JPH01319313A - Manufacture of surface acoustic wave element - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention provides an elastic transducer in which at least two transducers are provided on a piezoelectric substrate that propagates surface acoustic waves, one on the input side and the other on the output side. The present invention relates to a method of manufacturing a surface wave device.

[Conventional technology]

FIG. 4 shows a flowchart 1 of the procedure performed when forming input/output electrodes on a piezoelectric substrate. Further, a cross-sectional view of the substrate obtained by this procedure is shown in FIG.

In FIG. 3, a film of aluminum (2) is formed on a piezoelectric substrate (3) by vacuum evaporation, sputtering, or the like. Next, a resist is applied, and after pre-heat treatment, a pattern of a surface acoustic wave element is formed on the resist (6) by light exposure or EBil light. Thereafter, heat treatment is applied again, etching is performed, and dicing (4) is performed using a dicing saw (5).

Thereafter, a chip (not shown) is mounted on each package, and assembly is performed.

Next, the effect will be explained. After the pretreatment, an aluminum thin film (2) is formed on the piezoelectric substrate (3) by vacuum evaporation or sputtering. Next is aluminum thin ffl! (2+,
In order to form the pattern of the surface acoustic wave element, resist (6
) is applied and heat treated for exposure. After pattern formation by light exposure, electron beam exposure, etc., heat treatment is applied again. After this treatment, a pattern is formed by etching the aluminum thin film.

After that, it is diced (4) and finally assembled into a package.

By the way, this dicing process can be done using a dicing saw (
5), since the aluminum pattern (2) is directly cut, it becomes dirty and the pattern may be cut, so a protective film (non-conductive material) (6) is usually applied. Also dicing saw (5
) is rotating at high speed, so it is a piezoelectric substrate (3)
causes an electric charge.

[Problem to be solved by the invention]

Conventional surface acoustic wave devices were manufactured in the manner described above, which caused charging during dicing, which accelerated the deterioration between the aluminum thin film (after pattern formation) and the protective film, resulting in breakage of the electrode pattern. However, there were problems such as a decrease in yield.

This invention was made to solve the above problems. By changing the protective film applied during dicing from a non-conductive material to a conductive material, charging can be prevented and the yield can be improved. The purpose is to

[Means to solve the problem]

In the method for manufacturing a surface acoustic wave device according to the present invention, the protective film is made of a conductive material in order to prevent charging that occurs during dicing.

[Effect]

In the manufacturing method of the present invention, by making the protective film conductive, the pattern surfaces can be brought to the same potential, and the piezoelectric substrate is not charged, and deterioration of the aluminum pattern is also reduced.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (1) is a conductive protective film, (2) is a surface acoustic wave element pattern, (3) is a piezoelectric substrate, (4) is a cutting point with a dicing saw, and (5) is a dicing saw. be.

Moreover, FIG. 4 shows a flowchart of the manufacturing method,
A protective film is applied during dicing.

Next, the effect will be explained. The aluminum thin film formation, resist coating, heat treatment, exposure, and heat treatment are the same as the conventional method, but by applying conductive material 33v4 (1) during die-ring, charging can be prevented, and the aluminum pattern (2) Preventing deterioration (corrosion).

In the above example, a conductive material is added to the I film (1) during dicing.
By having conductivity inside, charging can be prevented, and even after pattern formation, a conductive resist α■ is applied.
The process of adding heat treatment can have the effect of preventing static electricity. (In the case of sintering, etc. performed on semiconductors), the effect is that it is easy to remove because it is a resist, and it is also effective against charging (FIG. 2).

〔Effect of the invention〕

As described above, according to the present invention, by changing the protective film during dicing from non-conductive to conductive in the conventional manufacturing method, deterioration of aluminum due to charging can be prevented. Improved paper yield can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a method for manufacturing a surface acoustic wave device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a process including a heat treatment step showing another embodiment of the present invention, and FIG. FIG. 4, a cross-sectional view of a conventional surface acoustic wave device manufacturing method, shows a flowchart of the surface acoustic wave device manufacturing process. In the figure, (1) is the protective film (conductive material), (2) is the SAW aluminum F41JI pattern, (3) is the substrate (piezoelectric), (4) is the cutting location of the dicing saw, and (5) is the dicing saw. , (6) is a protective film (non-conductive material). In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a method for manufacturing a surface acoustic wave device having at least two transducers formed on a piezoelectric substrate, one of which is used as an input and the other as an output, in particular, converting the surface acoustic wave device from a wafer state to a chip state. A method for manufacturing a surface acoustic wave device, comprising performing a process to prevent charging of a wafer in a dicing process and a heat treatment process.