JPH01140722A - Formation of pattern - Google Patents

Abstract

PURPOSE:To form a high-accuracy pattern by a method wherein an exposure operation is executed in a developing solution by making use of a patterned light-shielding layer on a photoresist layer as a mask so that an amount of an undercut can be reduced even in a thick photoresist layer. CONSTITUTION:An LSI substrate 101 is immersed in a resist developing solution 106; a beam 107 is irradiated simultaneously. During this process, because a resist 102 to be used is of a positive type, only a part irradiated with the beam 107 is dissolved in the developing solution 106. While an exposure operation and a developing operation are repeated continuously, a pattern 108 for electrode formation use is formed with reference to the thick-film resist 102. That is to say, a light-shielding layer on a photoresist layer acts as a mask during the exposure operation, and only the part of the resist 102 irradiated with the beam 107 is dissolved by the developing solution. In addition, because the exposure operation is executed in the developing solution, the exposure operation and the developing operation are executed continuously. By this setup, even when the thick photoresist layer 102 is used, exposure to light is suppressed sharply in a transverse direction of a pattern edge part; accordingly, it is possible to form a high-accuracy pattern whose amount of an undercut is small.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for forming a pattern on a photosensitive resist. and a pattern forming method using a developing method.

[Conventional technology]

Conventionally, as described in JPO 1854-92061, a light shielding layer is provided on a photoresist, and exposure and development are sequentially performed. These are usually performed with a resist film thickness in the range of several microns. Electronic materials for thick film pattern formation of 10 μm or more.

As described on pages 35 to 39 of the October 1985 issue, dry film resists are often used.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into consideration the thickening of the photoresist layer, and it is difficult to perform highly accurate butter ni/gu of a photoresist layer having a thickness exceeding 10 μm. That is, the conventional exposure and development method requires long exposure to expose the entire thick film resist to light. At this time, since the light spreads in the lateral direction of the pattern and the vicinity of the edge of the strip is also exposed to light, the pattern after development becomes a pattern with an extremely large amount of undercut.

An object of the present invention is to provide a pattern forming method that has a small amount of undercut even in a thick photoresist layer and allows highly accurate pattern processing.

[Means for solving problems]

The above object is achieved by exposing the photoresist layer to light in a liquid using a patterned light shielding layer formed on the photoresist layer as a mask.

[Effect]

The light-shielding layer on the photoresist layer acts as a mask during exposure, and only the resist portions irradiated with light are dissolved by the developer. Furthermore, since exposure is performed in a developer, exposure and development proceed continuously. As a result, even if a thick photoresist layer is used, exposure to light in the lateral direction of the pattern edge portion can be significantly suppressed, allowing highly accurate pattern processing with a small amount of undercut.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1(a) to 1(f).

Figure 1 shows CCB (Controlled Co11a)
FIG. 3 is a process diagram of a mounting bump electrode formation process (pseBonding). First, as shown in FIG. 1(a), a positive type film 102 (for example, TF-20 manufactured by Sibley) was coated on an LSI substrate 101.The thickness of the coating film was controlled by the height of the protruding electrode. Here, 20-150μm
The range was set to . Next, a 3000 thick AA vapor film was deposited on the photoresist film 102 as a light shielding film 103. Further, in order to pattern the light shielding film 103, a 1 μm thick photoresist film 104 was formed. The pattern processing of this photoresist group 104 is shown in FIG.
) As shown in FIG.
. The patterning of this light shielding film was carried out by chemical etching (etching solution containing diphosphoric acid, nitric acid, acetic acid, and water). Next, as shown in FIG. 1(C), the LSI board 1
01 is immersed in a resist developer 106, and at the same time exposed to light 107.
was irradiated. The resist used here is positive, so
Only the portion irradiated with light is dissolved in the developer 106.

By continuously repeating such exposure and development, a turf 108 for forming electrodes was formed on the thick film resist as shown in FIG. 1(d). Next, bump electrodes 109 were formed by the tN method (selective electroplating) as shown in FIG. 1(e). Furthermore, unnecessary portions of the resist were removed to form a bump electrode pattern as shown in FIG. 1(f).

In this step, the bump electrodes were formed by electrodeposition, but similar electrode turns can also be formed by vapor deposition lift-off.

In the normal photoring 2-fi process, pattern formation becomes difficult as the photoresist layer becomes thicker. For example, 5
When patterning a photoresist film with a thickness of 0 μm, the amount of side development becomes 15 μm or more. Since the amount of side development increases in proportion to the thickness of the resist film, high-precision pattern processing becomes impossible.

According to this example, when the resist film thickness was 50 μm, the side development amount was 5 μm or less.

Moreover, even if the resist film thickness is further increased (up to 150 μm), the amount of side development increases only slightly, and this has an extremely large effect on increasing the precision of thick film resist processing. moreover,
It is possible to process patterns with high aspect ratios (film thickness/pattern processing dimensions).

This is effective in increasing the reliability of bump electrodes. Additionally, compared to other thick film pattern processing (for example, forming CCB bump electrodes using a metal mask), these pattern processing can significantly shorten the pitch between electrodes, which has the effect of increasing the density of bump electrodes. be.

〔Effect of the invention〕

According to the present invention, high-precision patterning with a small amount of undercut can be performed in a thick film resist of 10 μm or more, resulting in the effect of a high aspect ratio of the patterned pattern.

Furthermore, thick film processing using photolithography can easily miniaturize the processed pattern, which has a great effect on increasing the density of the pattern.

[Brief explanation of the drawing]

FIG. 1 is a process diagram of a pattern forming method showing an embodiment of the present invention. 101...LSI substrate% 102...Thick film resist. 103... Light shielding film, 104... Thin film resist), 1
05... Open butter pattern, 106... Developer, 107
···light.゛ 108... Pattern for electrode formation, 109...
・Protruding electrode. . (: Agent A Patent attorney Katsuo Ogawa, Part I (C) (child)

Claims (1)

[Scope of Claims] 1. A method for forming a pattern of a photosensitive resist film, characterized in that pattern exposure of the resist film is carried out in a developer. 2. A pattern of a photosensitive resist film according to claim 1, characterized in that a light shielding film pattern formed on the photosensitive resist film is processed and the pattern is used as a mask during exposure and development. Formation method. 3. A pattern forming method for a photosensitive resist film according to claim 1 or 2, characterized in that the supply and discharge of a developer is repeated during exposure. 4. A resist film pattern forming method according to claim 2, wherein the light shielding film is made of one selected from Al, Cr, and Ti.