JPS62114232A - Semiconductor device - Google Patents

Abstract

PURPOSE:To obtain a semiconductor device which has high reliability by laminating a PSG layer on a metal layer and a PSG layer having higher density than the PSG layer on a semiconductor substrate. CONSTITUTION:The density of P of a PSG layer 3 formed directly on a metal layer 2a is that capable of preventing aluminum of the layer 2a from being corroded by phosphoric acid generated by reacting P with water, i.e., 6% or less. The density of a PSG layer 4 of high density may be relatively higher than the layer 3 of the lower layer, but must be that capable of sufficiently preventing it from invading into an element when hydrogen generated from a plasma SiN layer 6 is all absorbed. Since the layer 3 formed on the layer 2a to become wirings has low density, it can suppress the corrosion of aluminum, and since the layer 4 formed on the layer 3 has high density, hydrogen generated from the layer 6 is all absorbed to prevent elements such as transistor, resistor from varying in their characteristics.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor device, and particularly to a semiconductor device using plasma SIN as a passivation film.

[Summary of the invention]

The present invention provides a semiconductor device using a plasma 5iNt passivation film, by stacking a PSG layer and a high-resistance PSG layer on a metal layer on a semiconductor substrate. This makes it possible to obtain a highly reliable semiconductor device.

[Conventional technology]

Plasma SIN, which has traditionally been used as a passivation film for LSI (Large Scale Integrated Circuits), exhibits excellent protection against external contamination, but the large amount of hydrogen contained in it Transistor, polycrystalline S
There is a problem in that it invades the low resistance and changes the characteristics of the element. Therefore, in order to solve these problems, PS having a hydrogen adsorption effect was added under the plasma SiN layer.
A passivation film having a two-layer structure including a G (IJ insilicate glass) layer is formed entirely.

[Problem that the invention seeks to solve]

As mentioned above, since PSG has a hydrogen adsorption effect,
In order to increase the concentration of phosphorus in the PSG layer, plasma Si
Although the effect of preventing hydrogen from penetrating from the N layer is greatly improved, in the case of the conventional structure, it was not possible to increase the concentration of P by one inch.

The reason for this is that when a high-strength PSG layer is formed directly on the At wiring, the P in the PSG layer reacts with moisture, and the generated phosphoric acid corrodes the At wiring, deteriorating its moisture resistance. This is because there was Therefore, it is not possible to make the concentration of P in the PSG layer sufficiently high, and the plasma S
It is impossible to completely prevent hydrogen from entering the iN layer.

The present invention provides a semiconductor device that can solve the above problems.

[Means for solving problems]

In the present invention, a PSG layer (3) is formed on a metal layer (2a) formed on a semiconductor substrate (1) on which elements such as transistors and resistors are provided, and a PSG layer (3) is formed on this PSG layer (3). The PSG layer (4) has a higher concentration of P than 3).
) to form.

The concentration of P in the PSC layer (3) formed directly on the metal layer (2a) can prevent phosphoric acid generated by reaction of P with water from corroding the AL of the metal layer (2a). The concentration should be 6 or less. In addition, a high concentration PSG layer (
4) As the a-reverse of P, the relatively lower PSG layer (3
), but the plasma SiN layer (6)
The concentration must be such that it can adsorb all the hydrogen generated from the hydrogen and sufficiently prevent it from entering the device.

Furthermore, on top of this high concentration PSG layer (4), a lower concentration of P is added.
By forming the SG layer (5), a high concentration PSG layer (
4) P reacts with moisture to generate phosphoric acid, and plasma Si
N layer (6) 'Jk may be prevented from being corroded.

[For production]

According to the present invention, the PSG layer (3) formed on the metal layer (2a) serving as the wiring can suppress corrosion of At at a low concentration, and at the same time, it is possible to suppress corrosion of At. Since the formed PSG layer (4) has a high fIk degree, the plasma S
All the hydrogen generated from the iN layer (6) can be adsorbed to prevent variations in the characteristics of elements such as transistors and resistors.

〔Example〕

An embodiment of the present invention will be described together with a manufacturing method with reference to FIG.

First, as shown in Section 1-A, a transistor, a polycrystalline S
An At metal layer (2a) as a wiring and an electrode (2b) are formed on a semiconductor substrate (1) provided with a low resistance 7).

(8) Fisio□ layer.

Next, as shown in FIG. 1B, a layer of 5.5 wt to OP
SG is deposited by CVD (chemical vapor deposition) to form a low concentration PSG layer (3) with a depth of 7000X.

Next, as shown in Figure 1C, this low concentration PSG layer (3)
PSG having a P concentration of 14 vrt% is deposited thereon by CVD to form a high concentration PSG layer (4) with a thickness of 1000×.

Next, as shown in Figure 1 DK, this high degree PSG layer (4)
Further low concentration (5.5wt%) with a thickness of 3000X on top
A PSG layer (5) is formed to prevent the plasma SIN from reacting with the high pitch PSG.

Finally, as shown in FIG. 1E, a plasma SiN layer (6) is formed on the low-concentration PSG layer (5) at a height of 3000X by K j p /4 tsipation.

〔Effect of the invention〕

According to the present invention, the PSG layer formed on the At metal layer has a multilayer structure consisting of a low concentration PSG layer and a high concentration PSG layer, thereby suppressing corrosion of the At metal layer and increasing moisture resistance. At the same time, it is possible to adsorb all the hydrogen generated from the plasma SIN and prevent it from entering the At metal layer. Therefore, a highly reliable plasma SiN layer can be formed as a passivation film, and can be applied to technologies that require prevention of hydrogen penetration, such as doping into polycrystalline silicon high-resistance elements of static RAM and thinning them. be able to.

[Brief explanation of drawings]

FIG. 1 is a process diagram showing an example of the manufacturing method of the present invention. (1) is a semiconductor substrate, (2a) is a metal layer, (2b) is an electrode, (3) is a low concentration PSC N, (4) is a high concentration PSG
(5) is a low concentration PSG layer, (6) is a plasma SrN layer.
It is a layer. 3 low degree P5G layer * Power 1! Igeri's 1st step diagram

Claims (1)

[Claims] A metal layer formed on a semiconductor substrate; a phosphosilicate glass layer formed on the metal layer; A semiconductor device having a phosphosilicate glass layer.