JPS61170738A - Lift-off process by multi-layered resist - Google Patents

Abstract

PURPOSE:To laminate the same resist into two layers and to make possible the easy formation of an overhang shape by treating preliminarily the resist surface of the lower layer with a silane coupling agent thereby preventing the dissolution between the resists. CONSTITUTION:The photoresist 11 is coated on a substrate 10 and the entire surface is exposed with UV rays 14 after prebaking. The surface of the photoresist 11 is treated with the silane coupling agent 12 or titanate coupling agent 12 and after drying, the same resist 11 is similarly coated thereon and is dried. The resist is then exposed through a photomask of the prescribed pattern and the overhang shape is obtd. by one developing stage. A thin film 13 is formed at the temp. at which the photoresist does not deform and finally the photoresist layer is removed, by which the thin film pattern is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in a fine pattern forming process using the rear)-off method.

[Conventional technology]

Recently, there has been remarkable progress in increasing the degree of integration of L8 technology, and as a result, the role of lithography technology is becoming more and more important.

As methods for forming fine patterns, there are two methods: an etching method in which unnecessary portions are etched away using a resist pattern as a mask, and a lift-off method in which a resist on which a thin film has been deposited is removed by utilizing the undercut shape of the resist.

However, with the etching method, dry etching may cause property deterioration due to plasma damage to the item element.
Difficult to control the shape of the etch leg.

Furthermore, since the etching resistance of the resist is poor, a method of forming fine patterns using a lift-off method is attracting attention. Furthermore, since the lift-off method is advantageous for forming multilayer thin film structures, it is expected that its use will increase in the future. As a conventional technique of such lift-off method, M*Hat
zakis, et al rBtngle-Btap 0pti
cal Iaift-Off ProcasaJ,
From M J, R]! ! ! 3. DI! 1VIi! LOP
VOL, Q4 No.

4JULY 1980 and B, J, Lss and T
, Fi, X', Chang*rHybrid e-b
aatn/daap-Uv azposurttusi
ng portable conformable
t masking (PCM) taehntqxeJ
, :f, Vac, Bci, Tgchn.

1, vol, 16ano, 6.1979, etc.

[Problem that the invention seeks to solve]

In the case of the former method of the prior art, that is, a method in which a delamination resist is immersed in chlorobenzene and then developed to form an overhang shape, the following mass-market products are available.

(1) An overhang shape created by a single layer resist cannot completely prevent the enclosing of the deposited layer in the subsequent thin film deposition process, so the resist may not be removed sufficiently, resulting in residual resist, or the edge shape of the required pattern. becomes jagged and cannot be sharpened.

(2) There is a problem with workability because an organic solvent classified as the first petroleum class, such as chlorobenzene, is used.

The latter method of the prior art, that is, the method of laminating two types of resist to form an overhang shape, has the following problem.

(1) To laminate two completely different types of resist,
.

If the developer for the upper and lower layers is not properly selected, the over-leg shape cannot be formed properly. (2) Since two types of resist with completely different properties are used, multiple light sources, developers, and strippers must be prepared. Otherwise, the process becomes complicated.

[Means for solving problems]

The present invention has focused on the above-mentioned problems, and aims to make it possible to easily form an overhang shape by laminating two layers of the same resist, and to ensure lift-off.

In order to solve the above-mentioned problems, the present invention is a method in which identical resists are laminated, and the content is that after the lower layer resist is exposed, the resist is surface treated with a silane coupling agent or a titanate coupling agent, and then the upper layer is layered. The present invention provides a method for easily forming an overhang shape by coating resists so that identical resists can be stacked.

[Effect]

The details of the present invention will be explained below with reference to the drawings.

FIG. 1 schematically represents the process of the lift-off method according to the present invention. First, 7 photoresist 11i is applied to the substrate 10 (d), and after pre-baking, the entire surface is exposed to ultraviolet rays 14 (b). In the present invention, in order to be able to form an overhang shape in one development process, the lower layer photoresist is 11 exposure amount All upper layer photoresist 1
Exposure amount larger than 1. (preferably upper layer register)
The primary silane coupling agent is 1.5 to 8 times the exposure amount of resist 11, but since the overhang shape can be controlled by the exposure amount of lower resist 11, conditions that match the desired shape can be selected. C) Treat the surface of the photoresist 11 with a titanate coupling agent or a titanate coupling agent.
, after drying, apply 11 in the same manner (same resist) and dry (
The treatment process using a coupling agent must be performed after the entire surface of the lower photoresist 11 is exposed.9 For example, if the treatment is performed before the entire surface is exposed, the lower layer photoresist will partially dissolve with the upper layer photoresist and an overhang shape will not be formed properly. It disappears. This is presumed to indicate that the properties of the photoresist before exposure had poor adhesion to the coupling agent and that the surface treatment was not performed well. Also the concentration of the coupling agent.

0.06-0.5 ya o1. <76 well preferably 0.1-0.8 vol,% Good.

Coupling agent! ! If the concentration is less than 0.05 vol, 4, the surface treatment will be incomplete and the photoresist will not be laminated properly.
In the case of 6 or more, uneven coating of the coupling agent becomes noticeable and it becomes difficult to form a uniform overhang shape over the entire substrate.

Coupling agent can be applied using dipping method,
Any method such as a spinner method or a spray method may be used, but the dipping method is particularly desirable because it easily provides uniform processing and has excellent throughput.

Next (expose through 7 otomasks with a predetermined pattern,
- Obtain an overhang shape through the development process (e)
As described above, the overhang shape can be controlled by the difference in exposure amount between the lower layer and the upper layer resist, but it can also be controlled to some extent by the development conditions, such as the development time. For this reason, if both control methods are used together, fairly precise control is possible.The primary thin film 13 is formed at a temperature at which the photoresist does not deform, and finally the photoresist layer is removed to obtain the desired thin film pattern. As a method for forming a thin film, for example, a magnetron sputtering method, a vacuum evaporation method, etc. are typically used.

[Example 1] Positive type photoresist (MuZ-
1850J) was applied using a spinner to a film thickness of approximately 2 μm, and an additional pre-bake was performed at 10°C. 8. Next, the entire surface was exposed so that the exposure amount was twice that of the upper layer photoresist. 0.1 vol, % of 0-order silane coupling agent (Toshi Silicone Co., Ltd. Exhibition 5a-6020)
Create an aqueous solution.

After surface treatment by dipping method (capital)
After drying at 100°C for 10 minutes, the same resist was applied again using a spinner, this time to a film thickness of about 0.8μ, and prebaked at 100°C for 9 minutes. It was exposed through a mask and developed (the developer was MMD-Jl manufactured by Tokyo Ohka Co., Ltd.) to form an overhang shape. 8A as overhang amount 15
After obtaining a shape of about m, a film was formed to a thickness of m7t2000X using a primary magnetron sputtering device.Finally, the resist was stripped off using a resist stripping solution (Tokyo Ohka Co., Ltd. 502).As a result, the entire surface of the substrate was covered. The resist is removed cleanly and you can reach your desired goal! A pattern was obtained.

[Example 2] The exposure amount of the lower layer photoresist is 8 times that of the upper layer photoresist.
An overhang shape was formed in the same manner as in Example 1 except that the size was doubled. In this case, the overhang [15 is 9μt]
A rim degree shape was obtained. The following will be done in the same way and the purpose will be 5! A pattern was obtained.

[Example 8] As a silane coupling agent, KA manufactured by Shin-Etsu Silicone Co., Ltd.
Lift-off was performed in the same manner as in Example 1 except that -211t- was used and treated with a 0.2 vol, 96 aqueous solution, and as a result, the desired AJJl-on was successfully formed.

[Example] When the lift-off method was carried out in the same manner as in Example 1, using a titanate coupling agent (#, Sokema TT3) in place of the silane coupling agent, the same results were obtained. Ta.

[Example 5] A lateral structure MIM element (B*
Morotxmt, at al rapanDis
play '88. ? 404-407.1983), the cross-sectional shape of the two-layer film of the first electrode 4 and the insulator 2 was changed to improve the step coverage and reliability of the second electrode 5. As shown in Figure 2-(6), it is necessary to rub with a gentle taper.

In this case, it is difficult to form the shape by etching because of the complexity of the process and poor reproducibility.

However, if the lift-off method of the present invention is used, the taper shape can be easily controlled by controlling the overhang shape. In the same manner as in Example 1, a two-layer film of the first electrode (n) and the insulator (b) was formed by magnetron sputtering.

When lifted off, a pattern having the desired tapered shape was obtained. From now on, T with MXMg child added
When we made an N-type liquid crystal display and compared it, we found that the number of defects was reduced and the reliability in aging tests was also improved.

〔Effect of the invention〕

As described above, the present invention uses the same resist for the lower layer resist and the upper layer resist, and by surface treating the lower layer resist with a silane coupling agent or titanium coupling agent after exposure, it is possible to stack the upper layer resist. Furthermore, since the overhang shape can be controlled by adjusting the exposure amount of the lower resist layer, there is an advantage that the lift self-off method can be performed in a simple process from a fine pattern to a coarse pattern, as well as controlling a taper shape.

In addition, by making the exposure amount of the lower layer resist the same as that of the upper layer resist, overhang shapes are eliminated, and 1 to 2 μf
This method can be applied as a method for forming ultra-fine patterns with rL smoothness.

[Brief explanation of the drawings] Figure 1 - (4), (M), (c), (b),
(#) , (1) , ω is based on the present invention.
An outline of the off-method process is shown. FIG. 2-(α) shows a cross-sectional view of an M-work M element having a lateral structure, and FIG. 2-(6) shows a cross-sectional view of a portion of the M-work M element. lO... one substrate 11... photoresist 12... coupling agent 13... thin film of gold'f% or insulator 14... ultraviolet light 15... overhang amount... substrate 21... ...Passivation film η...WCl electric field of M-engine M element...Insulator...Insulator 5 of M-engine M element...Second electric field 261 of MIM element, transparent pixel Electric oven 1 or more

Claims (4)

[Claims] (1) In the lift-off method in which two or more layers of resist are applied and a pattern is formed using the overhang shape of the resist, the surface of the lower resist layer is pretreated with a silane coupling agent and the A lift-off process using a multilayer resist characterized by preventing resists from dissolving each other. (2) A lift-off process using a multilayer resist according to claim 1, characterized in that the treatment is performed with a titanate coupling agent instead of a silane coupling agent. (3) A lift-off process using a multilayer resist according to claim 1, wherein the concentration of the silane coupling agent and the titanate coupling agent is in the range of 0.05 vol% to 0.5 vol%. . (4) The lift-off process using a multilayer resist according to claim 1, wherein the surface treatment step using a silane coupling agent and a titanate coupling agent is performed after the resist to be surface treated is exposed.