JPH0624237B2 - Method for manufacturing amorphous silicon image sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is directed to the manufacture of an amorphous silicon contact image sensor having a density strength capable of mounting semiconductor elements even after a conductor circuit is formed and an amorphous silicon film deposition process is performed. Regarding the method.

[Conventional technology]

Conventionally, the thick film method and the thin film method have been adopted as conductor circuit forming methods for large-area electronic devices that require high reliability. Among them, the thick film method is characterized by inexpensive equipment and excellent productivity. is there.

In the thick film method, ceramics were conventionally used for the substrate and thick film gold was used as the conductor, but in order to significantly reduce the cost, a method has been proposed in which the substrate is made of glass and the metalloorganic gold paste is used as the conductor material. ing. Metalloorganic gold paste is a paste made by mixing an organic complex of gold with an organic solvent such as terpineol.
The adhesion strength of the paste becomes stronger as the firing temperature increases,
Although peeling of the conductor is less likely to occur, when an inexpensive general glass substrate such as barium borosilicate glass is used, 7
If the temperature is over 00 ° C, it will be softened and deformed.
The upper limit is 00 ° C. Therefore, using a glass substrate 700
In order to obtain sufficient adhesion strength by low-temperature firing at a temperature of ℃ or less, it is necessary to add an organic complex of a metal such as copper, which easily forms an oxide bond, to the metalloorganic gold paste.

[Problems to be solved by the invention]

However, in the conventional amorphous silicon contact image sensor manufacturing process using the method of adding an organic complex of a metal such as copper that easily forms an oxide bond in the metalloorganic gold paste, the amorphous silicon deposition film is formed after the conductor circuit is formed. For plasma CVD
In order to pass through the process, the oxide bond between the gold conductor and the substrate is broken by the reducing atmosphere of CVD, the adhesion strength between the glass substrate and the gold conductor is significantly lowered, and the glass element is peeled off when a physical force is applied. However, there is a problem in that it may not be possible to mount by the wire bonding method.

The present invention is intended to solve the above problems, and an amorphous silicon adhesion type image capable of mounting a semiconductor element without lowering the adhesion strength of a conductor film to a glass substrate even after an amorphous silicon film formation step. It is an object to provide a method for manufacturing a sensor.

[Means for solving problems]

Therefore, the method for manufacturing an amorphous silicon contact type image sensor of the present invention includes a step of forming a conductor circuit on a glass substrate by screen printing and firing using a metallo-organic gold paste, and depositing amorphous silicon by plasma CVD. In the manufacturing process of the equipped amorphous silicon contact image sensor,
The method is characterized by comprising a step of forming a protective glass layer on the conductor circuit before the plasma CVD step and a step of removing the protective glass layer after the plasma CVD step.

[Action]

The method for manufacturing an amorphous silicon contact type image sensor of the present invention comprises forming a conductor circuit on a glass substrate by screen printing and firing using a metalloorganic gold paste, and then forming a protective glass layer on the conductor circuit before the plasma CVD step. By forming and removing the protective glass layer after the plasma CVD step, it becomes possible to mount the semiconductor element without lowering the adhesion strength of the conductor to the glass substrate even after passing through the amorphous silicon film forming step. .

〔Example〕

 Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a sectional view of an image sensor substrate before the CVD process according to the present invention, in which 1 is a glass substrate, 2 is a gold conductor, 3 is a chrome electrode, and 4 is a protective glass layer.

In the figure, for example, a barium borosilicate glass substrate having excellent heat resistance is used as the glass substrate 1, and 1.5% by weight of cupric carboxylate is added to the glass substrate 1 to form a uniform metalloorganic material. A gold paste is screen-printed and low temperature firing at 700 ° C. is repeated twice to form a gold conductor film 2 having a thickness of 0.6 μm. After patterning the gold conductor film 2 by ordinary photolithography, a chromium electrode 3 serving as a sensor lower electrode is formed by vacuum vapor deposition and photolithography. A protective glass layer 4 is formed by screen printing firing of lead borosilicate glass paste so as to cover the gold conductor film 2 of the circuit thus obtained. In this case, when the baking temperature of the protective glass layer 4 is high, the blocking characteristic of the chromium electrode 3 is changed, and the ratio of the inter-electrode current value between when the light is irradiated and when the light is not irradiated becomes small, which deteriorates the sensor function. In order to prevent this, the firing temperature is 530 ° C.
The following is desirable. In this embodiment, the peak temperature is 5
The glass layer 4 having a thickness of 8 to 10 μm is formed by a firing cycle of 00 ° C., a peak time of 9 minutes, and a total of 55 minutes, and it is desirable to use lead borosilicate glass having a softening point of about 300 to 500 ° C. . The protective glass layer 4 need not be limited to lead borosilicate glass, but is preferably lead glass.

FIG. 2 is a cross-sectional view of the image sensor after the semiconductor element mounting process, in which 5 is a semiconductor element, 6 is a gold wire, 7 is a resin seal, 8 is amorphous silicon, and 9 is an ITO transparent electrode.

Plasma CV is applied to the substrate obtained as described above.
Amorphous silicon 8 is deposited by D, and a silicon ITO transparent electrode is formed on the amorphous silicon 8 by sputtering, the sensor portion of the ITO electrode is covered with a resist, and the protective glass layer 4 is removed by etching.

Since the lead borosilicate protective glass layer 4 used in this example has a high lead oxide content, it dissolves in both alkaline and acidic aqueous solutions. HNO ₃ : HCI: H ₂ as etching liquid
O = 1: 1: 8 (volume ratio) is used and the etching time is 6
0 seconds. At the same time as the etching of the protective glass layer,
The ITO electrode may be etched to improve the accuracy of defining the sensor area.

Thus, the tensile strength of the 30 μmφ gold wire 6 is about 8 g, which is about the same as that before the CVD process, and the conventional problem that the adhesion strength is reduced in the reducing atmosphere can be solved.

〔The invention's effect〕

As described above, according to the method for manufacturing an amorphous silicon contact type image sensor of the present invention, since the metal conductor is protected by the glass layer, the adhesion strength between the substrate and the conductor does not decrease even after deposition of the amorphous silicon, and the semiconductor It becomes possible to mount elements and the like. In addition, although ITO is conventionally etched to precisely define the sensor area, since ITO is etched with the glass layer etching solution of the present invention, ITO-glass simultaneous etching is also possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of an image sensor substrate before a CVD process according to the present invention, and FIG. 2 is a lateral sectional view of an image sensor after a semiconductor element mounting process. 1 ... glass substrate, 2 ... gold conductor, 3 ... chrome electrode,
4 ... Protective glass layer, 5 ... Semiconductor element, 6 ... Gold wire,
7 ... Resin seal, 8 ... Amorphous silicon, 9 ...
... ITO transparent electrode.

Claims (2)

[Claims] 1. A manufacturing process of an amorphous silicon contact type image sensor comprising a step of forming a conductor circuit on a glass substrate by screen printing and firing using a metalloorganic gold paste and depositing amorphous silicon by plasma CVD. A method of manufacturing an amorphous silicon contact image sensor, comprising: a step of forming a protective glass layer on a conductor circuit before the plasma CVD step; and a step of removing the protective glass layer after the plasma CVD step. 2. The protective glass layer has a softening point of 300 to 500.
The method for producing an amorphous silicon contact type image sensor according to claim 1, wherein the method is formed by screen-printing and firing lead borosilicate glass paste in the range of ° C.