JPH1041272A - Manufacture of semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the yield of a semiconductor device by preventing the defect of a semiconductor substrate and the development of a crystal defect by relieving the stresses of films by forming at least two films on the surface of the substrate and dividing the films into sections by forming grooves having a prescribed width in the films by photo-etching. SOLUTION: After a silicon oxide film 12 is formed on a semiconductor substrate 11 at about 900 deg.C by thermal oxidation, a polycrystalline silicon film 13 and a tungsten silicide film 14 are successively formed on the film 12 by the CVD method and PVD method, respectively. Then a TEOS film 15 composed of Si 4 and a high-resistance polysilicon film 16 are formed by the CVD method and grooves 102 and 103 having a width of 1μm are formed. Either isotropic etching or anisotropic etching can be used for forming the grooves 102 and 103. Thereafter, a TEOS film 17, a baron-phosphorus spin-on glass film 18, and a polycrystalline silicon film 19 are successively formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a method for forming a multilayer film on a semiconductor substrate.

[0002]

2. Description of the Related Art In recent years, when a semiconductor device is manufactured, a device structure in which a multilayer film is formed on a semiconductor substrate is increasingly used. In particular, with the advancement of technology for large-capacity storage devices, logic circuits, or devices incorporating storage devices, use of silicon oxide films, polycrystalline silicon films, amorphous silicon films, silicon nitride films, silicide films, metal films, etc. It has also evolved into devices with more complex multilayer structures.

[0003]

However, when a multilayer film structure made of such different materials and having different film characteristics is employed, the following problem occurs. When films of different materials are stacked, the film stress, that is, the stress increases due to a difference in lattice constant and a difference in thermal expansion coefficient, and further, a thermal stress of a process is applied, thereby causing an excessive stress on the semiconductor substrate. As a result, the semiconductor substrate was warped, chipped, cracked, etc. during the process. Alternatively, frequent occurrence of crystal defects and generation of crystal dislocations cause a failure of the device, resulting in a decrease in yield.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and in a method of manufacturing a semiconductor device having a multilayer film structure, a film stress is relaxed to prevent the occurrence of a defect or crystal defect in a semiconductor substrate, thereby improving the yield. It is an object of the present invention to provide a method for manufacturing a semiconductor device which can be performed.

[0005]

According to a method of manufacturing a semiconductor device of the present invention, at least two layers are formed on a surface of a semiconductor substrate, and a predetermined width is formed on the film by photolithography. Forming a groove and dividing the film in the thickness direction.

Alternatively, a manufacturing method according to the present invention comprises a step of forming at least two layers on a surface of a semiconductor substrate to form a first multilayer film, and a step of forming the first multilayer film by photolithography. Forming a groove of a predetermined width in the film to divide the first multilayer film in the thickness direction;
Forming a layer film to form a second multilayer film, and forming a groove having a predetermined width in the second multilayer film by using a photolithography method, and forming the second multilayer film in a thickness direction. And a step of dividing into two.

According to another manufacturing method of the present invention, at least two layers are formed on a surface of a semiconductor substrate, and a first film is formed on the surface of the film by forming a resist film to form a pattern. Performing an exposure process using a photomask, a process of performing an exposure process using a second photomask for forming a groove having a predetermined width for dividing the film in the thickness direction, Performing a developing process on the film, etching the film using a patterned resist film, and simultaneously forming the pattern and the groove in the film.

It is preferable that the groove is formed so as to separate a region to be a pellet and a region not to be a pellet on the semiconductor substrate.

The semiconductor substrate contains single crystal silicon,
The film may be formed of a material having a different coefficient of thermal expansion and lattice constant from single crystal silicon.

[0010] The film may include a polycrystalline silicon film, an amorphous silicon film, a silicon oxide film, a silicon nitride film, a silicide film, and a metal film.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows steps of a method of manufacturing a semiconductor device according to a first embodiment of the present invention. First, step 2
As a first step, films made of a plurality of different materials are sequentially deposited on the surface of the semiconductor substrate by using a CVD method or a PVD method.

Next, using a normal photolithography method, about 1 μm
A groove having a width of m is formed in the multilayer film along the depth direction so as to be discontinuous in the lateral direction.

In step 23, a film made of a plurality of different materials is formed on the surface.

FIG. 2 shows a method of manufacturing a semiconductor device according to a second embodiment of the present invention. Steps 31 to 33 are the same as steps 21 to 23 in the first embodiment. Further, as a step 34, the multilayer film formed in the step 33 is etched, and a groove having a width of about 1 μm is formed in the depth direction to be in a discontinuous state.

FIG. 3 shows a method of manufacturing a semiconductor device according to a third embodiment of the present invention. Steps 41 to 44 are the same as steps 31 to 34 in the second embodiment. Step 45
A plurality of films are sequentially formed on the surface of the multilayer film formed in step 43. The film is etched to form a groove having a width of about 1 μm in the depth direction to make the film discontinuous.

Here, the step of forming a groove in the film includes:
The treatment may be performed by performing exposure, development, and etching as follows. First, after forming a multilayer film, a resist film is formed on the surface. Exposure processing for forming a pattern on the film is performed on the resist film using a first photomask, and then exposure processing for forming a groove is performed on the same resist film using a second photomask. Next, a development process is performed on the resist film, and the multilayer film is etched using the patterned resist film, thereby simultaneously forming a desired pattern and a groove. Thus, an increase in the number of steps due to the formation of the groove can be suppressed. Further, a single photomask having both a first photomask for forming a pattern and a second photomask for forming a groove can be used as the photomask.

The grooves are formed so as to make the film on the semiconductor substrate 100 discontinuous as shown in FIGS. In particular, as shown in FIGS.
When the semiconductor substrate 100 is formed so as to divide the central region serving as the semiconductor pellet from the other peripheral region, the effect of reducing the stress generated in the multilayer film can be obtained.

Next, some specific examples implemented based on the above embodiment will be described.

As a first embodiment, as shown in FIG. 13, about 900 degrees Celsius is formed on a semiconductor substrate 11 by a thermal oxidation method.
A silicon oxide film 12, a polycrystalline silicon film 13 by a CVD method, a tungsten silicide film 14 by a PVD method, and a Si (OC) film by a CVD method.
A TEOS film 15 made of H2 CH3) 4 and a high-resistance polycrystalline silicon film 16 are formed. Thereafter, grooves 102 and 103 having a width of 1 μm were formed as shown in FIG. This groove may be formed by either isotropic etching or anisotropic etching. In this embodiment, the groove is formed by using reactive ion etching. Thereafter, as shown in FIG. 13, a TEOS film 17, a boron phosphorus spin-on-glass (hereinafter referred to as BPSG) film 18, and a polycrystalline silicon film 19 were sequentially formed.

In the second embodiment of the present invention, a silicon oxide film 12, a polycrystalline silicon film 13, a tungsten silicide film 14,
After forming a TEOS film 15 and a polycrystalline silicon film 16, FIG.
As shown in FIG. 1, grooves 102 and 103 having a width of 1 μm were formed, and a TEOS film 17, a boron-phosphorus-spin-on-glass (hereinafter, referred to as BPSG) film 18, and a polycrystalline silicon film 19 were formed. Further, grooves 102 and 103 as shown in FIG. 5 were formed in the films 17 to 19 to make them discontinuous.

A third embodiment of the present invention relates to a semiconductor substrate 11
A silicon oxide film 12, a polycrystalline silicon film 13, and a tungsten silicide film 14 are formed thereon, and grooves 102 and 103 having a width of 1 μm are formed as shown in FIG. next,
A TEOS film 15 and a polycrystalline silicon film 16 are formed on the surface to form a groove having a width of 1 μm as shown in FIG.
8. A polycrystalline silicon film 19 was formed to form a 1 μm groove as shown in FIG.

For comparison with the first to third embodiments, a first comparative example manufactured by a conventional method will be described. In this comparative example, as shown in FIG. 13, a silicon oxide film 12, a polycrystalline silicon film 13, a tungsten silicide film 14, a TEOS film 1
5, polycrystalline silicon film 16, TEOS film 17, BPSG
The film 18 and the polycrystalline silicon film 19 were formed into a multilayer structure, and the grooves as described in the example were not formed.

In the first, second and third embodiments, the first
FIG. 14 shows the results obtained by measuring the respective film stresses in the comparative example. In each of the examples, the film stress was lower than that of the first comparative example, and among the examples, the film stress was lower in the order of the first example, the second example, and the third example. Recognize. In particular, in the third embodiment, the film stress is reduced to about one third of that in the first comparative example. FIG. 15 shows measured values of the amount of warpage of the substrate. In the first comparative example, warpage of 100 μm or more has occurred.
In the first to third embodiments, the largest value in the first embodiment is 3
0 μm, and the amount of warpage is also significantly reduced in the example.

Next, results of comparison between the fourth and fifth embodiments of the present invention and the second comparative example will be described. In the fourth embodiment, a 1 Mbyte SRAM (static random access
memory) to which the manufacturing method of the present invention is applied.
After forming a polycrystalline silicon film on a semiconductor substrate and performing necessary patterning, a step of forming grooves 111, 113, 121 to 126 having a width of 1 μm as shown in FIG. 12 was added. The groove 111 divides the central region and the outer peripheral region of the semiconductor substrate 111 that will be semiconductor pellets.

In the fifth embodiment, unlike the fourth embodiment, after forming a polycrystalline silicon film on a semiconductor substrate and applying a resist in a 1M SRAM, a first pattern for forming a required pattern is different from the fourth embodiment. First, only the exposure process is performed using the photomask described above, then the exposure process is performed using the second photomask for forming the groove illustrated in FIG. 12, and then the resist film is simultaneously developed, Using the resist film as a mask, the polycrystalline silicon film was etched to simultaneously form a pattern and a groove.

In the second comparative example, the 1M SR
AM was formed, but no groove was formed. The fourth,
As the fifth example and the second comparative example, 100 semiconductor substrates were used each.

In FIG. 16, in the fourth, fifth and second comparative examples, the semiconductor substrate was inspected for chipping, cracking and warpage, and the ratio of defective substrates was calculated. In the fourth and fifth examples, no defect such as chipping of the substrate occurred at all, and the defective product ratio was 0%. In the second comparative example, chipping occurred in seven semiconductor substrates, cracked in five substrates, and warpage occurred in eight substrates, and the defective product ratio was 20%. In the second comparative example, chipping, cracking, and warping did not occur in the remaining 80 semiconductor substrates. However, when the characteristics after manufacturing the SRAM were examined, the fourth and fifth product yields were obtained. 15% lower than that of the example.

As described above, according to the manufacturing method according to the embodiment of the present invention, after forming a multilayer film having a different material and a different lattice constant or thermal expansion coefficient from the semiconductor substrate, a groove is formed in the depth direction. By forming the semiconductor substrate into a discontinuous state, stress can be relieved and excessive stress can be prevented from being applied to the semiconductor substrate. Thereby, as described in comparison between the example and the comparative example, according to the present embodiment, chipping, cracking, and warpage of the semiconductor substrate can be prevented, and the product yield can be improved.

The above embodiments and examples are merely examples, and do not limit the present invention. For example, the multilayer film on which the groove is to be formed is not limited to the one shown in FIG. 13, but may be any film formed of a material different from that of the semiconductor substrate. In addition, the width of the groove is set to 1 μm, but a groove having a different width may be formed as necessary according to the design rule.

[0031]

As described above, the method of manufacturing a semiconductor device according to the present invention comprises forming two or more films on a semiconductor substrate and then forming a groove in the film to form a discontinuous state. ,
Stress applied to the semiconductor substrate can be reduced, and a decrease in yield due to chipping of the substrate, crystal defects, or the like can be prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a method of manufacturing a semiconductor device according to a first embodiment of the present invention for each process.

FIG. 2 is a flowchart showing a method of manufacturing a semiconductor device according to a second embodiment of the present invention for each process.

FIG. 3 is a flowchart showing a method of manufacturing a semiconductor device according to a third embodiment of the present invention for each process.

FIG. 4 is a plan view showing grooves formed in a multilayer film on the semiconductor substrate in the embodiment.

FIG. 5 is a plan view showing a groove formed in a multilayer film on the semiconductor substrate in the embodiment.

FIG. 6 is a plan view showing a groove formed in a multilayer film on the semiconductor substrate in the embodiment.

FIG. 7 is a plan view showing a groove formed in the multilayer film on the semiconductor substrate in the embodiment.

FIG. 8 is a plan view showing a groove formed in the multilayer film on the semiconductor substrate in the embodiment.

FIG. 9 is a plan view showing a groove formed in a multilayer film on the semiconductor substrate in the embodiment.

FIG. 10 is a plan view showing a groove formed in a multilayer film on the semiconductor substrate in the embodiment.

FIG. 11 is a plan view showing a groove formed in a multilayer film over the semiconductor substrate in the embodiment.

FIG. 12 is a plan view showing a groove formed in the multilayer film on the semiconductor substrate in the embodiment.

FIG. 13 is a longitudinal sectional view showing a film formed in the first to third embodiments of the present invention.

FIG. 14 is a graph showing the results of measuring film stress for the first to third examples of the present invention and the first comparative example.

FIG. 15 is a graph showing the results of measuring the amount of warpage of the substrate for the first to third examples of the present invention and the first comparative example.

FIG. 16 is an explanatory diagram showing the number of occurrences of chipping, cracking, and warpage of the substrate in the fourth and fifth embodiments of the present invention and the second comparative example.

[Explanation of symbols]

11, 100 Semiconductor substrate 12 Silicon oxide film 13, 19 Polycrystalline silicon film 14 Tungsten silicide film 15, 17 TEOS film 16 High resistance polycrystalline silicon film 18 BPSG film 101, 102, 103, 105 to 108, 111 to 1
16, 121-126 grooves

Claims (6)

[Claims] A step of forming at least two layers of film on the surface of the semiconductor substrate; forming a groove of a predetermined width in the film by using photolithography;
A step of dividing the film in a thickness direction. 2. A step of forming at least two layers of film on the surface of a semiconductor substrate to form a first multilayer film, and forming a groove of a predetermined width in the first multilayer film by photolithography. Forming, dividing the first multilayer film in the thickness direction, further forming at least two layers of film on the entire surface to form a second multilayer film, and using a photolithography method. Forming a groove of a predetermined width in the second multilayer film and dividing the second multilayer film in a thickness direction. 3. A step of forming at least two layers of film on the surface of a semiconductor substrate, forming a resist film on the surface of the film, and exposing using a first photomask for forming a pattern. Performing a process, performing an exposure process using a second photomask for forming a groove having a predetermined width to divide the film in a thickness direction, performing a developing process on the resist film, and patterning the resist film. Etching the film using the resist film thus formed, and simultaneously forming the pattern and the groove in the film. 4. The method for manufacturing a semiconductor device according to claim 1, wherein said groove is formed so as to separate a region to be a pellet and a region not to be a pellet on the semiconductor substrate. 5. The semiconductor substrate includes single crystal silicon,
5. The film according to claim 1, wherein the film has a thermal expansion coefficient and a lattice constant different from those of single crystal silicon.
The manufacturing method of the semiconductor device described in the above. 6. The semiconductor device according to claim 1, wherein said film includes a polycrystalline silicon film, an amorphous silicon film, a silicon oxide film, a silicon nitride film, a silicide film, and a metal film. Production method.