JPH0499320A - Automatic centering method for wafer protective tape - Google Patents

Abstract

PURPOSE:To prevent the protective tape at a peripheral edge from protruding due to eccentricity when the protective tape having nearly the same size as that of a wafer is pasted by a method wherein an eccentricity amount with reference to a reference length and an eccentricity amount from a reference line are computed by using a microcomputer from the distance between detections by means of a position detection sensor. CONSTITUTION:The winding amount of a conveyance tape 3 is advanced by a distance of P+ X from a distance of S by using detection sensors 5A, 5B; the tape is once stopped. On the other hand, while a grit 7 as one example of a suction body of a wafer 1 is being advanced by a distance of L to its negative direction, it corrects + or - Y and is stopped. Then, the grit is situated on the same core as that of a protective tape 2 on the conveyance tape 3. While a suction force is being made to act, the conveyance tape 3 and the suction grit 7 are moved to the positive direction at the same speed. Then, the protective tape 2 is stripped from the conveyance tape 3. When the suction grit 7 corrects + or - Y and is stopped at the distance of L, it is returned to its original position. Thereby, the pasting operation of a wafer 1 and the protective tape 2 is started on the same core.

Description

Detailed Description of the Invention <Industrial Application Field> The present invention is related to the manufacture of ICs and LSIs, and is used to protect the wafer surface and prevent cracks or breakage of thin wafers in the process before polishing the backside of the wafer. In the process of attaching protective tape (e.g. PvC laminated tape) to the wafer surface for prevention purposes, an automatic centering method that increases the accuracy of aligning and attaching the protective tape, which has an outer circumference approximately the same size as the wafer, and fully automates this process. Regarding.

(Prior Art) In the past, after adhesive tape was attached to a wafer by hand, the tape was cut to fit the outer circumference of the wafer.

It should be noted that attempts have been made to semi-automatically or automatically attach adhesive tape that has been adjusted to the outer circumference of the wafer, but in this case,
One of the problems is the accuracy of pasting dimensions.

Problems to be Solved by the Invention In the above conventional method, when a protective tape of the same size as the wafer is attached, the tape protrudes at the peripheral edge due to eccentricity. causing the destruction of

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an automatic centering method that prevents the peripheral edge of the tape from protruding due to eccentricity when a protective tape of approximately the same size as the wafer is attached.

<Means for solving the problem> The means for solving the problem according to the present invention is as shown in Fig. 1.2.3.
A plurality of circular protective tapes 2 cut in advance to approximately the same size as the circular wafers 1 are arranged in a column on a conveying tape 3 at regular intervals in a peelable manner, and the conveying tape 3 is intermittently conveyed. The transport direction is the X axis and the perpendicular direction PY
If the axis is defined as an axis, two position detection sensors 5A and 5B are arranged in the Y-axis direction with an interval close to the radius R of the circular protective tape 2, and the X-axis direction passing through the center of these sensors 5A and 5B is the reference point. The line xo-xo is defined as the distance from the center position of the protective chip 12 detected during transportation to the center position where it is temporarily stopped, and the circular periphery of the protective tape 2 is defined as one of the position detection sensors 5A and 5B. is detected, then the other of the position detection sensors 5A and 5B detects, and the reference length P is determined by the distance S between the detections of these position detection sensors 5A and 5B.
Eccentricity -ΔX and reference line xo-x with respect to.

This method uses a microcomputer to calculate the eccentricity 1±ΔY from .

<Effect> In the above problem solving means, the detection sensor 5A.

5B, the winding amount of the transport tape 3 from the distance S is P + constant, /
) If the grid 7, which is an example of the suction body for the wafer 1, moves in the negative direction a distance of L while correcting ±△Y and then stops, the conveyance can be stopped at a distance of ΔX of m. It is located between the protective tape 2 and the tape 3.

Here, if the transport tape 3 and suction grid 7 are moved in the positive direction at the same speed while applying suction force, the protective tape 2 will be peeled off from the transport tape 3 and the suction grid 7 will be
After correcting ΔY and stopping at a distance of L, it returns to its original position, and the wafer 1 and protective tape 2 begin to be lazily pasted here.

<Example> Hereinafter, an example of the present invention will be described based on FIG. The conveying tape 3 is arranged in a column at regular intervals and releasably attached, and this conveying tape 3 connects a first pulse motor 4 (which can correct the eccentricity ΔX described later), a take-up roller 4A, a conveyance guide 4B, and a guide roller 4.
If the conveyance direction is the X-axis and the direction perpendicular to the X-axis is the Y-axis, two position detection sensors 5A are placed in the Y-axis direction at an interval close to the radius R of the circular protective tape 2.
, 5B, and this sensor 5A.

5B is the reference line X0-XO, the distance from the center position of the protective tape 2 detected during transportation to the center position where it is temporarily stopped is the reference length P, and the circular periphery of the protective tape 2 is defined as the reference line X0-XO. is detected by one of the position detection sensors 5A and 5B, and then by the other of the position detection sensors 5A and 5B, and the distance S between the detections of these position detection sensors 5A and 5B is determined relative to the reference length P. Eccentricity - ΔX
And the eccentricity 1±ΔY from the reference line xo-xo is calculated by a microcomputer.

Then, at a grid 7, which is an example of an adsorbent for the protective tape 2 between the wafer 1 and the wafer 1, which is located at a specific distance on the reference line xo-xo, a second pulse for driving the adsorption grid 7 Motor 8, feed screw 8A, nut body 8B, moving guide i ellipse 8C1 moving plate 8D, board 8E and third pulse motor 9, feed screw 9A, nut body 9B, moving guide mechanism 90, moving plate 9D and board 9E This is corrected by a device consisting of:

That is, the suction grid 7 moves the door concentrically with the protective tape 2 and stops, and the suction grid 7 peels off the protective tape 2 from the transport tape 3 and adsorbs it to the wafer 1 waiting at its original position. Ylll of eccentricity by a specific distance to the position
1 Correct the eccentricity 〒ΔY (the x-axis eccentricity is corrected by the first pulse motor) and return.

When pasting the protective tape 2 onto the surface of the wafer 1, in order to prevent air bubbles from entering the pasting surface and wrinkles from forming on the protective tape, air bubbles generated from the pasting press rubber roller 10, the protective tape 2, and the surrounding area are prevented. The electrostatic force between the protective tape 2 and the breath rubber roller 10 is utilized.

An air cylinder 11 (this includes a movement guide mechanism 110, a movement plate 11
D, the stroke of the tape (combined with the substrate 11E) can be adjusted according to the thickness and diameter of the protective tape 2, and the height difference t between the lower surface of the breath rubber roller 10 and the suction surface of the suction grid 7 can be selected. It is said that

As shown in Figures 2 (a) and (b), when the protective tape 2 is applied, the starting end is supported in a cantilevered manner, resulting in a distorted surface that hangs and waves due to the influence of the electric field strength, etc. In the first stage, the breath rubber roller 10 is moved by an air cylinder 11 to a height difference t (for example, 0.1 mm) with respect to the suction grid surface.
(below), the starting end 2A of the protective tape 2 is attracted to the breath rubber roller 10 by electrostatic force, as shown by the dotted line in FIG.

Next, as shown in FIG. 2(C), the air cylinder 1 shown in FIG. 1 moves up and down the suction grid 7 and the breath rubber roller 10.
2 (this is combined with the movement guide mechanism 12C1, the movement plate 12D, and the substrate 12E), the roller support frame IOA supporting the breath rubber roller 10 is pressed against the starting end of the wafer 1 with its own weight adjusted appropriately. At this time, a suitable distance U between the grid 7 and the wafer 1 is 0.05 mm.

As shown in FIG. 2(D), the table 13 of the wafer 1 is horizontally moved by a device consisting of a fourth pulse motor 14, a feed screw 14A, a nut body 14B, a movement guide mechanism 14C, a movement plate 14D, and a substrate 14E. Paste.

The protective tape 2 is precisely die-cut to match the size of the wafer 1, and in order to match their peripheral edges, it is necessary to match their center points. 1st
In the figure, a wafer 1 is waiting for a protective tape 2 to be applied on a predetermined reference line xo-xo. The center position of the wafer 1 and the center of the protective tape 2 to be adsorbed to the adsorption grid 7 (connected to a vacuum pump) coaxially and perpendicularly to the center position are located on the same axis.

On the other hand, the peripheral edge of the protective tape 2 on the transport tape 3 is detected by the detection sensor 5A5B at each position during transport, and the eccentricity in the X direction is 10ΔX and the eccentricity in the Y direction is ΔY according to the distance S between them. Determine.

The diameter 2R of the protective tape 2 and the distance a between the circumferential edges of the protective tapes 2, 2 are appropriately determined, and 2R+a=P.The detected protective tape 2 is located at the reference line xo-x.

If the center points coincide on the line, that is, if ΔX=O, then all you have to do is advance a distance of P and stop. If there is an eccentricity of ΔY, just move P plus ΔX and you will reach the predetermined position. Stop at.

The calculation standard is that if the circle O on the reference line in Figure 3 is eccentric to the circle C, then the average point d' of the detection points in the X direction is ΔX shorter than the detection line d for the eccentricity of △Y. Become.

That is, from FIG. 1, ΔX=dd' This equation (1) applies when the distance between the detection sensors 5A and 5B is chosen to be the radius of the protective tape 2 -R.

△Y=○C is guided.

FIG. 4 shows the amount of eccentricity ΔXmm with respect to the detected value Smm, and FIG. 5 shows the amount of eccentricity ±ΔYmm with respect to the detected value Smm.

Distance from the detection point on the reference line xo-xo determined from the measured values S detected by the position detection sensors 5A and 5B to the protective tape 2 at which it is temporarily stopped while the transport tape 3 with the protective tape 2 arranged is moving. P, at this time, the distance from the stop position to the center of the wafer 1 where the protective tape 2 is waiting and the accuracy of the arrangement interval of the detection sensors 5A, 5B must both be kept within ±0.01 mm from the viewpoint of processing technology. is easy, and the accuracy of the grid holding device 7A that performs corrective positioning of the suction grid 7 that holds the protective tape 2 under suction is also ±0.
01mm is obtained.

In addition, in the embodiment of the present invention, the position detection sensors 5A, 5
For B, a reflection type photoelectric switch was used, and when precision was required, a laser type photoelectric switch was used.

The minimum spot diameter of the light beam is 0.03 mm for the former and O for the latter.
,01mm, repeatability is 0.003~0゜001mm
Although we used the one that is easily available on the market, higher accuracy can be obtained by using a more accurate one.

Describing one process of this device, the suction grid 7 of the detection sensor 5 Eva 1 moves a distance L in the negative direction, corrects ±△Y, and stops, then the protective grid 7 on the conveying tape 3 2 and is located on the anniversary.

Here, if the conveyance team 13 and suction grid 7 are moved in the positive direction at the same speed while applying suction force, the protective tape 2 is peeled off from the conveyance tape 3 and the suction grid 7 is
After correcting ΔY and stopping at a distance of L, it returns to its original position, and here the pasting of the wafer 1 and the protective tape 2 is started.

In the present invention, when automating the manufacturing process of ICs and LSIs, attaching the protective tape 2 to the wafer 1 is an essential step, and for this purpose, bonding accuracy close to the size of the wafer 1 is required.

The sizes of the wafer 1 are 3, 4.5, and 6.8 inches, and since the protective tape 2 is not allowed to protrude from the outer periphery of the wafer 1, the wafer 1 has a size of 025 to 025 inches than the protective tape 2.
It is necessary to use one that is 0.3 mm smaller, and the amount of eccentricity is often kept within ±025 to 03 mm.

The reason why the interval between these two position detection sensors 5A and 5B is set equal to the radius R of the wafer 1 is that (i) the eccentricity ΔX, Δ
The microcomputer has a response time of 1 ms or less because the detected amount S is balanced and detected large with respect to the eccentric amount that is consistent with Y, and it is easy to calculate the eccentric amounts ΔX and ΔY from the amount of S. It can be processed by

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

<Effects of the Invention> As is clear from the above description, according to the present invention, two position detection sensors are selected and placed at appropriate intervals, their detection interval S is measured, and the amount of correction from the reference point is calculated. ΔX, ΔY
is calculated using a simple microcomputer. The error in the calculated value itself was less than (2-3)/1000 mm, and the correction result was several times more accurate than the conventional 0.25-0.3 mm to 0.1 mm or less.

Image processing using a CCD camera is often performed for this kind of centering, but with this method, it is not possible to obtain an overall accuracy of 0.1 mm or less for the entire device, and this is because the volume is small. There are major restrictions on installation, and the price is 20 times to 2
It takes 00 times more. However, since the position detection sensor of the present invention is compact and has a length of 20 to 50 mm, the installation is not limited by the position, and has the excellent effect of achieving high accuracy.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of an apparatus that implements the method of the present invention, Fig. 2 is a diagram explaining the action of the suction grid section, Fig. 3 is a diagram explaining the centering correction calculation method, and Fig. 4 is a graph showing the relationship between the detected value Smm. A diagram illustrating the amount of eccentricity ΔXmm, Figure 5 shows the detected value S
FIG. 3 is a diagram illustrating eccentricity ΔYmm with respect to mm. 1: Circular wafer, 2: Circular protective tape, 3. Conveying tape, 5A, 5B: Position detection sensor, Xo-XO: Reference line, 7: Adsorption grip as an example of adsorption body Applicant: Soatec Co., Ltd. Agent, Permanent Stirrer Nakamura Ayranzuru 1F whisper η Figure 5 4 Waiver of causes JiLS

Claims (1)

[Claims] 1. A plurality of circular protective tapes cut in advance to approximately the same size as a circular wafer are arranged in a column on a carrier tape at regular intervals so as to be peelable, and the carrier tape is applied intermittently. If the conveyance direction is the X axis and the direction perpendicular to the Y axis is the Y axis, then Y
Two position detection sensors are arranged in the axial direction, and the reference line is the X-axis direction passing through the center of these sensors, and the distance from the center position of the protective tape detected during transport to the center position where it is temporarily stopped is calculated. One of the position detection sensors detects the circular periphery of the protective tape, then the other position detection sensor detects it, and the reference length P is determined by the distance S between the detections of these position detection sensors. An automatic centering method characterized in that an eccentricity -ΔX from a reference line and an eccentricity ±ΔY from a reference line are calculated by a microcomputer. 2. In claim 1, at a specific distance L on the reference line,
The amount of eccentricity on both sides is −Δ due to the adsorbent of the protective tape that is concentric with the wafer.
An automatic centering method characterized by correcting X and ±ΔY. 3 In claim 1, the adsorbent is moved concentrically with the protective tape and stopped, and the adsorbent peels off the protective tape from the transport tape and adsorbs it, and the distance is set at a specific distance to the position of the wafer waiting at the original position. An automatic centering method characterized by correcting the Y-axis eccentricity ■ΔY with L and returning.