JP3351708B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor device, and more particularly to a planarization technique.

[0002]

2. Description of the Related Art Conventional planarization techniques include SOG (spin-on-glass), resist etch-back, and CMP (chemical mechanical polishing). However, SO
In the case of G or resist etch-back, as shown in FIG. 8, there is a problem that a step is left on the surface of the coated film 52 due to a difference in the pattern density of the base 51 in the semiconductor chip. In addition, reflow annealing is also performed to flatten the spin-coated film. However, as shown in FIG. 9, reflow annealing only smooths the corners of the steps, leaving absolute steps. In addition, even if a material having a very low viscosity is coated at a high temperature, a
As shown in FIGS. 0 (a) and (b), since the semiconductor substrate has warpage and variations in thickness, the thickness of the coating film itself greatly varies.

In addition, when CMP is used, the area that can be planarized by CMP is an area of about 200 to 500 μm. As shown in FIG. 11, it is difficult to flatten the entire coating film.

[0004]

As described above, when the pattern density of the underlayer is not uniform within the substrate (within the chip), it is difficult to planarize the entire film formed on the underlayer using CMP or the like. there were. An object of the present invention is to provide a method of manufacturing a semiconductor device which can easily planarize an entire film formed on a base using CMP even when the pattern density of the base is not uniform in the substrate. It is in.

[0005]

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: forming a material film having irregularities on the main surface side of a semiconductor substrate in accordance with an underlying pattern; A step of substantially uniforming the pattern density of the concave portions or convex portions in an arbitrary region by directly forming an etching pattern corresponding to the pattern density of the concave portions or convex portions in the material film without using a resist mask,
Flattening the material film in which the pattern density of the concave portions or the convex portions is substantially uniform by chemical mechanical polishing.

It is effective that the step of directly forming an etching pattern on the material film is performed by using ion beam excitation etching, light excitation etching, thermal excitation etching or wet etching.

When ion beam excitation etching is used, a method of scanning an ion beam in an etching gas atmosphere or a method of irradiating an ion beam through a stencil mask in an etching gas atmosphere is effective. When photoexcited etching is used, a method of scanning a light beam in an etching gas atmosphere or a method of irradiating a light beam through a stencil mask in an etching gas atmosphere is effective.

Further, according to the method of manufacturing a semiconductor device of the present invention, there is provided a step of forming a material film having irregularities on the main surface side of a semiconductor substrate according to an underlying pattern, Or a step of forming the film pattern corresponding to the pattern density of the convex portions directly without using a resist mask to substantially uniform the pattern density of the concave portions or convex portions in an arbitrary region; Flattening a material film having a substantially uniform pattern density by chemical mechanical polishing.

The step of directly forming a film formation pattern on the material film uses ion beam excitation film formation, light excitation film formation, thermal excitation film formation, particle transport film formation, or film formation by vapor deposition through a stencil mask. It is effective to do it.

In the case of using ion beam excitation film formation,
A method of scanning an ion beam in a film forming gas atmosphere or a method of irradiating an ion beam through a stencil mask in a film forming gas atmosphere is effective. When photoexcited film formation is used, a method of scanning a light beam in a film formation gas atmosphere or a method of irradiating light through a stencil mask in a film formation gas atmosphere is effective. When fine particle transport film formation is used, a method of scanning a nozzle for transporting fine particles is effective.

[0011] In CMP, the area which can be planarized is 20
It is in the range of about 0 to 500 μm. Therefore, 200
If the pattern density is made uniform in a region of μm square or less, the entire inside of the substrate can be flattened in the subsequent CMP process. Further, it is not necessary to control the position and the size of the etching pattern and the film formation pattern formed on the material film to be planarized with high precision, and the size to be controlled may be, for example, about 50 μm. Therefore, even if an etching pattern or a film formation pattern is directly formed without using a resist mask (without using a photolithography technique),
The pattern density in a region of about 200 μm square can be made substantially uniform throughout the entire substrate. Therefore, it is not necessary to use an expensive photolithography apparatus or a complicated lithography process when forming an etching pattern or a film formation pattern.

According to the present invention, an etching pattern or a film formation pattern corresponding to the pattern density of a concave portion or a convex portion is directly formed on a material film to be planarized without using a resist mask. Since the pattern makes the pattern density in an arbitrary region substantially uniform in the substrate by the pattern, the entire inside of the substrate can be easily flattened by the subsequent CMP.

[0013]

Embodiments of the present invention will be described below with reference to the drawings. First, a first embodiment of the present invention will be described with reference to the process chart shown in FIG.

In FIG. 1A, reference numeral 11 denotes a base on which a predetermined pattern is formed on a main surface side of a semiconductor substrate (not shown).
1a and a convex portion 11b. A material film 12 made of a desired insulating material is formed on the base 11. In this material film 12, a concave portion 12a and a convex portion 12b are formed corresponding to the concave portion 11a and the convex portion 11b of the base 11.

Next, as shown in FIG. 1B, in order to make the pattern density uniform within the substrate (within the chip), an etching pattern 1 corresponding to the pattern density of the concave portion or the convex portion is formed.
2c without using a photolithography method (without using a series of photolithography methods such as a resist mask forming process by applying a photoresist, pattern exposure and development, and an etching process using the resist mask). Directly. That is, the ratio of the formation of the etching pattern 12c is increased in a region where the ratio of the convex portions is large. Hereinafter, an etching method for directly forming the etching pattern 12c on the material film 12 without using the photolithography technique will be described.

The etching method includes ion beam excitation etching, light excitation etching, heat excitation etching,
Wet etching and the like. Examples of the method of performing ion beam excitation etching include a method of performing etching by scanning an ion beam, and a method of performing etching by irradiating an ion beam through a stencil mask. In the former method, as shown in FIG. 3, the substrate 10 on which the material film to be planarized is formed is placed in an etching gas atmosphere, and the ion beam is scanned by scanning the substrate 10 with the ion beam. Is selectively etched. The ion beam may be irradiated continuously or intermittently along the scanning direction. In the latter method, as shown in FIG.
The substrate 10 is irradiated with an ion beam through the stencil mask 21 in an etching gas atmosphere to perform selective etching corresponding to the pattern formed on the stencil mask 21.

The photo-excited etching is basically the same as the above-mentioned ion beam-excited etching. The etching is performed by scanning a light beam in an etching gas atmosphere, and the etching is performed through a stencil mask in an etching gas atmosphere. There is a method of performing etching by irradiating light.

In the case of performing the thermal excitation etching, as shown in FIG. 5, an etching gas is injected from the nozzle 22 onto the heated substrate 10, and the nozzle 22 is caused to scan the portion where the etching gas is injected. Selectively etch. The etching gas may be jetted continuously or intermittently along the scanning direction.

FIG. 6 shows the change in the ratio of the convex portions on the material film before and after forming the etching pattern on the material film to be planarized in the first embodiment.
That is, the substrate 10 is divided into a 200 μm square area,
An etching pattern is formed in accordance with the ratio of the projection (recess) in each region, and the ratio of the projection (recess) in each region is made uniform. In the example shown in FIG. 6, the ratio of the convex portions is 30 to 80% before the etching pattern is formed.
However, by forming an etching pattern in accordance with the ratio of the convex portion (concave portion), the ratio of the convex portion was reduced to 30.
-40%, and the ratio of the convex portions (concave portions) in each region is made uniform.

Next, a second embodiment of the present invention will be described with reference to the process chart shown in FIG. FIG.
1A, reference numeral 11 denotes a base on which a predetermined pattern is formed on a main surface side of a semiconductor substrate (not shown), and a concave portion 11a and a convex portion 11b are formed according to an element pattern or a wiring pattern.
have. A material film 12 made of a desired insulating material is formed on the base 11. This material film 12 has a base 1
A concave portion 12a and a convex portion 12b are formed corresponding to one concave portion 11a and a convex portion 11b.

Next, as shown in FIG. 2B, in order to make the pattern density uniform within the substrate (within the chip), a film forming pattern 12d corresponding to the pattern density of the concave portions or the convex portions is formed by photolithography. It is formed directly on the material film 12 without using any technique. In other words, the proportion of the film forming pattern 12d is increased in the region where the proportion of the concave portion is large. Hereinafter, a film forming method for directly forming the film forming pattern 12d on the material film 12 without using the photolithography technique will be described.

Examples of the film forming method include ion beam excited film formation, photo-excited film formation, thermally excited film formation, fine particle transport film formation, and film formation by vapor deposition (normal vacuum vapor deposition, sputter vapor deposition, etc.) through a stencil mask. can give.

Examples of a method of forming a film by ion beam excitation film formation include a method of forming a film by scanning an ion beam, a method of forming a film by irradiating an ion beam through a stencil mask, and the like. In the former method,
As shown in FIG. 3, a substrate 10 on which a material film to be planarized is formed is placed in a film forming gas atmosphere, and an ion beam is scanned on the substrate 10 to select a portion irradiated with the ion beam. The film is formed. The ion beam may be irradiated continuously or intermittently along the scanning direction. In the latter method, as shown in FIG. 4, the substrate 10 is irradiated with an ion beam through a stencil mask 21 in a film forming gas atmosphere, and the stencil mask 2 is irradiated.
Selective film formation is performed in accordance with the pattern formed in Step 1.

The photo-excited film formation is basically the same as the above-mentioned ion beam-excited film formation. A method of forming a film by scanning a light beam in a film-forming gas atmosphere, and a method of forming a film in a film-forming gas atmosphere. There is a method of forming a film by irradiating light through a stencil mask.

In the case of performing the thermal excitation film formation, as shown in FIG. 5, a film formation gas is injected from the nozzle 22 onto the heated substrate 10 and the nozzle 22 is scanned so that the film formation gas is injected. The film is selectively formed in the place where it is. The deposition gas may be continuously or intermittently injected in the scanning direction.

In the case of forming a film for transporting fine particles, a nozzle for transporting fine particles is scanned to selectively form a film on a substrate. FIG. 7 shows a change in the ratio of the convex portions on the material film before and after forming the film formation pattern on the material film to be planarized in the second embodiment. That is, the substrate 10 is divided into regions of 200 μm square, and a film formation pattern is formed in accordance with the ratio of the concave portion (convex portion) in each region, and the ratio of the concave portion (convex portion) in each region is made uniform. I have. In the example shown in FIG. 7, the ratio of the projections is 30 to 80% before the formation of the film formation pattern. However, by forming the film formation pattern in accordance with the ratio of the recesses (projections). The ratio of the convex portions is 70 to 80%, and the ratio of the concave portions (convex portions) in each region is made uniform. The present invention is not limited to the above embodiments, and can be implemented with various modifications without departing from the spirit thereof.

[0027]

According to the present invention, an etching pattern or a film formation pattern is formed on a material film to be planarized in accordance with the pattern density of a concave portion or a convex portion, and the pattern in an arbitrary region is formed by the etching pattern or the film forming pattern. Since the density is made substantially uniform in the substrate, the entire inside of the substrate can be flattened by the subsequent CMP. Further, since the etching pattern and the film formation pattern are formed directly without using a resist mask, the entire substrate can be easily flattened without using an expensive photolithography apparatus or a complicated lithography process. .

[Brief description of the drawings]

FIG. 1 is a process sectional view according to a first embodiment of the present invention.

FIG. 2 is a process sectional view according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a method for performing etching or film formation by scanning an ion beam or a light beam in the first and second embodiments of the present invention.

FIG. 4 is a diagram showing a method of performing etching or film formation by irradiating an ion beam or light via a stencil mask in the first and second embodiments of the present invention.

FIG. 5 is a diagram illustrating a method of performing thermally excited etching or thermally excited film formation in the first and second embodiments of the present invention.

FIG. 6 is a diagram showing a ratio of convex portions on a material film before and after forming an etching pattern on the material film to be planarized in the first embodiment of the present invention.

FIG. 7 is a diagram showing a ratio of convex portions on a material film before and after forming a film formation pattern on a material film to be planarized in a second embodiment of the present invention.

FIG. 8 is a diagram showing a problem in the related art.

FIG. 9 is a diagram showing a problem in the related art.

FIG. 10 is a diagram showing a problem in the related art.

FIG. 11 is a diagram showing a problem in the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Base 11a ... Concave part of base 11b ... Convex part of base 12 ... Material film 12a ... Concave part of material film 12b ... Protrusion of material film 12c ... Etching pattern 12d ... Formation pattern

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int. Cl. ⁷ , DB name) H01L 21/3205 H01L 21/304 621 H01L 21/304 622 H01L 21/3065

Claims (9)

(57) [Claims] 1. A step of forming a material film having irregularities on the main surface side of a semiconductor substrate in accordance with an underlying pattern, and etching the material film having irregularities on the surface in accordance with the pattern density of concave portions or convex portions. A step of forming the pattern directly without using a resist mask to make the pattern density of the concave portion or the convex portion in an arbitrary region substantially uniform, and a material film in which the pattern density of the concave portion or the convex portion is made substantially uniform. Flattening by chemical mechanical polishing. 2. The semiconductor according to claim 1, wherein the step of directly forming an etching pattern on the material film is performed using ion beam excitation etching, light excitation etching, thermal excitation etching, or wet etching. Device manufacturing method. 3. The step of directly forming an etching pattern on the material film includes using ion beam excitation etching for scanning an ion beam in an etching gas atmosphere or light excitation etching for scanning a light beam in an etching gas atmosphere. The method according to claim 1, wherein the method is performed. 4. The step of directly forming an etching pattern on the material film is performed by ion beam excitation etching in which an ion beam is irradiated through a stencil mask in an etching gas atmosphere or through a stencil mask in an etching gas atmosphere. 2. The method for manufacturing a semiconductor device according to claim 1, wherein the method is performed using light excitation etching for irradiating light. 5. A step of forming a material film having unevenness on the main surface side of the semiconductor substrate according to the underlying pattern, and forming the material film having the unevenness on the surface in accordance with the pattern density of the concave portions or the convex portions. A step of forming the film pattern directly without using a resist mask to make the pattern density of the recesses or protrusions in an arbitrary region substantially uniform, and a material film in which the pattern density of the recesses or protrusions is made substantially uniform Flattening the substrate by chemical mechanical polishing. 6. The step of directly forming a film-forming pattern on the material film includes ion-beam-excited film-forming, photo-excited film-forming, heat-excited film-forming, fine particle transport film-forming, or film forming by vapor deposition through a stencil mask. 6. The method for manufacturing a semiconductor device according to claim 5, wherein the method is performed by using. 7. The step of directly forming a film formation pattern on the material film includes ion beam excitation film formation in which an ion beam is scanned in a film formation gas atmosphere or light excitation in which a light beam is scanned in a film formation gas atmosphere. The method for manufacturing a semiconductor device according to claim 5, wherein the method is performed using film formation. 8. The step of directly forming a film-forming pattern on the material film includes ion-beam-excited film-forming for irradiating an ion beam through a stencil mask in a film-forming gas atmosphere or stencil-forming in a film-forming gas atmosphere. The method for manufacturing a semiconductor device according to claim 5, wherein the method is performed by using photo-excited film formation that irradiates light through a mask. 9. The semiconductor device according to claim 5, wherein the step of directly forming a film-forming pattern on the material film is performed using fine-particle transport film-forming for scanning a nozzle for transporting fine particles. Manufacturing method.