JPH1092885A - Wafer probing apparatus and method of cleaning it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly test a wafer and clean the apparatus by melting and polishing bump dust deposited to the top end of a probe. SOLUTION: After testing a semiconductor wafer, a polishing board stage 13 is moved just below a card stage 1, a probe 3 is aligned with a polishing board 14 by a drive unit 8a, the board 14 is heated by a controller 18 which switches on and off a feed power to a heater 16 according to electric signals of the temp. of a thermocouple 17 to control for a const. temp. of the board 14 and contacts the probe 3 to the board 14. When the probe top end dirtied with bump dust contacts the beard 14, the temp. near the probe top end rises to melt the bump dust wetting the surface of a metal layer 14b which absorbs the dust to result in a clean surface of the probe 3. Thus it is possible to easily clean the wafer probing apparatus for a short time and test the wafer quickly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a wafer probing apparatus and a cleaning method thereof, and more particularly to an improvement in cleaning of a probe.

[0002]

6 to 9 are views for explaining a conventional wafer probing apparatus and a cleaning method thereof. As shown in FIG. 6A, a probe card 2 is mounted on a card stage 1 of a wafer probing apparatus. The probe 3 made of a tungsten needle is fixed to the probe card 2. The wafer stage 5 is fixed on the stage base 4. For example, a semiconductor wafer (hereinafter, referred to as a wafer) 6 is held on the wafer stage 5. On the wafer 6, bumps 7 made of, for example, solder (hereinafter, referred to as solder bumps) are formed. The card stage 1 is moved by the driving device 8 in the vertical direction in FIG.

FIGS. 6 (b) to 6 (d) and FIGS. 9 (a) to 9 (c)
7 shows a case where the tip of the probe 3 is spherical, and FIGS.
FIG. 9D shows a case where the surface is almost flat. The number of probes 3 provided on one probe card 2 is 200 to 30
In many cases, the number is zero, and in some cases, the number is 1000 or more.

[0004] The procedure and the state of contacting the probe 3 with the bump 7 during the inspection of the wafer 6 (hereinafter referred to as wafer inspection) will be described. As shown in FIG. 6B, the solder bump 7 and the probe 3 are aligned and in contact. As shown in FIG. 6C, the wafer 6 is moved upward together with the wafer stage 5 in the figure to further ensure the contact. The bump 7 changes from the position of the dotted line 7a to the position of the solid line 7b, and the probe 3 is pushed by the bump 7 to the position of 3b from the position of 3a. At this time, bump 7
The probe 3 b is pushed into the bump 7 because of its softness. For example, the solder bump 7 is formed to a height of about 50 μm by plating, and the probe 3 is
The wafer 6 is further raised by 50 μm from the position where the wafer 6 comes into contact. Under these conditions, the tip of the probe 3 has a maximum of 10 μm.
m. When the solder bumps 7 are not reflowed, the solder bumps 7 are composed of solder particles having a maximum particle size of about 5 μm. Under the above conditions, as shown in FIG. 6D, the solder particles (hereinafter, referred to as bump dust) 9 are easily peeled off from the grain boundaries and adhere to the tip of the probe 3.

[0005] As shown in FIG.
The bump waste 9 has adhered to c. As shown in FIG. 8, when the distal end face 3c of the probe 3 is further enlarged, in addition to the large bump dust 9a, countless fine bump dust 9b adheres.

On the other hand, the pad is made of aluminum (hereinafter referred to as Al).
As described above, when a large number of chips are inspected, Al debris and Au debris become bump debris 9 and become bump debris 9 when the bump is made of gold (hereinafter referred to as Au).
Is dirty. Alternatively, a current flows through the probe 3 to generate heat, and as a result, a thin oxide is formed at the tip of the probe 3. That is, the electrical and mechanical contact with the Al pad and the Au bump becomes insufficient, and the inspection becomes impossible.

As shown in FIG. 9, in order to avoid this, every time a certain number of chips are inspected, the tip of the probe is polished with a ceramic grindstone 10 made of alumina or the like to remove deposits and oxides. Had been removed.

A method of cleaning the conventional wafer probing apparatus will be described. As shown in FIG. 9A, first, the wafer 6 is replaced with a ceramic grindstone 10 formed of, for example, alumina ceramic.
The probe 3 is brought into contact with the ceramic grindstone 10. Thereafter, as shown in FIG. 9B, the ceramic grindstone 10 is moved in the vertical direction in FIG. 6 between the position of the dotted line 10a and the position of the solid line 10b further raised.
When the bump dust 9 is Al or Au, the deposits and oxides are polished and removed by friction between the tip of the probe and the ceramic grindstone 10. This cleaning method is common to probes having a spherical tip and a flat tip.

[0009]

However, in the above configuration, as described above, the bump debris 9 adhering to the spherical tip of the probe 3 is removed by the ceramic as shown in FIGS. 9 (c) and 9 (d). There is a problem that it is not removed except in the region where it is in contact with the grindstone 10.

[0010] Particularly, similarly, in the case of a bump formed mainly on lead (hereinafter referred to as Pb) / tin (hereinafter referred to as Sn) on an aluminum (Al) pad,
Bump dust adheres to the tip of the probe 3. In particular, in this case, the tip of the probe 3 is easily stained because the hardness of the bump is small and the malleability is large. Further, the ceramic grindstone 10
When a bump material containing Pb / Sn as a main component is used even in a region where the bump material contacts Pb / Sn, the bump material attached to the tip of the probe 3 has a large malleability. Cannot be easily removed. At this time, if the bump dust 9 mainly composed of Pb / Sn remains at the tip of the probe 3 without being completely removed, cleaning of a dirty probe may be impossible. In addition, there are cases where wafer inspection becomes impossible. An object of the present invention is to provide a wafer probing apparatus capable of inspecting a wafer in a short time and an easy and short cleaning method thereof.

[0011]

Means for Solving the Problems In order to solve the above problems and achieve the object, the following means are taken in a wafer probing apparatus and a cleaning method thereof according to the present invention. (1) A wafer probing apparatus according to the present invention, wherein when inspecting a semiconductor device having bumps, a stage arranged to face a holding means for holding an inspection probe that contacts the bumps. And a polishing plate held on the stage and in contact with the probe. Temperature detection means for detecting the temperature of the stage, a heater attached to the stage, and controlling power supply to the heater in accordance with the temperature detected by the temperature detection means; A controller for raising the temperature of the plate.

In the wafer probing apparatus of the present invention, since the probe is polished by melting the bump debris attached to the tip of the probe, the hardness is small.
Cleaning is surely performed even for bump debris made of a material having high malleability. Therefore, semiconductor wafer inspection is not impossible. In addition, since cleaning is easily performed in a short time and is easily automated, semiconductor wafer inspection is completed in a short time, which is effective for cost reduction.

Further, as set forth in claim 2, the polishing plate includes a metal polishing plate base and a metal layer formed on a surface of the polishing plate base with a metal having a melting point higher than that of the bumps. Consists of

In the wafer probing apparatus of the present invention, the degree of wettability with the bumps attached to the probe can be easily determined by selecting the metal of the metal layer of the polishing plate regardless of the base material of the polishing plate. Can be set to Therefore, the extent to which the melted bump debris spreads on the surface of the metal layer is optimized, and the probe is relatively cleanly cleaned. Further, the time required for cleaning is reduced.

Further, as set forth in claim 3, the metal layer of the polishing plate contains at least one of tin, copper, lead, nickel and gold. In the wafer probing apparatus of the present invention, since the metal layer of the polishing plate contains any of tin, copper, lead, nickel, and gold, the wettability with the bump attached to the probe is reduced. Good. Therefore, the degree of the melted bump dust spreading on the surface of the metal layer is good, and the probe is relatively cleanly cleaned. Further, the time required for cleaning is reduced.

Further, in any one of claims 1 to 3, holding means for holding a semiconductor wafer including the semiconductor device is attached to the stage via a connecting portion of a heat insulating structure.

In the wafer probing apparatus of the present invention, the probe can be easily cleaned at any time while the semiconductor wafer is inspected, so that the cleaning can be performed frequently, and the accuracy of the semiconductor wafer inspection can be improved. Is improved. Further, the flexibility of operation at the time of semiconductor wafer inspection is increased, and the time required for semiconductor wafer inspection can be reduced. (2) In the cleaning method of the wafer probing apparatus according to the present invention, the polishing plate is heated, and the polishing plate is brought into contact with a probe for inspecting a semiconductor wafer. Thereafter, the polishing plate is pressed against the probe from the contact position.

In the method of cleaning a wafer probing apparatus according to the present invention, the contact between the probe and the polishing plate and the temperature rise of the polishing plate are simultaneously performed.
The cleaning of the wafer probing device is performed in a shorter time than before.

According to a sixth aspect of the present invention, in the cleaning method of the wafer probing apparatus, the polishing plate is heated,
Thereafter, the polishing plate is brought into contact with a probe for inspecting a semiconductor wafer, and the polishing plate is pressed against the probe from the contact position.

In the method for cleaning a wafer probing apparatus according to the present invention, the temperature of the polishing plate is raised in advance, for example, during a semiconductor wafer inspection. Be shortened.

[0021]

Embodiments of the present invention will be described below with reference to the drawings. 6 and 9 are denoted by the same reference numerals. FIG. 1 is a view showing a configuration of a wafer probing apparatus according to an embodiment of the present invention, and FIG. 2A is a sectional view taken along line 2a-2a in FIG.
FIG. 2B is a cross-sectional view taken along line 2b-2b in FIG. 3 (a) to 3 (c) and 4 (a) to 4 (c) are enlarged views of the distal end portion of the probe 3, and are views for explaining the embodiment of the present invention.

As shown in FIG. 1, a stage base 4a is mounted on a moving rail 12 on a stage base movable base 11.
Is arranged. A wafer stage 5 on which a wafer 6 is fixed is arranged on a stage base 4a.
The card stage 1 on which the probe card 2 on the left side of the wafer stage 5 in FIG. 1 is mounted is mounted on a driving device 8a. Dotted line 1 under card stage 1
A polishing plate stage indicated by reference numeral 3 is arranged, and a dotted line 1
The polishing plate indicated by 4 is fixed. Stage base 4a
A drive device (not shown) is attached to
2A, the probe 3 and the wafer 6 or the polished plate are moved by moving in the vertical and horizontal directions in FIG. Position adjustment is performed. Further, the card stage 1 is moved in the up, down, left, and right directions by the driving device 8a, and the position thereof is finely adjusted.

The configurations of the card stage 1 and the wafer stage 5 are the same as those of the related art. The difference from the related art is mainly about the polishing plate stage 13, and the difference will be described below.

As shown in FIG. 2A, the polishing plate stage 13 is fixed to the stage base 4a via a connecting portion 15. A heater 16 and a thermocouple 17 are attached to the polishing plate stage 13. A polishing plate 14 is fixed on the polishing plate stage 13.

As shown in FIG. 2B, the polishing plate 14 on the polishing plate stage 13 is composed of a polishing plate base material 14a made of, for example, copper (hereinafter referred to as Cu) and a metal layer 14b thereon. The controller 18 controls electric power to the heater 16 by an electric signal corresponding to the temperature supplied from the thermocouple 17. The metal layer 14b may be a metal coating or a metal sheet formed by forming a metal film on the surface of a thin polyimide film or an acrylic film. The advantage of this sheet is that it can be easily replaced when it has deteriorated and workability is good. Polyimide film is a heat insulating material,
Its thickness is, for example, about 100 μm, and does not hinder the heat conduction.

The metal layer 14b on the surface of the polishing plate substrate 14a
Is formed by a method of electroless plating, vapor deposition, sputtering, or the like using a metal having Pb / Sn as a main component and having good wettability with the bump material 9 in FIG. 3A, for example, Sn. I have. This metal layer 14b prevents an oxide film from being formed on the surface of copper in the air, thereby preventing the wettability with the bump material from being deteriorated. Further, the polishing plate 14 may be formed by depositing or sputtering Cu or Sn on a ceramic plate or the like. The metal layer 14b is not limited to Cu and Sn, but may be Pd, nickel (hereinafter, referred to as Ni), Au, or the like.

The polishing plate stage 13 is made of aluminum having a good thermal conductivity.
It is good to be formed with. The polishing plate stage connecting portion 15 between the stage base 4a and the polishing plate stage 13 is thin so that heat does not easily escape, and a metal member having relatively low thermal conductivity such as stainless steel is used. That is, the stage base 4a and the polishing plate stage 13
(Hereinafter referred to as a heat insulating structure). In addition, the polishing plate stage connecting portion 15 may have a structure in which a plurality of cylindrical metals having a small cross-sectional area perpendicular to the direction in which heat escapes from the polishing plate stage 13 to the stage base 4a are bundled to improve the heat insulation effect. .
The heat insulating material may have a honeycomb structure. When inspecting the wafer, the wafer stage 5 holding the wafer 6 to be inspected and the card stage 1 are aligned, and the inspection is performed using the probe 3.

An operation of cleaning the probe 3 using the apparatus having the above configuration and a method thereof will be described. After inspecting a certain number (for example, 500) of chips, that is, a semiconductor wafer inspection, as shown in FIGS. 1 and 2 (b),
The polishing plate stage 13 is moved directly below the card stage 1. As shown in FIG. 3A, the position of the probe 3 and the polishing plate 14 are aligned by the driving device 8a, and the temperature of the polishing plate 14 is raised by the controller 18 in FIG.
The controller 18 interrupts the power supply to the heater 16 in accordance with the temperature electric signal from the thermocouple 17, and controls the temperature of the polishing plate 14 to be constant. Then, the probe 3 and the polishing plate 1
And 4.

Subsequently, as shown in FIG. 3C, the contact state between the probe 3a and the polishing plate 14c indicated by a dotted line is reduced by 50%.
The polishing plate 14d is moved via the polishing plate stage 13 to a position indicated by a solid line 14d about μm to 100 μm above. Further, the vertical movement between the position of the dotted line 14c and the position of the solid line 14d of the polishing plate is repeated.

As shown in FIG. 4A, when the tip of the probe 3 soiled with the bump dust shown by the dotted line 9c contacts the polishing plate 14, the temperature near the tip of the probe 3 rises. And
As shown by the solid line 9d, the bump debris is melted and wetted by the polishing plate 14 as shown by the solid line 9e, and the metal layer 14 on the surface of the polishing plate 14 is removed.
b. Further, when the polishing plate 14 is moved up and down, in addition to the friction between the tip of the probe 3 and the polishing plate 14, that is, polishing, the bump dust adhering to the tip of the probe 3 is surely melted and wet on the surface of the metal layer 14b. It will be sucked. Therefore, as shown in FIG.
All the bump debris at the tip is removed, and the tip of the probe 3 is cleaned. When the tip of the probe is flat, the cleaning is performed in the same manner. And FIG.
As shown in (c), the bump debris at the tip is removed and becomes clean.

The temperature of the polishing plate 14 is set to a temperature at which the bump debris melts and wets the metal layer 14b. That is, the metal layer 14b is formed of a metal having a melting point higher than the melting point of the bump dust. For example, when the bump material is a solder having a eutectic composition of Pb / Sn, its melting point is 183 ° C.
4b has a melting point higher than at least 183 ° C., for example, an indium-based metal, such as Cu, Sn, Pd, Ni,
It is formed of any one of Au. Alternatively, alloys of these and other metals may be used. The temperature of the polishing plate 14 is preferably higher than the melting point of the eutectic solder, for example, around 200 ° C. The temperature of the polishing plate 14 differs depending on the bump material. The melting point of the above metal at 1 atm is 108 for Cu.
4.5 ℃, 327.5 ℃ for Pd, 1455 ℃ for Ni, Au
1064.43 ° C.

In the wafer probing apparatus according to the embodiment of the present invention, the probe 3 having high hardness and being easily contaminated is used.
When the bump dust 9 adheres to the tip, the bump dust 9 is melted and the probe 3 is polished. Therefore, the bump dust 9 made of a material having low hardness and high malleability, such as a bump material mainly composed of Pb / Sn, is used. The cleaning of the wafer probing device is reliably performed. Therefore, the inspection cannot be disabled. In addition, the cleaning is performed easily and in a short time, is easily automated, and does not affect the wafer inspection, which is effective in reducing the cost. Further, the metal layer 14b of the polishing plate 14 is independent of the polishing plate base 14a.
By selecting the metal, the degree of wettability with the bump debris 9 attached to the probe 3 can be easily set. The degree to which the melted bump dust 9e spreads on the surface of the metal layer can be optimized. That is, when a metal having good wettability with the bump dust 9 is used for the metal layer 14b, the melted bump dust 9 spreads on the surface of the metal layer 14b, and the probe 3 becomes more clean.

In the method of cleaning a wafer probing apparatus according to the embodiment of the present invention, the positioning of the probe 3 and the polishing plate 14, their contact, and the polishing plate 1 are performed.
Since the temperature increase of 4 is performed at the same time, the cleaning of the wafer probing apparatus is performed in a shorter time than before. Therefore, the time required for wafer inspection is reduced. (Modification) FIG. 5 is a diagram showing a configuration of a modification of the wafer probing apparatus according to the above embodiment.

The configuration of this modification is almost the same as that of the embodiment. The difference is that, as shown in FIG. 5, the polishing plate stage 13 is attached to the wafer stage 5 holding the wafer 6 via the inter-stage connecting portion 19,
This is a point attached to the stage base 4b. The distance between polishing plate stage 13 and wafer stage 5 is relatively small. The inter-stage connecting portion 19 has a heat insulating structure, similarly to the polishing plate stage connecting portion 15 described above. That is, a thin metal member such as stainless steel having a relatively small thermal conductivity is used so that heat is hard to escape. In this case, both the wafer stage 5 and the polishing stage 13 move up and down.

The cleaning method of this embodiment is performed, for example, between semiconductor wafer inspections. At this time, the polishing plate 1 is passed through the polishing plate stage 13 together with the semiconductor wafer inspection.
4 is heated. Subsequently, similarly to the above-described embodiment, the cleaning of the probe 3 is performed by this apparatus. That is, the vertical positioning of the probe 3 and the polishing plate 14 is performed simultaneously with the wafer stage 5, and the horizontal positioning in FIG. 1 is performed by moving the stage on the stage movable base 11 in FIG. adjust. Further, fine adjustment is made by moving the card stage 1 up, down, left and right by the driving device 8a. Then, the polishing plate 14 is brought into contact with the probe 3 and polished.

The effect of the wafer probing apparatus of the above modification is almost the same as that of the embodiment, but the probe 3 can be easily cleaned at any time while the wafer 6 is inspected. It is also possible to improve the accuracy of wafer inspection. It is not necessary to align the probe 3 and the polishing plate 14 in the vertical direction by moving the stage on the stage movable table 11, and the time required for wafer inspection is saved. Further, since the flexibility of the operation at the time of the wafer inspection is increased, the time required for the wafer inspection can be reduced.

In the method of cleaning a wafer probing apparatus according to the above-described modified example, since the wafer inspection by the probe 3 and the temperature rise of the polishing plate 14 are performed simultaneously, the cleaning time of the probe 3 is further reduced. In addition, the time for wafer inspection is further reduced.

[0038]

As described above, according to the present invention, it is possible to provide a wafer probing apparatus capable of inspecting a wafer in a short time and a method of cleaning the wafer probing apparatus easily and in a short time.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a wafer probing apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a wafer probing apparatus according to an embodiment of the present invention.

FIG. 3 is a view for explaining a cleaning method of the wafer probing apparatus according to the embodiment of the present invention.

FIG. 4 is a view for explaining a cleaning method of the wafer probing apparatus according to the embodiment of the present invention.

FIG. 5 is a sectional view illustrating a modification of the wafer probing apparatus according to the embodiment of the present invention.

FIG. 6 is a diagram illustrating a conventional wafer probing apparatus and a cleaning method thereof.

FIG. 7 is a diagram illustrating a wafer probing apparatus according to the present invention and a conventional example.

FIG. 8 is a diagram illustrating a wafer probing apparatus according to the present invention and a conventional example.

FIG. 9 is a diagram illustrating an example of a conventional wafer probing apparatus and a cleaning method thereof.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Card stage, 2 ... Probe card, 3 ... Probe, 4, 4a, 4b ... Stage base, 5 ... Wafer stage, 8, 8a ... Driving device, 13 ... Polishing plate stage, 14 ... Polishing plate, 14a ... Polishing plate Substrate, 14b: metal layer, 15: polishing plate stage connection portion, 16: heater, 17: thermocouple, 18: controller, 19: interstage connection portion.

Continuing on the front page (72) Eiichi Hosomi Inventor Toshiba Research and Development Center, Komukai Toshiba-cho, Kawasaki City, Kanagawa Prefecture (72) Inventor Yoichi Hiruda 1 Komukai Toshiba-cho, Saiwai-ku, Kawasaki City, Kanagawa Prefecture Address Toshiba Research & Development Center Co., Ltd. No. 1 In the Toshiba R & D Center (72) Inventor Kazuhide Doi 1 in Komukai Toshiba-cho, Sachi-ku, Kawasaki-shi, Kanagawa Prefecture In-Toshiba R & D Center (72) Inventor Naohiko Hirano, Kawasaki-shi, Kanagawa 1, Komukai Toshiba-cho, Ward Inside Toshiba R & D Center

Claims (6)

[Claims] When inspecting a semiconductor device having a bump, a stage arranged opposite to holding means for holding an inspection probe that comes into contact with the bump; and a stage held on the stage and in contact with the probe. A polishing plate, a temperature detecting means for detecting a temperature of the stage, a heater attached to the stage, and controlling power supply to the heater in accordance with the temperature detected by the temperature detecting means. A controller for raising the temperature of the polishing plate through the wafer probing apparatus. 2. The polishing plate comprises a metal polishing plate base and a metal layer formed on the surface of the polishing plate base with a metal having a melting point higher than that of the bumps. The wafer probing apparatus according to claim 1. 3. The polishing plate according to claim 1, wherein the metal layer comprises tin, copper,
3. The wafer probing apparatus according to claim 2, comprising at least one of lead, nickel, and gold. 4. The stage according to claim 1, wherein holding means for holding a semiconductor wafer including the semiconductor device is attached to the stage via a connection part of a heat insulating structure. 2. The wafer probing apparatus according to 1. 5. A wafer probing apparatus, comprising: raising a temperature of a polishing plate, bringing the polishing plate into contact with a probe for inspecting a semiconductor wafer, and then pressing the polishing plate against the probe from the contact position. Cleaning method. 6. A wafer probing apparatus, comprising: raising a temperature of a polishing plate; thereafter, bringing the polishing plate into contact with a probe for inspecting a semiconductor wafer; and pressing the polishing plate against the probe from the contact position. Cleaning method.