JPH02176406A - Position adjusting apparatus - Google Patents

Abstract

PURPOSE:To align the position of a bump measuring line with a scanning line simply and highly accurately by obtaining a correcting angle formed between a line including the top points of a bump line and the scanning line, and turning a table by the correcting angle. CONSTITUTION:A table 21 on which an IC wafer 10 is attached is provided so that the table can be turned in the X-Y directions with pulse motors 22-24. The light from a semiconductor laser 31 is projected on the top of a bump 14a of the IC wafer 10. The reflected light is detected by a position detecting element 34. The detected signal is operated in a position operating circuit 40. The coordinates of the top are specified. The coordinates of the top of a bump 14b are specified in a similar way. An angle theta between a line connecting the tops of both bumps 14a and 14b and a scanning line is computed. The pulse motor 24 is driven with the signal from a microcomputer 100. The table 21 is turned by a correcting angle. Thus the position of the measuring line can be aligned with the scanning line.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a height measurement method that measures the height of an object such as a bump on an IC wafer using a non-contact displacement meter that applies triangulation. The present invention relates to a system, and particularly relates to a position adjustment device suitable for adjusting the measurement position of the object in the height measurement system.

(Prior art) Conventionally, in this type of height measurement system, the height of a series of bumps aligned on an IC wafer is measured using a non-contact displacement meter that applies triangulation after adjusting the measurement position. There are some devices that measure the
2-277504).

(Problem to be Solved by the Invention) However, in such a configuration, since there is variation in the position of the bump rows with respect to the outer diameter of the IC wafer for each IC wafer, the bump rows are determined based only on the outer diameter of the IC wafer. By simply adjusting the row by one, it is not possible to properly align the bump row with respect to the measurement position determined by scanning with the non-contact displacement meter, resulting in positional deviation. Therefore, even if you try to perform scanning measurement using a non-contact displacement meter under such conditions, the measurement error will become large, or several scans will be required to scan the required measurement position, making the measurement time-consuming. . To correct this, it is possible to add an image processing device using a television camera or a special position adjustment device featuring positioning marks to correct the above-mentioned positional deviation, but this is costly. become.

Therefore, in order to cope with this problem, the present invention adjusts the measurement position of the object to be measured in the height measurement system.
It is an object of the present invention to provide a position adjustment device that can perform position adjustment simply and with high precision.

(Means for Solving the Problems) In order to solve the problems, the configuration of the present invention, as illustrated in FIG. a table 2 on which a plurality of rows of objects 1 are placed and supported movably and rotatably within a plane; and a table 2 that is driven to move within the plane. a first driving means 3 for rotating the table 2 in the plane; and a second driving means 3 for driving the table 2 to rotate on the plane.
a driving means 4; and a height measuring means 5 that receives a reflected light beam from the surface of the object 1 when the light beam is incident on the surface of the object 1, and measures the height of the height measuring section according to the displacement of the light receiving position. and the first driving means 3 moves the table 2 so that the height measuring means 5 scans two height measuring parts located apart from each other in the measurement row with its light beam, In addition, when the respective heights of the two height measuring sections are respectively determined according to the measurement results of the height measuring means 5 while the table 2 is moving, the positions of the table 2 are determined based on the respective determination results. The angle formed by the determining means 6, a scanning line on the surface of the object 1 to be scanned by the light beam of the height measuring means 5, and a line including each of the determined positions according to each of the determined positions is defined as a correction angle. A correction angle determining means 7 for determining the correction angle is provided so that the second driving means 4 rotates the table 2 by the correction angle.

(Function) By configuring the present invention in this way, the first driving means 3 moves the table 2 so that the height measuring means 5 scans the two height measuring sections of the measuring row with its light beam. In the process of moving, when the position determining means 6 determines the respective heights of the two height measuring parts according to the measurement results of the height measuring means 5, each position of the table 2 is determined based on the respective determination results. is determined, and the correction angle determining means 7
According to each of these determined positions, the angle formed by the scanning line and a line including each of the determined positions is determined as a correction angle, and the second driving means 4 rotates the table 2 by the correction angle.

(Effect) This allows you to
Moreover, without scanning the entire surface of the object with the height measuring means 5, the measurement row can be easily and quickly aligned with the scanning line with high precision.

This means that this type of device can be provided as a device capable of high-speed measurement at low cost and with high precision.

(Example) Hereinafter, one example of the present invention will be described with reference to the drawings.
In the figure, reference numeral 10 indicates an IC wafer, and reference numeral 2 indicates an IC wafer.
0 indicates a position adjustment mechanism for the IC wafer 10. The position adjustment mechanism 20 has a table 21 on which the IC wafer 10 is placed, and this table 214 has imaginary, XY
Can move in the X and Y directions within a plane, and can move in the same X and Y directions.
It is supported so as to be able to rotate within a plane based on its rotation center. The table 21 also has each pin 11°1.
2.13 are provided, and each of these bins 11°, 12.
Reference numeral 13 positions the IC wafer 10 by contacting the positioning end surface of the IC wafer 10.

The pulse motor 22 functions to reciprocate the table 21 along the Y direction. The pulse motor 23 is connected to the table 21
It functions to move back and forth along the X direction. Further, the pulse motor 24 functions to rotate the table 21 within the XY plane.

The non-contact displacement meter 30 is fixedly supported directly above the table 21, and is composed of a semiconductor laser 31, a biconvex lens 32° 33, and a position detection element 34. has been done. The semiconductor laser 31 is
A laser beam is generated, passed through a convex lens 32, and is incident on the upper surface of the IC wafer 10 in an inclined manner under the condensing effect. The convex lens 33 condenses the reflected light beam of the laser beam incident on the upper surface of the IC wafer 10 and makes it enter the light receiving surface of the position detection element 34 as a spot light. The position detection element 34 is P
The position detection element 34 is composed of an element having a one-dimensional light-receiving surface made of SD, and the position detection element 34 detects the difference between the reference point on the light-receiving surface and the point of incidence of the spot light on the light-receiving surface. , displacement id), respective light-receiving currents llI2 are generated from both terminals thereof. However, the displacement d is
It is proportional to the height of any of the bumps on the top surface of the IC wafer 10.

The displacement calculation circuit #140 calculates each light receiving current 11. from the position detection element 34. I2 difference ΔI (=It I2),
The sum ΣI (=11 + 12) of each light-receiving current, I2, is calculated, and the displacement amount d is calculated based on Δ■/Σ■ for d=, and this calculation result is generated as a displacement signal. The A-D converter 50 digitally converts the displacement signal from the displacement calculation circuit 40 and generates a digital signal. The encoder 60 detects the rotation angle of the pulse screw 23 corresponding to the moving distance of the table 21 in the X direction, and sequentially generates a number of pulses corresponding to the detection result. On the other hand, encoder 7
0 detects the rotation angle of the pulse motor 22 corresponding to the moving distance of the table 21 along the Y direction, and sequentially generates a number of pulses corresponding to the detection result. However, K represents a linear correction coefficient.

Pulse counter 80 counts the number of a series of pulses from encoder 60 and generates a count signal. On the other hand, the pulse counter 90 counts the number of a series of pulses from the encoder 70 and generates a count signal. The microcomputer 100 follows the flowchart shown in FIG.
In cooperation with the A-D converter 50 and both pulse counters 80 and 90, calculation processing necessary for drive control of each drive circuit 110, 120, 130 connected to each pulse motor 22, 23, 24, respectively is performed. However, - the above-mentioned computer program is stored in the ROM of the microcomputer 100 in advance.

In this embodiment configured as described above, when the device of the present invention is put into operation, the microcomputer 100 starts executing a computer program in step 200a according to the flowchart of FIG.
In step 220, the displacement amount data Daaxa is cleared to zero. Furthermore, when the present invention is put into operation as described above, the laser beam generated from the semiconductor laser 31 of the non-contact displacement meter 30 is transmitted to the convex lens 32.
and enters the upper surface of the IC wafer 10. Then, this incident light flux is reflected by the upper surface of the IC wafer 10, passes through the convex lens 33, and enters the light receiving surface of the position detection element 34 as a spot light. However, it is assumed that the IC wafer 10 is positioned based on each of the fixed bins 11, 12, and 13, as shown in FIG. Next, when the position detecting element 34 generates each light receiving current 11°I2 in relation to the position of the incident spot light, the displacement calculation circuit 40 calculates the difference ΔI (=I+I2) between the respective light receiving currents from the position detecting element 34. ) and the sum of each light receiving current ΣI (=It +12 ), d=
The displacement amount d is calculated based on Δ■/Σ and generated as a displacement amount signal, and the A-D converter 50 generates the displacement amount signal as a digital signal and provides it to the microcomputer 100.

After the arithmetic processing in step 220, the microcomputer 100, in step 230, converts the table 21 into y
A y-axis stop direction movement signal is generated to move the table 21 in the y-axis stop direction by a predetermined amount Δy. move it. However, the predetermined amount Δy corresponds to the rectangular area A (the rectangular area A) required for scanning the bumps 14a in one bump row 14 (see FIGS. 5), the length in the y-axis direction yo (for example, 400 (μ
Corresponds to the value obtained by dividing m)) by the predetermined number of times n.
, and are stored in advance in the ROM of the microcomputer 100.

As described above, when the IC wafer 10 and the table 20 move by a predetermined amount Δy in the y-axis stop direction, the microcomputer 100 converts the value of the digital signal from the A-D converter 50 into the y-direction displacement amount in step 240. At the same time, the count value of the pulse counter 90 based on the rotation angle detection result of the encoder 70 for the pulse motor 22 is stored as
Store it as the amount of movement in the y direction of the table 21, and step 2
At 50, it is determined that it is rNOJ. Thereafter, at each step 230 until the determination at step 250 becomes rYES,
The cyclic operations at ~250 are repeated until IC wafer 1
0 and the table 21 are repeatedly moved in the y-axis stopping direction by a predetermined amount Δy, and the y-direction displacement amount and the y-direction movement amount are sequentially stored in the same manner as described above.

After that, the microcomputer 100 performs step 26.
0, the maximum value of the y-direction displacement amount for n1 in step 240 is set as y-direction displacement amount data Dmax, and haxa (・0) in step 220 and of the y-direction displacement amount data Dmax in step 260 are set. The larger value of is updated as Dmaxa, and the position (Xa, Ya) of the table 21 corresponding to this larger value is determined and stored. Next, in step 280, the microcomputer 100 moves the table 21 by a predetermined amount Δ in the X-axis direction.
Generates an X-axis stop direction movement signal to move by X,
In response to this, the pulse motor 23 is driven by the drive circuit 120 to move the table 2 by a predetermined amount ΔX in the X-axis stopping direction.
Move 1. However, the predetermined amount ΔX is
This corresponds to a value obtained by dividing the axial direction X0 (for example, 400 (μm)) by a predetermined number of times nb, and is stored in advance in the ROM of the microcomputer 100 together with the predetermined number of times nb.

Therefore, the microcomputer 100 performs step 2.
At 90, a y-axis negative direction movement signal is generated to move the table 21 in the y-axis negative direction by a predetermined amount Δy, and in response, the pulse motor 22 is driven by the drive circuit 110 to move the table 21 in the y-axis negative direction. The table 21 is moved by a predetermined amount Δy. Next, in step 300, the microcomputer 100 stores the value of the digital signal from the A-D converter 50 as the amount of displacement in the y direction, and stores the count value of the pulse counter 90 as the amount of movement in the y direction. rNc) at 310. Thereafter, the cyclic operations in each step 290 to 310 are repeated until the determination in step 310 becomes "rYES".
The C wafer 1o and the table 21 are repeatedly moved in the negative direction of the y-axis by a predetermined amount Δy, and the amount of movement in the y-direction and the amount of displacement in the y-direction are sequentially stored in the same manner as described above.

After that, the microcomputer 100 performs step 32.
0, the maximum value of the y-direction displacement amount for n8 in step 300 is set as y-direction displacement amount data Dmax, and in step 330, D@ in step 270 is set.
The larger one of axa and D++ax in step 320 is updated to Dmaxa, the position (xb, yb) of the table 21 corresponding to this larger value is determined and stored, and in step 340, the X-axis stop direction movement signal is updated. occurs,
In response to this, the pulse motor 23 moves the table 21 along with the IC wafer 10 by a predetermined amount ΔX in the X-axis stopping direction, as described above. Thereafter, until the determination at step 350 becomes rYESJ, the cyclic operation through each step 230 to 350 is repeated to achieve substantially the same effect as described above.

As explained above, in scanning the rectangular area A including the bump 14a, in the calculation process passing through each step 230 to 350, the rectangular area A is scanned along the solid line in the direction of the arrow as shown in FIG. The table 21 is moved together with the IC wafer 10 by Δy in the y-axis stopping direction, by Δχ in the X-axis stopping direction, and by Δy in the negative y-axis direction so as to be scanned by the parallel light beam from the convex lens 3'2. Then, based on the updated displacement amount data Dmaxa in step 330 immediately before the determination rYES in step 350,
Since the position of the table 21 is determined by the coordinates (Xa, ya) at that time, the maximum value of the displacement amount signal from the displacement calculation circuit 40, that is, the maximum value of the height of the bump 14a is determined at the vertex of the bump 14a. The position is specified by coordinates (xa, ya).

After determining rYESJ in step 350, the microcomputer 100 determines that bump row 1 is rYESJ in step 360.
An X-axis negative direction movement signal is generated to move the table 21 along the X-axis to a position where the bump 14b of No. 4 can be scanned, and in response to this, the pulse motor 23 is driven by the drive circuit 120. Table 21 and IC wafer 10
and move it in the negative direction of the X-axis. However, it is desirable that the distance L between the bumps 14b and 14a (see FIG. 4) be as large as possible. Next, in step 370, the microcomputer 100 obtains the displacement data Dm
axb is cleared to zero and the computer program proceeds to table position calculation routine 380.

Therefore, in this table position calculation routine 380, when scanning another rectangular area (substantially the same as the rectangular area A) including the bump 14b on the upper surface of the IC wafer 10, the calculation processing in each step 230 to 350 is performed. Perform substantially the same calculation processing. That is, in order to scan the other rectangular area with the parallel light beam from the convex lens 32 in the same way as in the case of the rectangular area A, in the y-axis stopping direction, by Δy,
The table 21 is moved together with the IC wafer 10 by ΔX in the X-axis stopping direction and by Δy in the negative y-axis direction, and the table 21 is moved by Δχ in the X-axis stopping direction for a predetermined number of times nb.Updated immediately before finishing moving the table 21 by Δχ in the X-axis stopping direction. Displacement amount data Dmaxb (Dmax
Since the position of the table 21 is determined by the coordinates (xb, yb) at that time, the maximum value of the displacement signal from the displacement calculation circuit 40, that is, the bump 14b
The position of the vertex of the bump 14b that has the maximum height is the coordinate (xb).

yb).

After that, the microcomputer 100 performs step 39.
0, the correction angle θ is calculated based on the following equation (1) according to both coordinates (xa, ya) and (xb, yb).

θ=jan”! (xb-xa)/(yb-ya)
)...(1) Here, the correction angle θ is defined as follows. As shown in FIG. 6, both coordinates (x
a.

Both bumps 14 specified by ya), (xb, yb)
The vertices of a and 14b are represented by A' and B', and the line parallel to the reference line (parallel to the X axis) passing through the point of incidence on the wafer 10 of the parallel light beam from the convex lens 32 is represented by S. Then, the angle formed between the straight line connecting both vertices A and A' and the reference line S is defined as the correction angle θ. Note that equation (1) is stored in advance in the ROM of the microcomputer 100.

Next, the microcomputer 100 performs step 40.
0, the calculated correction angle θ is generated as a correction angle signal, and in response to this, the pulse motor 24 is driven by the drive circuit 130, and the table 21 is moved by the correction angle θ to the IC wafer 10.
Rotate together.

As a result, both vertices A' and B' are located on the parallel line S. After that, microcomputer 100
However, in step 410, the correction angle θ and both coordinates (xa, y
a), (xb, yb), both points A based on the following equation (2)
, B are calculated.

For example, by substituting x' = xa and y' - ya in equation (2), it is determined as (X, Y) = (XA, YA). Also, if the coordinates and marks of point B are (Xa, YB), then in equation (2), χ"""Xb and Y'"
By substituting Yb, it is determined as (X, Y)=(XB, YB). Note that equation (2) is determined by the geometric relationship between both vertices A'' and Bo, and both points A, B, and θ shown in FIG. 6, and is stored in advance in the ROM of the microcomputer 100.

Therefore, the microcomputer 100 performs step 4.
At step 20, based on the calculation result at step 410, a y-axis direction correction signal is generated for aligning both vertices A' and B' with the reference line after being corrected by θ as described above;
In response to this, the pulse motor 22 is driven by the drive circuit 110 to move the table 21 together with the IC wafer 10 in the y-axis direction so that each vertex of both bumps 14a, 14b is positioned on the reference line. Thereby, the bump array 14 can be positioned on the scanning line of the parallel light beam from the convex lens 32.

As can be easily understood from the above explanation, the positions of the vertices of the two bump rows 14a and 14b separated from each other in the bump row 14 of the IC wafer 10, and the correction made between the line including each vertex and the parallel line S. By measuring the angle, each vertex of both bumps 14a, 14b is aligned with the reference line, so there is no need to employ a special position adjustment device and without scanning the entire top surface of the IC wafer 10. The alignment of the bump row to the reference line can be easily and quickly performed with high precision. As a result, this type of device can be provided as a low-cost, high-accuracy, high-speed measurement device that can scan each bump row in one scan.

Note that in implementing the present invention, the position detection element 34 is not limited to a PSD, and may be configured by a CCD. Further, instead of each of the pulse motors 22 to 24, a DC servo motor or an AC servo motor may be used.

Further, in the above embodiment, the case where the center of rotation of the IC wafer 10 is known has been described; however, the center of rotation of the IC wafer 10 is not limited to this.
Even when the center of rotation of the C wafer 10 is unknown, the same effects as in the embodiment described above can be achieved. In such a case, steps 230 to 3 are also performed for both points A and B on the above-mentioned parallel line S.
50 is performed to obtain the coordinates (XA, YA), (XB, YB) of each position.
) to determine.

Further, in carrying out the present invention, the present invention can be applied not only to the bumps of the IC wafer 10 but also to objects having various height measuring parts such as alignment marks on the wafer.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the claims, FIG. 2 is a block diagram showing an embodiment of the present invention, and FIG. 3 is a flow chart showing the operation of the microcomputer shown in FIG.
FIG. 4 is an enlarged view of the bump rows on the IC wafer, FIG. 5 is an explanatory view of bump scanning, and FIG. 6 is an explanatory view for determining the correction angle. Explanation of symbols in FIG. 1 10... IC wafer, 14... Bump row, 14a,
14b... Bamboo, 21... Table, 22.23
．． 24...Pulse motor, 30...Non-contact displacement meter, 4
0...Displacement calculation circuit, 60.70...Encoder, 80.90...Pulse counter, 100...Microcomputer. Figure 4 Figure 5

Claims (1)

[Claims] A table on which an object is placed and is supported so as to be movable and rotatable within a plane, on which a plurality of measurement rows in which a series of height measurement parts are arranged in a straight line are formed parallel to each other on the surface. a first driving means for driving the table to move within the plane; a second driving means for driving the table to rotate within the plane; and a first driving means for driving the table to rotate in the plane; height measuring means for receiving the reflected light beam from the same surface when the light beam is incident thereon, and measuring the height of the height measuring section according to the displacement of the light receiving position; The first driving means moves the table so as to scan two height measuring sections located apart from each other in the measurement row, and the measurement result of the height measuring means is controlled while the table is moving. a position determining means for determining each position of the table based on the respective determination results when each height of the two height measuring units is respectively determined according to the above, and the height measuring means according to each of the determined positions correction angle determining means for determining, as a correction angle, an angle between a scanning line on the surface of the object to be scanned by the light beam and a line including each of the determined positions; A position adjustment device configured to rotate the table by the correction angle.