JPH06163389A - Fabrication method of semiconductor device - Google Patents

Abstract

PURPOSE:To make uniform the thickness of a polyimide resin film in a wafer surface by removing, upon a polyimide precursor composition being rendered to spin application on a surface of a semiconductor substrate, the polyimide precursor composition existent at an end on the surface of the substrate with a scraper tool, and further rotating the semiconductor substrate. CONSTITUTION:A polyimide precursor composition 4 is dropped from a dispenser nozzle 3. Then, the polyimide precursor composition 4 is effused in the direction of a surface end of a semiconductor substrate 2. Further, since the polyimide precursor composition 4 partly goes around the back surface of the semiconductor substrate 2, a scraper tool 7 makes contact with the polyimide precursor composition 4 existent at the surface end of the substrate and temporarily removes the composition together with cleaning by a back surface cleaning solution 6 infected from a back surface cleaning nozzle 5. Then, the scraper tool is separated from the composition and is rotated successively, whereby the polyimide precursor composition 4 on the surface of the substrate 2 is made uniform in its surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for forming a polyimide resin film, and more particularly to spin coating of a resin having a high viscosity to form a thick film. More specifically, a polyimide precursor composition is spun on a surface of a semiconductor substrate. The present invention relates to a technique suitable for removing the above-mentioned composition that has risen at the end of the substrate during coating.

[0002]

2. Description of the Related Art Conventionally, a polyimide resin film has been used as a surface protective film or an interlayer insulating film for various electronic parts such as semiconductors. Polyimide resin is PSG, SiO ₂ , S
For example, a flat film can be formed on a substrate having larger irregularities than an inorganic insulating film such as iN, a thick film of 1 μm or more can be easily formed, and heat resistance is higher than other organic materials. Because of its advantages, it has been adopted as an interlayer insulating film for bipolar ICs, and has recently been widely used as an α-ray shielding film and a buffer coat film for memory devices. The above-mentioned polyimide resin film is formed by applying a polyimide precursor composition onto a wafer which is a semiconductor substrate by a spinning method or the like and heat-treating it, and patterns such as through holes are formed in this polyimide resin film. It

However, when the polyimide precursor composition is dropped onto the center portion of the wafer surface and spin-coated, and the wafer coated with the polyimide precursor composition is heat-treated on a hot plate, the edge portion of the surface of the wafer is Since the polyimide-based resin film rises and the film thickness becomes thicker, a photoresist used as a mask material for forming the pattern of the polyimide-based resin film is formed, and an etching process is performed after the exposure. The polyimide resin film becomes thicker than in the vicinity of the central portion of the wafer, etching cannot be performed in a predetermined time, and the semiconductor element at the edge of the wafer cannot be used.
This is one of the causes of the decrease in yield. This problem is more likely to occur when the viscosity of the polyimide precursor composition used is higher and the low-speed spinning coating is performed. For this reason, recently, in order to prevent the polyimide-based resin film from rising on the edge portion of the wafer surface, (1) N-methyl-2-, which is used in a polyimide precursor composition during spin coating, is used.
A method in which a polar solvent such as pyrrolidone or N, N-dimethylformamide is sprayed onto the end portion from a cleaning nozzle provided on the wafer surface portion, or (2) a gas such as N ₂ is directly sprayed is adopted.

However, in the method (1), since the polar solvent is poor in dryness, when the film is heated by a hot plate in this state, bleeding of the coating film is observed at the edge of the wafer surface. Further, since the polar solvent is sprayed for a predetermined time, the amount used becomes large, and in the method (2), the N ₂ pressure needs to be adjusted depending on the viscosity of the polyimide precursor composition.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, and when a polyimide precursor composition is spin-coated on a semiconductor substrate or the like, a composition in which the edge portion of the surface of the wafer is raised is formed. Provided is a method for manufacturing a semiconductor device, which can be easily removed to suppress the swelling of a polyimide-based resin film at an end portion and to make the thickness of the polyimide-based resin film within the wafer uniform.

[0006]

The present invention provides a method for spin coating a polyimide precursor composition on the surface of a semiconductor substrate,
The present invention relates to a method for manufacturing a semiconductor device in which a polyimide precursor composition on the surface end portion of the substrate is removed with a scraping tool, and the semiconductor substrate is rotated.

The scraping tool used in the present invention is made of N-type metal such as plastic, SUS, and aluminum.
Examples thereof include those that are highly resistant to polar solvents such as methyl-2-pyrrolidone. It is particularly preferable to use a soft material such as Teflon, polyethylene or polypropylene, which is unlikely to be broken when it comes into contact with the semiconductor substrate.

The polyimide precursor composition used in the present invention contains 4,4'-diamino in an organic solvent such as N-methyl-2-pyrrolidone, N, N-dimethylacetamide or N, N-dimethylformamide. Diamine component such as diphenyl ether is dissolved, and then 3,3 ', 4,4
The composition is obtained by adding an organic tetrabasic acid dianhydride component such as 4'-benzophenone tetracarboxylic acid dianhydride and stirring and reacting at a temperature of 50 ° C or lower, more preferably around room temperature or lower. The polyimide-based resin film is obtained by adding a solvent to the above polyimide precursor composition at 50 to 80 ° C.
After stirring at a temperature of, and adjusting the viscosity to be suitable for use, spin coating on a semiconductor substrate and heat treating at a temperature in the range of 100 to 350 ° C. for 3 hours or less with a hot plate, a hot air dryer, etc. Obtained by dehydration ring closure. Examples of commercially available polyimide precursor compositions include PIQ and PIX.
(All are trade names manufactured by Hitachi Chemical Co., Ltd.) and the like.

Temporary removal of the polyimide precursor composition at the surface end portion of the substrate during spin coating in the present invention by a scraping tool is performed as follows. First, a polyimide precursor composition is dropped on the central portion of the surface of a semiconductor substrate by a dispense method and spin-coated. A scraping tool is brought into contact with the polyimide precursor composition that has flowed to the edge portion of the surface of the substrate by spin coating, and the polyimide precursor composition at the contact portion is removed. For the removal treatment, the rotation speed during spin coating is 50 to 200.
0r. p. m (rotation / minute) is preferable, and the area where the scraping tool contacts the composition is 20 mm from the edge of the substrate.
The distance is preferably within the range of 2 to 10 mm, more preferably within the range of 2 to 10 mm. The rotation time is appropriately determined depending on the viscosity of the polyimide precursor composition and the like. Furthermore, separate the scraping tool,
The rotation speed is preferably 2500 r.p.m. p. The rotation of the semiconductor substrate is continued for m or more and the rotation time of 0.5 to 5 seconds. At this time, if the substrate does not break, the scraping tool can be brought into contact with the surface end portion of the substrate.

An embodiment of the present invention is shown in FIG. 1. The explanation will be given with reference to this figure. First, from the dispense nozzle 3 to the central portion of the surface of the semiconductor substrate 2 adsorbed by the spin head 1 in the coater cup 9. The polyimide precursor composition 4 is dropped (a). Next, spin coating is started by the rotation of the spin head 1, the polyimide precursor composition 4 flows out toward the front end portion of the semiconductor substrate 2, and a part of the polyimide precursor composition 4 wraps around to the back surface side of the semiconductor substrate 2. Therefore, the scraping tool 7 comes into contact with the polyimide precursor composition 4 at the edge of the front surface of the substrate simultaneously with the cleaning by the back surface cleaning liquid 6 sprayed from the back surface cleaning nozzle 5, and the composition is temporarily removed (b). Next, the scraping tool is separated from this composition and continuously rotated to make the thickness of the polyimide precursor composition 4 on the surface of the substrate 2 uniform (c). Next, the semiconductor substrate 2 coated with the polyimide precursor composition 4 is heat-treated with a hot plate or the like to form a polyimide resin film 8 (d).

The scraping tool is movably mounted near the coater cup 9 at the end of the surface of the semiconductor substrate.
A top view of an example of the device is shown in FIG. (A) shows a state in which the polyimide precursor composition is dropped, and (b) shows a state in which the polyimide precursor composition on the surface end portion of the semiconductor substrate is scraped by a scraping tool. In the figure, the arrow indicates the flow direction of the polyimide precursor composition to be scraped. The scraping tool preferably has its tip end in contact with the composition inclined so as to scoop up the composition.

[0012]

EXAMPLES The present invention will now be described in detail with reference to examples, but the present invention is not limited to the following examples. Example 1 54.05 g of 4,4'-diaminodiphenyl ether
(0.27 mol) and 1,3-bis (aminopropyl) tetramethyldisiloxane 7.45 g (0.03 mol) were dissolved in 800 g of N-methyl-2-pyrrolidone by thoroughly stirring, 4,3 ', 4,4'-benzophenone tetracarboxylic acid dianhydride 48.33 g (0.1
5 mol) and pyromellitic dianhydride 32.71 g
(0.15 mol) was gradually added and reacted at room temperature for 6 hours.
Viscosity 140 poise (25
C.) and a resin content concentration of 18.6% by weight to obtain a polyimide precursor composition. Next, using the apparatus shown in FIGS. 1 and 4, the polyimide precursor composition was spin-coated by the following steps to form a polyimide resin film on the surface of the semiconductor substrate. First, the semiconductor substrate 2 (wafer size: 6 inches)
5 g of the polyimide precursor composition 4 was dropped on the upper central portion and left standing for 10 seconds (FIGS. 1A and 3A). Then 1
000r. p. m for 8 seconds, further 2500 r. p. m
It was spun by spinning for 15 seconds. Next 1500
r. p. m for 5 seconds, the composition that has spilled around the back surface edge of the semiconductor substrate 2 is washed with the back surface cleaning liquid 6, and continuously subjected to 500 r.p.m. p. At the same time as cleaning the back surface of the substrate for 10 seconds at m, a scraping tool 7 made of soft polyethylene was brought into contact with the polyimide precursor composition 4 in a region of 5 mm from the front end portion of the semiconductor substrate 2 for removal treatment (FIG. b), Figure 3
(B)). Next, the scraping tool 7 is released, and the scraping tool 3500 r. p. m
The semiconductor substrate was continuously rotated for 1.5 seconds (FIG. 1C). Next, the semiconductor substrate 2 coated with the polyimide precursor composition 4 is heated at 100 ° C. for 6 hours using a hot plate.
Heat treatment for 0 seconds at 125 ° C for 60 seconds (prebaking)
Then, a 15.0 μm thick polyimide resin film 8 was formed (FIG. 1D).

At the edge of the surface of the obtained semiconductor substrate, no swelling was observed in the polyimide resin film, and the film thickness of the film was uniform up to the edge of the semiconductor substrate. Further, a phenol novolac-based positive resist layer (OFPR-5000: trade name of Tokyo Ohka Kogyo Co., Ltd.) on the polyimide-based resin film.
Of the g-line stepper (FPA-
1550: manufactured by Canon Inc.) by a known photo-etching technique using an aqueous tetramethylammonium hydroxide solution NMD-3 (concentration 2.38% by weight,
Using the Tokyo Ohka Kogyo Co., Ltd. product name), the positive resist layer is developed and the polyimide resin film is simultaneously etched by the paddle method at 23 ° C. for 100 seconds to form a 100 μm square via hole and an 80 μm scribe line in the bonding pad. Patterned, all semiconductor devices (dimensions: 5.
It was possible to form a uniform polyimide resin film pattern in a size of 5 × 13.6 mm.

Comparative Example 1 The procedure of Example 1 was repeated, except that the polyimide precursor composition 4 was not removed by the scraping tool 7 during spin coating. As shown in FIG. 2, a swelling of the polyimide resin film was observed at the end of the surface of the obtained semiconductor substrate 2 with a width of 8 mm from the end. Further, as a result of confirming the pattern shape in the same manner as in Example 1, the etching is insufficient in a region of 6 to 8 mm from the surface end portion of the semiconductor substrate 2, a uniform pattern is not formed, and the yield of semiconductor elements is high. It was 90%.

[0015]

By spin coating according to the present invention, a polyimide resin film having a uniform film thickness can be formed up to the end of the semiconductor substrate surface, and the pattern can be formed in the semiconductor substrate surface with a uniform size during pattern production. Therefore, it is possible to suppress a decrease in the yield of semiconductor elements due to defective pattern formation of the polyimide resin film.

[Brief description of drawings]

FIG. 1 is an explanatory view of a method for manufacturing a semiconductor device according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of a semiconductor substrate obtained by a method of manufacturing a semiconductor device obtained in Comparative Example 1.

FIG. 3 is a top view of an apparatus used in the manufacturing method of the present invention.

[Explanation of reference numerals] 1 spin head 2 semiconductor substrate 3 dispensing nozzle 4 polyimide precursor composition 5 back surface cleaning nozzle 6 cleaning liquid 7 scraping tool 8 polyimide resin film 9 coater cup

Claims (1)

[Claims] 1. When the polyimide precursor composition is spin-coated on the surface of a semiconductor substrate, the polyimide precursor composition on the edge of the surface of the substrate is removed by a scraping tool, and the semiconductor substrate is rotated. A method of manufacturing a characteristic semiconductor device.