KR950009291B1 - Sililated photo resist removing method - Google Patents

Abstract

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Description

Method of Peeling Cyrilized Resist

1 to 6 are views for explaining a conventional DESIRE process.

7 to 12 are views showing a pattern forming method according to the present invention.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method for manufacturing a semiconductor device, and more particularly, to a method of removing a resist patterned by a DESIRE (Diffusion Enhanced Silylatig Resist) process.

The high integration of LSI has resulted in the need for half-micron or lower lithography on high reflection and high stepped substrates. The multilayer resist process meets such demands, but has a large number of processes, which causes problems such as yield and cost in mass production. Solving this problem is a resist silylation process, which is a one-layer resist process, which was first published by Coopmans and Roland as the DESIRE process. (Proc. Of SPIE, Vol. 631, pp. 34, 1986)

The DESIRE process will be described with reference to FIGS. 1 to 6 as follows.

After applying a photoresist (PR) 2 on a substrate to be processed, for example, a wafer 1, the PR 2 is exposed by ultraviolet light 4 through a mask 3, whereby PR As the acid is formed in the exposed region 5, the PAC (Photo Active Compound) is combined (FIG. 1).

Subsequently, when the exposed PR (2) is baked at a temperature of 110 ° C. or higher, crosslinking of resin occurs as acid diffuses in the exposed region 5 of the PR. Crosslink to increase molecular weight (Figure 2).

Subsequently, when the exposed PR is exposed to a gas atmosphere (7) of HMDS (Hexa Methyl Di Silazne) or TMDS (Tetr Methyl Di Silazne), which is a silylated agent containing silicon in an oven at 100 ° C., the PR is exposed. In the non-exposed portion 6 in which the region 5 is cross-linked with the resin, the resin is suppressed by cross-linking of the resin, and the resin reacts with the silicon atoms of the HMDS or TMDS in the non-exposed portion 6 having a relatively weak bonding force. (Fig. 3).

Subsequently, when O2 Reactive Ion Etching (RIE) is performed during dry development, which is an actual pattern forming process, silicon in the silylated layer 8 is combined with O2 to form SiOx (9), which serves as a mask during PR etching. A pattern is formed (FIG. 4).

When the PR is removed after reworking the PR or etching the substrate after forming the pattern as described above, O2 ashing (10), which is generally used, is performed (FIG. 5). However, ashing slightly progresses to the side surface of the resist under the influence of the silylated layer 9 on which SiOx is formed, but the SiOx structure becomes harder due to the influence of O2, which makes it impossible to remove PR particularly in a wide area. This is because the O2 ashing process is the same mechanism as the O2 RIE process at the time of dry development after the cylylation process.

In addition, when CF4, C2F6, CHF4, etc., which are fluorine (F) -based gases, are used to remove the SiOx structure (9), partial removal is possible, but residues remain, and unwanted etching occurs in the patterned region. This occurs (Figure 6).

Accordingly, an object of the present invention is to provide a method capable of exfoliating a silylated resist without remaining undesired or damaged by an etching gas that remains or uses in order to solve the above problems.

In order to achieve the above object, the present invention is a process of applying a resist on a substrate to be processed, followed by exposing and baking by applying a predetermined mask pattern, forming a silylated layer on the non-exposed area of the resist, and drying the resist. A pattern forming method comprising a step of patterning by development and a process of etching a substrate by using the patterned resist as a mask, wherein the resist is formed on the resultant after the process of etching the substrate by using the patterned resist as a mask Using a mask as a mask, and then applying a resist on the resultant, and then applying a predetermined mask pattern to expose the pattern, and then patterning the patterned resist in opposite tone with the patterned resist by wet development. Process of removing, removing all remaining resist Provided is a peeling method of a silylated resist, characterized in that it further comprises a tablet.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

7 to 12 show a method for peeling a resist according to the present invention.

First, reprocess the PR pattern (see FIG. 4) in which dry development is performed using the DESIRE process or the PR containing silicon, or as a mask using the PR pattern as a mask as shown in FIG. After etching (1), the same PR 12 as the PR (2) used for the patterning is applied (Fig. 8). In this case, the PR uses a resist based on Novolac and PVP (Poly Vinyl Phenol) resins having excellent flatness and etching characteristics generally used in photolithography during semiconductor manufacturing. The PR thickness to be applied may be a thickness that is entirely covered by the PR 6 using the SiOxized silylated layer 9 as an etching mask.

Subsequently, the PR 12 is exposed to the ultraviolet ray 4 (FIG. 9) using a mask used for patterning the PR (see FIG. 1). Then, wet development is first performed. It is patterned in tones opposite to the patterned PR (FIG. 10). The reason why the pattern is formed in the opposite tone is because the resin crosslinks in the exposure region during the wet development, as opposed to the dry phenomenon. In the dry development, since the diffusion of silicon does not occur in the exposure area and thus no SiOx structure is formed, the exposure area is etched by O 2, but in the wet development, the exposure area remains in a pattern without melting in a solution.

Subsequently, in order to remove the SiOxylated silylated layer 9, a mixed gas such as CF4, C2F6, CHF3 and O2, N2, which are fluorine-based gases, is removed to remove the SiOxylated silylated layer (FIG. 11). In this case, since the PR 12 is patterned in the opposite tone, not only the sidewall of the patterned PR 6 is protected, but the etched portion is also masked by the PR 12 patterned in the opposite tone. It is possible to remove the SiOxized silylation layer 9 without damaging the processing substrate 1. In the pattern in which only PR (6, 12) remains after removing the SiOxized silylation layer as shown in FIG. 11, if the remaining PR layers 6, 12 are removed by O2 ashing 13, the substrate to be processed has a step. Also, the PR can be peeled off without being damaged by residues and gases.

Next, an embodiment of the present invention will be described.

After applying the SAL601-ER7 resist 2 to a thickness of about 0.8 μm to 1.0 μm on the substrate 1 to be made of silicon wafer or oxide film, the PR 2 is applied to the ultraviolet ray 4 through the mask 3. After exposure (FIG. 1), the exposed PR (2) was subjected to PSB (Pre Silylation Bake) for 60 seconds at a temperature of 110 ° C (Figure 2), and then the exposed PR was subjected to a temperature of 100 ° C. When exposed to the gas atmosphere 7 of the TMDS for 100 seconds at, a silylated layer 8 of about 3000 Å is formed on the non-exposed part 6 of the PR 2 (FIG. 3). Subsequently, when dry development is performed using O2 RIE (Reactive Ion Etching), the silicon in the silylation layer 8 combines with O2 to form an SiOx (9) structure and forms a pattern by acting as a mask during PR etching (fourth). Degree). Subsequently, the substrate 1 to be etched is etched using the PR 6 having the SiOxized silylated layer 9 formed thereon as a mask (FIG. 7).

After applying the same PR 12 as the PR (2), that is, the SAL601-ER7 resist (Fig. 8) to the structure formed as described above (Fig. 8), the mask 3 used at the time of patterning the PR (2) is applied. The film is exposed to ultraviolet light (248 nm) 4 (FIG. 9) and wet-developed to pattern the tone opposite to the patterned PR 6 (FIG. 10).

Subsequently, using MRC's BMC-600, which is a MERIE system (RIE or ECR system is also available), RF power 1.5㎾, reaction gas CF4: 50sccm, O2: 20sccm, N2: 70sccm, time 60 seconds This removes the SiOxized silylated layer 9 (FIG. 11).

Subsequently, the remaining PR (6, 12) was removed using RF power 1.5 kW, reaction gas O2: 70 sccm, time 180 seconds using the above BMC-600 equipment (FIG. 12).

As a result of measuring the result of the embodiment of the present invention by the Tencor (Tencor facility), which is a particle measuring machine, it was confirmed that perfect peeling was performed without difference from the resist peeling process in the general single layer resist process.

As described above, according to the present invention, it is possible to rework after resist etching, which has been the most problematic during pattern manufacturing by the DESIRE process, and to remove the resist without damaging the substrate to be processed. The advantage is easy removal of resist in a pattern.

Claims (10)

Applying a resist on a substrate to be processed and then applying a predetermined mask pattern to expose and bake; forming a silylated layer on the non-exposed areas of the resist; patterning the resist by dry development; patterning A pattern forming method comprising etching a substrate to be processed using a resist as a mask, wherein a pattern of the mask is applied to the resultant after a process of etching the substrate to be processed using the patterned resist as a mask. Cylindrical resist, characterized in that it further comprises the step of patterning the resist to the patterned resist and then exposed to the wet by the development, the step of removing the silylation layer, the step of removing all the remaining resist Peeling method. The method of claim 1, wherein the dry phenomenon is performed using O 2 RIE. The method of claim 1, wherein the etching of the substrate is performed by an O2 ashing process. 2. The method of claim 1, wherein the resist applied after the etching of the substrate is a same resist as the resist on which the silylated layer is formed. The method of claim 4, wherein the resist is a resist based on a novolak / PVP resin having excellent flatness and etching characteristics. 2. The method of claim 1, wherein the resist applied after the etching of the substrate is made thicker than the resist thickness at which the silylated layer is formed. The method of claim 1, wherein the step of removing the silylated layer is performed using a fluorine (F) -based gas or a gas in which N2 and O2 are mixed with a fluorine-based gas. 8. The method of claim 7, wherein the fluorine-based gas is any one of CF4, C2F6, CHF3. The method of claim 1, wherein the step of removing the silylated layer is carried out using any one of RIE, MERIE or ECR. The method of claim 1, wherein the resist is removed by an O2 ashing process.