JPS58123403A - Method for detecting position of body - Google Patents

Abstract

PURPOSE:To detect the body whose angle is slightly deviated and whose position is slightly deviated, accurately in a short time, by using a random access type image pickup device, obtaining the maximum value among the integrated values of the rates of changes of the outputs obtained by performing the scanning in the directions of X axis and Y axis, obtaining the X and Y coordinates corresponding to that value so as to get the position expressed by the X and Y axes. CONSTITUTION:In consideration of the fact that there are many linear elements in an IC pattern, and by utilizing the characteristics that the random access type image pickup device can perform the zigzag scanning in the free directions, the edges of the body and the straight lines themselves can be detected as the variation in the products of the quantities of variations in a short time. Especially, in the case of the IC pattern, the position of each part of the pattern is accurately determined by an original drawing in advance by the preliminary learning of the sample pattern in order to keep repeating accuracy. Therefore the peak value, which can be clearly discriminated even though conditions are slightly expanded, can be selected.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for determining the position of an object, and particularly to a method for determining the position of an object.
The present invention relates to a method for automatically determining Y-seated posture using optical means.

For example, when processing an object using NO control, the position of the object to be processed is fRv? Accurate and fast discrimination is essential. Generally, these are moved by the t-No control of the workpiece itself, so originally
There are many cases where the Y value is known, or because the shape of the workpiece is constant, the XYIII value can be detected by physically touching a specific part of the workpiece, but on the other hand, In the case of the wire binding process in the manufacturing process, the pattern drawn on the chip is extremely accurate, but the process of cutting the chip and pasting it onto the metal substrate for the Sonatsu F bottle is inaccurate. Therefore, the shape of the chip and the position where the IC pattern is drawn vary not only in the ZY position but also in the angle, making it difficult to easily detect the position V. That is, as shown in the first WJ (&), a metal board [1 with 0 chips and 2
In order to take out the terminal with an accuracy of 3 to 4 μn when affixed and welded with the pace 5 provided on the IQ chip 2 and the wiring II 5 connected to the peripheral input/output bin 6 using a tube automatic pounding machine. For each pad 4 of 0 hands 2
It is necessary to accurately detect the digit M. Therefore, a method of detecting the position of the pad by double-image processing as shown in Fig. 1~) has been conventionally used. Initially set m value 'f: A part where the carpeting part (this corresponds to the metal part 4 of the pattern 0) continuously appears at a certain value or more is selected as a corner.

However, this method does not take into account the slope of the 0 pattern, so if the 0 pattern is
When scanning at an angle as shown in the figure, the TV output that exceeded the threshold value was obtained at the pad section 4 of P before the pad section 4 of A, which should be detected.
In other words, the direction of pad nourishment and Y
When detecting the edge III (X&tτ&) of the direction,
In the first scan shown in Fig. 1 (c-1), it passes through the top surface of the pad part 4 without twisting.
As shown in , there is a1gm? near the '1 position of edge 9 in one direction that should be detected. There is no Merukou τ7 output\. In the next scan (■), it does not touch the top surface of the person's pad part number, but it passes through the pad part 4 of B, so as shown in FIG. You can get a Tv output that exceeds all of the above, but this much W! I misidentify l as A's pad part hand. Moreover, even if there is no inclination as shown in FIG.
Microscopically, microscopically, there are many irregularities on the edges, and as shown in the fJ1 diagram (c-3), jaggies appear in the part that exceeds the threshold, and the Y coordinate of the pad part in A is not accurate. Even if it can be grasped, there is a drawback that the starting position of the X coordinate is likely to be inaccurate.

In addition, as a general method for image processing, a method has been developed in which a certain shape in a pattern, for example, the shape information of a pad with a specified size, is given in advance and the shape is searched from within the field of view. This method involves performing complex calculations using a medium-sized or large-sized computer over several minutes to several tens of minutes, and is not suitable for practical use because it takes too much time.

In detecting the position of this more precise pattern, the method is as simple as 1!
It is said that productivity will decrease if detection is not possible within several tens (IJ seconds to one hundred and several tens of milliseconds).

Further, the detection accuracy is required to be 2 to 3 μst. On the other hand, the actual work C pattern has a gate around the centrally swept gate.
There are many pads (metal parts) used for bonding, and there are many elements parallel to the X1m and Y axes. Many of them have hearths within the area.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional art, and to accurately and quickly calculate the number of patterns drawn on an object, such as an IO chip, whose angle or position is slightly deviated. The object of the present invention is to provide a method for detecting the position of an object.

In order to achieve the above object, a method for detecting the position of an object according to the present invention uses a random access type imaging device in an apparatus for detecting an X coordinate position tYt in a field of view of a plaster pattern including several linear elements. , (1) I in the field of view! Since it is obtained by scanning in the X-axis direction with a small displacement in the width direction from the likely position of the line element, the integral value of the rate of change of force (ζ, )' is memorized, and ■ Only a small step in the Y-axis direction is recorded. The integral value of the rate of change of the output obtained by moving the entire reading position and performing the same scanning tube as above (memorize S & R and perform the same process'g:
Repeatedly, the integral value of the output change rate (S&l 9 S&l
...), (3) Rotate the X-axis by a small angle at the τ-axis position where the maximum value was obtained, perform the same process as CL) (2) above, and obtain the integral value of the output change rate. (S,,# Sb
,...), and correct the angle at this time.
The direction of the x-axis is determined to be the direction of the x-axis.
Move by small steps in the axial direction, perform the process of CL)■, and obtain the integral value of the output change rate (S00.S.,・
), and find the first value (8°1
)) Select all and select xMfl corresponding to the numerical value (Bo, )
Let l be the X-axis position to be sought, β) Move minute steps from one end of the Y wheel to the τ axis perpendicular to the (s,,
, 咄) Find t-, select all values (), , ) that fall within the initial setting value llH and appear first, and set the Y-axis position ntt
-Characterized by seeking).

Here, the X-axis direction and the size of the minute steps in the X-axis direction need to be smaller than the detection accuracy. but,
If the detection accuracy is less than 1/100, it is not desirable because a very large number of scanning lines must be run until the X-axis position and Y-axis position are determined, which takes time. Further, when the amplitude exceeds the size of the minute step, there is WIIWl, which is preferably the same as or smaller than the size of the minute step, and preferably 1/10 or more of the size of the minute step.

The rotation angle depends on the width of the subject and the detection accuracy, and it is desirable that the moving distance m due to the rotation angle from the rotation center to the fastest end of the measurement object does not exceed the detection accuracy. In the process of (2) above. The number of repetitions is determined by the size and increments of the pads, and is usually several to several dozen times until an appropriate peak value is found.

Hereinafter, the implementation of the present invention will be explained with reference to the drawings.

Figure @2 is a functional block diagram of a C pattern reading system showing one embodiment of the present invention. , random access imaging device 1 in a stationary state
Read in 3. The position and direction to be read are determined via the controller 14 and interface 15'. Controlled by the Ikuma computer 16, the reading results also go through the same route! The data is input to the executor computer 16. The character display 7 and keyboard 6 are used as an operator console for setting initial values, etc.)
It will be done.

FIG. 3 is an explanatory diagram showing a method of reading the IC pattern in FIG. 2.

In Fig. 2, when the xC pattern 11 is moved under the field of view of the microscope 12, no problem will occur unless the arrangement of the xC pattern 11 is tilted at all like the view IF2O in Fig. 3. . However, as mentioned above, due to improper cutting of the chip and attachment to the chip substrate, the arrangement is often slightly tilted as shown in view f19.

Apparatus, i.e. random access imaging device 13
Since it is unclear whether or not they are arranged at the correct angle, first, the correct angle is checked. This angle check procedure is performed according to steps ① to ② in Fig. 3. First, scanning is performed in the X-axis direction from an appropriate position (3) within one field of view. In addition, the position ■ is as follows.
At the time of initial setting, it is desirable to select a position where the pad 4 is likely to be located, and also take into account the allowable range of position -2. When scanning in the direction of the X wheel from the position,
11 [Instead of M scanning] Lloyd's curve or zigzag line [Using the dawn direction (X-axis direction) with respect to the
Also, the magnification of the subject is converted to 'vr' and IC pattern 11
When scanning a uniform area as in the path (■), the output signal produced by this has relatively little change, but If scanning is performed from position ■, ■
As shown in the path, the total part of the pad part 4 and the base 5
The black part of the chip will be replaced and output, so 1. As a result, the output signal obtained is rich in variation.

Therefore, create a change t in the output by shifting the position W in the X-axis direction several to several dozen times. The integral value of the output change amount of the imaging device 13 when roofing is done along the routes of
Assuming that n is the maximum value of 5ar1, the position ■ in FIG. 3 can be detected. Note that the integral value S&U of the amount of change can generally be easily and quickly obtained by using an integrating circuit or the like. Amount of change B&! The peak value of i occurs when the path passes many edge portions of bad 4 of M, B, 0, . . . , and the scanning start position at that time can be found. Incidentally, if the scanning start position is further downward than ◯ in FIG. 3, the lower ends of the pads A, B, and O will be detected.

Next, in order to detect a more accurate direction than the current fixed scanning direction, after slightly rotating an appropriate point in the field of view 19 as a fulcrum, scanning is performed in the same direction from the previously determined position (2).

As before, find the integral value of the output change as 8 and U:・
1. Find the peak value of the integral value of the amount of change while completely shifting the position in the Y-axis direction. The integral value of 'bn becomes the largest value when the position and angle are ■, since Lfm of the pad portion 4 of M, B, O, . . . coincides with the important direction. This means that each scan W when the base 3 is rotated at a certain angle
This can be determined by comparing the amount of change in force Sゎ'``bn''``an...''. Is the angle at which the integral value of the output change is maximum the correct X-axis direction? At that time, the field of view becomes 20.

So, next, tjJ, I! 1iit-
demand. In the case of Fig. 3, one clear peak is obtained at the transition from background 8 to tip-base 3, and then A,
A second clear peak value is obtained at the position where the pad portions 4 of B, O, . . . are aligned. To distinguish between these two peak values, scan the entire sample pattern at the correct angle under the same conditions from one end in advance, check the magnitude of the peak value of each output change, and check the difference between them. After confirming that the second peak is within the upper and lower limits,
The upper average value S&E and the lower limit value 51m1□ are registered in the microcomputer 16 as initial values, and by comparing this with the peak value of is? distinguish.

In this way, the pad parts 4 of A, B, O... are aligned on the Y axis! ('8) is detected, next, the X-axis position M1. which is perpendicular to this is detected. In order to detect (XB), the peak n value of the integral value S of the amount of output change is obtained by scanning in the same manner in 3Pm steps in the Y-axis direction from the left end. In this case as well, one clear peak is obtained at the transition from 7-kei 8 to chip base 3, and then AI
A second clear peak value is obtained at the position ■ where the pad portions 4 of the DS cursor are aligned. Using the same method as before, calculate the maximum peak value of these 86□ and the upper limit S1, which was set in advance as the initial value. . Since the left end ■ where the pad portions 4 of A, D, I... are aligned is detected, this is set as the X-axis position t(X,)
shall be.

In this way, in FIG. 3, we focus on the fact that there are many linear elements in the 0 pattern, and take advantage of the characteristics of the random access imaging device 13 that allows it to scan in any direction with a trochoidal curve or a zigzag curve. Edges and straight lines of objects can be detected in a short time as changes in the amount of change. In particular, in the case of a pattern with 0 work, in order to maintain repeatability of 1, by learning from a sample pattern in advance, the positions of each part of the pattern are accurately determined in advance by the original drawing, so It is possible to select a peak value ' that can be clearly distinguished even if the conditions are expanded.

As explained above, according to the present invention, even if an object is slightly angularly or misaligned, its position can be detected accurately and in a short time, and especially in the case of an IO chip, the position of a pattern drawn therein can be detected accurately and in a short time. can be exactly 115, so 10
It is possible to improve the yield of @ manufacturing process.

5. Detailed Description of the Invention Figure 1 is an explanatory diagram of a method for detecting the position of a pattern of light variation;
Figure 2 shows an Xa pattern reading system showing an embodiment of the present invention.
FIG. 3 is an explanatory diagram showing a method of reading the IC pattern in FIG. 2.

ll: 10 patterns, 12: li microscope, 13: random access imaging device, 14: controller, 15
: Inter 7 Ace, 16: Microcomputer, 1
7: Character display, 18: Keyboard, 3
: Chip base, 4: Pad part, 8: Background, 19, 2
0: field of view.

Patent applicant Mitsubishi Rayon Co., Ltd. Kinsha, 7゜, □1. ;-
−1゜Patent Attorney Masaru Isomura (゛璽

Claims (1)

[Claims] In an apparatus for detecting an Xτ coordinate position in a field of view of an image pattern including a plurality of linear elements, a random access type image carrier device is used to (L) Scan in the X-axis direction with a small displacement, calculate the integral value (8,,) of the rate of change of the output obtained by the scan,
c2) Move the reading position in small steps in the Y-axis direction,
Obtain the integral value of the output change rate (sa, I'& 8...) obtained by performing the same scan as in α) above, and calculate the integral value of the output change rate (S, 1. Sas...) Find the maximum value of @, rotate the X-axis by a small angle at the Y-axis position corresponding to the maximum value, - Same as α) ■ above - IJl! ! Then, calculate the maximum value of the integrated value of the output change rate ("bl l 'bl...), determine the angle at this time as the correct X-axis direction, and (a) move the X-axis from one end of the field of view. Step by step in the direction, perform the same process as α)c2) above, calculate all the integral values of the output change rate (S00.Sa,...), and make sure that the integral values are initialized in advance. The first greeting value (5o1) that is within the range of the upper and lower limits
) as the X-axis position to find the X-coordinate corresponding to the integral value (scp). , perform the same processing as α)12) above, and obtain the integral value of the output change rate (
S , S ...), and the value (SIip) where the integral 41 is included in the range of initial setting value < 11, is and appears first (SIip)
Select Th, and Y seat a corresponding to the number (3o)! - A method for detecting the position of an object, characterized by determining the desired Y-axis position.