JP2869898B2 - Semiconductor chip separation method - Google Patents

Description

The present invention relates to a method for separating a semiconductor chip, which is a semiconductor product, from a semiconductor wafer.

(Prior Art) Conventionally, a semiconductor wafer is attached to a vinyl sheet and fixed, and a semiconductor chip is separated from the semiconductor wafer by mechanical cutting using a dicing saw.

(Problems to be Solved by the Invention) Since mechanical stress is applied to the semiconductor wafer, the semiconductor wafer is easily broken, and the yield of manufacturing semiconductor chips may be deteriorated. In the step of separating the semiconductor chips, if the semiconductor wafer is immersed in a chemical solution such as a KOH solution in the previous chemical treatment, the dicing saw may be contaminated at the time of chip separation.

SUMMARY OF THE INVENTION It is an object of the present invention to reduce the stress applied to a wafer when separating chips from a semiconductor wafer, thereby reducing the possibility of mechanical destruction.

[Configuration of the invention]

(Means for Solving the Problems) In the present invention, a mask pattern having a separation groove formed thereon is formed on a semiconductor wafer, and the separation groove is etched by wet etching to separate semiconductor chips.

In a preferred embodiment of the present invention, the mask pattern includes a mask region for leaving a beam connecting the chips to be separated between the separation grooves in order to prevent chips from being randomly separated during the chip separation processing.

(Function) Since the wafer is separated by wet etching, mechanical stress is not substantially applied to the wafer and destruction is eliminated.

Assuming that the mask pattern includes a mask region for leaving a beam connecting the chips to be separated between the separation grooves,
Since the chips are connected with the beams immediately after the wet etching, the chips are not randomly dispersed, and the chips are not substantially required to be aligned in a subsequent pickup for processing each chip. A mechanical force is applied when removing the chip from the beam, but the force required for this is small, and the possibility of destruction is low.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

(Example) FIG. 1 shows an example of a semiconductor chip 1 obtained separately from a semiconductor wafer. This is used as the basis of the acceleration sensor. This is because a groove 3 is formed around the weight body region 5 and the neck 4 connected thereto by photolithography on the silicon wafer, and the weight region 5 is made to easily swing under the neck 4. 6, a weight supporting beam 7 continuous with the neck 4 is formed, and the outside of the frame 2 is separated from the wafer by wet etching. Strain gauges 8, 9 are provided on the weight support beam 7.
Are joined.

As shown in FIG. 2, a mask pattern 1P for forming the sensor base 1 shown in FIG. 1 is formed on the silicon wafer.
Are formed side by side, and a separation pattern is formed between these patterns 1P, leaving a beam connecting them and removing most of them by etching.

In this embodiment, since the grooves 3 and 6 of the sensor base 1 and the groove for separating the sensor chip are simultaneously formed by the etching for separating the chip, the silicon wafer 20 is formed.
Have openings 3P and 6P (in each of the patterns 1P) and openings 11P and 12P for separating the sensor chip, and have a sensor area (1
In P), a resist mask pattern for masking a region corresponding to the frame 2, the neck portion 4, the weight region 5 and the weight supporting beam 7 and a beam corresponding region 13P for preventing chip dispersion is formed by a photographic photosensitive technique. In FIG. 2, the opening (the part to be etched) is indicated by oblique lines falling to the right. In each of the sensor regions (1P), there is an opening having the same shape as the openings (3P, 6P) shown in the pattern 1P. The upper surface of the silicon wafer is the (110) plane of the silicon crystal.

Silicon wafer 20 with the above mask pattern formed
Is subjected to anisotropic etching by dipping in an anisotropic etching solution (alkaline etching solution). When the etching is started, a (111) plane appears as shown in FIG. 3, which is at 54.47 degrees with respect to the bottom surface of the wafer, and the anisotropic etching proceeds, but the etching along the (111) plane is performed. Since the speed is very slow, under-etching is virtually negligible. Since the etching rate in the direction toward the (100) plane, that is, the etching rate in the depth direction is the highest, the etching proceeds in this direction, and the wafer 20
The 11P portion serves as a cutout groove, and becomes a planar array of a plurality of sensor bases 1 (1P portions) connected to each other only at the beam mask 13P portion.

Each chip (1) is easily separated by applying a force to the beam remaining under the beam mask 13P. Since these beams are provided, each chip does not fall apart immediately after the above-described separation etching, and can be recovered from the etching solution in the original shape of the wafer.

〔The invention's effect〕

Since the wafers are separated by wet etching, mechanical stress is not substantially applied to the wafer, and destruction is eliminated.

Assuming that the mask pattern includes a mask region for leaving a beam connecting the chips to be separated between the separation grooves,
Since the chips are connected with the beams immediately after the wet etching, the chips are not randomly dispersed, and the chips are not substantially required to be aligned in a subsequent pickup for processing each chip. A mechanical force is applied when removing the chip from the beam, but the force required for this is small, and the possibility of destruction is low.

[Brief description of the drawings]

FIG. 1 is an enlarged perspective view of a semiconductor chip separated according to the present invention. FIG. 2 is an enlarged plan view of a part of the silicon wafer before separation. FIG. 3 is an enlarged cross-sectional view showing an etching region and a crystal plane of a silicon wafer. 1: Semiconductor chip (semiconductor chip) 2: Frame, 3: Draft groove 4: Neck, 5: Weight region 6: Draft groove, 7: Weight support beam 8, 9: Strain gauge 1P, 3P, 6P, 11P, 12P, 13P: Mask opening 20: Silicon wafer (semiconductor wafer)

Claims (2)

(57) [Claims] 1. A method for separating semiconductor chips, comprising: forming a mask pattern having a separation groove on a semiconductor wafer; and etching the separation groove by wet etching to separate semiconductor chips. 2. The method according to claim 1, wherein the mask pattern includes a mask region for leaving a beam connecting the chips to be separated between the separation grooves.