KR100764631B1 - Rounding shape processing method for tip of probe - Google Patents

Abstract

A method for rounding a probe tip is provided to shorten the time taken for a polishing process by preventing a probe from being separated from a polishing sheet until the final process is finished. A method for rounding a probe tip includes a first step of fixing probes(115) by fixing probe cards on which probe tips(115b) are positioned on the same plane, and a second step of rounding the probe tips by carrying out relative swirling movement between the probes and a polishing sheet(130) having a polishing layer(133) with polishing particles formed on a base sheet at the state where the probe tips contact the polishing sheet. In the second step, the degree of polishing is controlled by varying the contact load in accordance with the relative vertical position between the probe tips and the polishing sheet.

Description

ROUNDING SHAPE PROCESSING METHOD FOR TIP OF PROBE}

1 is a cross-sectional view showing the structure of a typical probe card,

2 and 3 are photographs showing an example of a probe tip shape of a typical probe card;

Figure 4 is a cross-sectional view showing a probe tip round shape processing method according to the prior art,

5 is a cross-sectional view showing a probe fixing step of the probe tip round shape processing method according to the present invention,

Figure 6 is a cross-sectional view showing a rotary polishing step of the probe tip round shape processing method according to the present invention,

7 and 8 are a perspective view and a schematic diagram for explaining the operation of the rotary polishing step of Figure 6, and

9A to 9B are photographs showing probe tips before and after round shape processing by the probe tip round shape processing method according to the present invention.

Explanation of symbols on the main parts of the drawings

10; wafer

11; Integrated circuit chip

13; Bond pad

110; Probe card

111; Probe card motherboard

113; Probe block

115; Probe

130; Polishing sheet

131; Base sheet

133; Abrasive layer

134; Abrasive particles

135; air gap

The present invention relates to a probe card for inspecting electrical properties of a wafer, and more particularly, a probe tip round shape for processing a tip portion of a probe in contact with a bond pad of an integrated circuit chip in a probe card in a round shape. probe tip round shape).

Integrated circuit chips formed on wafers through a fabrication process are classified into good and defective products through electrical die sorting (EDS). Typically, electrical characterization involves the tester, which generates the test signal and the resulting data, and the probe station, which electrically loads the wafer and allows the tester to perform the test, and the electrical connection between the wafer and the tester. Inspection equipment consisting of a probe card is used.

1 is a cross-sectional view showing the structure of a typical probe card. As the probe card used for inspecting the electrical properties of the wafer, as shown in FIG. 1, an epoxy resin (A) is formed on a probe block 313 of ceramic material fixed on a probe card main board 311. A cantilever method in which a needle-type probe 315 is fixed to the bond pad 13 used as an external connection terminal of the integrated circuit chip 11 by an epoxy resin (319). Probe card 310 is well known. The probe 315 contacts the bond pad 13 to make electrical connection between the tester (not shown) and the integrated circuit chip 11.

2 and 3 are photographs showing an example of a probe tip shape of a general probe card, and photographed after a certain period of use. As the probe card, it is well known that the probe tip has a flat shape as shown in the photograph of FIG. 2. However, as shown in the photograph, bond pad debris adheres, thereby increasing contact resistance and thus causing inspection failure. In order to solve this problem, a probe in which the probe tip portion has a round shape has been proposed. As shown in FIG. 3, a probe having a rounded tip portion does not significantly bond bond pad debris to the flat probe of a tip shape. Since there is almost no bond pad debris, there is no change in contact resistance. Therefore, it can be seen that more accurate inspection is possible by manufacturing and managing the shape of the probe tip in a round or semi round shape.

However, the probe card is not well known as a method of fixing a flat probe tip to a round shape or a semi round shape or a method of periodically maintaining the round or semi round shape. Conventionally, as a method for processing a probe tip round shape to maintain a tip cross section of a probe, a method of fitting each probe to an etching process is known, but the time required for this is not small.

Figure 4 is a cross-sectional view showing a probe tip round shape processing method according to the prior art. Alternatively, as shown in FIG. 4, the probe tip portion is repeatedly polished by repeatedly moving the probe 315 to the polishing sheet 330 on which the gel-like polishing layer 333 is formed on the base sheet 331. The probe pin round shape processing method which rounds 315b is known. However, this method increases the manufacturing cost of the probe card because it uses an expensive polishing sheet having a gel-like polishing layer.

Accordingly, an object of the present invention is to provide a probe tip round shape processing method capable of rapid polishing without using an expensive polishing sheet having an abrasive layer in the form of a gel in the rounding process of the tip portion of the probe. .

In order to achieve the above object, the present invention is a probe tip round shape processing method of a probe card having a plurality of probes in contact with the bond pad of the integrated circuit chip formed on the wafer, the plurality of probes on the same plane Fixing the probes by fixing the probe card in which the probe tip is positioned; Rotation of cutting the tip portion of the probe into a round shape by friction due to the relative rotational movement of the probe and the polishing sheet while the probe tip portion is in contact with the polishing sheet having the abrasive layer having abrasive particles formed thereon on the base sheet. It provides a probe tip round shape processing method comprising a; polishing step.

In the probe tip round shape processing method according to the present invention, the rotary polishing step preferably controls the polishing degree by changing the contact load by controlling the relative vertical position of the tip portion of the probe and the polishing sheet. As the polishing sheet used in the rotary polishing step, it is preferable to use a polishing sheet containing abrasive particles made of aluminum oxide (Al ₂ O ₃ ).

In addition, in the probe tip round shape processing method according to the present invention, the probe fixing step is preferably a step of fixing the probes to the probe block of the probe card in which the probes are actually installed. Here, the fixing of the probe may include removing a predetermined length from the probe tip.

Hereinafter, an embodiment of a probe tip round shape processing method according to the present invention will be described in detail with reference to the accompanying drawings. However, in the accompanying drawings, some components are somewhat exaggerated or schematically illustrated or omitted in order to help clearly understand the drawings.

Example

Figure 5 is a cross-sectional view showing a probe fixing step of the probe tip round shape processing method according to the present invention. Referring to FIG. 5, first, a probe fixing step is performed. The plurality of probes 115 are fixed to the ends of the probes 115 contacting the bond pads 13 for the external connection terminals of the integrated circuit chip 11 provided on the wafer 10. The fixing of the probes 115 may be performed by fixing the probes 115 to the probe block 113 of the probe card 110 in which the probes 115 are actually installed. The probe 115 is aligned and fixed on the probe block 113 in accordance with the arrangement position of the bond pads 13 formed on the integrated circuit chip 11 of the wafer 10 to be inspected. The fixing of the probe 115 may be performed at both the probe block level and the probe card level. Before fixing the probe 115 to the probe block 113, it is also possible to fix it by using a separate member that can fix the probes 115 in the probe manufacturing step.

The probe 115 may be manufactured using MEMS (Micro Electro Mechanical System) technology, or may be a probe having a flat cross-sectional tip by various methods such as punching or etching, or a round shape having a predetermined period after installation. It may be a probe having a tip of. The fixing of the probe 115 may include removing a predetermined length from the probe tip by polishing such that the ends of the probes are positioned on the same plane after the fixing of the probe 115.

Figure 6 is a cross-sectional view showing a rotary polishing step of the probe tip round shape processing method according to the present invention, Figures 7 and 8 are a perspective view and a schematic view for explaining the operation of the rotary polishing step of FIG.

6 to 8, a rotary polishing step is next performed. The polishing sheet 130 is fixed flat, and the polishing sheet 130 and the probe 115 are disposed so that the probe tip end surface 115a is parallel to the polishing sheet 130. In this case, the polishing sheet 130 is a polishing sheet having the polishing layer 133 formed on the base sheet 131 so that the polishing particles 134 have voids 135.

In this state, as shown in FIG. 7, the probe tip portion 115b is rounded and rounded by contact between the polishing sheet 130 and the probe tip portion 115b and relative rotational movement of the probe 115 and the polishing sheet 130. do. The probe tip portion 115b may be rounded by the entire turning motion with the probe 115 embedded in the polishing sheet 130 to a depth desired to be processed. In the repetitive turning motion, the probe tip portion 115b is polished by friction to the hatched portion as shown in FIG. 8.

Here, as the abrasive sheet 130, it is preferable to use an abrasive sheet formed of an abrasive layer on the base sheet by allowing the abrasive particles made of aluminum oxide (Al ₂ O ₃ ), which are frequently used for cleaning the abrasive or probe, to have voids. This polishing sheet is because the probe tip is not excessively worn. Of course, it is also possible to use abrasive sheets comprising other abrasive particles having a similar degree of polishing in addition to the aluminum oxide abrasive particles. Such abrasive sheets are currently known to be on the order of one hundredth as compared to abrasive sheets having a gel-type abrasive layer.

Meanwhile, the degree of polishing may be controlled by changing the contact load by controlling the relative vertical position of the probe tip portion 115b and the polishing sheet 130 in the rotation polishing process. Increasing the contact load between the polishing sheet 130 and the probe 115 increases the polishing degree of the probe 115, and decreasing the contact load decreases the polishing degree of the probe 115. By adjusting the degree of rounding by raising or lowering the height of the polishing sheet 130 in units of micrometers, the degree and shape of polishing of the probe tip portion 115b may be adjusted. As a result, the probe tip portion 115b may have a round shape or a semi-round shape in a flat shape and maintain the round shape of the probe tip portion 115b after a predetermined period.

In the above-described embodiment of the present invention, a rotary polishing apparatus may be used for rounding the probe tip. The polishing sheet may be attached to and fixed to the chuck of the rotary polishing apparatus. The probe card may be secured by a probe card holder of a rotary polishing device. The degree of contact between the probe and the polishing sheet can be controlled by the vertical movement of the chuck. If the chuck is raised to increase the degree of polishing, the contact area between the probe and the polishing sheet may increase, or the contact load may increase to increase the degree of polishing.

For example, a probe card including a probe having a flat tip portion is mounted in a holder of a rotary polishing apparatus. In accordance with the pivoting motion of the chuck, the polishing sheet makes a pivoting motion relative to the probe. As a result, the probe tip round shape processing is performed for the entire probe of the probe card. The tip portion is rounded as the abrasive layer rubs against the probe tip. Thereby, the shape of a probe tip part is processed into a round shape from a flat shape.

The polishing sheet is raised in micrometers by raising the chuck in micrometers. The shape or cross-sectional area of the probe tip can be managed and the degree of rounding can be adjusted according to the degree of elevation of the chuck and the polishing time. By adjusting the degree of polishing of the probe tip portion, processing such as round shape or semi-round shape is possible. Practical application has shown that the diameter of the flat probe tip can be reduced to 13 µm. Since the pivoting movement is performed around the probe, there is little change in the position of the X, Y, and Z axes on the probe block.

9A to 9B are photographs showing probe tips before and after round shape processing by the probe tip round shape processing method according to the present invention.

As shown in FIG. 9A, the tip of the probe is flat before the round shape of the probe tip, but after the round of the tip shape, the diameter of the probe is reduced and the end is rounded. While the diameter of a general probe was 25 micrometers, the probe tip round shape process by this invention was able to reduce the diameter of a probe to 13 micrometers.

Meanwhile, the probe tip round shape processing method according to the present invention may be performed in the process of installing the probe in the probe block. As is well known, the probe is a bending process, a hole forming process by film punching, a process of inserting into a hole on the film, a process of applying epoxy adhesive to fix the module block, a polishing process to match the height of the probe tip, a probe They are installed in the probe block through a masking process of aligning them, a process of soldering a probe to a substrate, and the like. After the height of the probe tip is adjusted by the polishing process, a round shape processing of the probe can be performed by performing a rotary polishing step.

According to the probe round shape processing method according to the present invention as described above, the tip portion round shape processing of the probes are made in a batch and the probe is not separated until the final polishing in contact with the polishing sheet. Therefore, the time required for polishing is short. In addition, it is possible to use a polishing sheet which is less expensive than a polishing pad having a gel type polishing layer. This can extend the life of the probe and reduce the cleaning cycle and contact resistance.

Claims (5)

In the probe tip round shape processing method of a probe card having a plurality of probes in contact with the bond pad of the integrated circuit chip formed on the wafer, Fixing the probes by fixing a probe card in which a plurality of probes are installed with the probe tip positioned on the same plane; In the state in which the probe tip portion is in contact with an abrasive sheet having an abrasive layer having abrasive particles formed on the base sheet with voids, the tip portion of the probe is trimmed by friction due to relative rotational movement of the probe and the abrasive sheet in a round shape. Rotating polishing step; Probe tip round shape processing method comprising a. According to claim 1, The rotating polishing step is a probe tip round shape processing method characterized in that for controlling the degree of polishing by changing the contact load by the relative vertical position control of the tip portion of the probe and the polishing sheet. According to claim 1, The polishing sheet in the rotary polishing step is a probe tip round shape processing method, characterized in that the polishing sheet containing abrasive particles of aluminum oxide (Al ₂ O ₃ ) material. According to claim 1, The probe fixing step is a probe tip round shape processing method comprising the step of fixing the probes to the probe block of the probe card in which the probes are actually installed. According to claim 1, The probe fixing step is a probe tip round shape processing method comprising the step of removing a predetermined length from the probe tip.

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