JPH01310906A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To reduce the generation of silicon fragments and prevent the short circuit and surface crack in assembling process from generating by a method wherein the kerf is made by moving a rotating blade to a semiconductor wafer and, after that, the blade is moved to the opposite direction for parting the wafer. CONSTITUTION:Each kerf is made so as to leave the uncut thickness of 50-100mum in a semiconductor wafer by moving a blade 3 from right to left. Next, the wafer 1 is turned by 90 degrees and, after that, the blade 3 is moved along scribing lines in the Y-axis direction so as to make kerfs having the same depth of cut as that of the kerf in X-axis direction. After the formation of the kerfs, the semiconductor wafer is again turned in a counterclockwise direction by 90 degrees. The blade 3 is moved along the kerf made along the scribing line in the X-axis direction to the direction opposite to the direction of movement at the formation of the kerf so as to cut to the depth, which reaches the halfway of the thickness of an adhesive tape 2 beneath the semiconductor wafer 1 in order to separate the semiconductor wafer into semiconductor elements. Similar operation is done to the kerf made along the scribing line in the Y-axis direction, resulting in completing the separation of the semiconductor wafer 1 into semiconductor elements.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for manufacturing a semiconductor device in which a semiconductor wafer is divided into semiconductor elements using a rotating blade, and it solves problems such as cracks on the surface of the semiconductor elements and short circuits between terminals. The purpose of this method is to provide a method for dividing semiconductor wafers that generates fewer fragments into the semiconductor wafer, and to prevent this from occurring. is formed, and the blade is moved in the opposite direction with an upper cut at the cut groove portion to divide it into semiconductor elements.

[Industrial application field]

The present invention relates to a method of manufacturing a semiconductor device, and particularly to a method of dividing a semiconductor wafer into semiconductor elements using a rotating blade.

2. Description of the Related Art With the recent increase in the degree of integration of semiconductor devices, there is a strong demand for high reliability of semiconductor devices.

In order to divide a semiconductor wafer into semiconductor elements, a dicing method is used in which the semiconductor wafer is fixed with adhesive tape and a blade is used to completely cut the scribe lines between the semiconductor elements formed on the semiconductor wafer. However, at this time, the semiconductor wafer is chipped and many silicon fragments are generated. These fragments adhere to semiconductor elements and cause short circuits and surface cracks during the assembly process.

Under the above circumstances, there is a need for a dicing method that can reduce the generation of silicon fragments when dividing a semiconductor wafer into semiconductor elements.

(Prior Art) A conventional dicing method will be explained with reference to FIGS. 5 and 6.

The conventional dicing method shown in FIG. 5(a) involves attaching a semiconductor wafer 1 to an adhesive tape 2, adhering it to a chuck 4 having a vacuum suction port, and attaching the semiconductor wafer 1 to a chuck 4 with a blade attached to a rotating shaft 5 in the direction of the arrow α shown in the figure. In this method, the entire thickness of the semiconductor wafer 1 is completely cut at once by rotating the blade 3 and moving the blade 3 in the direction of the arrow β with respect to the semiconductor wafer 1.

In this method, the direction in which the blade 3 is moved is such that the cutting dust on the semiconductor wafer is rubbed up by the peripheral edge 3a of the blade, and the cutting in this case is called an uppercut.

If it goes in the opposite direction, it is called a down cut.

In this conventional dicing method, A-A in Figure 5+a)
'This is a force direction drawing. As shown in Fig. 5 (mountain 5), a crank occurs particularly at the lower part 1a of the semiconductor wafer that contacts the blade 3, and chipping occurs, resulting in elongated silicon fragments 11.
occurs.

Although the amount of fragments 11 generated is smaller in an upper cut than in a down cut, the following problems still occur.

After dividing the semiconductor wafer into semiconductor elements, the semiconductor elements are peeled off from the adhesive tape by pushing up from the back side of the adhesive tape with a stick or bottle, but due to the vibrations at this time, the surface of the semiconductor elements stuck to the adhesive tape without being peeled off. Published in

This fragment 11 is caught between the semiconductor element and a collet for picking up the semiconductor element, and external force is locally applied to the surface of the semiconductor element, causing damage to the semiconductor element and deterioration of element characteristics. Further, the terminals on the surface of the semiconductor element are connected by the fragments 11, causing a short circuit failure.

Therefore, as shown in No. 6 (a), the semiconductor wafer 1 is cut halfway through its thickness with an upper cut using the blade 3.
6 (b) in the cross-sectional view of "-B", then lift the blade 3 and return it to the same cutting start position as in (a), (same cutting start position as in al). A method has been considered in which the blade 3 is lowered further and the cut groove 6 is cut while moving the blade 3 in the same direction again as shown in FIG. 6 (C1), cutting down to the adhesive tape 2 and dividing it.

By dividing the cutting into two steps in this way, the friction between the outer peripheral edge of the blade 3 and the semiconductor wafer 8 during cutting is reduced, vibration of the semiconductor wafer is reduced, and cracks and chips in the semiconductor wafer are reduced.

When actually scribing using the method shown in Figure 6, since a semiconductor wafer has multiple scribe lines in the X-axis direction and in the Y-axis direction perpendicular to it, first, all scribe lines in the X-axis direction are Cutting shown in FIG. 6+a) is performed to form a cut groove along the scribe line in the X-axis direction. After forming one cut groove of the scribe line in the X-axis direction, the semiconductor wafer is moved in the Y-axis direction by the Y-axis stage provided under the vacuum chuck 4 in order to form the next cut groove. .

After forming cut grooves on all the scribe lines in the X-axis direction, the rotary stage installed under the vacuum chuck 4 is
001 For example, rotate it to the right and cut the scribe line in the Y-axis direction in the same way as the scribe line in the X-axis direction to form a cut groove.

After forming cut grooves on all the scribe lines in the Y-axis direction, rotate the rotary stage 90' in the opposite direction, for example, to the left, return the semiconductor wafer to its original position, and cut the cut grooves in the X-axis direction. The semiconductor wafer is completely divided down to the bottom surface. Rotate the rotation stage 90 degrees to the right again,
The cut grooves in the Y-axis direction are cut to completely divide the semiconductor wafer down to the lower surface, thereby dividing the semiconductor wafer into a plurality of semiconductor elements.

[Problem to be solved by the invention]

Although the method shown in Fig. 6 has reduced the amount of minute fragments generated on semiconductor wafers, it has not been possible to completely prevent the generation of large structural fragments with a length of 30 μm or more, and There were problems such as the occurrence of cracks and short circuits between terminals.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for dividing a semiconductor wafer in which fewer semiconductor wafer fragments are generated so as to prevent problems such as cracks on the surface of semiconductor elements and short circuits between terminals.

[Means for solving problems]

The peripheral blade of a rotating disc-shaped blade is pressed against the semiconductor wafer to cut it, and the blade is moved relative to the semiconductor wafer in a direction where the peripheral blade scrapes up the cutting powder from the semiconductor wafer. Then, a cut groove is formed halfway through the thickness of the semiconductor wafer, and then the direction of movement of the blade relative to the semiconductor wafer is reversed, and the direction in which cutting dust from the semiconductor wafer is scraped up by the peripheral blade is set. This problem is solved by the method of manufacturing a semiconductor device of the present invention, which further comprises the step of further cutting the cut groove by moving the blade relatively, and divides the semiconductor wafer into semiconductor elements.

[For production]

In the present invention, after forming the cut groove 6 by moving the blade 3 rotated relative to the semiconductor wafer 1 as shown in FIG. The blade 3 is moved in the opposite direction to perform division.

In FIG. 1 (Ml, (bl), the blade 3 rotates in the direction of arrow α and moves in the direction of arrow β.

In this way, the semiconductor wafer is divided into multiple semiconductor elements, the semiconductor elements are peeled off from the adhesive tape one by one and arranged on a tray, and the size and number of fragments on the surface of the multiple semiconductor elements are measured using a metallurgical microscope. This was observed and compared with the conventional case of moving the blade in the same direction.

In the conventional method, there were several fragments of the model with a length of 30 μm or more, but according to the method of the present invention, such large fragments did not exist, and the total number of fragments was also reduced by the method of the present invention. This is considerably less than the conventional method.

〔Example〕

FIG. 2 is a schematic diagram of the scribing device used in the present invention,
FIG. 3 is a cross-sectional view taken along line c-c' in FIG. 2, and FIG. 4 is a diagram for explaining one embodiment of the present invention. The present invention will be explained in detail using these figures.

First, the holding state of the semiconductor wafer and the scribing device will be explained with reference to FIGS. 2 and 3.

A semiconductor wafer 1 made of silicon is attached to an adhesive tape 2 with a thickness of about 90 to 100 μm on the side opposite to the side on which circuits and wiring are formed, and the adhesive tape 2 is attached to a metal frame 6. There is.

The semiconductor wafer 1 is transported together with the frame 6 and the adhesive tape 2 attached thereto, and is held in a semiconductor wafer holding section of a scribing device.

The adhesive tape 2 is made of a resin whose adhesive strength decreases when exposed to ultraviolet rays, and is irradiated with ultraviolet rays after the semiconductor wafer 1 is divided into semiconductor elements and before the semiconductor elements are peeled off from the adhesive tape.

The scribing apparatus is provided with a semiconductor wafer holding section that holds and moves the semiconductor wafer 1 and a blade rotation moving section that rotates and moves the blade 3. The semiconductor wafer holding section includes a chuck 4 that sucks the semiconductor wafer.
For example, a vacuum chuck with a vacuum suction port formed on the suction surface, a motor M2 that rotates the chuck 4, and a rotating shaft 2.
2. Y-axis stage 7 on which motor M2 is installed, base 8,
A motor M3 and a rotating shaft 23 are provided to move the Y-axis stage 7 in the Y-axis direction along the rails 8a of the base 8.

A rotating shaft 25 is connected to the blade rotation moving part by a motor M5.
The main body 9 moves in the X-axis direction by a belt 20 hung on a rotating shaft 27, and the head section lO1 connected to the main body 9 via a shaft 26 is installed in the main body 9 and pushes and pulls the lever 10a of the head section, centering on the shaft 26. a motor M4 that rotates the head section 10 up and down, a shaft 24 that is rotated by the motor M4 and has a threaded tip, a connecting rod 28 connected to the lever 10a, and a connecting portion 29 that connects the connecting rod 28 and the shaft 24. ,
A motor M1 installed in the head section 10 and rotating the blade 3 is provided.

The disk-shaped blade 3 has a diameter of about 50 mm, and its outer edge 3a has a thickness of about 35 to 60 μm, and is connected to a shaft 5 rotated by a motor Ml with a bolt 21 or the like.

This blade 3 is 30. The semiconductor wafer 1 is cut by rotating at a rotation speed of approximately OOOrpm.

In one embodiment of the present invention, first, the semiconductor wafer 1 is
The semiconductor wafer 1 is set in the state shown in FIG. 1A, and the scribe line in the X-axis direction of the semiconductor wafer 1 is cut. In the figure, 1a is an Origny chision flat.

As shown in FIG. 2, the blade 3 is rotating in the direction of the arrow α, and the rotating shaft 25 is rotated by the motor M5 to cut the blade 3 with an upper cut in the direction of the arrow β. Blade 3 is shown in Figure 4 (al, from the right xl+x2.x3
+...X? The blade 3, which has moved to the left as indicated by the + arrow and has moved to the left end, is lifted and returned to the right end as shown by the dotted line. When the blade 3 is lifted and returned to the right end, the Y-axis stage 7 of the semiconductor wafer holder is moved in the Y-axis direction so that the blade 3 is positioned at the next scribe line in the X-axis direction. For example, cutting is performed in the order of xI, x2+ x3+, . . . 7+, to form a cut groove in a semiconductor wafer with a thickness of about 400 to 600 μm, leaving a thickness of about 50 to 100 μm.

Next, the semiconductor wafer 1 is rotated counterclockwise by the motor M2 90 degrees.
Rotate the blade 3 to the scribe line in the Y-axis direction as shown in Fig. 4(b).
ff+...y7. A cut groove having the same depth as the scribe line in the X-axis direction is formed by moving as shown in FIG.

In the figure, X I' + x2' + x3
”, .

After cutting grooves are formed in all the scribe lines, the semiconductor wafer is rotated counterclockwise by 90'' again by the motor M2.

As shown in FIG. 4(C), in the cut groove of the scribe line in the X-axis direction, arrow X II x9+...X
As shown in 14, the blade 3 is moved to cut the adhesive tape 2 under the semiconductor wafer 1 halfway through its thickness, and the semiconductor wafer is divided into semiconductor elements along the scribe line in the X-axis direction.

Next, the semiconductor wafer is rotated counterclockwise by motor M2 for 90 minutes.
6 rotations, and cut grooves yb', 'Is''l)'4'1 on the scribe line in the Y-axis direction as shown in Fig. 4(d).
yz'+)'z', arrow 'I' in the opposite direction to y1゛
'? , yo.

)'9. )'I. , y++, )'I□, the blade 3 is moved to cut halfway through the thickness of the adhesive tape under the semiconductor wafer. This completes the division of the semiconductor wafer 1 into semiconductor elements.

The plurality of semiconductor elements thus formed were peeled off one by one and arranged on a tray using a collet or the like. Then, silicon fragments on the surfaces of multiple semiconductor elements were observed using a metallurgical microscope. In the case of 56 semiconductor elements, the number of fragments with a size of 10 to 29 μm and the number of fragments with a size of 30 μm on the surface of the semiconductor elements were determined using the method of the above example and the conventional method for multiple wafers. The average results are shown in the table below.

As can be seen from this result, according to the method of the present invention, 3
No more fragments larger than 0μm, 10μm
It was possible to significantly reduce the number of occurrences of fragments with a size of ~29 μm.

In the above embodiment, a scribing device as shown in FIGS. 2 and 3 was used, but instead of a moving mechanism for moving the blade 3 in the X-axis direction, an X-axis stage was provided in the semiconductor wafer holding section to The wafer may be moved in the X-axis direction, and the semiconductor wafer may be moved up and down instead of moving the blade 3 up and down. Further, the rotation of the blade 3 by the motor may be reversed if necessary.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by changing the direction of relative movement between the blade and the semiconductor wafer during dicing of the semiconductor wafer, the generation of silicon fragments can be reduced, and the assembly process It has advantages such as being able to prevent the occurrence of short circuits and surface cranks, and can be expected to have significant economical and reliability improvement effects, making it extremely effective industrially.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view for explaining the method of manufacturing a semiconductor device of the present invention, FIG. 2 is a schematic diagram of a scribing device used in the present invention, FIG. FIG. 4 is a diagram for explaining one embodiment of the present invention, and FIGS. 5 and 6 are sectional views for explaining a conventional dicing method, respectively. In the figure, ■ indicates a semiconductor wafer, 2 indicates an adhesive tape, 3 indicates a blade, and 4 indicates a chuck. ＋Invention led to the establishment ♂ Disappearance of wealth and poverty to drink 1j trace surface 7 fig.
, com; 1j Shiko No. 2 IXi 17 C-C” bank Fig. 3 + Q) tb)

Claims (1)

[Claims] The peripheral edge of a rotating disc-shaped blade is pressed against the semiconductor wafer to cut it, and the blade is moved relative to the semiconductor wafer in a direction in which the cutting powder of the semiconductor wafer is scraped up by the peripheral blade. The blade moves to form a cut groove halfway through the thickness of the semiconductor wafer, and then the direction of movement of the blade relative to the semiconductor wafer is reversed, and the cutting powder of the semiconductor wafer is scraped up by the peripheral blade. 1. A method for manufacturing a semiconductor device, comprising the step of further cutting the cut groove by relatively moving the blade in the direction of the semiconductor wafer, and dividing the semiconductor wafer into semiconductor elements.