JP3337867B2 - Method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a semiconductor device.

[0002]

2. Description of the Related Art In general, in a highly integrated semiconductor device such as an LSI or a VLSI, wiring is performed on a certain layer on a substrate to form an n-th wiring layer, and then an n + 1-th wiring layer is further provided via an insulating layer. A so-called multi-layer wiring structure is used. The insulating layer (interlayer insulating film) constituting such a multilayer wiring structure has the purpose of ensuring insulation between the upper and lower layers (between the substrate and the wiring layer above or between the upper and lower wiring layers). Another object is to smoothly cover an uneven substrate or a wiring layer and flatten it.

Conventionally, as a method of forming an interlayer insulating film,
(1) SiH_FourChemical vapor deposition (C) using a compound gas such as
VD) method to form SiO on the substrate surface._TwoThose who form the film
Method, (2) ozone-tetraethoxysilane (TEOS)
Using SiO_TwoTo form a CVD film of (3) Shiroki
Sun-based SOG resin (When applied on a substrate and baked, SiO
_TwoA resin material that forms a glassy film of
The SOG film is dissolved in
And the like.

[0004] Among these methods, the method (3) for forming an interlayer insulating film is characterized in that it is inexpensive, has a large processing capability, and is advantageous for flattening. There is a problem. One is that after the resin is spin-coated, the resin brought to the edge of the wafer by the centrifugal force can swell. When cracks occur in the SOG film that rises at the wafer edge, a very large amount of dust is generated, which greatly reduces the yield of semiconductor devices. Therefore, in order to eliminate the swelling of the resin at the wafer edge portion, this portion is washed with a solvent after spin coating. In addition, the resin that wraps around the back side of the wafer or scatters during spin coating and is used as a cup in a spin coater (the wafer is rotated in this cup)
Solvent washing is also performed to wash away the resin adhering to the inside of the device.

[0005] As a resin for forming an SOG film, in addition to a conventionally used siloxane-based resin (for example, a resin produced by hydrolysis of tetraethoxysilane), a new material has recently been put to practical use. I have. These new materials are, for example, a molecular terminal and side chain as perhydro silazane and perhydro silsesquioxane has a large amount of Si-H groups, SiO ₂ by firing in an oxidizing atmosphere
It is expected that its use will increase in the future in order to enable the formation of an excellent inorganic insulating film made of. For example,
When the thickness of the SOG film formed from the siloxane resin obtained by hydrolysis of tetraethoxysilane exceeds about 0.5 μm, the SOG film cracks after firing, whereas perhydrosilazane and perhydrosilsesquioxo The film formed from the sun can be made to have a thickness of about 1.4 μm and 0.8 μm, respectively, without cracking, which is very advantageous for eliminating steps (flattening). Perhydrosilazane and perhydrosilsesquioxane are represented by the following formulas (I) and (II), respectively.

[0006]

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[0007] In the ordinary siloxane-based SOG, washing of the wafer edge after spin coating and the cup of the spin coater is performed using alcohol or cellosolve as a water-soluble organic solvent. However, new SOG materials such as perhydrosilazane and perhydrosilsesquioxane react with conventional water-soluble organic solvents such as alcohols and cellosolves for cleaning with Si-H at molecular terminals and side chains. It is known that sufficient washing cannot be performed due to gelation. Therefore, these useful S
In order to make it possible to manufacture a semiconductor device using a material for forming an OG interlayer insulating film, excess SOG resin adhering to a wafer edge portion or an inner wall of a cup of a spin coater can be easily cleaned. Is urgently needed.

[0008]

DISCLOSURE OF THE INVENTION The present invention relates to a novel compound such as perhydrosilazane or perhydrosilsesoxane, which has Si--H groups at the molecular terminals and side chains and enables the formation of an excellent inorganic insulating film. A method for manufacturing a semiconductor device through a step of forming an inorganic insulating film using an SOG material, which facilitates solvent cleaning of excess SOG material on a substrate and SOG material attached to the inner wall of a cup of a spin coater. The aim is to provide a method.

[0009]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method of manufacturing a semiconductor device through a step of forming an inorganic interlayer insulating film from a resin material having a structure of Si-H at a molecular side chain and a terminal. The excess resin material present at the edge of the substrate coated with the resin material, the resin material adhered to the back surface of the substrate, or the resin material scattered in the coating device is converted into a water-insoluble ketone or substituted aromatic compound as a cleaning solvent. This is achieved by a method for manufacturing a semiconductor device, which includes a step of cleaning and removing. The main chain of the resin material is generally composed of a silazane bond, a siloxane bond, or the like.

[0010]

SOG such as perhydrosilazane or perhydrosilsesoxane having Si-H groups at the molecular terminals and side chains
As described above, the resin material cannot be sufficiently cleaned with a water-soluble organic solvent such as alcohol or cellosolve, unlike a conventional siloxane-based SOG material. The water-insoluble ketones and substituted aromatic compounds used in the method of the present invention have an excellent action of dissolving and removing such SOG resin materials such as perhydrosilazane and perhydrosilsesoxane.

The water-insoluble ketone used in the present invention includes an aliphatic ketone represented by methyl isobutyl ketone (MIBK) and a cyclic ketone represented by cyclohexanone. It is more preferable that both the aliphatic ketone and the cyclic ketone have 5 to 8 carbon atoms. Examples of the substituted aromatic compound used in the present invention include toluene and xylene. In the present invention, a mixture of two or more compounds may be used as a washing solvent.

[0012]

Next, the present invention will be further described with reference to examples.

First, the SOG coater used in the following embodiment will be described with reference to FIG. In this figure, 1 is a wafer, 2 is an SOG coater cup, 3 is an edge cleaning solvent discharge section, 4 is a wafer edge cleaning solvent discharge section, 5 is a cup cleaning solvent outlet, and 6 is a drainage pipe. The edge cleaning solvent discharge section 3 is formed of a syringe or a similar shape, and is set above the wafer edge only when cleaning the wafer edge as shown in the figure. Solvent outlet for cleaning wafer edge 4
Discharges the cleaning solvent obliquely upward to clean the back surface of the wafer. Cup cleaning solvent outlet 5 indicated by a black circle in FIG.
Performs cleaning by discharging a cleaning solvent toward the inner wall of the cup 2. The drained liquid after the washing is discharged to the outside of the apparatus through a drain pipe 6.

Example 1 In this example, rinsing of a spin coater was performed using various organic solvents. Solvents include methanol, ethanol and isopropyl alcohol (IPA) as water-soluble alcohol, methyl cellosolve as water-soluble cellosolve, acetone as water-soluble ketone, methyl isobutyl ketone (MIBK) as water-insoluble ketone, aromatic non-water-soluble solvent As benzene, xylene and toluene, cyclohexane and cyclohexanone as alicyclic solvents,
Hexane was used as a hydrocarbon solvent.

[0015] For the rinsing solution composed of the respective solvents, the FOX manufactured by Dow Corning having a perhydrosilsesquioxane structure was used as the SOG material.
After continuous spin coating on a single wafer, the SOG material scattered and attached to the cup of the spin coating device was washed with each rinse solution. After the washing, the SOG material remaining in the cup of the spin coater was scraped and collected, and its weight was measured to evaluate the washing ability of the rinsing liquid.

The results are as shown in Table 1, and it was confirmed that no SOG material remained in the cup when a rinse solution of cyclohexanone, xylene, toluene, and MIBK was used.

[0017]

[Table 1]

Example 2 In this example, the edge portions of the wafer after the application of the SOG material were cleaned using the same various cleaning solvents used in Example 1. The SOG material used is a perhydrosilazane-structured Ceramate CIP manufactured by Catalyst Chemicals, Inc.
And FOX manufactured by Dow Corning. As described above, using a SOG coater equipped with a mechanism for directly applying a rinsing liquid to the wafer edge portion during wafer rotation and cleaning the edge portion, the film thickness of each SOG material after pre-baking is 610 nm. Was applied.

After the application of the SOG material, the wafer edge is washed with each rinse solution, the surface of the edge is observed with a metallographic microscope, and the rise of the edge portion is examined by a contact-type step measuring device. An evaluation was performed.
Table 2 shows the results. An effective rinse was cyclohexanone, followed by xylene.

[0020]

[Table 2]

Thus, the tendency is that alcohol,
A non-water-soluble organic solvent has a higher cleaning ability than a water-soluble organic solvent such as cellosolves, and even a non-water-soluble organic solvent has a cyclic structure including aromatics rather than a linear structure. It was found that the structure has a higher cleaning ability, and is effective when a ketone group is contained as a substituent.

[0022]

As described above, according to the present invention,
Resin materials such as perhydrosilazane or perhydrosilsesquioxane existing at the wafer edge or adhered to the inner wall of the cup of the spin coater can be easily cleaned and removed, and therefore, use these new inorganic interlayer insulating film forming materials. As a result, it becomes easy to manufacture a semiconductor device.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating an SOG coater used to carry out the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Wafer 2 ... Cup 3 ... Solvent discharge part for edge cleaning 4 ... Solvent discharge part for wafer edge cleaning 5 ... Solvent outlet for cup cleaning 6 ... Pipe for drainage

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 21/304

Claims (4)

(57) [Claims] 1. A method of manufacturing a semiconductor device through a step of forming an inorganic interlayer insulating film from an SOG material having a structure of Si—H at a molecular side chain and a terminal, wherein the edge of a substrate coated with the SOG material is provided. excess SOG material present in the portion, SOG material attached to the back surface of the substrate, or an SOG material scattered in the coating apparatus, further comprising the step of washing away the non-water-soluble ketones or substituted aromatic compound as a cleaning solvent A method for manufacturing a semiconductor device. 2. The method according to claim 1, wherein the main chain of the SOG material comprises silazane bonds. 3. The method of claim 1, wherein the backbone of the SOG material comprises siloxane bonds. 4. The method according to claim 1, wherein the water-insoluble ketone is an aliphatic ketone having 5 to 8 carbon atoms or a cyclic ketone having 5 to 8 carbon atoms.