JP2002050589A - Method and device for stretching and separating semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for stretching and separating a semiconductor wafer, which can efficiently and surely separate the wafer into semiconductor pieces along all cleavage lines, without taking trouble and time. SOLUTION: A stretch sheet 22, having a flat semiconductor wafer sticking face 22a to which the semiconductor wafer 21 where the cleave lines 26 are formed, is stuck is held in a part at the outer peripheral side of the semiconductor wafer sticking face 22a. A depressing means 27 gives depression force from the reverse side of the semiconductor wafer sticking face 22a, and the whole semiconductor wafer sticking face 22a is swollen into a curved shape and is stretched. Then, the semiconductor wafer 21 is separated into plural semiconductor pieces 21a along the cleavage line 26.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer stretching separation method and apparatus for separating a semiconductor wafer attached to a stretched sheet into a plurality of semiconductor pieces along a cleavage line.

[0002]

2. Description of the Related Art FIG. 5 is a sectional view for explaining a conventional semiconductor wafer stretching / separating step. In FIG. 5A, the semiconductor wafer 1 is attached on the semiconductor wafer attachment surface 2a of the stretched sheet 2 made of an adhesive resin. A cleavage line 3 is formed in the semiconductor wafer 1 by being scratched with a diamond cutter or the like.

When the stretched sheet 2 is stretched in the horizontal direction indicated by an arrow, for example, by pulling the outer peripheral portion of the semiconductor wafer attaching surface 2a with a clamp member or the like, as shown in FIG. 5B, the semiconductor wafer 1 has crystals. Due to the property of easily cracking in a certain direction to form a plane (cleavability), the semiconductor chip 1a is separated along the cleavage line 3 into a plurality of semiconductor pieces 1a.

In Japanese Patent Publication No. 7-79095,
As shown in FIG. 6, a semiconductor wafer 7 is attached to a tape 6 whose outer peripheral side is fixed by a ring-shaped frame 5, and a push-up member 8 is disposed below the tape 6 so as to be movable up and down and left and right. Has been established. The semiconductor wafer 7 has break lines 11a to 11a extending along a direction penetrating the paper surface.
11e, the push-up member 8 also extends along that direction, and a plurality of balls 9 are attached to the tip of the push-up member 8 side by side.

The push-up member 8 is pushed up from below the tape 6 so that the direction in which the balls 9 at the tip end are aligned and the direction in which the break lines 11a of the semiconductor wafer 7 extend are aligned. The ball 9 comes into contact with the lower surface of the tape 6 by this upward movement, pushes up the semiconductor wafer 7 attached to the tape 6, generates bending stress with this contact point as a fulcrum, and generates the semiconductor piece 7a along the break line 11a. Are separated. Then, to the next break line 11b,
The push-up member 8 is moved on the cam 10 and the same break operation is performed on the break line 11b. Since then
The same applies to other breaklines in succession.

[0006]

In the conventional example shown in FIG. 5 described above, there are cases where a region cannot be separated into the semiconductor pieces 1a due to a difference in the stretching ratio of the stretched sheet 2. In particular, in the central part, the stretching ratio is smaller than that on the outer peripheral side, and poor separation 1b is likely to occur. After the separation process, the separated semiconductor pieces are identified one by one by image processing and picked up (adsorbed). However, if there are a plurality of (two in the figure) chips that could not be separated, an error occurs at that time. This causes a reduction in equipment operation rate and a decrease in yield.

In Japanese Patent Publication No. 7-79095 (FIG. 6), the arrangement direction of the balls 9 is aligned with the direction of the break lines 11a to 11e each time, and only one specific break line is set. Divided into two
It is necessary to go once for each break line, and the workability is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a method and an apparatus for stretching and separating a semiconductor wafer, which can efficiently and surely separate all the cleavage lines into semiconductor pieces without any trouble and time. And

[0009]

In order to solve the above problems, the method for stretching and separating a semiconductor wafer according to the present invention comprises:
The stretched sheet is held at a portion on the outer peripheral side from the semiconductor wafer sticking surface, and a pressing force is applied from the back side of the semiconductor wafer sticking surface to expand the entire surface of the semiconductor wafer sticking surface into a curved surface and stretched to attach the semiconductor wafer. The semiconductor wafer attached to the surface is separated into a plurality of semiconductor pieces along a cleavage line.

[0010] Further, the semiconductor wafer stretching / separating apparatus of the present invention comprises a stretched sheet having a flat semiconductor wafer attaching surface on which a semiconductor wafer having a cleavage line formed thereon is attached, and the stretched sheet being separated from the semiconductor wafer attaching surface. Holding means for holding the outer peripheral portion, and pressing force from the back side of the semiconductor wafer attachment surface of the stretched sheet held by the holding means, stretches the entire surface of the semiconductor wafer attachment surface in a curved shape and stretches. The semiconductor wafer is separated into a plurality of semiconductor pieces along a cleavage line by swelling and extending the entire surface of the semiconductor wafer attachment surface on which the semiconductor wafer is attached, in a curved shape.

That is, with one pressing operation, the entire surface of the semiconductor wafer to which the semiconductor wafer is attached is inflated in a curved shape so as to uniformly apply the stress required for cleavage to all the cleavage lines formed on the semiconductor wafer on the semiconductor wafer attachment surface. And stretched to prevent poor separation.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a stretching / separating apparatus 20 according to an embodiment of the present invention, and FIG.
B indicates a state where the sheet is stretched and separated. FIG. 2 is a plan view before separation.

A flat central portion of the stretched sheet 22 made of an adhesive resin or the like forms a semiconductor wafer attaching surface 22a to which the semiconductor wafer 21 is attached. This outer peripheral portion is sandwiched and fixed between a support base 24 having a hollow hole 24a and a support ring 23. As a fixing method, for example, a bolt 25 is attached to the support ring 23 and the stretched sheet 22.
And is screwed to the support 24. Instead of using the bolt 25, the outer peripheral portion of the stretched sheet 22 is narrowed between the support ring 23 and the support base 24 by a clamp member or the like, or the outer peripheral portion of the stretched sheet 22 is directly adhered to the support base 24 and fixed. May be.

Semiconductor wafer sticking surface 2 of stretched sheet 22
The semiconductor wafer 21 is attached to 2a. The semiconductor wafer 21 is made of, for example, silicon or gallium arsenide (G
aAs), which is a long plate (bar) cut out from a disk-shaped semiconductor wafer. Then, as shown in FIG. 2, a plurality of semiconductor chips are attached to the semiconductor wafer attachment surface 22a. In FIG. 2, the semiconductor wafers 21 are arranged in one row, but may be arranged in multiple rows such as two rows, three rows,... Depending on the length of the semiconductor wafer 21.

In parallel with the lateral direction of the semiconductor wafer 21,
Plural pieces (4 in the figure for one semiconductor wafer 21)
The cleavage line 26 of the present embodiment is formed in advance in a previous step using a diamond cutter or the like. Although the cleavage line 26 is formed only at the upper part of the semiconductor wafer 21, it may be formed as a complete dividing line to the lower part.

On the back side of the semiconductor wafer attaching surface 22a,
A pressing body 27 is disposed in the hollow hole 24a of the support base 24 so as to be movable in the vertical direction. The upper surface of the pressing body 27 facing the back surface of the semiconductor wafer attaching surface 22a is spherical. The pressing body 27 is moved up and down by moving means using a motor or the like as a driving source. Or you may make it move up and down manually.

The stretching / separating apparatus 20 constructed as described above
Next, the operation will be described.

First, as shown in FIG.
2 and the cleavage line 26
The semiconductor wafer 21 on which is formed is adhered, and a portion on the outer peripheral side from the semiconductor wafer attaching surface 22a is fixed to a support base 24 by a support ring 23 and bolts 25.

In this state, the pressing body 27 rises, and the spherical surface at the tip comes into contact with the back surface of the semiconductor wafer attaching surface 22a, and further rises to push up the semiconductor wafer attaching surface 22a, thereby covering the entire surface of the semiconductor wafer attaching surface 22a. Inflate into a spherical shape (FIG. 1B). As a result, the stress to be cleaved acts uniformly on all of the cleavage lines 26, and is separated into a plurality of semiconductor pieces (semiconductor chips) 21a without causing separation failure. In addition, a single push-up (pressing) applies a stress to all the cleavage lines to enable efficient separation. And each semiconductor piece 21
When the pitches a are substantially equalized and separated, the pushing of the pressing body 27 is stopped, and the separation is completed.

The pushing amount z of the pressing body 27 (FIG. 1B)
And the radius of curvature r of the spherical surface is
If the thickness of the semiconductor wafer 21 is represented by t (shown in FIG. 1A) and the length of the semiconductor wafer 21 in the lateral direction is represented by L (shown in FIG. 2), r ≦ L × 5
00, z ≧ t × 5, so that the semiconductor wafer 21 can be stably and reliably separated into the semiconductor pieces 21 a according to the size of the semiconductor wafer 21. The constants in the above relational expressions are values obtained by experiments and calculations in order to obtain the push-up amount z and the radius of curvature r of the spherical surface that allow good separation even if the semiconductor wafer size varies.

Although the embodiment of the present invention has been described above, the present invention is, of course, not limited to this, and various modifications can be made based on the technical idea of the present invention.

In the above embodiment, as shown in FIG.
Although applied to the separation of the long plate-shaped semiconductor wafer 21, as shown in FIG. 3, the semiconductor piece 28c is separated from the disk-shaped semiconductor wafer 28 along cleavage lines 28a and 28b formed in a vertical and horizontal lattice. You may make it. Also,
As shown in FIG. 4, when separating a long plate-shaped semiconductor piece 29 b from a disk-shaped semiconductor wafer 29, if a pressing force is applied on a spherical surface, there is a possibility that the semiconductor chip 29 may be broken at a portion other than the cleavage line 29 a. Therefore, a pressing body having a cylindrical side surface is used, and pressing is performed with the axial direction of the cylindrical side surface being parallel to the cleavage line 29a. In this way, a force that extends only in the vertical direction in FIG. 4 is applied, so that the long plate-shaped semiconductor piece 29b can be separated without breaking. Of course, also in the above embodiment, the pressing body 2
The upper surface of 7 may be a cylindrical side surface.

In the above embodiment, the semiconductor wafer 21 is made of silicon or gallium arsenide. However, other materials, for example, Al2O3 which has low cleavage and is liable to cause separation failure in the conventional method shown in FIG. However, the present invention enables reliable separation of semiconductor pieces (chips) even from a semiconductor wafer having such a low cleavage property.

In the above embodiment, the pressing member 27
Is moved with respect to the stretched sheet 22 fixed to the support table 24, but the pressing body 27 is fixed, and the stretched sheet 22 is gripped by a clamp member or the like at the outer periphery thereof, and the fixed pressing is performed. You may move with respect to the body 27. Of course, both the stretched sheet 22 and the pressing body 27 may be moved, that is, the stretched sheet 22 and the pressing body 27 are relatively moved so that the pressing body 27 can be moved by pressing the back surface of the semiconductor wafer attaching surface 22a. What is necessary is just to be able to move temporarily.

Also, instead of using the pressing body 27 to press the back surface of the semiconductor wafer attachment surface 22a, a fluid pressure such as air pressure or hydraulic pressure is applied to expand the entire surface of the semiconductor wafer attachment surface 22a into a curved surface and stretch it. You may make it.

[0027]

According to the first or second aspect of the present invention, it is possible to reduce defective separation into semiconductor pieces and to improve the yield and equipment operation rate. Further, separation can be performed for more cleavage lines at one time, and the working efficiency can be improved, which is effective for mass production.

According to the fourth aspect, it is possible to apply an optimal stress for separation in accordance with the wafer size.

According to the fifth aspect, a long plate-shaped semiconductor piece can be separated without causing breakage.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a stretching separation apparatus according to an embodiment of the present invention, wherein A shows a state before stretching and separation, and B shows a state after stretching and separation.

FIG. 2 is a plan view of the same.

FIG. 3 is a plan view of a disc-shaped semiconductor wafer on which cleavage lines are formed in a lattice shape.

FIG. 4 is a plan view of a disc-shaped semiconductor wafer in which parallel cleavage lines are formed only in one direction.

FIG. 5 is a view for explaining a stretching separation action of a conventional example.
Indicates a state before separation, and B indicates a separated state.

FIG. 6 is a view showing separation of a semiconductor wafer according to another conventional example.

[Explanation of symbols]

20: Stretch separation device, 21: Semiconductor wafer, 21
a ... semiconductor piece, 22 ... stretched sheet, 22a ... semiconductor wafer attachment surface, 26 ... cleavage line, 27 ... pressing body.

Claims (5)

[Claims] 1. A semiconductor wafer having a cleavage line formed thereon is attached to a flat semiconductor wafer attachment surface formed on a stretched sheet, and the semiconductor sheet is stretched by stretching the stretched sheet to form a plurality of semiconductor wafers along the cleavage line. In the method of stretching and separating a semiconductor wafer to be separated into semiconductor pieces, the stretched sheet is held at a portion on the outer peripheral side from the semiconductor wafer attaching surface, and a pressing force is applied from the back side of the semiconductor wafer attaching surface to attach the semiconductor wafer. A method of stretching and separating a semiconductor wafer, comprising: expanding the entire surface in a curved shape and stretching the semiconductor wafer, and separating the semiconductor wafer into a plurality of semiconductor pieces along the cleavage line. 2. A stretched sheet having a flat semiconductor wafer attaching surface to which a semiconductor wafer having a cleavage line formed thereon is attached, and holding means for holding the stretched sheet at a portion on an outer peripheral side from the semiconductor wafer attaching surface. Pressing means for applying a pressing force from the back side of the semiconductor wafer attachment surface of the stretched sheet held by the holding means to expand and stretch the entire surface of the semiconductor wafer attachment surface in a curved shape, A semiconductor characterized in that the entire surface of the semiconductor wafer attachment surface on which the semiconductor wafer is attached is expanded and extended in a curved shape, whereby the semiconductor wafer is separated into a plurality of semiconductor pieces along the cleavage line. Wafer stretching separation equipment. 3. The pressing means has a spherical or cylindrical side surface facing the back surface of the semiconductor wafer attaching surface, and the spherical or cylindrical side surface presses the back surface of the semiconductor wafer attaching surface to bulge. 3. The semiconductor wafer stretching / separating apparatus according to claim 2, further comprising a moving means for relatively moving the pressing body and the stretched sheet. 4. The radius of curvature of the spherical or cylindrical side surface is r, and the amount of movement by which the pressing body presses the back surface of the semiconductor wafer attaching surface with the spherical or cylindrical side surface and moves relative to the stretched sheet. Where z is the thickness of the semiconductor wafer, t is the length of the semiconductor wafer in the lateral direction, and L ≦ L × 500 and z ≧ t × 5. The apparatus for stretching and separating a semiconductor wafer according to the above. 5. The semiconductor wafer is disc-shaped,
The semiconductor piece to be separated is in the shape of a long plate, and the pressing means includes a pressing body having a cylindrical side surface facing the back surface of the semiconductor body wafer attaching surface; 3. A moving means for relatively moving the pressing body and the stretched sheet so as to press and expand the back surface of the semiconductor wafer attaching surface in accordance with the longitudinal direction of the semiconductor wafer. The apparatus for stretching and separating a semiconductor wafer according to the above.