JPH0555859B2 - - Google Patents

Description

[Detailed description of the invention]

TECHNICAL FIELD OF THE INVENTION The present invention relates to positive photoresist developer compositions. [Technical Background of the Invention] The electronic industry has made remarkable progress in recent years, and with the improvement of the degree of integration of semiconductor devices and the improvement of microfabrication technology,
There is a strong demand for high-resolution resists used in lithography. For this reason, the type of resist is also shifting from negative type to positive type with excellent resolution. Most of the commercially available positive photoresists are o-
It is a combination of a quinonediazide compound and an alkali-soluble resin such as m-cresol novolac resin. Since such positive photoresists produce carboxylic acid groups when irradiated with light and become soluble in alkali, organic alkalis containing mainly quaternary ammonium bases, such as tetramethylammonium hydroxy, are used as developing solutions. Hydroxide, trimethylhydroxyethylammonium hydroxide, etc. are used. [Problems with Background Art] When a positive photoresist is developed using a conventional developer, the selectivity ratio of the dissolution rate of the light irradiated area and the non-irradiated area with respect to the developer is not satisfactory. For this reason, when a resist film is subjected to fine patterning of 1.0 to 1.5 μm or less, the resist profile and dimensional control accuracy are significantly degraded. Therefore, if the alkali concentration of the developer is increased, the temperature of the developer is increased, or the development time is lengthened in order to increase the resist sensitivity, the amount of film loss in the non-irradiated areas becomes even greater. There is a problem with so-called throughput, in which a large amount of processing time is spent just on the development process, making it impossible to realize a smooth manufacturing process. [Object of the Invention] The present invention provides a positive photoresist developer that can enhance the selectivity between exposed and unexposed areas of the resist and control patterning at the so-called near-submicron dimension of 1 to 1.5 μm with high precision. The object is to provide a composition. [Summary of the Invention] The present invention uses quaternary ammonium hydroxide as the main component of the developer, contains ethylene glycol or polyethylene glycol, and at a developer temperature of 15 to 40°C, can be used locally. By using it on exposed resist, it increases the selectivity between the exposed and unexposed areas of the resist and increases the thickness of 1 to 1.5 μm.
This is a positive photoresist developer composition that can control level patterning at so-called near-submicron dimensions with high precision. Here, the content of ethylene glycol is 1 to
50000ppm, preferably in the range of 500 to 1000ppm. The degree of polymerization of polyethylene glycol is
Set to 10 or less. [Embodiments of the Invention] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Example 1 As shown in FIG. 1, a UV positive resist OFPR800C (trade name, Tokyo Ohka Kogyo Co., Ltd.) was coated on the main surface of the oxide film 1 to a thickness of about 1.5 cm by spin coating so as to cover the main surface. A resist film 3 was formed. Next, this was baked at 80°C for 10 minutes. Next, add ethylene glycol to 0,
Developed at 30℃ for 30 seconds with each developer consisting of an organic alkaline solution mainly containing trimethylhydroxyethylammonium containing 200ppm, 500ppm, 1000ppm, and 10000ppm, and the minimum exposure time, unexposed area dissolution rate, gamma When each of the (γ) values was investigated, the results shown in the table below were obtained. Further, when the relationship between the unexposed area dissolution rate and the ethylene glycol content was investigated, a characteristic line A shown in FIG. 2 was obtained. As is clear from the table, the exposure time (minimum exposure time) required to dissolve the resist film 4 of a predetermined thickness does not vary greatly depending on the ethylene glycol content, but the dissolution rate of the unexposed area It can be seen that there is a clear difference in the γ value below 200 ppm and above 500 ppm. In other words, it can be seen that by containing a predetermined amount of ethylene glycol, a resist profile with good contrast and a high residual film in the unexposed areas can be obtained. Furthermore, as is clear from Figure 2, in areas where the ethylene glycol content is outside the range of 500 to 10,000 ppm, the unexposed area dissolution rate is in the region ( ) above the broken line, and the residual film is poor and becomes a fine pattern. It was confirmed that mass production would be limited. It was confirmed that similar results could be obtained when polyethylene glycol was contained instead of ethylene glycol and the degree of polymerization of polyethylene glycol was set to 10 or less. This effect can be obtained because quaternary ammonium base-based developers are generally used with NaOH and KOH.
The problem is that the remaining film in the unexposed areas is smaller than metal-based developing bulbs such as . This problem is the fourth
This is because the problem can be solved by containing a predetermined amount of ethylene glycol or polyethylene glycol with a low degree of polymerization in the grade ammonium base. In other words, to solve this problem, create a condition in which the developer is difficult to penetrate into the unexposed areas (low exposure areas) of the resist film 3, and create a condition where the developer easily penetrates into the exposed areas (high exposure areas). good. When ethylene glycol or polyethylene glycol is contained in the quaternary ammonium base, as shown in FIG. 1, a film layer 5 that is difficult to attack by the developer is formed in the low exposure area of the resist film 3. This is because when the film resistance becomes large, a concentration gradient of the developer is created, the development speed of the unexposed area becomes slow, and the selectivity of unexposed/exposed becomes large. Note that 6 in FIG. 1 is a photomask.

〔Effect of the invention〕

According to the positive photoresist developer composition of the present invention, it is possible to improve the selectivity between exposed and unexposed areas of the resist and control patterning in the so-called submicron size of 1 to 1.5 μm level with high precision. It is possible.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a state in which a resist film is formed on an oxide film of a semiconductor substrate and developed with the developer composition of Example 1. FIG. FIG. 3 is a characteristic diagram showing the relationship with the exposed area dissolution rate. 1... Oxide film, 2... Opening, 3... Resist film, 4... Space, 5... Boundary film, 6... Photomask.

Claims (1)

[Scope of Claims] 1. A positive photoresist developer characterized by containing ethylene glycol or polyethylene glycol at a concentration of 500 to 10,000 ppm in an organic alkaline solution mainly containing a quaternary ammonium hydroxide base. Composition. 2. The positive photoresist developer composition according to claim 1, wherein the degree of polymerization of polyethylene glycol is 10 or less. 3. Positive photoresist development according to claim 1, wherein the quaternary ammonium hydroxide base is trimethylhydroxyethylammonium or tetramethylammonium hydroxide, and is used at a developer temperature of 15 to 40°C. liquid composition.