JP3329551B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device, and more particularly, to a method of forming a large number of semiconductor devices having slits in each semiconductor device region on a single wafer, and then forming each semiconductor device region. The present invention relates to a semiconductor device manufacturing method for dicing (cutting) a boundary portion to separate each semiconductor device.

[0002]

2. Description of the Related Art In recent years, as a sensor for detecting acceleration,
Semiconductor acceleration sensors that are small and lightweight and have the characteristic of directly outputting acceleration information as electric signals are widely used, and are employed, for example, as collision detection sensors in airbag systems for automobiles.

As shown in FIG. 2, for example, such a semiconductor acceleration sensor includes a cantilever beam 10 formed by selectively etching a part 20 of a semiconductor substrate in a U-shape, and a cantilever beam 10. It comprises a gauge section 11 formed near the fixed end of 10 (root) and an amplifier circuit section 12.

In such a semiconductor acceleration sensor, when the free end 10a of the cantilever beam 10 is displaced in accordance with the deceleration, the gauge portion 11 is distorted, and the carrier mobility of the FET formed there is reduced by the external pressure. The magnitude of the acceleration is converted into an electric signal by utilizing the change depending on the acceleration.

Conventionally, such a semiconductor acceleration sensor has also been manufactured by a process similar to that of other semiconductor chips. That is, in each of the semiconductor chip regions of the semiconductor wafer, a "U-shaped" slit penetrating to the back surface is formed by selective etching such as wet etching to form a cantilever.

Next, the semiconductor wafer is placed on an adhesive tape having elasticity in the vertical and horizontal directions, and then pressed by rolling a pressure roller from the wafer surface to fix the semiconductor wafer to the adhesive tape.

[0007] Next, using a dicing saw, dicing is performed on the boundaries between the semiconductor chip regions. At this stage, the cut chips are kept fixed on the adhesive tape.

Next, after the adhesive tape is stretched vertically and horizontally to form a gap between the chips, these are taken out by an appropriate method.

Prior art relating to such a method of manufacturing a semiconductor device is disclosed in, for example, JP-A-63-6223.
No. 5 publication.

[0010]

In the prior art described above, when a semiconductor wafer is bonded to an adhesive tape for dicing, a cantilever is already formed in each semiconductor chip area of the wafer. There is a problem in that the cantilever and its surroundings are easily damaged by transport during loading until the paper is placed on the adhesive tape and subsequent pressing by a pressure roller.

Further, even after dicing, it is necessary to apply a physical force when peeling each semiconductor chip from the adhesive tape, so that the stress is transmitted to each chip, and the cantilever beam and the like is also damaged. There was a problem.

An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a method of manufacturing a semiconductor device in which damage to a semiconductor chip in a process relating to dicing is prevented.

[0013]

According to the present invention, there is provided a method of manufacturing a semiconductor device having a slit formed by selectively etching a part of a semiconductor substrate. A step of uniformly fixing one main surface and a planar sample stage with an adhesive; a step of selectively etching a semiconductor wafer to form a slit in each semiconductor device region; It is characterized in that a step of dicing the portion and a step of dissolving the adhesive body and separating each semiconductor device from the sample stage are provided.

[0014]

According to the above arrangement, the semiconductor wafer is fixed to the sample table before the slit is formed, and the process of transporting and pressing the semiconductor wafer after the slit is formed can be eliminated. Damage to the semiconductor device during fixation can be prevented. Separation of each semiconductor device from the sample table after dicing is performed by dissolving the adhesive, and no physical force is applied to each semiconductor device. Therefore, damage to the semiconductor device during the separation can be prevented. .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram for explaining a manufacturing process of a semiconductor acceleration sensor according to one embodiment of the present invention.

In the present embodiment, a GaAs substrate is used as the wafer 1, and a wax 2 having an adhesive property is first coated on a flat sample table 3 made of glass, Si, or the like at a uniform thickness. It is applied over a large area [FIG. (A)]. As the wax 2, an adhesive having heat curability or room temperature curability can be used, and examples thereof include proof wax and nick HF wax.

Next, the wafer 1 is placed on the wax 2, and the wafer 1 is fixed to the sample table 3. At this time, if necessary, a pressure roller may be used. However, if the wax 2 is applied in advance with a uniform thickness and flat, the back surface of the wafer 1 and the surface of the wax 2 are sufficiently adhered. It is not necessary to use a pressure roller.

Next, a "U-shaped" slit is formed in each semiconductor chip area of the wafer 1 by using an appropriate wet etching technique or the like, so that the cantilever beam whose free end is displaced in accordance with acceleration. To form
(b)].

In this embodiment, as a solvent for wet etching, a mixture of phosphoric acid and hydrogen peroxide (H ₃ PO ₄ : H ₂ O ₂ : H ₂ O) is used.
= 1: 8: 1) and ammonia peroxide (NH ₄ OH: H
₂ O ₂ = 1: 50).

Next, the sample table 3 with the wafer 1 fixed thereon is placed on a dicing saw, and the boundaries between the semiconductor chip regions are vertically and horizontally diced.

Next, the sample table 3 with the wafer 1 fixed thereon is immersed in the solution to dissolve the wax 2. When the proof wax is used as the wax 2,
As the solution for dissolution, heated toluene, methacrene, or trichlene can be used. When the wax dissolves, the fixed state of each semiconductor chip is released,
These are taken out appropriately.

As described above, in this embodiment, the wafer 1
After the wafer is fixed to the sample table 3, cantilever beams are formed in the respective semiconductor chip areas, so that the process of transporting the wafer with the cantilever beam formed thereon can be eliminated, and chip damage during the transport can be eliminated. Can be prevented.

Also, if the wax is previously applied in a uniform thickness and flat, and the back surface of the wafer and the wax surface are in close contact, there is no need to press with a pressure roller.
Even if pressure by the pressure roller is necessary, since no cantilever is formed on the wafer, chip breakage, which has conventionally occurred when pressed by the pressure roller, can be prevented.

Further, a fusible adhesive is used as a means for fixing the wafer 1 to the sample stage 3, and each semiconductor chip after dicing is separated from the sample stage 3 by dissolving the adhesive. Therefore, no physical force is applied to each chip, and breakage of the chip during separation can be prevented.

In the above-described embodiment, the present invention has been described by taking as an example a semiconductor acceleration sensor in which a "cantilever" formed by a "U-shaped" slit functions as a cantilever. Not limited to this,
The present invention can be applied to any semiconductor acceleration sensor having a cantilever formed by an “L” -shaped slit or a slit having another shape.

[0026]

As described above, according to the present invention, the following effects can be achieved. (1) After the wafer is fixed to the sample stage, cantilever beams are formed in each semiconductor chip area, so the process of transporting the wafer with the cantilever beam formed can be eliminated. Chip breakage, which has sometimes occurred, can be prevented. (2) Conventionally, pressing with a pressure roller, which has been performed after placing a wafer with a cantilever formed on an adhesive tape, is no longer necessary. Since the process is performed on the wafer before the cantilever beam is formed, breakage of the chip when the wafer is fixed to the sample stage can be prevented. (3) A fusible adhesive was used as a means for fixing the wafer to the sample table, and each semiconductor chip after dicing was separated from the sample table by dissolving the adhesive. No physical force is applied, preventing chip breakage during separation

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a manufacturing process of a semiconductor acceleration sensor according to one embodiment of the present invention.

FIG. 2 is a perspective view of a semiconductor acceleration sensor.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor wafer, 2 ... Wax, 3 ... Sample stand, 4 ... Semiconductor acceleration sensor, 10 ... Cantilever, 11 ... Gauge part, 12 ... Amplifier circuit part

Continuation of front page (56) References JP-A-4-130647 (JP, A) JP-A-4-69949 (JP, A) JP-A-6-302690 (JP, A) JP-A-7-83707 (JP) , A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/78 H01L 21/301

Claims (1)

(57) [Claims] 1. A method for selectively etching a part of a semiconductor wafer.
In a method of manufacturing a semiconductor device in which a cantilever is formed in each semiconductor device region, the cantilever is formed before the cantilever is formed.
That a step of one main surface and a planar semiconductor wafer and a sample stage uniformly adhered with adhesive material, selectively etching a portion of the semiconductor wafer from the other main surface, the semiconductor device regions Forming a cantilever beam , dicing the boundary of each semiconductor device region from the other main surface , and dissolving the adhesive to separate each semiconductor device from the sample stage. A method for manufacturing a semiconductor device.