JPS5951746B2 - Semiconductor wafer separation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor wafer separation method for separating a semiconductor wafer into a large number of pellets.

Conventionally, in order to separate a semiconductor wafer on which a large number of semiconductor elements are formed into pellets for each element, the wafer is previously fixed on a table using a vacuum chuck. Next, separation grooves of a predetermined depth are cut vertically and horizontally along the pellet separation area using a diamond cutter, and the grooves are placed face down on a table 1 made of a soft material, as shown in FIG. The wafer 4 is separated by placing an elastic member 2 such as a rubber mat on the back side of the wafer and rolling a roller 3 on the surface of the elastic member 2. The so-called die and diamond scribing method, in which the separation grooves 4a are formed with a diamond cutter and the wafers 4 are separated by the roller 3, is a simple device, but when the roller 3 separates the wafers into pellets, The corners of the pellets collide with each other, causing cracks and chips in the pellets.

Furthermore, it has the disadvantage that it is not suitable for separating thick wafers 4 or large-diameter wafers 4 due to dependence on crystal orientation. A so-called blade dicing method is also used in which a diamond blade with ultra-thin teeth is rotated at high speed to directly cut the wafer in the pellet separation region.

The blade dicing method allows a vertical cut surface to be obtained regardless of the 5th crystal orientation, but there is a problem in that the equipment is complicated and maintenance of the equipment is time-consuming. In addition, a laser scribing method in which the pellet separation region is melted and evaporated using a laser beam to separate the pellets has also been put into practical use.

However, cutting speed with laser is fast;
Although it is easy to operate, the problem is that the equipment is extremely expensive. The present invention has been made in view of the above problems, and provides a method for separating semiconductor wafers that can easily separate five-piece semiconductor wafers into pellets of a desired shape while preventing cracking or chipping of the pellets with simple operations. This is what I found.

The method of the present invention will be explained below.

In the method of the present invention, separation grooves of a predetermined shape are drilled in advance on the surface of a semiconductor wafer along the pellet separation area, and then this semiconductor wafer is fixed to a suction plate with fine suction holes. In this method, a semiconductor wafer is separated into a large number of pellets by spraying fluid at a predetermined pressure into the separation groove.

Here, the shape of the separation groove is such that the width of the groove serving as a cutting margin is small in order to increase the number of pellets per wafer.

Usually, it is desirable to set the groove width to a size of 40 to 100 microns. The depth of the groove is set to 1/2 to 9/10 of the wall thickness of the wafer so that cracks are generated quickly from the separation groove by the spraying of the fluid and the semiconductor wafer is separated into pellets of a predetermined shape.
It is desirable to set the size to . The separation groove forming means may be of any type, such as a diamond cutter, as long as it can form a predetermined separation groove on the wafer with a simple operation.

The fluid to be sprayed into the separation grooves may be any fluid as long as it does not contaminate the elements formed on the semiconductor wafer, and it is preferable to use an inert gas such as nitrogen gas or air.

The method of spraying the fluid into the separation groove is, for example, using a nozzle with a diameter of about 10 mm.
Using a 0μ injection nozzle, inject 5 to 3
It is desirable to spray a fluid at zero pressure.

The suction plate fixes the semiconductor wafer by connecting one end of a suction device such as a vacuum pump to a base with a large number of suction holes, and also uses fluid to spray the wafer to scatter separated pellets. This is to prevent

The size of the suction hole is 10% depending on the size of the semiconductor pellet.
It is desirable to set the size appropriately within the range of ~100μ. In addition, the suction force by the suction device is 0.5 to 1 kg/Cm.
It is desirable to set it appropriately within the range of 2.

Next, examples of the present invention will be described.

As shown in Fig. 2, approximately 1000 semiconductor pellets 10 of 2 x 2 mm are formed, the diameter is 76 mm, and the thickness is 0.3 mm.
diamond blade in advance on the semiconductor wafer 11? A separation groove 12 having a groove width of 40 μm and a groove depth of 200 μm was bored along the pellet separation region.

Next, as shown in FIG. 3, this semiconductor wafer 11 was fixed to the surface of a suction plate 15, which had a substrate 14 having a plurality of suction holes 13 and one end of a vacuum pump (not shown) connected thereto. Next, the tip of the injection nozzle 16 with a nozzle diameter of 100μ is positioned directly above the separation groove 12 of the semiconductor wafer 11, and nitrogen gas is sprayed into the separation groove 12 at a pressure of about 10 kg/Cm. Injection nozzle 1 along 12
Moved 6. After spraying the fluid, it was confirmed that all the pellets 10 were completely separated on the surface of the suction plate 15 without any damage such as cracks or chips. Incidentally, suction plate 1
The pellets 10 were taken from the pellets 10 and 10 were examined for changes in the mass of the suction plate 15 before and after the separation of the semiconductor wafers 11, and the mass of cracks and chipped portions was measured and found to be 0 mmg. As described above, according to the method of the present invention, by spraying fluid at a predetermined pressure into the separation groove 12, cracks are generated from the tip of the separation groove 12, and the semiconductor wafer 11 is easily separated into pellets 10 of a predetermined shape. can do.

Furthermore, since the semiconductor wafer 11 is attracted to the attraction plate 15 with a predetermined attraction force, it is possible to prevent adjacent pellets 10 from colliding with each other when separating into pellets 10. For comparison with the example, as shown in FIG. 1, separation grooves 4a were formed using a diamond blade on a semiconductor wafer 4 similar to that of the example, and pellets were separated using the roller 3. The mass of cracks and chipped parts that occurred during separation was approximately 18.4 mmg. It was also found that the yield of the example was improved by about 5% compared to that of this comparative example. As explained above, according to the semiconductor wafer separation method according to the present invention,
By a simple operation, a semiconductor wafer can be easily separated into pellets of a desired shape while preventing the pellets from cracking or chipping.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a conventional method for separating semiconductor wafers, FIG. 2 is a perspective view of a semiconductor wafer, and FIG. 3 is a state in which a semiconductor wafer is separated into pellets of a desired shape by the method of the present invention. FIG. 10... Pellet, 11... Semiconductor wafer, 12... Separation groove, 15... Adsorption plate.

Claims (1)

[Claims] 1 Separation grooves of a predetermined shape are drilled on the surface of a semiconductor wafer along a pellet separation area for separating the wafer into pellets of a predetermined shape, and then the wafer is placed on a suction plate with fine suction holes. A method for separating semiconductor wafers, comprising: fixing the wafers, and then spraying fluid at a predetermined pressure into the separation grooves to separate the wafers into a large number of pellets.