KR101144674B1

KR101144674B1 - Device for measuring thickness of wafer

Info

Publication number: KR101144674B1
Application number: KR1020110069817A
Authority: KR
Inventors: 서재석
Original assignee: 에스엔티코리아 주식회사
Priority date: 2011-07-14
Filing date: 2011-07-14
Publication date: 2012-05-24

Abstract

PURPOSE: An apparatus for measuring the thickness of a wafer is provided to measure wafer thicknesses having various diameters by changing the location of a probe according to the diameter of a wafer. CONSTITUTION: An upper plate(40) is combined with a plurality of guide shafts(41). A top moving plate(20) is prepared at a lower portion of the upper plate. A lower moving plate(30) is prepared at the lower part of the top moving plate. A measuring unit is composed of a lower probe and an upper probe. A driving device(100) measures the thickness of a wafer by running the top and lower probes.

Description

Wafer thickness measuring device {Device for measuring thickness of wafer}

The present invention relates to a wafer thickness measuring apparatus, and specifically, the thickness of a wafer positioned horizontally can be measured on both sides using probes at the top and bottom thereof, so that the thickness of the wafer can be measured more accurately, and the defect rate of the wafer can be measured. It relates to a wafer thickness measuring apparatus that can reduce the.

Resistivity measurement on semiconductor wafers is mainly measured by Four Point Probe (FPP) method, which has a close relationship with thickness and greatly affects precision and accuracy. In the conventional semiconductor wafer thickness measurement, the resistivity was calculated by measuring the thickness with a digital micrometer or a vernier caliper. However, the thickness measurement at the center position of the wafer is somewhat inconvenient and difficult to accurately measure. In addition, when using a digital micrometer, there is a concern about damage to the sample and difficulty in accurate measurement in order to measure the thickness at the center of the sample.

Therefore, there is a need for a thickness measuring apparatus that can accurately measure not only the central position of the semiconductor wafer but also the entire surface.

Patent Registration 10-0634763 The registered patent is configured such that the measuring body of the fixed body and the digital micrometer are opposed to each other, and the height adjusting unit freely moving the wafer up and down so that the center of the wafer is located at each electrode, and the measuring body and the fixing body are spaced apart from the wafer. Form a measuring transfer unit for freely moving the thickness measuring device to measure the thickness so as to form a space in which the position is located. However, the above-described patent is because the probe measures the thickness of the wafer only in one direction, if the foreign matter such as dust on the surface of the surface, the product is not defective, but will be judged as defective, and also the smooth bend of the entire wafer However, there is no problem in the case of cutting and using the same thickness to maintain the same thickness, so even if the semiconductor chip can be used, the thickness of the wafer is measured only at the top, so that it is judged to be defective, resulting in inferior economic efficiency.

The present invention has been invented to solve the above problems, the object of which consists of a structure for measuring the thickness of the wafer at the top and bottom at the same time, by configuring the LM guide on the probe to change the position of the probe according to the diameter of the wafer The purpose is to provide a wafer thickness meter capable of measuring the thickness of wafers of various diameters.

The present invention for achieving the above technical problem is provided at the top, coupled to the plurality of guide shafts provided in the edge region; The upper support unit is provided in the lower portion of the upper plate, the edge region is penetrated to the guide shaft, the upper support unit is provided with a ball screw nut at one end, and the first ball screw is penetrated to the ball screw nut, the upper and lower A moving upper plate; The lower support unit is provided in the lower portion of the upper moving plate, the edge region is penetrated and coupled to the guide shaft, and the lower support unit having a ball screw nut is coupled to one end thereof, and a second ball screw penetrates the ball screw nut. A lower moving plate coupled and moved up and down; A measuring unit including a lower probe coupled to the upper moving plate and an upper probe provided to face the lower probe and having one side coupled to one side of the lower moving plate; And driving means for measuring the thickness of the wafer by driving the upper and lower probes upward or downward, and a support unit coupled to each lower end of the guide shaft.

In one embodiment, the driving means, the upper and lower pulleys are provided on the first and second ball screw, coupled to the upper and lower; An upper control motor connected to the upper and lower timing belts and the upper and lower timing belts respectively coupled to the upper and lower pulleys to transmit power, and connected to the upper timing belts to control vertical movement of the upper moving plate; It is connected to the timing belt and includes a lower control motor for adjusting the vertical movement of the lower moving plate.

In one embodiment, the lower probe is formed in a predetermined length, the lower probe is divided into a horizontal portion and a vertical portion, the lower probe is supported on the end portion, fixed to the one side by the fixing means, vertical The upper probe is supported by a lower probe fixing block having a crank lever at the upper part, and the upper probe is formed to have a predetermined length, and is divided into a horizontal part and a vertical part, coupled to the vertical part, and slid up and down, and the upper probe at the end part. Is supported and supported by the upper probe fixing block fixed to the one side by the fixing means, characterized in that the vertical portion of the upper probe fixing block is coupled to the vertical portion of the lower probe fixing block by the LM guide.

In one embodiment, the upper and lower probes, characterized in that the radially centered around the center portion and the center portion with respect to the upper plate.

In one embodiment, the upper and lower probes, characterized in that the fixed position of the wafer is variablely installed.

According to the wafer thickness measuring apparatus of the present invention, first, it is possible to adjust the position of the probe can be applied to different diameter wafers.

Second, since the probe for measuring the thickness of the wafer is provided on the upper and lower parts, it is possible to measure the more accurate thickness, which is more convenient and accurate than the conventional thickness measuring method, where a lot of defects occurred in the precision measurement of the thickness. It can be effective.

Third, even if the wafer is slanted overall or there is foreign matter on the surface on which the wafer is placed, the wafer is inclined, so if the thickness is constant, the upper and lower probes measure the thickness, so the same value as the flat surface thickness is obtained. It can be used without processing the defects, thereby reducing the defective rate.

1 is a perspective view showing a state of the wafer thickness measuring apparatus of the present invention.
2 is a front view of FIG. 1.
3 is a side view of FIG. 1.
4 is a cross-sectional view taken along line BB.
5 is a cross-sectional view taken along line CC of FIG. 4.
6 is a perspective view showing the upper and lower probes of the wafer thickness measuring apparatus of the present invention.
7 is a view illustrating an operating state of the upper and lower probes of FIG. 6.

In order to fully understand the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. The embodiments of the present invention may be modified into various forms, and the scope of the present invention should not be construed as being limited to the embodiments described in detail below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and the like of the elements in the drawings can be exaggeratedly expressed to emphasize a clearer description. It should be noted that the same members in each drawing are sometimes shown with the same reference numerals. In addition, detailed descriptions of well-known functions and configurations that are determined to unnecessarily obscure the subject matter of the present invention are omitted.

Hereinafter, with reference to the accompanying drawings illustrating a preferred embodiment of the present invention, a wafer thickness measuring apparatus of the present invention will be described in detail.

1 is a perspective view showing a state of the wafer thickness measuring apparatus of the present invention, Figure 2 is a front view of Figure 1, Figure 3 is a side view of Figure 1, Figure 4 is a cross-sectional view taken along line BB, Figure 5 is a CC of Figure 4 6 is a perspective view illustrating the upper and lower probes of the wafer thickness measuring apparatus of the present invention, and FIG. 7 is a view illustrating an operating state of the upper and lower probes of FIG. 6.

1 to 7, the wafer thickness measuring apparatus of the present invention includes an upper plate 40 at an uppermost portion, an upper moving plate 20 at a lower portion thereof, and a lower moving plate 30 at a lower portion thereof.

The upper plate 40 is formed in a rectangular shape, and a through hole 42 for easily adjusting the position of the probes 210 and 220 to be described later is formed. In addition, the guide shaft 41 is coupled to the four corner regions, and the upper moving plate 20 and the lower moving plate 30 are sequentially penetrated to the guide shaft 41.

Meanwhile, first and second ball screws 21 and 31 coupled to the upper moving plate 20 and the lower moving plate 30 are respectively provided, and each of the ball screws 21 and 31 is connected to the upper plate ( 40 is fixedly coupled to the support unit 43. The first ball screw 21 is coupled to the upper moving plate 20 and the second ball screw 31 is coupled to the lower moving plate 30, and the first ball screw 21 faces each other in a diagonal direction. It is coupled to the upper moving plate 20 in the position, the second ball screw 31 is coupled to the lower moving plate 30 in a position facing each other in the diagonal direction.

Accordingly, the first and second ball screws 21 and 31 are coupled to the upper and lower moving plates 20 and 30, respectively.

The first ball screw 21 is coupled to the upper support unit 22 on the same line as the support unit 43, and a ball screw nut 23 is coupled to the support unit 22 to the first ball screw. It moves up and down along the outer peripheral surface of (21).

Like the first ball screw 21, the second ball screw 31 is also coupled to the lower support unit 32 on the same line as the support unit 43, and the support unit 32 has a ball screw. The nut 33 is coupled and moved up and down along the outer circumferential surface of the second ball screw 31.

In addition, the first and second ball screws 21 and 31 are coupled to the support unit 10 for coupling to semiconductor processing lines, various shelves, or equipment.

Meanwhile, the upper moving plate 20 and the lower moving plate 30 are further provided with a measuring unit 200 having an upper probe 210 and a lower probe 220 to measure the thickness of the wafer. The upper probe 210 and the lower probe 220 may be configured as a linear variable differential transformer (LVDT) for converting a minute mechanical displacement into an electrical signal.

In more detail, as shown in FIGS. 6 and 7, the measurement unit 200 includes an upper probe fixing block 212 having a crank lever 225 on the upper portion of the upper moving plate 20. It is penetrated through. The upper probe fixing block 212 includes a horizontal portion 223 and a vertical portion 224, and a lower probe 220 is provided at an end of the horizontal portion 223. In addition, the lower probe 220 is provided with a fixing means 221 to adjust the length to protrude to the top and bottom. The upper moving plate 20 has a through hole 26 for movement in a longitudinal direction of a predetermined section in an area where the crank lever 225 is coupled. This is to move the measurement unit 200 in accordance with the diameter of the wafer through the through hole 25 for movement.

The lower probe fixing block 222 is coupled to the vertical portion 224 of the upper probe fixing block 212. The lower probe fixing block 222 includes a horizontal portion 213 and a vertical portion 214, and the vertical portion 214 is coupled to the vertical portion 224 of the upper probe fixing block 212. An upper probe 210 is provided at the end of the horizontal portion 213, and the upper probe 220 is provided with fixing means 211 to adjust the length of protruding upward and downward.

In addition, the upper probe fixing block 212 and the lower probe fixing block 222 are coupled to each other by the LM guide 230, the LM guide 230 is coupled to one side of the surface of the lower moving plate (30).

The upper and lower probes 210 and 220 configured as described above are provided in plural radially with respect to the center portion and the center portion, to measure thicknesses of the center portion and the edge region of the wafer.

On the other hand, the driving means 100 is provided in each of the ball screw (21, 31), the upper and lower pulleys (101, 102) coupled to the upper and lower, and the upper and lower pulleys (101, 102) And upper and lower timing belts 111 and 112 coupled to each other.

The upper timing belt 111 is connected to the motor pulley 141 provided in the upper control motor 121 and the upper pulley 101 provided in the first ball screw 21 to drive the upper control motor 121. Accordingly, the first screw 21 is rotated, thereby moving the upper moving plate 20 up and down.

In addition, the lower timing belt 112 is connected to the motor pulley 142 provided in the lower control motor 122 and the lower pulley 102 provided in the second ball screw 31 to drive the lower control motor 122. As a result, the second screw 31 is rotated, thereby moving the lower moving plate 30 up and down.

In summary, the upper timing belt 111 drives the upper moving plate 20 and the lower timing belt 112 drives the lower moving plate 30 to surface the first and second ball screws 21 and 31. Each moving plate is moved up and down.

Meanwhile, the timing belts 111 and 112 are provided with two pairs of idlers 131, 132, 133, and 134 to more flexibly support the driving force transmitted from the upper and lower control motors 121 and 122. The idlers 131, 132, 133, and 134 are provided with upper and lower pulleys to be in line with the upper and lower timing belts 111 and 112. For convenience, the idlers 131, 132, 133, and 134 have a pair of idlers on the upper control motor 121 side as the first and second idlers 131, 132, and a pair on the lower control motor 122 side. The idlers will be referred to as third and fourth idlers 133 and 134.

The first and second idlers 131 and 132 are provided between the upper control motor 121 and the upper timing belt 111 to support the upper timing belt 111 to be smoothly rotated. The third and fourth idlers 133 and 134 are provided between the lower control motor 122 and the lower timing belt 112 to support the lower timing belt 112 to be smoothly rotated.

Accordingly, the upper pulleys of the first and second idlers 131 and 132 are directly connected to the upper timing belt 111, and the lower pulley is in the form of idling in contact with the lower timing belt 112. In addition, the lower pulleys of the third and fourth idlers 133 and 134 are directly connected to the lower timing belt 112, and the upper pulley is in contact with the upper timing belt 111 to be idling.

The operating state of the wafer thickness measuring apparatus of the present invention configured as described above will be described.

First, in order to measure the thickness of the wafer, unlock the crank lever 225 according to the diameter of the wafer loaded in the magazine and then move along the moving through hole 25 and lock the crank lever 115 to lock the probe 210. , 220) to adjust the position.

Thereafter, the wafer loaded in the magazine (not shown) is loaded on the surface plate 50 provided with a loading arm (not shown) between the probes, and the upper and lower control motors 121 and 122 operate to move the probe. Let's go.

Specifically, the upper probe 210 is the upper probe fixing block 212 is coupled to the lower moving plate 30 to be lowered by the driving of the lower moving plate 30, at the same time the lower probe 220 ) Is the lower probe fixing block 222 is coupled to the upper moving plate 20 to rise upward by the driving of the upper moving plate 20.

Here, the upper probe fixing block 212 and the lower probe fixing block 222 are relatively slid by the LM guide 230.

Therefore, according to the above-described driving, the upper probe 210 moves downward, and the lower probe 220 moves upward to contact the upper and lower portions of the same position of the wafer to measure the thickness of the wafer. Here, the reference for measuring the thickness of the wafer is, for example, by operating the upper and lower probes in the absence of the wafer to determine the contact point as a reference value, and based on the reference value, the difference between the values of the probe contacting the upper and lower parts of the wafer. The thickness of the wafer is measured by calculating. Therefore, even if there is a gentle curvature of the wafer, since the thickness is measured at the top and bottom, it can be determined that it is not a defect. In addition, even if the surface of the surface plate has foreign matter or the like and the wafer is in a finely excited state, the thickness is measured at the top and the bottom, so that it can be determined that the defect is not defective.

The embodiment of the wafer thickness measuring apparatus of the present invention described above is merely exemplary, and it is well understood that various modifications and equivalent other embodiments are possible to those skilled in the art. You will know. Therefore, it is to be understood that the present invention is not limited to the above-described embodiments. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims. It is also to be understood that the present invention includes all modifications, equivalents, and substitutes within the spirit and scope of the invention as defined by the appended claims.

10: support unit 20: upper moving plate
21: ball screw 22: upper support unit
23: ball screw nut 24: through hole
25: through hole for movement 30: lower moving plate
31: Ball screw 32: Lower support unit
33: ball screw nut 40: upper plate
41: guide shaft 42: through hole
43: support unit 50: surface plate
100: drive means 101: upper pulley
102: lower pulley 111: upper timing belt
112: lower timing belt 121: upper control motor
122: lower control motor 131: first idler
132: second idler 133: third idler
134: fourth idler 141, 142: motor pulley
200: measuring unit 210: upper probe
211: fixing means 212: upper probe fixing block
213: horizontal portion 214: vertical portion
220: lower probe 221: fixing means
222: lower probe fixed block 223: horizontal portion
224 vertical portion 225 crank lever
230: LM Guide

Claims

An upper plate 40 provided at an uppermost portion and coupled to a plurality of guide shafts 41 provided at an edge region;
The upper support unit 22 is provided at the lower portion of the upper plate 40, the edge region is penetrated through the guide shaft 41, and the upper support unit 22 is provided with a ball screw nut 23 at one end thereof. An upper moving plate 20 having a first ball screw 21 penetrated to the screw nut 23 and moving up and down;
The lower support unit 22 is provided at the lower portion of the upper moving plate 20, the edge region is penetrated and coupled to the guide shaft 41, and the lower support unit 22 is provided with a ball screw nut 33 at one end thereof. A lower moving plate 30 which is coupled to the ball screw nut 33 through a second ball screw 31 and is moved up and down;
The lower probe 220 is coupled to the upper moving plate 20, and the lower probe 220 is provided so as to face each other and one side is composed of an upper probe 210 coupled to one side of the lower moving plate 30 Measuring unit 200;
Driving means 100 for measuring the thickness of the wafer by driving the upper and lower probes 210 and 220 to the upper or lower and
Wafer thickness measuring apparatus characterized in that it comprises a support unit (10) for being coupled to the lower end of the guide shaft (41) to the equipment body.

The method according to claim 1,
The drive means 100,
Upper and lower pulleys 101 and 102 provided on the first and second ball screws 21 and 31 and coupled to upper and lower portions thereof;
Upper and lower timing belts 111 and 112 coupled to the upper and lower pulleys 101 and 102, respectively;
An upper control motor 121 and a lower timing connected to the upper and lower timing belts 111 and 112 to transmit power, and connected to the upper timing belt 111 to adjust a vertical movement of the upper moving plate 20. Wafer thickness measuring device, characterized in that it comprises a lower control motor (122) connected to the belt 112 to adjust the vertical movement of the lower moving plate (30).

The method according to claim 1 or 2,
The lower probe 220 is formed to a predetermined length, the lower probe 220 is divided into a horizontal portion 223 and a vertical portion 224, the lower probe 220 is supported at the end, It is fixed by the fixing means 221 on one side, supported by the lower probe fixing block 222 is provided with a crank lever 225 on the top of the vertical portion 224,
The upper probe 210 is formed to have a predetermined length, and is divided into a horizontal portion 213 and a vertical portion 214, coupled to the vertical portion 224, and slid up and down, and an upper probe 210 at an end portion thereof. Is supported, is supported by the upper probe fixing block 212 is fixed by the fixing means 211 on one side,
Wafer thickness measuring apparatus characterized in that the vertical portion 214 of the upper probe fixing block (212) is coupled to the vertical portion (223) of the lower probe fixing block (222) by the LM guide (230).

The method of claim 3,
The upper and lower probes 210 and 220,
Wafer thickness measuring apparatus characterized in that the radially centered on the center portion and the center portion with respect to the upper plate (40).

The method of claim 3,
The upper and lower probes 210 and 220,
Wafer thickness measuring apparatus characterized in that the fixed position is installed to be variable depending on the diameter of the wafer.