JPS62202556A - Semiconductor device - 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 [Field of Industrial Application] The present invention relates to a semiconductor device having a circuit section requiring light shielding, and particularly to a semiconductor device intended to prevent light from entering the circuit section.

[Prior Art] As an example, a case of an optical sensor device in which an optical sensor section and peripheral circuits such as an amplifier are formed on the same substrate will be described.

FIG. 3 shows a conventional optical sensor device (2003) (which was eventually described in Japanese Patent Application No. 183149/1983).

)'s J! It is a schematic cross-sectional view.

In the same figure, an optical sensor IPD is mounted on a P-type semiconductor substrate l.
, MOS) transistor section MO9 and bipolar transistor section BI are formed with a P1 region serving as an element isolation region sandwiched therebetween.

Light sensor? In BPD, P+ region 3 within N- region 2
is formed, and a P+-N- type photodiode is formed. MOS transistor part MO9 has N-
A P+ region 5 is formed as a source and drain region in the region 4, and a P+ region 7 as a base region is formed in the N- region 6 in the bipolar transistor section Bl.

A gate oxide film to a thickness of 500 mm is formed on the substrate 11z, and the portion where the N0 region is to be formed is selectively removed by kneeling. Then, by depositing and patterning polysilicon doped with phosphorus, the electrode 8 of the photodiode, the gate electrode 3 of the MOS transistor, and the emitter electrode 10 and collector electrode 11 of the bipolar transistor are formed. Subsequently, oxidation I) to a thickness of 1500-2000 by 8 intoxication! At the same time as forming 212, the impurity phosphorus in the polysilicon is removed.
(diffuse into the plate 1, N+ region 13, emitter region 14
and N+ region 15 are respectively formed.

Next, after forming the psc film 1B to a thickness of 6000 mm on the oxidized film 12 by CVD method, the oxide film 12 and the PSG
Form a contact hole in It16 and connect AI wiring 1
7 is formed on each element. Next, plasma nitriding 11!2
After forming 18, a light shielding layer 19 of AI is formed, and a plasma nitride film 20 for passivation is further formed. continue.

The plasma nitride films 20 and 18 and the light shielding layer 19 on the photodiode PD are removed by plasma etching to form the light receiving section 21.

In such a configuration, external light only enters the photodiode PD through the light receiving section 21.

Other parts are blocked from external light by a light blocking layer 19.

[Problems to be Solved by the Invention] However, in a semiconductor device having such a configuration, when strong light is incident obliquely, the light enters an element part that needs to be shielded, causing fluctuations in output characteristics. It had

FIG. 4 is a schematic cross-sectional view of the end portion of the conventional example. In the figure, light 22 is incident obliquely.

(Multiple reflections occur between the interface of the plate 1 and the interface of the light-shielding layer 19, and the light reaches the element part such as a transistor.)Normally, the light intensity is rapidly attenuated after several reflections. However, in the case of strong light, multiple reflections occur repeatedly and reach the element, resulting in fluctuations in its output characteristics.Such multiple reflections occur when insulating layers with different refractive indexes are laminated. It also occurs between interfaces when

Further, similar fluctuations in output characteristics occur when light is incident obliquely not only from the end of the optical sensor device but also from the light receiving section 21.

[Means for Solving the Problems] A deconductor device according to the present invention includes a circuit portion formed on a substrate, and a light-shielding layer laminated on the board via an insulating layer and shielding the circuit portion from light. In a conductor device having ゛h.

A scattering means is provided in the insulating layer around the circuit section.

[Function] By providing the above-mentioned scattering means around the circuit section, obliquely incident light is not reflected as a bundle of parallel light, and therefore the light is rapidly attenuated within the insulating layer around the circuit section. . Therefore, even when strong light is incident obliquely, it is possible to almost completely prevent external light from affecting the circuit section.

[Embodiment 1] Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1(A) is a JIwlS plan view of a photosensor device which is a first embodiment of a semiconductor device according to the present invention, and FIG.
) is a schematic cross-sectional view of the surrounding area.

In each figure, a circuit section C consisting of a photodiode section P port and a MOS transistor or a bipolar transistor is formed on a semiconductor substrate 101, and the output of the photodiode is sent to the circuit section C through A1 wiring &1102. Further, an insulating layer IQ3 and a light shielding layer 104 are provided on the substrate 101.
are layered. Insulating layer 103 corresponds to insulating layers 12, 16 and 18 in the conventional example. Furthermore, the insulating layer 103
Inside, two rows of polysilicon layers 105 as scattering means are formed around the substrate 101, and one row of polysilicon layers 105 is formed between the photodiode section PD and the circuit section C.

This polysilicon layer 105 forms the photodiode portion PD.
They may be formed simultaneously when forming the polysilicon electrodes (electrode 8, gate electrode 9, electrode 10 and +t7 in the conventional example) in the circuit portion C.

By providing such a polysilicon layer 105, as shown in the figure, the obliquely incident light 10B is
is scattered by the polysilicon layer 105 and is attenuated during that time, so that no propagation occurs due to multiple reflections. Therefore, the light does not reach the circuit section C and does not affect the output characteristics of the circuit section C.

Note that although the polysilicon layer 105 has an effect even if it is arranged in rows, it has an even greater effect if it is arranged in multiple rows and the pitch is random.

Further, the scattering means does not need to be polysilicon, and may be AI, which is the wiring material used in the circuit section C.
In short, without increasing the process of forming the scattering means,
It suffices if it can be formed at the same time as forming the electrodes, wiring, etc. in the circuit section C.

FIG. 2(A) is a schematic plan view of the first and second embodiments of the present invention, and FIG. 2(B) is a schematic sectional view of the peripheral portion thereof.

In each figure, a circuit portion C is formed on a conductive substrate 107, and a light shielding layer 109 is formed on the circuit portion C with an insulating layer 108 interposed therebetween. Further, in the same area of the circuit portion C, polysilicon layers 11G and AI layers 111 are alternately arranged. These forming methods are as described above,
A polysilicon layer 110 is simultaneously formed when forming the gate electrode of a transistor, and an AI layer 110 is formed when forming an AI wiring.
K/:llll is formed simultaneously.

In this embodiment, since the positions of the polysilicon layer 110 and the AI layer 111 as scattering parts are different in the direction perpendicular to the substrate, multiple reflections can be more effectively prevented. Furthermore, the attenuation of light due to diffuse reflection on the surfaces of the polysilicon layer 110 and the AI layer 111 also increases the anti-reflection effect.

[Effects of the Invention] As explained in detail above, in the semiconductor device according to the present invention, since the scattering means is provided around the circuit section, obliquely incident light is not reflected as a group of parallel lights. Light is rapidly attenuated within the insulating layer around the circuit section. Therefore, even when strong light is incident obliquely, the influence of external light on the circuit section can be almost completely prevented. Therefore, the semiconductor device can operate stably without being affected by external light.

[Brief explanation of drawings]

FIG. 1(A) is a schematic f-plane view of a sensor device which is a first embodiment of a semiconductor device according to the present invention, and FIG. 1(B) is a
2(A) is a schematic plan view of the second embodiment of the present invention, and FIG. 2(8) is a schematic sectional view of the peripheral portion. Fig. 3 shows a conventional optical sensor device (Japanese Patent Application No. 1983-
It is described in No. 183149. FIG. 4 is a schematic sectional view of the end portion of the conventional example. No. 101, 107... Substrate 103, 108... Insulating layer 104, 109 - Light shielding layer 105, tto@φ - Polysilicon layer 111
...A1 layer agent B C Physician Yama F Jo Taira Figure 1 (A) I (B) Figure 2 A) (B)

Claims (5)

[Claims] (1) In a semiconductor device having a circuit section formed on a substrate, and a light shielding layer laminated on the substrate via an insulating layer and shielding the circuit section from light, the area around the circuit section and inside the insulating layer. A semiconductor device characterized in that a scattering means is provided in the semiconductor device. (2) The semiconductor device according to claim 1, wherein the scattering means comprises one or more rows of scattering sections. (3) The semiconductor device according to claim 2, wherein the pitch of the rows of scattering parts is random. (4) The semiconductor device according to claim 2, wherein the scattering section is made of the same material as the wiring used in the circuit section. (5) The semiconductor device according to claim 2, wherein the scattering section is made of the same material as the gate electrode used in the circuit section.