JP3182663B2 - Photodiode array and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photodiode array and a method for manufacturing the same. More specifically, the present invention relates to a photodiode array having a simple structure and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
02, a p-type impurity diffusion layer 103 is formed in the separated portion, and a high-concentration n-type impurity diffusion layer 104 is disposed in a surface layer of the p-type impurity diffusion layer 103. Are arranged in series, and the pn junction is appropriately insulated by the silicon oxide film 105 and connected in series by a conductive film to form a photodiode array.

However, as is apparent from FIG. 16, the photodiode array having such a structure has an isolation oxide film 102 formed in a predetermined shape in a semiconductor substrate 101, and a pn junction is formed in a portion separated thereby. The structure is complicated due to the formation of. Therefore, not only the yield in the manufacturing process is poor, but also the cost of the product is increased.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has a simple structure, thereby improving the yield in the manufacturing process and reducing the product cost. It is an object of the present invention to provide a photodiode array capable of achieving the above and a method for manufacturing the same.

[0005]

According to the present invention, there is provided a photodiode array comprising: a semiconductor substrate; an insulating film laminated on the semiconductor substrate; a first impurity diffusion layer disposed on the edge film; High concentration second layer formed in the first impurity diffusion layer
A separation band wall made of an impurity diffusion layer, a plurality of first impurity diffusion layer blocks formed in the first impurity diffusion layer by the separation band wall, and a second body formed from the surface in the block body. A photoelectric conversion element including an impurity diffusion layer, a high-concentration first impurity diffusion layer formed from the surface in the second impurity diffusion layer, and a first element including the photoelectric conversion element.
An insulating film having an electrode forming window formed in a predetermined pattern on the surface of the impurity diffusion layer, an electrode formed in the electrode forming window, and the electrode for connecting the photoelectric converter in series are connected. Wiring pattern, a second impurity diffusion layer formed in the block body, and a wiring pattern for converting a parasitic transistor into a diode bridged between the first impurity diffusion layer forming the block body. It is characterized by becoming.

[0006] In the photodiode array of the present invention, it is preferable that the block bodies formed in tandem are arranged in a plurality of rows.

In the photodiode array according to the present invention, the first impurity diffusion layer is an n (p) -type impurity diffusion layer, and the second impurity diffusion layer is a p (n) -type impurity diffusion layer. Is preferred.

Further, in the photodiode array according to the present invention, A is provided above the high-concentration second impurity diffusion layer.
It is preferable that a light shielding layer made of a metal thin film such as l is provided.

According to a method for manufacturing a photodiode array of the present invention, a step of forming an oxide thin film layer on a surface of a semiconductor substrate,
Joining the impurity-diffused semiconductor plate, polishing the surface of the joined first impurity semiconductor substrate,
Forming a separation wall made of a high-concentration second impurity diffusion layer in the first impurity diffusion layer, and blocking the first impurity diffusion layer in tandem; A second impurity diffusion layer is formed from the surface in the layer, and thereafter, a high concentration first impurity diffusion layer is formed in the second impurity diffusion layer.
Forming a photoelectric conversion body by forming an impurity diffusion layer from a surface; and forming an insulating film having an electrode formation window in a predetermined pattern on a surface of the first impurity diffusion layer on which the photoelectric conversion body is formed. A step of forming a film, a step of forming an electrode in the electrode forming window, a step of forming a wiring pattern that connects the photoelectric converters in series, and a step of forming a wiring pattern in the blocked first impurity diffusion layer. A step of forming a wiring pattern between the second impurity diffusion layer and the first impurity diffusion layer to convert a parasitic transistor into a diode.

In the manufacturing method according to the present invention, it is preferable that in the step of blocking the first impurity diffusion layer in a cascade, a plurality of the blocked regions are formed.

In the method of the present invention, the first impurity diffusion layer is an n (p) -type impurity diffusion layer, and the second impurity diffusion layer is a p (n) -type impurity diffusion layer. preferable.

Further, in the manufacturing method of the present invention, it is preferable that a step of arranging a light shielding layer with a metal thin film of Al or the like is added above the high concentration second impurity diffusion layer.

[0013]

In the photodiode array of the present invention,
A first impurity diffusion layer is formed on an insulating film formed on a semiconductor substrate, and the first impurity diffusion layer is separated by a high-concentration second impurity diffusion layer formed vertically in the layer. The sectional structure is simplified. Further, in the preferred embodiment, in addition to the short-circuiting of the base and the emitter of the parasitic transistor to form a diode, the light blocking layer is disposed on the separation PN junction, thereby preventing the parasitic operation.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described based on embodiments with reference to the attached drawings, but the present invention is not limited to only such embodiments.

FIG. 1 is a cross-sectional view of a main part of one embodiment of the present invention, FIG. 2 is a plan view of one embodiment of the present invention, FIG. 3 is an equivalent circuit diagram of one embodiment of the present invention, and FIG. FIG. 5 is a sectional view of a main part of an embodiment.
15 are explanatory views of one embodiment of the production method of the present invention.

As shown in FIGS. 1 and 2, a photodiode array according to an embodiment of the present invention includes a semiconductor substrate 1, an oxide insulating film 2 laminated on the semiconductor substrate 1, and an oxide insulating film. An n-type semiconductor layer (first impurity diffusion layer) 3 provided on the film 2 and a high-concentration p-type impurity diffusion layer (high-concentration second impurity diffusion layer) formed in the n-type semiconductor layer 3 A separation band wall 4, a plurality of blocks 3 a of n-type semiconductor layers formed in the n-type semiconductor layer 3 by the separation band wall 4 and arranged in tandem, and the surface inside the block 3 a A formed p-type impurity diffusion layer (second impurity diffusion layer) 5; a high-concentration n-type impurity diffusion layer (high-concentration first impurity diffusion layer) 6 formed on the surface of the p-type impurity diffusion layer 5; And an n-type semiconductor on which the photoelectric converter 7 is formed. A silicon oxide insulating film 8 having an electrode forming window formed in a predetermined pattern on the surface of the layer 3, an electrode 9 formed in the electrode forming window, and the photoelectric converter 7 are connected in series. The parasitic transistor formed between the wiring pattern 10 connected to the electrode 9, the p-type impurity diffusion layer 5 formed in the block 3a, and the n-type semiconductor layer 3 forming the block 3a is formed. It is composed of a wiring pattern 11 for forming a diode and a protective film 12.

Since the semiconductor substrate 1 is a support substrate for the active region laminated thereon, a substrate having a sufficient strength is used. Specifically, those having a thickness of usually 200 to 500 μm are used.

The oxide insulating film 2 is made of a silicon oxide film. Further, the film thickness is set to 1000 to 10000 °.

The thickness of the n-type semiconductor layer 3 is set to 5 to 20 μm in order to limit the diffusion depth.

Further, each separated block body 3a is
The length of the side is a rectangle of about 0.3 to 0.6 mm.

The thickness of the silicon oxide insulating layer 8 formed on the surface of the n-type semiconductor layer 3 is 100
It is set to 0 to 10000 °. The insulating layer 8 is not limited to a silicon oxide film as long as it has an insulating property and an appropriate translucency, and a nitride film or the like can be suitably used.

Thin film electrode 9 and wiring patterns 10 and 11
An aluminum film having a thickness of 1.0 to 2.0 μm is used.

FIG. 3 is an equivalent circuit in which a parasitic transistor is formed into a diode by the wiring pattern 11. A portion surrounded by a chain line in the drawing indicates a portion where the parasitic transistor is converted into a diode.

Although not shown, a contact hole, a pad bonding hole and the like are formed in the present invention as in the conventional photodiode array.

In another embodiment, in order to prevent light irradiation on the high-concentration p-type impurity diffusion layer 4, an aluminum film is formed on the protective film 12 on the high-concentration p-type impurity diffusion layer 4. A light blocking layer 13 is formed. The formation of the light blocking layer 13 ensures prevention of the parasitic operation of the parasitic transistor.

Next, a manufacturing process according to an embodiment of the present invention will be described with reference to FIGS.

Step 1: A silicon oxide film 2 is formed on a semiconductor substrate 1. (See Fig. 5)

Step 2: The semiconductor substrate 1 prepared in Step 1 and an n-type semiconductor plate (an oxide film is not formed on this n-type semiconductor plate) are prepared, and the oxide films 2 and n of the semiconductor substrate 1 are prepared. One side of the mold semiconductor plate is faced back to back, and two pieces are arranged in each slot of the diffused quartz board,
The semiconductor substrate 1 and the n-type semiconductor plate are joined by forming an atmosphere of O ₂ gas or water vapor in a diffusion furnace at 1000 to 1250 ° C. and leaving the atmosphere for a predetermined time. Then, the bonded n-type semiconductor plate is used as an n-type semiconductor layer. (FIG. 6
reference)

Step 3: The surface of the n-type semiconductor layer 3 is polished. (Refer to FIG. 7) This polishing is performed so that the film thickness from the oxide film 2 to the surface of the n-type semiconductor layer 3 is 5 to 20 μm.

Step 4: A silicon oxide insulating layer is formed on the surface of the n-type semiconductor layer 3. Thereafter, the oxide film in a predetermined region is removed using a high-concentration p-type impurity diffusion mask. (See Fig. 8)

Step 5: A p-type impurity is diffused at a high concentration, a high-concentration p-impurity diffusion layer 4 is formed, the n-type semiconductor layer 3 is blocked, and a block 3a is formed. (See Fig. 9)

Step 6: A p-type impurity diffusion mask is formed on the surface of the n-type semiconductor layer. (See Fig. 10)

Step 7: A p-type impurity is diffused into the block 3a to form a p-type impurity diffusion layer 5. (See Fig. 11)

Step 8: A high concentration n-type impurity diffusion mask is formed on the surface of the n-type semiconductor layer 3. Then, p
A high-concentration n-type impurity diffusion layer 6 is formed in the impurity diffusion layer 5. (See Fig. 12)

Step 9: A contact hole is formed in a predetermined area using a rectangular mask. (See FIG. 13)

Step 10: The electrodes 9 and the wiring patterns 10 and 11 are formed on the surface of the n-type semiconductor layer 3 using a mask of a predetermined shape in order to ohmic-connect the pn junction formed in the block body 3a. The wiring pattern 10 is appropriately insulated by the silicon oxide film insulating layer 8. (See Fig. 14)

Step 11: A surface protection layer 12, a hole for pad bonding and the like are formed to complete a photodiode array. (See Fig. 15)

In another embodiment, after the surface protection layer 12 is formed, a light blocking layer 13 made of an aluminum film is disposed above the high concentration p-type impurity diffusion layer 4.

In the above embodiment, a photodiode array is formed by forming a p-type impurity diffusion layer using an n-type semiconductor plate (layer) as a base material. However, the semiconductor plate to be used is limited to an n-type semiconductor plate. However, a p-type semiconductor plate can also be suitably used. In this case, as a matter of course, it is necessary to use an n-type impurity as the impurity diffused in the base material.

[0040]

As described above, in the photodiode array of the present invention, the first impurity diffusion layer is formed on the insulating film formed on the semiconductor substrate, and the first impurity diffusion layer is formed in this layer. Since the block body is separated by the high-concentration second impurity diffusion layer formed in the vertical direction and a pn junction is formed therein, the sectional structure is simplified. Therefore, it can be easily manufactured, and the yield of products is improved. In addition, since the base and the emitter of the parasitic transistor are short-circuited to form a diode, an effect of preventing a parasitic operation can be obtained.

Further, according to the method of manufacturing the photodiode array of the present invention, the photodiode array of the present invention can be manufactured by a simple process, and the cost of the product can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention.

FIG. 2 is a plan view of one embodiment of the present invention.

FIG. 3 is an equivalent circuit diagram of one embodiment of the present invention.

FIG. 4 is a sectional view of a main part of another embodiment of the present invention.

FIG. 5 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 6 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 7 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 8 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 9 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 10 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 11 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 12 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 13 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 14 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 15 is a part of an explanatory view of one embodiment of the production method of the present invention.

FIG. 16 is a longitudinal sectional view of a conventional photodiode array.

[Explanation of symbols]

 Reference Signs List 1 semiconductor substrate 2 oxide insulating film 3 n-type semiconductor layer 3a block 4 high-concentration p-type impurity diffusion layer (separation band wall) 5 p-type impurity diffusion layer 6 high-concentration n-type impurity diffusion layer 7 photoelectric converter 8 silicon oxide Object insulating film 9 electrode 10 wiring pattern 11 wiring pattern 12 protective film 13 light blocking layer

Claims (4)

(57) [Claims] A semiconductor substrate; an insulating film stacked on the semiconductor substrate; a first impurity diffusion layer disposed on the edge film; and a high-concentration impurity formed in the first impurity diffusion layer. A separation band wall made of a second impurity diffusion layer; a plurality of first impurity diffusion layer blocks formed in the first impurity diffusion layer by the separation band wall; and a block formed from the surface in the block body. A photoelectric conversion body comprising a second impurity diffusion layer, a high-concentration first impurity diffusion layer formed from the surface in the second impurity diffusion layer, and a surface of the first impurity diffusion layer on which the photoelectric conversion body is formed To
An insulating film having an electrode forming window formed in a predetermined pattern; an electrode formed in the electrode forming window; and a wiring pattern connected between the electrodes for serially connecting the photoelectric converters; It is characterized by comprising a wiring pattern for converting a parasitic transistor into a diode, formed between a second impurity diffusion layer formed in the block body and a first impurity diffusion layer forming the block body. Photodiode array. 2. The method according to claim 1, further comprising the step of:
The photodiode array according to claim 1, wherein a light blocking layer is provided. A step of forming an oxide thin film layer on a surface of the semiconductor substrate; a step of bonding the semiconductor substrate on which the oxide thin film layer is formed to a first impurity diffusion type semiconductor plate; Polishing the surface of the first impurity semiconductor plate; forming a separation band wall composed of a high-concentration second impurity diffusion layer in the first impurity diffusion layer; blocking the first impurity diffusion layer in a cascade And forming a second impurity diffusion layer from the surface in the blocked first impurity diffusion layer, and thereafter, forming a high concentration first impurity diffusion layer from the surface in the second impurity diffusion layer. A step of forming a photoelectric converter, a step of forming an insulating film having an electrode forming window in a predetermined pattern on the surface of the first impurity diffusion layer on which the photoelectric converter is formed, Forming electrodes in the forming window Forming a wiring pattern that connects the photoelectric converters in series; forming a wiring pattern that connects the photoelectric converters in series; and forming the second impurity diffusion layer formed in the blocked first impurity diffusion layer, and the first impurity diffusion layer. Forming a wiring pattern in order to convert the parasitic transistor into a diode. 4. The method according to claim 1, further comprising the step of:
4. The method for manufacturing a photodiode array according to claim 3, further comprising a step of providing a light shielding layer.