 are referred to as a cooling mechanism, the heater 13 and the heater power supply 16 are referred to as a heating mechanism, and the cooling mechanism and / or the heating mechanism are collectively referred to as a wafer. Sometimes referred to as a temperature adjustment mechanism.

  The wafer temperature adjustment mechanism can set the wafer W held on the wafer chuck 11 to an arbitrary temperature from −55 ° C. to + 200 ° C., for example. The wafer temperature adjustment mechanism can also be realized by a heat pump mechanism or the like.

  When the wafer is inspected at a predetermined temperature, the controller 17 controls the wafer temperature adjusting mechanism based on the temperature detected by the temperature sensor 20 while the wafer W is held on the wafer chuck 11, and the wafer chuck 11 Set to a predetermined temperature. The wafer chuck 11 is made of aluminum, copper, ceramic having good thermal conductivity, or the like, and the surface holding the wafer W is considered to have substantially the same temperature. Accordingly, only one temperature sensor 20 is provided, and control is performed assuming that the detected temperature of the wafer chuck 11 is the same in other portions.

  Further, the wafer W has a thin plate shape, and when it is attracted to and held by the wafer chuck 11, the thermal resistance between the wafer W and the surface of the wafer chuck 11 is sufficiently small, and the entire surface of the wafer W can be quickly removed from the wafer chuck 11. 11 surface temperature is considered.

  Since the configuration of the prober and wafer test system described above is widely known, further description is omitted here.

JP-A-6-53298 (Overall)

  When inspecting the electrical characteristics of a device, a power supply and a signal are supplied to the device to operate, and an output signal is detected. Therefore, the device generates heat during inspection. However, even if the device generates heat, since the device is in close contact with the wafer chuck 11, the device immediately reaches the temperature of the wafer chuck 11, the heat capacity of the wafer chuck 11 is large, and the thermal conductivity of the wafer chuck 11 is good. The temperature of the device under inspection is considered to be the temperature of the wafer chuck 11 and temperature control has been performed.

  However, the wafer chuck 11 is not sufficiently small in surface thermal resistance due to the internal structure and the like, and when the held wafer device generates heat, the temperature of that portion may rise above the temperature of other portions. I understood. Furthermore, the degree of close contact between the device and the surface of the wafer chuck 11 is not sufficient, and heat generated by the device is not immediately absorbed by the wafer chuck 11, resulting in a problem that the device becomes hot. Therefore, even if the temperature detected by the temperature sensor 20 is set to a predetermined inspection temperature, there is a problem that the device is not actually at the inspection temperature and the device cannot be inspected at the predetermined inspection temperature.

  This problem becomes a big problem particularly in the case of a device having a large calorific value, and if the heat transfer from the device to the wafer chuck 11 is insufficient, the device becomes an abnormally high temperature and the device itself is destroyed. Produce.

  In order to solve such a problem, it is conceivable to control the wafer temperature adjustment mechanism so that the temperature of the wafer chuck is lowered by taking into account the temperature rise due to the heat generation of the device. Since the temperature control response is slow, it is difficult to bring the device to a predetermined inspection temperature. For example, if the temperature of the wafer chuck is lowered in consideration of the heat generation of the device, the device is inspected at a temperature lower than the inspection temperature when the device does not generate heat sufficiently.

  In addition, a structure has been proposed in which a part of the wafer chuck has a porous structure in which fine holes are formed, and a coolant or a cooling gas flows through the part, but in order to improve the temperature control response of the device on the wafer not enough.

  In order to solve such a problem, Patent Document 1 discloses that a groove is provided on the surface of a wafer chuck, and a helium gas is allowed to flow in the groove while the wafer is adsorbed to the wafer chuck to directly cool the lower surface of the wafer. The configuration for improving the temperature control response of the above device is described. However, since this configuration forms a helium gas path between the wafer chuck surface and the adsorbed wafer, it is necessary to improve the flatness and surface roughness of the wafer chuck surface in order to prevent helium gas from leaking. There is a problem of high cost.

  The present invention solves such a problem, and an object thereof is to realize a prober capable of accurately setting the temperature of a device under inspection to a desired temperature at a low cost.

  In order to achieve the above object, the prober of the present invention immerses the wafer held by the wafer chuck in an immersion liquid that is electrically insulating and highly thermally conductive.

  That is, the prober of the present invention is a prober for connecting each terminal of the tester to an electrode of the semiconductor device in order to inspect a plurality of semiconductor devices formed on the wafer by the tester, A probe card having a probe that contacts the electrode and connects the electrode to a terminal of the tester, a wafer chuck that holds the wafer, and an electrically insulating and high thermal conductivity on the wafer held by the wafer chuck An immersion liquid source for supplying the immersion liquid.

  In the prober of the present invention, since the immersion liquid on the wafer held by the wafer chuck is supplied, the device under inspection comes into direct contact with the immersion liquid, and even if it generates heat, the heat is immediately taken away by the immersion liquid. A desired inspection temperature can be obtained. In particular, since the device is formed on the upper surface of the wafer and the upper surface of the wafer is cooled in the present invention as compared with the configuration described in Patent Document 1 that cools the lower surface of the wafer, the temperature control of the device is performed. Response is further improved.

  The immersion liquid is an electrically insulating and high thermal conductivity liquid such as Florinart (trade name), and does not affect the inspection.

  It is desirable to provide recovery means for recovering the immersion liquid supplied on the wafer held by the wafer chuck to the immersion liquid source, and to reuse the recovered immersion liquid.

  The recovery means preferably includes a filter that removes foreign substances from the recovered immersion liquid. When the probe is brought into contact with the electrode of the device, wrinkles are generated. However, such wrinkles adhere to the surface of the device and cause problems such as failure of the device and an increase in detection error of the probe tip position. In the present invention, since the immersion liquid is supplied onto the wafer held by the wafer chuck, it is possible to wash away the wrinkles with the immersion liquid, and it is possible to remove the wrinkles from the wafer. Since the recovered immersion liquid contains such soot, it is removed by a filter and reused.

  In order to ensure the contact between the wafer and the immersion liquid, it is desirable to immerse the wafer in the immersion liquid. For this purpose, an immersion liquid holding member for holding the immersion liquid is provided around the wafer chuck, and the wafer is provided with the immersion liquid. So that it is immersed. The immersion liquid holding member includes an inlet for collecting the held immersion liquid in the immersion liquid source, and an outlet for ejecting the immersion liquid supplied from the immersion liquid source onto the wafer. Thereby, the immersion liquid flows from the jet nozzle to the inlet, and the above-described soot can be washed away.

  The spout can also be provided on the probe card. With this configuration, since the immersion liquid is directly jetted onto the device being inspected, the cooling efficiency is good. Also in this case, an immersion liquid holding member having an inlet is provided around the wafer chuck, and the immersion liquid is collected in the immersion liquid source.

  In the wafer test method of the present invention, a wafer on which a plurality of semiconductor devices are formed is held on a wafer chuck, a probe of a probe card connected to a terminal of a tester is brought into contact with an electrode of the semiconductor device, and the tester A wafer test method for inspecting the semiconductor device by supplying power and an inspection signal to the semiconductor device and detecting an output signal from the semiconductor device, the wafer being held by the wafer chuck during the inspection An immersion liquid that is electrically insulating and has high thermal conductivity is supplied onto the wafer.

  In the present invention, it is possible to bring the wafer to a predetermined inspection temperature by controlling the temperature of the immersion liquid supplied onto the wafer, but the wafer temperature can be efficiently controlled by using the above-described wafer temperature adjusting mechanism. Temperature control is also possible.

  As described above, according to the present invention, a prober that can accurately set the temperature of a device under inspection to a desired temperature can be realized at low cost.

  FIG. 2 is a diagram showing a configuration of a wafer test system having a prober according to the first embodiment of the present invention. FIG. 2 corresponds to FIG. 1, and corresponding portions are denoted by the same reference numerals. A difference from the configuration of FIG. 1 is that an immersion liquid holding member 31 for immersing the held wafer W in the immersion liquid DL is provided around the upper surface of the wafer chuck 11. The temperature adjustment mechanism including the heater 11 and the coolant path 12 in the wafer chuck 11 shown in FIG. 1 is not necessarily provided, but is desirably provided. In FIG. 2, the temperature adjustment mechanism is not shown, but the prober of the embodiment includes a heater 11, a coolant path 12, a coolant source 14, a path 15, a heater power supply 16, a control unit 17, and a temperature sensor. 20 is provided.

  The immersion liquid holding member 31 is provided around the vicinity of the upper surface of the wafer chuck 11 so as to form a water plate having the upper surface of the wafer chuck 11 as a bottom. The immersion liquid holding member 31 is, for example, an electrically insulating and high thermal conductivity immersion liquid such as Fluorinart (trade name) that is held inside by attaching an annular member to the wafer chuck 11 via an elastic member. Hold DL. One side of the bank of the immersion liquid holding member 31 is provided with a jet port 32 that ejects the immersion liquid DL supplied from the immersion liquid source 34 via the path 37 onto the inner wafer W, An inlet 33 through which the immersion liquid DL flows is provided. The immersion liquid DL in the basin formed by the immersion liquid holding member 31 flows into the inflow port 33 and is collected by the immersion liquid source 34 via the path 38. The paths 37 and 38 are constituted by, for example, a flexible hose. The bank of the immersion liquid holding member 31 needs to be shaped so as not to prevent relative movement with respect to the probe 19 and the probe card 18.

  The immersion liquid source 34 includes a filter 36 that removes foreign matter in the collected immersion liquid DL, and a temperature control unit 35 that sets the immersion liquid DL from which foreign matter has been removed to a predetermined temperature. The immersion liquid DL that has been brought to the temperature of is supplied to the spout 32 through the passage 37 again. The temperature adjusted by the temperature adjusting means 35 is actually set in consideration of the temperature change in the path 37 and the like.

  When inspecting the device of the wafer W at a predetermined inspection temperature, the wafer chuck 11 is brought to the inspection temperature by the wafer temperature adjusting mechanism (not shown) while the wafer W is held, and thereby the wafer W becomes the inspection temperature. . In this state, the immersion liquid DL is further set to a predetermined temperature in consideration of the inspection temperature by the temperature control means 35 of the immersion liquid source 34, and the immersion liquid DL is supplied onto the wafer W. In this state, the wafer chuck 11 is relatively moved with respect to the prober 19, and the probe 19 is brought into contact with the electrode of the device for inspection.

  In this embodiment, the wafer W is at the inspection temperature at the time when the inspection is started, and the inspection is performed while the immersion liquid DL at the inspection temperature is supplied onto the wafer W. Even if the device on the wafer W generates heat due to the inspection, the immersion liquid DL at the inspection temperature is supplied to the surface of the device, and the immersion liquid DL directly absorbs the heat of the device and immediately brings the temperature of the device to the inspection temperature. To do.

  In addition, the soot generated when the probe is brought into contact with the electrode of the device is washed away by the immersion liquid DL flowing out from the ejection port 32, and the soot is removed from the wafer.

  When inspection is performed at normal room temperature, the wafer W may be immersed in the immersion liquid DL without providing the wafer temperature adjusting mechanism.

  Various modifications of the shape of the immersion liquid holding member 31 are possible. FIG. 3 is a view showing one of the modified examples, and three jet outlets 32A, 32B, and 32C for jetting the immersion liquid DL in a parallel direction are provided on one side of the bank of the immersion liquid holding member 31. The peripheral part of the wafer chuck 11 of the immersion liquid holding member 31 has the same height as the surface of the wafer chuck 11 on the side where the three jet nozzles 32A, 32B, 32C are provided, but the inlet 33 is provided. The side is inclined to the height position of the inflow port 33. Accordingly, the immersion liquid DL ejected from the three ejection ports 32A, 32B, and 32C flows from the right side to the left side on the wafer W, the temperature of the surface of the wafer W is set to the temperature of the immersion liquid DL, and the wafer W Rinse the upper bowl.

  FIG. 4 is a diagram showing a configuration of a wafer test system having a prober according to the second embodiment of the present invention. FIG. 4 corresponds to FIG. 2, and corresponding portions are denoted by the same reference numerals. The difference from the configuration of the first embodiment of FIG. 2 is that the nozzle 51 of the immersion liquid DL is provided in the probe 19 portion of the probe card 18. The immersion liquid holding member 31 has the same outer shape as that of the first embodiment, but the jet port 32 is not provided, and a plurality of inflow ports 33A and 33B (three or more) may be provided. The immersion liquid DL is supplied to the ejection port 51 from the immersion liquid source 34 via the path 37, and the immersion liquid DL is ejected from the ejection port 51 toward the surface of the device under inspection, that is, the device that is generating heat, and efficiently. Take the heat of the device. The immersion liquid DL ejected toward the surface of the device flows around the wafer W, passes through the inlets 33A and 33B of the immersion liquid holding member 31, and is collected by the immersion liquid source 34 via the path 38.

  As mentioned above, although the Example of this invention was described, it cannot be overemphasized that various modifications are possible.

  The present invention can be applied to any prober that inspects a wafer under a predetermined temperature condition. By applying the present invention, the temperature of a device to be inspected can be accurately set with a simple configuration.

It is a figure which shows schematic structure of a wafer test system provided with the prober which has a wafer temperature adjustment mechanism. It is a figure which shows the structure of the wafer test system of 1st Example of this invention. It is a figure which shows the structure of the modification of the immersion liquid holding member of the prober of 1st Example. It is a figure which shows the structure of the wafer test system of 2nd Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Wafer chuck 18 Probe card 19 Probe 21 Tester main body 31 Immersion liquid holding member 32 Jet outlet 33 Inlet 34 Immersion liquid source 35 Temperature control means 36 Filter DL Immersion liquid W Wafer

Claims (8)

A prober for connecting each terminal of the tester to an electrode of the semiconductor device in order to inspect a plurality of semiconductor devices formed on the wafer with a tester,
A probe card having a probe that contacts the electrode of the semiconductor device and connects the electrode to a terminal of a tester;
A wafer chuck for holding the wafer;
A prober, comprising: an immersion liquid source that supplies an electrically insulating and highly thermally conductive immersion liquid onto the wafer held by the wafer chuck.   2. The prober according to claim 1, further comprising a recovery unit that recovers the immersion liquid supplied onto the wafer held by the wafer chuck to the immersion liquid source.   The prober according to claim 2, wherein the recovery means includes a filter that removes foreign matter from the recovered immersion liquid.   4. The immersion liquid holding member that is provided around the wafer chuck and holds the immersion liquid so that the wafer held by the wafer chuck is immersed in the immersion liquid. 5. The prober described in 1.   5. The prober according to claim 4, wherein the immersion liquid holding member includes an inflow port that collects the immersion liquid in a portion surrounded by the immersion liquid holding member in the immersion liquid source.   6. The prober according to claim 4, wherein the immersion liquid holding member includes an ejection port that ejects the immersion liquid supplied from the immersion liquid source onto the wafer held by the wafer chuck.   The prober according to any one of claims 1 to 5, wherein the probe card includes a jet outlet that jets the immersion liquid supplied from the immersion liquid source onto the wafer held by the wafer chuck. Holding a wafer on which a plurality of semiconductor devices are formed on a wafer chuck,
The probe of the probe card connected to the terminal of the tester is brought into contact with the electrode of the semiconductor device,
A wafer test method for inspecting the semiconductor device by supplying power and an inspection signal from the tester to the semiconductor device and detecting an output signal from the semiconductor device,
A wafer test method comprising supplying an electrically insulating and high thermal conductivity immersion liquid onto the wafer held by the wafer chuck during inspection.

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