CN1841149A - Passivation protection method for silicon-based liquid crystal aluminum reflecting electrode - Google Patents

Abstract

A passivation protection method for a liquid crystal on silicon (LCOS) aluminum reflective electrode belongs to the technical field of microelectronic device preparation, and the process steps are as follows: 1. Photoetching a reflective electrode pattern on the surface of a silicon substrate; The surface of the patterned silicon wafer is evaporated with an electron beam to form an aluminum film; 3. The required aluminum reflective electrode pattern is obtained by using a conventional stripping process; 4. Silicon dioxide is grown on the aluminum reflective electrode as a passivation layer to complete the production. The method of the invention has the advantages of low cost and simple process.

Description

Passivation protection method of silicon-based liquid crystal aluminum reflective electrode

technical field

The invention belongs to the technical field of preparation of microelectronic devices, in particular to a passivation protection method for a liquid crystal on silicon (LCOS) aluminum reflective electrode.

Background technique

Liquid crystal on silicon (LCOS) is a high-tech product that combines silicon semiconductor technology and optical imaging technology on the basis of traditional liquid crystal display devices. As an important part of liquid crystal on silicon (LCOS), the reflective electrode has a direct impact on the overall display performance of liquid crystal on silicon (LCOS). At present, the reflective electrode of liquid crystal on silicon (LCOS) is made of aluminum, but aluminum The reflective surface is easily oxidized to form aluminum oxide, which reduces the reflectivity and finally leads to a decrease in the overall performance of the device.

Contents of the invention

The purpose of the present invention is to provide a method for solving the problem that the aluminum reflective electrode of liquid crystal on silicon (LCOS) is easily oxidized and the reflectivity is reduced.

In order to achieve the above object, the technical solution of the present invention is to firstly process the aluminum reflective electrode on the silicon wafer, and then vapor-phase deposit silicon dioxide on the reflective electrode as a passivation protection layer.

The passivation protection method of described a kind of liquid crystal on silicon (LCOS) aluminum reflection electrode, its steps are as follows:

Step 1, photoetching a reflective electrode pattern on the surface of the silicon substrate;

Step 2, evaporating an aluminum film on the surface of the photolithographically patterned silicon wafer with a low-temperature electron beam;

Step 3, using a conventional stripping process to obtain the required aluminum reflective electrode pattern;

Step 4, growing a silicon dioxide passivation layer on the aluminum reflective electrode.

The passivation protection method of the described a kind of liquid crystal on silicon (LCOS) aluminum reflective electrode, in its described step 1, photoetch the reflective electrode pattern on the silicon substrate surface, coat 9912 glue earlier before photoetching, thick 1000- 1500nm.

The passivation protection method of a kind of described a kind of liquid crystal on silicon (LCOS) aluminum reflection electrode, the aluminum thin film deposited on the silicon substrate surface of its described step 2, thickness is 45～55nm, evaporated with low-temperature electron beam method to obtain.

According to the passivation protection method of a liquid crystal on silicon (LCOS) aluminum reflective electrode, the stripping process in step 3 is completed in acetone with ultrasonic waves.

The passivation protection method of a kind of described liquid crystal on silicon (LCOS) aluminum reflective electrode, its described step 4 grows silicon dioxide passivation layer on the aluminum reflective electrode, thickness is 200-350nm, with plasma enhanced chemical vapor deposition (PECVD) method to obtain.

According to the passivation protection method for silicon-based liquid crystal aluminum reflective electrodes, after the glue is applied, it is baked on a hot plate at 85-90° C. for 2.5-3.5 minutes.

The method of the invention has the advantages of low cost and simple process.

Description of drawings

Fig. 1-1 to Fig. 1-5 are the flowchart of the passivation protection method of liquid crystal on silicon (LCOS) aluminum reflective electrode of the present invention;

2-1 to 2-5 are flow charts of the embodiments of the present invention.

Detailed ways

The specific implementation steps of the passivation protection method of silicon-based liquid crystal (LCOS) aluminum reflective electrode of the present invention are as follows:

1. As shown in Fig. 1-1, coat an optical photoresist 102 on the surface of the silicon substrate 101, the optical photoresist is S9912, and the thickness of the photoresist is 1000-1500nm.

2. As shown in FIG. 1-2 , the top layer of optical photoresist 102 is exposed by optical lithography, and the top layer of optical photoresist is developed to obtain a pattern 103 .

3. As shown in Figures 1-3, an aluminum thin film 104 is deposited on the surface of the optical photoresist 102. The aluminum thin film 104 has a thickness of 45-55 nm and is obtained by low-temperature electron beam evaporation.

4. As shown in Figures 1-4, the photoresist and the aluminum film on the photoresist are stripped and removed by acetone plus ultrasonic method, and finally the aluminum film pattern 105 on the silicon wafer is obtained.

5. As shown in Figures 1-5, a silicon dioxide film 106 is grown on the aluminum reflective electrode with a thickness of 200-350nm by plasma enhanced chemical vapor deposition (PECVD), and the passivation protective layer of the aluminum reflective electrode is completed.

Example

1. As shown in Figure 2-1, apply an optical photoresist 202 on the surface of the silicon substrate 201, the optical photoresist is S9912, and the thickness of the adhesive is 1000-1500nm; after coating, bake on a hot plate at 85°C for 3 minutes .

2. As shown in FIG. 2-2 , the top-layer optical photoresist 202 is exposed by the optical lithography method, and the top-layer optical photoresist is developed to obtain a pattern 203 .

3. As shown in Figures 2-3, an aluminum film 204 is deposited on the surface of the optical photoresist 202. The thickness of the aluminum film 102 is 50nm, which is obtained by low-temperature electron beam evaporation.

4. As shown in FIG. 2-4, the photoresist and the aluminum film on the photoresist are stripped and removed by acetone plus ultrasonic method, and finally the aluminum film pattern 205 on the silicon wafer is obtained.

5. As shown in FIG. 2-5, a silicon dioxide film 206 is grown on the aluminum reflective electrode with a thickness of 200-350nm by plasma enhanced chemical vapor deposition (PECVD), and the passivation protective layer of the aluminum reflective electrode is completed.

Claims (6)

1, a kind of passivation protection method of silicon-based liquid crystal aluminium reflection electrode is characterized in that, its key step is as follows:

Step 1, on the silicon chip surface, make the reflecting electrode figure by lithography;

Step 2, go out the aluminium film in the silicon chip surface deposited by electron beam evaporation that makes figure by lithography;

Step 3, the conventional stripping technology of employing obtain required aluminium reflection electrode figure;

Step 4, on aluminium reflection electrode the growthing silica passivation layer.

2, the passivation protection method of a kind of silicon-based liquid crystal aluminium reflection electrode according to claim 1 is characterized in that, described step 1 on the silicon chip surface, make the reflecting electrode figure by lithography, be coated with S9912 glue before the photoetching earlier, thick 1000～1500nm.

3, the passivation protection method of a kind of silicon-based liquid crystal aluminium reflection electrode according to claim 1 is characterized in that, the aluminium film of the deposit on the silicon chip surface of described step 2, and thickness is 45～55nm, with the method acquisition of cryotronics beam evaporation.

4, the passivation protection method of a kind of silicon-based liquid crystal aluminium reflection electrode according to claim 1 is characterized in that, the stripping technology of described step 3 is in acetone and adopt ultrasound wave to finish.

5, the passivation protection method of a kind of silicon-based liquid crystal aluminium reflection electrode according to claim 1; it is characterized in that; described step 4 is the growthing silica passivation layer on aluminium reflection electrode, obtains with the plasma reinforced chemical vapour deposition method, and thickness is 200～350nm.

6, the passivation protection method of a kind of silicon-based liquid crystal aluminium reflection electrode according to claim 2 is characterized in that, after the described gluing, toasts 2.5～3.5 minutes on 85～90 ℃ of hot plates again.

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