JPS58196036A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the deterioration of LSI characteristics as well as to improve the yield rate for the titled semiconductor device by a method wherein a reflecting film, which reflects energy rays, is formed on the prescribed region located on the surface of a semiconductor substrate. CONSTITUTION:A reflecting film 21 is formed on a silicon substrate 20, and the substrate is placed in the atmosphere containing gas to be used for formation of a thin film. At this time, a beam of light having the wavelength liable to reflect by the film 21 and also absorbed by the substrate 20, is irradiated. No temperature rise is observed on the film 21, but temperature rise is observed on a groove 23. Accordingly, almost no thin film is formed on the film 21, but an SiO2 film for isoration is formed in the groove.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for manufacturing a semiconductor device in which a thin film can be formed only in a predetermined region on the surface of a semiconductor substrate.

When a thin film is formed on a semiconductor substrate by the CVD5 method, a thin film of approximately the same thickness is formed on the surface of the substrate, so that unnecessary thin films must be removed after the thin film is formed.

For example, conventional insulation isolation methods are shown in FIGS. 1A-C.

First, a groove 2 having a depth D of approximately 16 μm is formed in an isolation formation region of a Si substrate 1 (FIG. 1A).

Then, by the CVD method, an S x02 film 3 having a thickness of about 16 μm is formed, and the groove 2 is filled with the 5102 film 3. A photoresist film 4 is then formed on the top of the groove (FIG. 1B).

Next, the S X 02 film 3 is etched by plasma etching or sputter etching, leaving the 8102 film 3 only in the groove 2 . When etching the S102 film, the etching progresses unevenly, or the area 6 where the 8102 film remains because the thickness of the 5102 film 3 is uneven, or the area 6 where the etching progresses too much and the Si substrate is etched. occurs (Fig. 1C).

As mentioned above, there is a problem that the yield of LSI is low because the 8102 film remains 6 and the recesses 6 are formed on the Si substrate.

Further, a conventional method in the case of multilayer wiring is shown in FIG. S
A Sio2 film 11 is formed on the i-substrate 10, and a first layer Aμ wiring 12 with a thickness of about 0.4 μm is formed, and an 8102 film 1 with a thickness of about 1 μm is formed on it by plasma CVD.
0 forming 3 and on to the first layer! A second layer of AIt wiring 14 is formed directly to the wiring 12. In this case, a difference 16 is generated due to the first layer Afi wiring 12,
The second layer M wiring 14 is easily disconnected, and it is difficult to form a fine pattern.

The present invention raises the temperature only in a predetermined area on a semiconductor substrate,
A thin film is formed only on the area where the temperature has risen. As a method of increasing the temperature of only a predetermined region on a semiconductor substrate, the energy of a light beam, etc. is +1! The reflective film is formed by forming a reflective film that reflects energy on the substrate, and irradiating the substrate with the energy rays such as heat rays, infrared rays, visible light, and ultraviolet rays to raise the temperature of the area where the reflective film is not formed. The present invention provides a method for manufacturing a semiconductor device in which a reaction product is formed on a semiconductor substrate that is not stained. When applied to the formation of an insulating isolation region, a reflective film that reflects light is formed on the semiconductor substrate, the reflective film on the semiconductor substrate in the isolation formation region is removed, and the semiconductor substrate is etched to form grooves. After forming an insulating film in the groove, place the substrate in a gas atmosphere that generates an insulating film so that the temperature in the groove is higher than that in the reflective film region.1-1 Width of the isolation region To provide a method for manufacturing a semiconductor device in which the separation region does not become large, there is no protrusion (bird's beak) in the isolation region, and the distortion in the isolation region is small.

When applied to multilayer wiring, after forming the first layer of wiring, the substrate is irradiated with light in a gas atmosphere that generates an insulating film to form an insulating film in areas other than the wiring area, as in the case of forming insulation separation described above. As a first embodiment of the present invention, the case where MO3LSI is manufactured by applying it to insulation isolation is shown in FIGS.
This will be explained according to FIG. 3E.

A reflective film (for example, a metal film such as AJL or Cr) 21 that reflects light is formed on a p-type silicon (St) substrate 20 to a thickness of about 01 μm. Then, using photolithography technology, a photoresist film 22 is formed in areas other than the isolation region forming area (
Diagram A).

Next, the reflective film 21 is removed using the photoresist film 22 as a mask. Then, the silicon substrate 2o is etched by about 0.6 μm to form a groove 23. Furthermore, the photoresist film 22
A boron ion implantation region 24 is formed on the bottom surface of the trench 23 using the mask as a mask (FIG. 3B).

Next, the photoresist film 22 is removed. As shown in FIG. 4, the cooling board 26. Frame 26. transparent glass window 27
A silicon substrate 2 is placed on the cooling substrate 26 of the reactor surrounded by
Place 0'5. Then, the inside of the reactor was filled with S III (4 gases,
Create an atmosphere of a mixed gas of O2 gas and reflect it easily by the reflective film 21. light)?Nigarasu window 27
irradiate through.

Then, as shown in FIG. 6, light is reflected on the reflective film 21 and the temperature does not rise, but since the silicon substrate is exposed in the groove 23, light is absorbed and the temperature in the groove 23 area increases. Since the cooling substrate 26 is cooled to about 30° C. by flowing Freon gas or cooling water, the heat generated in the groove 23 region flows toward the back side of the silicon substrate 2o. Therefore, the temperature of the silicon substrate 2o under the reflective film 21 does not rise much. Therefore, the power of the laser blower or the lamp is set so that the temperature in the groove 23 region becomes a temperature (approximately sso° C.) at which the SIH4 gas and the 02 gas react to form a Si02 film.

When light is irradiated under the above conditions, a separation S z 02 film 28 is formed in the groove 23, filling the groove, as shown in FIG. 3C. On the other hand, the temperature on the reflective film 21 does not rise, so almost no S
102 film is not formed, and only an island-shaped Sio2 film 29 film 9 is formed.

Next, when the reflective film 21 is etched, the SiO2 film 29 is removed together with the reflective film 21 (FIG. 3D).

Thereafter, the source region 30. Drain region 31° gate oxide film 32. A polycrystalline Si film 33 is formed.

Further, during the heat treatment, boron in the ion implantation region 24 is diffused to form a p+ type channel stopper region 34 (FIG. 3E).

According to the method shown in FIG. 3, an insulating film (S102 film in the example) is formed only in the region to be separated and fills the trench, so when the metal film 21 is removed, a flat Si substrate is exposed. do. Therefore, LSIs with high yield can be obtained.

Furthermore, since the groove 23 is filled with an insulator (5IO2 in the example) without a high-temperature heating process, no distortion occurs in the substrate and no crystal defects occur.

Therefore, the leakage current at the pn junction between the substrate 20 and the source and drain 30, 31 is small. However, since the area of the isolation region does not become larger than the width of the trench 23, the area of the passive and active element formation regions does not become smaller, and deterioration of the characteristics of the LSI can be prevented. Furthermore, since bird's beaks do not occur and a flat separation region is possible, fine patterns can be formed with high yield.

Although the above process describes MO3LSI,
The same can be said for bipolar LSIs. 0 As described above, the method shown in Figure 3 does not cause crystal defects, does not increase the width of the isolation region, can form isolation regions without protrusions, and is suitable for high-density semiconductor devices. This greatly contributes to the production of

A second embodiment of the present invention in which the present invention is applied to multilayer wiring is shown in FIGS. 6A to 6C.

First, an 8102 film 41 with a thickness of about 06 μm is placed on the St substrate 4o.
A first layer conductor wiring 42 (for example, Aj!, An-Si alloy) having a thickness of about 0.4 μm is formed thereon (FIG. 6A).
.

Next, as shown in FIGS. 4 and 6, the substrate is placed in an SiH4 and 02 gas atmosphere without being irradiated with light.

Then, in order to reflect the light beam, the conductor wiring 42
Sio2 film 43 with a thickness of approximately 04 μm is placed only on the 102 film 41.
The surface is flattened (FIG. 6B).

Next, a 3102 film 44 having a thickness of about 05 μm is formed on the substrate by CVD. Then, a second layer of conductor wiring 46 is formed which is perpendicular to the first layer of conductor wiring 42 (FIG. 6C).

In the step shown in FIG. 6, since the surface of the S102 film 44 is flat, a fine pattern can be formed in the second layer conductor wiring 46 without causing any disconnection.

The above process describes the case of forming an S 102 film as a thin film, but if it is in an S IH4 gas atmosphere, a Si thin film will be formed, and if it is in a mixed gas atmosphere of NH3 gas and 5iH2C22 gas, a Si3N4 thin film will be formed. Therefore, it is sufficient to use a gas atmosphere in which a desired thin film can be obtained.

According to the present invention, it is possible to form a thin film only in a predetermined region, so if it is applied to the isolation of MO8LSI or bipolar LSI, the area for forming passive and active elements will not become small, and it is possible to obtain a high-yield LSI. can. Also,
When applied to multilayer wiring, it is possible to form fine conductor wiring with a high yield.

[Brief explanation of the drawing]

Figures 1A-C are manufacturing process diagrams for conventional insulation isolation, Figure 2 is a cross-sectional view of a conventional multilayer wiring, and Figures 3A-E are manufacturing process diagrams for MO8LSI when the present invention is applied to insulation isolation. , 4th
5 are schematic configuration diagrams of an apparatus for forming an insulator according to the present invention, and FIGS. 6A to 6C are manufacturing process diagrams when the present invention is applied to multilayer wiring. 20...0 semiconductor substrate, 21... reflective film,
23...groove, 28.43-...S i02 film, p,, p, 1...fist/light, h...heat. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 2/2 - Figure 3 2 Figure 3 8 Figure 4 Figure 6 181-

Claims (4)

[Claims] (1) A method for manufacturing a semiconductor device, comprising the steps of forming a reflective film that reflects energy rays in a predetermined region on the surface of a semiconductor substrate, and forming a thin film on the surface of the semiconductor substrate. . (2) a step of forming a reflective film that reflects light on the surface of the semiconductor substrate; a step of removing the reflective film in a predetermined region; and further etching the semiconductor substrate to a predetermined depth to form a groove; A manufacturing method for placing the substrate on top of the substrate, the substrate being placed in an atmosphere containing a thin film forming gas. (3) The method for manufacturing a semiconductor device according to claim 1, wherein the thin film is an insulating film. (4) Method 0 of manufacturing a semiconductor device according to claim 1, wherein the reflective film is a conductive wiring.