JPS5842237A - Formation of irregular pattern - Google Patents

Abstract

PURPOSE:To obtain a minute and highly accurate resist pattern by a method wherein a photoresist layer is formed after forming a heat resistant resin layer on a substrate and patterning is performed to obtain a predetermined pattern and after performing dry etching by using the resist pattern as a mask, the resist pattern is removed. CONSTITUTION:A metal thin film 5 such as silicon dioxide is formed on the whole surface of a silicon substrate 4 having good plane and after applying a polyimide resin as heat resistant resin on the film 5, a heat resistant resin layer 6 is formed by baking the polyimide resin. Positive-type photoresist is similarly rotated and applied on the layer 6 for baking and a photoresist layer 7 is obtained. Furthermore, light is irradiated at the layer 7 through a photo mask for printing. Next, a predetermined resist pattern is obtained by executing development. Furthermore, etching is performed to the layer 6 by using the resist pattern as a mask.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a concavo-convex pattern, and particularly to a method for forming a fine and highly accurate concavo-convex pattern using a heat-resistant resin in the production of semiconductor integrated circuits and high-performance electronic parts.

Recently, as the performance of semiconductor elements or microelectronic components has improved, various methods have been proposed for forming fine and highly accurate concavo-convex patterns. Classifying this method from the viewpoint of phosphorography technology used for microfabrication, it can be divided into the following five types depending on the difference in the radiant energy used to form an image on the resist. namely, photolithography, electron beam lithography, X-ray phosphorography, D...p-UV lithography, and ion beam lithography.
It is.

Each of these technologies is indicated by its historical origin, and is closely related to the requirements of the era for nine technologies and the overall level of industrial technology of that era. Except for lithography, special resists have been developed and supplied for each type of lithography.

As examples of conventional fine pattern forming processes, FIG. 1 shows an etching method, and FIG. 2 shows a lift-off method.

First, the etching method shown in Fig. 1 involves forming a thin metal to be processed *(2) on a substrate α), followed by a resist layer 0) such as photoresist or electron beam resist (see the same figure), and then etching with ultraviolet light. , the resist layer is selectively irradiated with radiation such as an electron beam, and developed to form a predetermined pattern (see the same figure), and then the remaining resist layer is covered using the remaining resist layer as a mask. The same figure (C) shows the processed metal thin film (2) being selectively etched.
'), further remove the remaining resist layer (3),
The desired metal thin film pattern is formed (see figure (b)). In addition, in the lift-off method shown in Figure 2, a resist layer (
This resist layer (3) is selectively irradiated with radiation and processed to form a predetermined pattern (as shown in the same figure), and then by vapor deposition or sputtering). After forming the metal thin layer 11 (2) on the entire surface (see (15') in the same figure, the resist layer (3) and the metal thin layer a (2) on the same layer are dissolved and removed using a solvent, and the metal thin layer a (2) on the same layer is removed in the same way. A metal thin film pattern is then formed ((2) in the same figure).

Of course, the processing accuracy of the entertainment thin film pattern obtained in this way is directly influenced by the processing accuracy of the resist pattern 1, such as sensitivity, resolution, and the angle between the resist and the substrate. In this regard, the characteristics of the resist material become an important factor.

As mentioned above, many resists have been developed in the past, but resists for electron beams are the best in terms of high resolution, but on the other hand, they are inferior in terms of sensitivity and dry etching resistance, and are not always sufficient. X
Ray resists are attracting attention as they enable excellent image quality, but there is a desire for higher sensitivity than that of electron beam resists. Furthermore, Deep-U
V resists are sensitive to the short wavelength ultraviolet range (200 to 350 m), so they have higher resolution than photoresists, and are easier to introduce into production sites than those that use electronic equipment or xIs. Although there are advantages, there is no resist that can satisfy the overall characteristics in all respects like the first two. In addition, each of these new b-resist products requires its own dedicated exposure equipment, so it has different problems than regular photoresists in terms of equipment cost and equipment operability, as well as resist pattern There are also problems with reliability and stability.

In view of these conventional circumstances, the present invention company provides a method for forming concave and convex turns using a heat resistant, fine and highly precise surface resin, using current common materials and equipment. A process of forming a heat-resistant resin layer on a substrate, a process of forming a photoresist layer on this heat-resistant resin layer, a process of patterning this photoresist layer into a predetermined pattern, and a process of (using the turned resist pattern as a master). and selectively dry etching the heat-resistant resin layer, and removing the remaining resist pattern.
It is considered to be a 4I symptom.

Hereinafter, one embodiment of the method of the present invention will be described in detail, taking the manufacture of a semiconductor device as an example, with reference to FIG. 5WIA and FIG.

#I3 Figure (2) to ) shows this practical example method in the process application. That is, first, a silicon substrate with good planarity (
4) Spread a metal thin film (5) of silicon dioxide etc. on the entire surface for about 20 minutes.
A polyimide resin 2 as a heat-resistant resin, such as an electronic insulating coating agent 8, is applied on the molding formula to a thickness of 0OA.
P510 (product name, Toshisha II) was applied using a spin coating machine.
After coating at 3000 rpm, it was baked at about 1000°C for 1 hour and at about 200°C for 1 hour in a threatening atmosphere to form a thick heat-resistant resin layer (6) of about 2.4 μm. Mu Z1350J (
(trade name, Silapray Co., USA) was applied by spin in the same manner, and baked at about 80°C for 30 minutes in a nitrogen atmosphere.
A photoresist layer (7) of approximately 2.4 .mu.m is obtained, and the photoresist layer (7) is roughly irradiated with a photoresist through the photoresist and baked. Irradiation with ζOat was performed for 3 seconds using an ultra-high pressure mercury lamp (Mikasa Co., Ltd. mask alignment: output 25OW). This shaped portion is shown in FIG. 3 (4).

Then, development II1 [MK-5 (product name, Sanei Kagakusha Exhibition)
The product is stirred and immersed in this solution for 90 seconds to develop the product. Through this operation, the light irradiated area is removed and a predetermined resist pattern is obtained. is the third stage).

Further, this is etched using a parallel plate layer etching device D.
By IM451 (Product 4. Nichiden Anelpa II,),
Heat resistance using resist pattern as a mask @HIMm)0
Etching t-eggplant. Os gas was used as an etchant for this etching process at 20 BCCM (Btamdar4
Cvablc C@ntim@terper M1mi
tt+e) decrease, applied voltage a: soow, pressure & 17iT
Orr for 4 minutes. At this time, like the heat-resistant resin layer photoresist, the round part, which is an organic material, was simultaneously etched with O3 gas, and the uneven pattern shown in the middle of FIG. 3 was obtained.

Figure 4 shows the etching rate, baking temperature, and Ogl relationship of the heat-resistant resin layer (8P510) and the photoresist layer (AX 1350JTh! and 0MR83° trade name, manufactured by Tokyo Ohka Co., Ltd.). In addition, Jilt510
ti○ mark, Ag1350J#iΔ mark, 0M183ijO
In addition, the conditions are gas: 08, flow rate: zo
sccm, mark 7 JIt crab s o ow, pressure crab Q,
17! ! ? As is clear from Figure 0JI4, which is @rr, the polyimide used as the heat-resistant resin! Since the etching speed of F-fat varies greatly depending on the baking temperature, the etching rate is about &6μas/wak as shown in the experimental results by the circle. A good value of 1 to 1.1 Pg/sin can be obtained, but on the other hand, the etching density of the photoresist does not depend much on the baking temperature, and is about 0.1 Pg/sin.
55 Pvm/ra i m to α65 pm/ml
Therefore, based on this relationship, by appropriately setting the thickness of the heat-resistant resin layer (2) and the photoresist layer σ) and appropriately selecting the resin processing temperature, these values can be obtained. It becomes possible to perform etching of both layers (6) and (7) at the same time.Actually, the heat-resistant resin layer (6) and the photoresist layer (7) were etched with a thickness of 2.4 PmC) using the actual IIAfB. As a result, as seen in IIK3E9), 1g of photoresist was simultaneously removed along with the etching part of the ima*resin layer. It was confirmed that different surfaces of the heat-resistant resin layer (6) and metal thin MCI) could be cleaned at the same time by etching for a slightly longer time than the etching time (3 minutes and 40 seconds in the above example). Furthermore, the cross-sectional etch angle (#) t; In the example, the baking temperature of the heat-resistant resin was set to 2.
00℃, but even if the temperature is below 200℃ or above 200℃, it is possible to obtain similarly highly accurate uneven patterns (in experiments, i[gL
9) In addition, even if the baking treatment is performed again after the formation of the uneven pattern, there is no adverse effect on the cross-sectional edge angle gL'1 (experiments have shown that baking is performed at 460°C for 1 hour under conditions of leaving it in a nitrogen gas atmosphere). ), it was found that a stable pattern could be maintained and the thermal reliability was excellent.Furthermore, in the above implementation, a positive photoresist was used as a shielding material on the heat-resistant AlIf resin. Film formability of T5 concave and convex pattern using negative thought F resist, Butter 2/
There was no effect on the performance. Furthermore, the resolving power of the concavo-convex pattern of the obtained heat-resistant resin is not dependent on its thickness, but is affected by the resolving power of the photoresist used. Pwa? It was possible to easily obtain a concavo-convex pattern with a thickness of 8 μm and an aspect ratio (main width/film thickness) of 4. Furthermore, in the above embodiment, an 8it substrate was used as the substrate, but any substrate can be used as long as the flatness is good. At best, there are no special restrictions on glass, ceramics, etc., and on these substrates there may be Cr, its oxides, Ni, F, metals, etc.
Other examples of photoresists include, for example, group *r.
+e Pe5ltiv*Nezistist 809 (product name, made by Kodak, USA), oFPIL-IC product name, Tokyo Ohka Co., Ltd. IIiKMR747 (product name, made by Kodatsuri, USA) e Way Coat I C-Seal (product name) There is a corresponding developer.

Furthermore, heat-resistant resins such as PIQ (product name 9, manufactured by Hitachi Chemical Co., Ltd.), PYLALIN (product name, manufactured by DuP@nt, USA), and HL-600 (product name 9
Polyamide resins such as Tachi Kasei Co., Ltd.11).

There is polyamideimide resin.

As detailed above, the method of the present invention has excellent heat resistance, is fine and highly accurate, and can form an uneven pattern with a dimensional deviation of 01%/'h11 compared to the conventional photoresist pattern. Lithography technique wt- Because it can be used as is, electron beam etc! It is easier to introduce into production sites more effectively than the technology using I, it can greatly contribute to the production of semiconductor devices, etc., it does not require any capital investment, and the resulting uneven pattern is heat resistant. It has good lasma resistance and can expand the range of semiconductor devices and electronic components to which it can be applied.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views showing a conventional method for forming a concavo-convex pattern in the order of steps, Figure 3 is a cross-sectional view showing a method for forming a concavo-convex pattern on a resin in the order of steps according to an embodiment of the present invention, and Figure 4 is a heat-resistant FIG. 2 is an explanatory diagram showing the baking temperature dependence of the etching rate of polyimide as a polymeric resin and photoresist. (4... Silicon substrate, (ω... Metal thin film, (
6)... Heat-resistant resin layer, σ) Fist... Photoresist layer. Agent: Nobu Kuzu (1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Jing Renpun 51 Pi (0C)

Claims (1)

[Claims] (1) A process of forming a heat-resistant resin layer on a substrate, a process of forming a photoresist layer on this heat-resistant resin layer, a process of patterning this photoresist layer into a predetermined pattern, and a process of mastering the patterned resist pattern. a) Select the formation curing temperature of the heat-resistant resin layer, control the speed of dry etching, and remove the resist pattern by etching when the selective etching of the heat-resistant resin layer is completed. A method for forming a concavo-convex pattern according to claim 1, characterized in that the concave-convex pattern is characterized by: C) The heat-resistant wood 11 is made of board resin, and the dry etching is performed using a parallel flat*ii dry etching device. I-n-oh-we-do.