JPS62160730A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent diffusion of phosphorus atoms, by forming an SiO2 film, which has a form that is protruded to the side end part of a PSG film, so as to wrap the side end part of the PSG film, which is formed for the purpose of flattening the surface of a substrate, and in which a window is formed for forming an electrode window. CONSTITUTION:An SiO2 film 22 is formed on a substrate 21. A photoresist film 24, in which a base forming region 23 is opened, is formed. Thereafter, boron atom ions are implanted. Then, a PSG film 25 is formed. Thereafter the PSG film is dissolved, and a glass flow film is obtained. A first SiO2 film 26 is further formed by a CVD method. A window is formed through the SiO2 film 22, the PSG film 25 and the SiO2 film 26 on a base-contact forming region 28 and a collector contact region 29. Thereafter, a second CVD SiO2 film 30 is formed. Then, the CVD SiO2 film 30 undergoes anisotropic etching. The side end part of the PSG film 25, in which the window is provided, is surrounded with the CVD SiO2 film 30. Then the surface is coated with a poly Si film 31. Arsenic ion atoms are implanted, and an emitter region 27 and a collector contact region 29 are formed. Since the phosphorus atoms in the glass flow film are not diffused in the base contact film, the highly reliable device can be obtained.

Description

[Detailed Description of the Invention] [Summary] A method for manufacturing a semiconductor device, which comprises forming a phosphosilicate glass film (
In the manufacturing of semiconductor devices, which includes a process of forming a PSG film (hereinafter referred to as a PSG film) and planarizing the substrate surface, the side edges of the PSG film, which are opened to introduce impurity atoms, are covered with a silicon dioxide (SiO2) film. The S of the Si substrate is formed on the PSG film, and the H of the wiring film for forming electrodes is formed on the PSG film.
The poly-Si film provided to prevent erosion of the PS
A manufacturing method that prevents phosphorus atoms in the G film from diffusing and further introducing into the base contact region of the substrate.

[Industrial application field]

The present invention relates to a method for manufacturing a semiconductor device, and in particular, in order to flatten a substrate on which an element is formed, a glass-flowed PSG is used.
The present invention relates to a method for manufacturing a bipolar semiconductor device using a film.

When forming an MO3 type semiconductor device, P is placed on the gate electrode.
After forming the SG film, this PSG film is treated at high temperature in a wet oxidation atmosphere, the glass of this PSG film is melted and glass flowed, and this glass flowed PSG film is used to form an insulating film with a gentle slope on the gate electrode. A method has been adopted in which cracks do not occur in the metal film on the shoulder portion of the gate electrode by forming a full-reflection film for electrode formation thereon.

Flattening the surface of a Si substrate with such an element formation region is required even when forming a bipolar semiconductor device, and in order to flatten the surface of the substrate, such a glass-flowed PSGH is used. 'A is formed on the substrate, and when forming the emitter region by diffusion, this PS
It is desired to eliminate the disadvantage that phosphorus atoms in the G film diffuse into the base region, making it impossible to form a contact.

[Prior Art] A conventional method for manufacturing a bipolar semiconductor device using a PSG film to flatten a Si substrate on which a semiconductor element formation region is formed will be described with reference to FIG.

As shown in FIG. 7, conventional bipolar semiconductor device manufacturing involves the formation of a highly concentrated N-type buried layer 2 by diffusing atoms such as phosphorus into a P-type Si substrate 1, and then forming a highly concentrated N-type buried layer 2 on the substrate 1. N-type Si
An epitaxial layer 3 is formed.

Thereafter, P-type impurity atoms such as boron (B) are diffused into the substrate to form P-type element isolation regions 4.

Next, P-type impurity atoms are introduced into the epitaxial layer 3 to form a P-type base region 5 in a predetermined pattern.

On the substrate thus formed, 5i02 was deposited by thermal oxidation.
After forming the film 6, a PSG film 7 is formed on the entire surface of the substrate to make it flat, and heated in a water vapor atmosphere to form the PSG film 7.
is melted to form a glass flow membrane.

Next, an emitter formation region 8 and a collector contact region 9 are formed.
, and for forming the base contact region 10, the sio21m! 6, and the psc membrane 7 is opened.

Then, in a later step, a poly-Si film 11 is formed by CVD in order to prevent the substrate 1 from being eroded by the aluminum (All) of the wiring film formed on the substrate.

Next, a photoresist If is applied over the base contact region 10.
After arsenic (As) atoms are ion-implanted using a mask such as f, the substrate 1 is heat-treated to form an emitter region 8 and a collector contact region 9.

[Problem that the invention seeks to solve]

However, in such a conventional method, phosphorus atoms in the PSG film 7 enter into the poly-Si film 11 during the diffusion step of heat-treating the ion-implanted arsenic atoms, and these phosphorus atoms also enter the base contact region 10. When introduced, the resistance of that part becomes high, causing a problem that contact cannot be made with the N electrode formed thereon.

The present invention eliminates the above problems and provides a semiconductor in which phosphorus atoms in the PSG film are not introduced into the base contact region even when PSG glass flow is used to flatten the substrate. The purpose is to provide equipment.

[Means for solving problems]

In the method of manufacturing a semiconductor device of the present invention, after forming a 5i02 film 22 on a Si substrate 21 provided with a semiconductor element formation region,
forming a sc film 25 and melting the PSG film 25; depositing SiO on the substrate by a first chemical vapor deposition (CVD) method;
After the 2-film 26 film type 6, the 5i02 film 26 formed by the first CVD method on the impurity doped region, the molten PSGlff25 and S
A step of forming a 5i02 film 30 on the substrate 21 by a second CVD method, and then anisotropically etching the second CVD SiO2 film 30. A step of etching the entire iO2 film 22 on the substrate 21 After forming 31, there is a step of introducing impurity atoms into the substrate through the apertured portion.

[Effect]

In the method of manufacturing a semiconductor device of the present invention, the PSG film 25 is formed so as to wrap around the side edge of the PSG film 25, which is formed for the purpose of planarization on the substrate 21 and has an opening for forming an electrode window.
By forming an overhanging 5i02 film 30 on the side end of the PSG film 25, the poly-Si film 31 is formed to prevent the electrode from corroding the Si of the S+ substrate. This is to prevent phosphorus atoms from diffusing into the base contact region 28 and preventing phosphorus atoms of the PSG film 25 from being diffused into the base contact region 28.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 to FIG. 6 are cross-sectional views showing one embodiment of the method for manufacturing a semiconductor device of the present invention in the order of steps, and in order to simplify the drawings, only the main part where the epitaxial layer is formed on the substrate is shown. It shows.

First, as shown in FIG. 1, the N type heavily doped buried layer 2 shown in FIG. 7 is formed, an N type Si epitaxial layer 3 is formed thereon, and a P type element isolation region 4 The two P-type Si substrates on which are formed are used.

Next, a SiO2 film 22 is formed on the substrate 21 by thermal oxidation.

Next, after forming a photoresist film 24 with an opening in the base formation region 23, this photoresist film 24 is made into a mass I and the dose amount is 5×10 to 5×10 atoms/clT.
Boron atoms are ion-implanted under conditions of +2 and acceleration energy of 30 KV.

Next, as shown in FIG. 2, after forming a PSG film 25 on the substrate, the substrate is heated in a steam atmosphere to melt the PSG film and form a glass flow film.

Further, 5102M'A26 is formed thereon by first CVD.

Furthermore, as shown in FIG. 3, the 5i02 film 22, the PSG film 25, the first CV
After opening the DSiO2 film 26, a second CV is formed on the substrate.
A DSiO2 film 30 is formed.

Next, as shown in Fig. 4, reactive ion (RIE)
)-C etching method to anisotropically etch the second CVD5iOz film 30 so that the side edges of the window-opened PSG film 25 are surrounded by the second CVDSiO2 film 30.

Next, as shown in FIG.
Make sure to cover it with

This poly-Si film 31 is provided in order to prevent this sardine from corroding the St of the substrate when the wiring films .about. are formed on the substrate in a later step.

The base contact region is then covered using a mask such as photoresist, and arsenic atoms are ion-implanted to form emitter region 27 and collector contact region 29.

In this way, psGB'i! is generated in the process of forming the emitter region by heat treatment after ion implantation of arsenic atoms. 25
Phosphorus atoms diffuse into the poly-Si film 31, which is formed to prevent the sardines from eroding the St of the substrate when forming the electrode, from the side edge side of the substrate, and enter the base contact region of the substrate. A highly reliable semiconductor device with well-formed base contacts can be obtained.

Furthermore, since the surface of the substrate becomes smooth, the phenomenon of disconnection or short-circuiting of wiring formed on the substrate is eliminated.

Also, a second 5iz21e! film is formed on the side surface of the first 5i02 film 26, which serves as a mask during ion implantation of arsenic atoms to form an emitter. Since the ion implantation region is narrowed by 30 and the emitter region is formed finely, a high-speed, highly integrated semiconductor device can be obtained.

Furthermore, since the psc film for planarizing the substrate is covered with a 5i02 film having good moisture resistance, a highly reliable semiconductor device with improved moisture resistance can be obtained.

Although the embodiments described above have been described using bipolar semiconductor devices as an example, the method of the present invention can also be applied to CMO5 semiconductor devices.

〔Effect of the invention〕

As described above, according to the method of manufacturing a semiconductor device of the present invention, the phosphorus atoms of the glass flow film of the PSG film provided to flatten the substrate are separated from the Si of the Si substrate and the wiring film. Since the poly-Si film formed to prevent corrosion by the polysilicon is diffused into the base contact region of the substrate, a highly reliable semiconductor device with a sufficient number of base contacts can be obtained. effective.

[Brief explanation of drawings]

1 to 6 are cross-sectional views showing one embodiment of the method for manufacturing a semiconductor device according to the present invention in the order of steps, and FIG. 7 is a cross-sectional view for explaining a conventional method for manufacturing a semiconductor device. In the figure, 21 is a Si substrate, 22 is an SiO2 film, 23 is a base region, 24 is a photoresist film, 25 is a PSG film, and 26 is a first
CVD5i02 film, 27 is an emitter region, 28 is a base contact region, 29 is a collector contact region, 3
0 is the second 5iO211! f! , 31 indicates a poly-Si film. N LNg no C - Susu 9 draw sA'Nio
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Claims (1)

[Claims] A silicon (Si) substrate (2) provided with a semiconductor element formation region.
1) After forming a silicon dioxide film (22) on the substrate, forming a phosphosilicate glass (25) film and melting the phosphosilicate glass film (25), a first chemical vapor deposition process on the substrate (21); After forming the silicon dioxide film (26) by the method, the silicon dioxide film (26) by the first chemical vapor deposition method, the molten phosphosilicate glass film (25), and the silicon dioxide film (22) on the impurity introduction region are opened. After forming a silicon dioxide film (30) on the substrate (21) by a second chemical vapor deposition method, forming the silicon dioxide film (30) on the substrate (21).
After forming a polysilicon film (31) on the substrate (21),
A method for manufacturing a semiconductor device, comprising the step of introducing impurity atoms into the substrate (21) through the open window.