JP2861264B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for dicing a semiconductor wafer, and provides a method for manufacturing a semiconductor device capable of reducing the generation of minute debris or the like that causes a short circuit failure or the like. [1] A step of attaching an adhesive tape 12 to the front surface 1A side of the wafer 1 and cutting the wafer 1 into a lattice from the back surface 1B side where the surface is metallized by the rotating dicing saw 21 And a step of cutting the wafer 1 by the dicing saw 21 so as to perform a full cut by a down cut method.
[2] or the step of cutting the wafer 1 by the dicing saw 21 is configured such that the wafer is first cut in half by a down-cut method, and then further cut in an up-cut method to perform a full cut. [3] The above [1] or In [2], the pressure-sensitive adhesive of the pressure-sensitive adhesive tape 12 is configured to be an ultraviolet-curable pressure-sensitive adhesive.

[Industrial applications]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for dicing a semiconductor wafer.

In order to manufacture a semiconductor device, first, elements for a large number of chips are collectively formed in the state of a wafer, and then divided into individual chips (this is called dicing).
In recent years, this dicing has been generally performed by a method of cutting and dividing by a rotating dicing saw. This dicing was initially cut with a dicing saw so that part of the thickness of the wafer remained (this is called half-cut), and then divided into chips by cracking. A method of cutting the entire thickness of a wafer with a dicing saw (this is called a full cut) has become mainstream.

[Conventional technology]

A typical example of a conventional wafer dicing method will be described with reference to FIG.

FIGS. 4A and 4B are schematic sectional views showing a conventional dicing method. In the figure, reference numeral 1 denotes a wafer, on the surface 1A of which elements are formed, while on the rear surface 1B, no elements are formed and a metal film is sometimes applied. Reference numeral 2 denotes a plurality of chips obtained by dicing the wafer 1, on which elements are formed on the front surface 2 A side, while a metal film is applied on the back surface 2 B in some cases. Reference numeral 14 denotes an adhesive tape, which has an ultraviolet-curable adhesive on one surface, and is adhered to the frame 14a. Reference numeral 21 denotes a dicing saw of a dicing device (not shown).

First, an adhesive tape 14 is attached to the back surface 1B side of the wafer 1 on which the element formation has been completed. Next, the surface 1A of the wafer 1 is fixed on a dicing apparatus with the surface 1A facing upward, and the wafer 1 is cut in a grid shape from the surface 1A of the wafer 1 along the scribe line by a rotating dicing saw 21 along the scribe line (see FIG. FIG. (A)). Thereafter, the adhesive tape 14 is irradiated with ultraviolet rays to weaken the adhesive force (see FIG. 2B), and each chip 2 is peeled off from the adhesive tape 14.

[Problems to be solved by the invention]

However, in such a conventional method, especially when a metal film is deposited on the back side of the wafer, a large number of burrs of the metal are generated at the edge portion of the chip at the time of cutting, and fragments of the wafer are formed by the fragments of the metal. Remains on the burr,
There has been a problem that these fall off during handling in the subsequent steps and become conductive fine fragments, which adhere to the chip surface or the like and often cause a short circuit failure. SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of manufacturing a semiconductor device capable of solving such a problem and reducing the generation of minute debris or the like that causes a short circuit fault or the like.

[Means for solving the problem]

According to the present invention, according to the present invention, [1] a step of attaching an adhesive tape 12 to the front surface 1A side of the wafer 1 and the rotating dicing saw 21 divide the wafer 1 from the back 1B side where the surface is metallized. And cutting the wafer 1 by the dicing saw 21. The step of cutting the wafer 1 by the dicing saw 21 is a full cut by a down cut method. In the method for manufacturing a semiconductor device, [2] or the step of cutting the wafer 1 by the dicing saw 21 may be a step of first performing a half-cut by a down-cut method and then further cutting by an up-cut method to perform a full cut. [3] The semiconductor device according to [1] or [2], wherein the adhesive of the adhesive tape 12 is an ultraviolet-curable adhesive. With manufacturing method, it is achieved.

[Action]

Generally, when a silicon wafer is affixed to a soft adhesive tape and fixed horizontally and full-cut with a rotating dicing saw, the down-cut method (a method of sending a workpiece in the direction of rotation of the saw) is applied to the edge of the upper surface of the wafer. Causes almost no chipping of silicon, but causes some chipping of silicon at the edge of the lower surface. When metal is deposited on both sides of the wafer, almost no metal burrs or chipping of silicon occurs at the upper edge of the wafer, but many metal burrs and chipping of silicon occur at the lower edge. In the case of the up-cut method (a method in which the workpiece is fed against the rotation of the saw), since the wafer is vibrated by an upward cutting force because the fixing is not strong, metal burrs are particularly generated by the down-cut. Much more than you would.

Therefore, in the case of a wafer on which metal is deposited on one side, if a full cut is performed by the down-cut method with the metal-deposited side facing up, metal burrs are also formed on the edge of the upper surface of the wafer by silicon. Almost no chipping occurs, and the edge of the lower surface only needs to cause some silicon chipping.

Also, in the same manner as described above, the surface on which the metal is deposited faces up,
First, the top side is half-cut by the down-cut method, and then the remaining part is cut by the upper-cut method along the groove formed by this half-cut to make a full cut. Almost no occurrence.

〔Example〕

A first embodiment of dicing according to the present invention will be described with reference to FIGS.

1 (a) to 1 (f) are schematic sectional views showing the steps of the first embodiment of the present invention. In the figure, reference numeral 1 denotes a wafer having a thickness of about 600 μm. An element is formed on the front surface 1A side, while a metal film (gold, titanium gold, etc.) is applied on the rear surface 1B. Reference numeral 2 denotes a plurality of chips obtained by dicing the wafer 1, and elements are formed on the front surface 2A side, while a metal film is applied on the back surface 2B. Reference numerals 11, 12, and 13 denote a first adhesive tape, a second adhesive tape, and a third adhesive tape, respectively. Each of them has a thickness of about 100 μm and has an ultraviolet-curable adhesive on one side. These are frames 11a, 12 respectively
a, 13a is attached. 21 is a dicing saw of a dicing device (not shown), 22 is a roller, 23
Is a table.

FIGS. 2A and 2B are explanatory diagrams of a reference line creation method in the embodiment of the present invention. In the figure, 1S is a scribe line of the wafer 1, and 1X is a created reference line.

First, a reference line 1X for alignment is created on the wafer 1. In the present invention, since the scribe line cannot be directly observed due to the dicing with the back surface 1B side of the wafer 1 facing upward, it is created as an alternative to this. First, the back surface 1B side of the wafer 1 is attached to the first adhesive tape 11. The wafer 1 is fixed on a dicing apparatus with the surface 1A side facing upward, and the wafer 1 is fully cut by a dicing saw 21 in parallel with the scribe line 1S of the wafer 1. The resulting edge becomes the reference line 1X. One reference line 1X is provided in each of the X direction and the Y direction (first
FIG. (A) and FIG. 2). The reference line 1X is provided on the periphery of the wafer 1 as shown in FIG. 2A, but may be provided on the scribe line 1S as shown in FIG. 2B.
Next, the first adhesive tape 11 is irradiated with ultraviolet rays to weaken its adhesive strength (see FIG. 1 (b)).

Thereafter, the wafer 1 is peeled off from the first adhesive tape 11,
This time, the surface 1A side is attached to the second adhesive tape 12.
The wafer 1 is fixed on a dicing machine with the back 1B side facing upward, and aligned with the reference line 1X.
By means of 21, the wafer 1 is fully cut in a grid pattern (in the X and Y directions) along the scribe line 1S by a down-cut method (see FIG. 1 (c)). As a result, the wafer 1
Is divided into a number of chips 2. Then the second adhesive tape
12 is irradiated with ultraviolet rays to reduce its adhesive strength (see FIG. 1 (d)).

Next, the third adhesive tape 13 is opposed to the second adhesive tape 12 placed on the base 23, and the third adhesive tape 13 is pressed and adhered to the back surface 2B of the chip 2 by the roller 22 (first Fig. (E). Next, the second adhesive tape 12 is peeled off from the surface 2A of the chip 2. Thereafter, the third adhesive tape 13 is irradiated with ultraviolet rays to weaken its adhesive strength (see FIG. 1 (f)),
Each chip 2 is peeled off from the adhesive tape 13.

A second embodiment of dicing according to the present invention will be described with reference to FIG. FIGS. 3A and 3B are schematic cross-sectional views showing a part of the steps of the second embodiment of the present invention. All the symbols of each part in the figure are the same as those in FIG.

This embodiment is different from the above-described first embodiment only in the step of cutting the wafer 1 in a lattice shape along the scribe line 1S (see FIG. 2) by the dicing saw 21, and the other steps are the same. Only this cutting step will be described. Reference line
1X (see FIG. 2), the wafer 1 is fixed on a dicing apparatus with the rear surface 1B side facing upward, the wafer 1 is aligned with a reference line 1X, and the wafer 1 is scribed with a dicing saw 21 to form a scribe line 1S (see FIG. 2). Half-cutting is performed in a grid-like manner along a down-cut method (see FIG. 2A) (see FIG. 2A). The uncut thickness is about 70 to 100 μm. Subsequently, the sheet is further cut by the up-cut method to perform a full cut (see FIG. 13B). The other steps are the same as those in the first embodiment, and will not be described.

In the chip 2 obtained by the method of the above two embodiments, metal burrs and chipping of silicon at the edge portion on the back surface 2B side were extremely small. Alternatively, no adhesion of the adhesive to the surface 2A was observed at all.

The present invention is not limited to the above embodiments, and can be implemented in various modifications.

〔The invention's effect〕

As described above, according to the present invention, it is possible to provide a method of manufacturing a semiconductor device capable of reducing the generation of minute debris or the like that causes a short-circuit fault or the like. This greatly contributes to improvement and reliability of the semiconductor device.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing the steps of the first embodiment of the present invention, FIG. 2 is an explanatory view of a method for creating a reference line in the embodiment of the present invention, and FIG. 3 is a second embodiment of the present invention. And FIG. 4 is a schematic cross-sectional view showing a conventional dicing method. In the figure, 1 is a wafer, 1A is a front surface, 1B is a back surface, 2 is a chip, 11 is a first adhesive tape, 12 is a second adhesive tape (adhesive tape), 13 is a third adhesive tape, and 21 is dicing. Saw.

Claims (3)

(57) [Claims] 1. A step of attaching an adhesive tape (12) to a surface (1A) of a wafer (1), and the wafer (1) is rotated by a rotating dicing saw (21).
Cutting into a plurality of chips (2) by cutting in a grid form from the back (1B) side where the surface is metallized,
A method of manufacturing a semiconductor device, wherein the step of cutting the wafer (1) by the dicing saw (21) is to perform a full cut by a down cut method. 2. A step of attaching an adhesive tape (12) to the surface (1A) of the wafer (1), and the wafer (1) is rotated by a rotating dicing saw (21).
Cutting into a plurality of chips (2) by cutting in a grid form from the back (1B) side where the surface is metallized,
Wherein the step of cutting the wafer (1) by the dicing saw (21) is performed by first performing a half-cut by a down-cut method and then further cutting by an up-cut method to perform a full cut. Manufacturing method. 3. The method for manufacturing a semiconductor device according to claim 1, wherein the adhesive of the adhesive tape is an ultraviolet-curable adhesive.