JPH0452644A - Formation of multilayered resist pattern - Google Patents

Abstract

PURPOSE:To obviate the generation of contraction even if a resist is baked at an ordinary baking temp. by using a coating type silicon oxide film of a coating type inert to the acid generated from the resist as a intermediate layer. CONSTITUTION:A substrate agent for multiple layers is applied on a substrate 1 and is baked. SOG of formula with which the SiO2 unit formed by changing one of the bonds of the silicon in, for example, silanol to a methyl group is half of the entire part is applied thereon and is baked to form an SOG film 3; thereafter, the negative type resist contg. an acid generating agent is applied thereon. The resist is then subjected to baking by exposing with an electron rays then to developing with an aq. alkaline soln. and further to baking on a hot plate, by which the resist patterns are formed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for forming a fine multilayer resist pattern.

[Prior art and its problems] High energy beams, such as electron beams, ion beams,
Resists containing substances that generate acids when exposed to radiation, deep ultraviolet light, excimer laser, etc. have been developed.

This is a material in which crosslinking, cleavage, decomposition, etc. occur in a chain manner with acid as a catalyst, and a negative or positive pattern can be formed with high sensitivity.

On the other hand, the multilayer resist method is used as an effective method for improving resolution, flattening unevenness on the device surface, and reducing the proximity effect, which is the effect of scattering of electrons within the resist during electron beam exposure. .

In the conventional multilayer resist method, first, a photoresist or a base agent for multilayer processes with excellent flatness is applied as a base organic film to a thickness of one layer or more that can flatten the steps, and then a base organic film is coated as an intermediate layer. When the film is subjected to oxygen gas reactive ion etching, a coated oxide film (SOG), which serves as an etching-resistant mask, is applied to a thickness of about 0.1 to 0.21 IM.
Next, a resist for forming a pattern by exposure is applied as an upper layer resist. At this time, the upper layer resist needs to be applied to a thickness that is at least thick enough to withstand as a mask when etching the SOG. Moreover, a single layer resist can be used as the upper layer resist.

In the multilayer resist method described above, when the above-mentioned acid-generating substance is used as the upper layer resist on an inorganic SOG film containing silanol as the main component and formed at a baking temperature of 200°C or less, the upper layer resist is In the case of a negative resist, the resist 34 and SOG are connected as shown in FIG.
A constriction occurs at the interface with the film 35, and in a positive resist,
As shown in FIG. 3, a residue is formed at the interface between the resist 44 and the SOG film 45.

As a solution to this problem, for example, in the case of negative resist, SO
Suga, Yamaro, and Okazaki reported at the 36th Applied Physics Association Conference that constriction can be prevented by beta-heating the G film at 400°C. However, this process has the disadvantage that the carbon skeleton of the underlying organic film is decomposed by baking at 400'C.

Constrictions and residues that occur at the interface between the resist and the SOG film are
Protons generated by exposure are incorporated into the 5-O-H bond of silanol remaining on the SOG surface, and the resist and SO
This occurs because the crosslinking or decomposition reaction that occurs when activated by an acid at the G interface does not occur. Once upon a time, I wondered if it would be sufficient to change all the 5i-0-H bonds contained in SOG into Si-〇-3i bonds, and to do this, as reported by Suga et al. Is there a need to beta it? However, at this temperature, the carbon skeleton of the lower organic film will decompose, so silanol-type SOG
It is difficult to put the high-temperature beta method into practical use.

The present invention eliminates the need for such a high-temperature beta process, and uses a conventional acid-generating upper layer resist and silanol-type inorganic SO.
An object of the present invention is to provide a method for forming a multilayer resist pattern in which reaction with G is suppressed.

[Means for Solving the Problems] The present invention provides a pattern forming method using a multilayer resist including a substance that generates acid upon exposure as the uppermost layer and an intermediate layer that generates acid from the resist as the intermediate layer. This is a multilayer resist pattern forming method characterized by using a coated silicon oxide film that is inert to acids.

In the present invention, as a coating type silicon oxide film that is inert to acids, a silanol into which an organic functional group is partially introduced, such as monoalkyl silanol, is used as part or all of the raw material. An example is a silicon oxide film.

[Function] When a resist containing an acid-generating substance is used as the upper layer resist, the constrictions and residues in the resist pattern are caused by crosslinking or decomposition reactions activated by the acid at the interface between the resist and silanol-type SOG. This is caused by the protons generated by exposure being incorporated into the S i -OH bond at the terminal of the silanol condensate remaining in the silanol condensate, thereby preventing this phenomenon.

In the present invention, in order to prevent this proton-incorporating reaction, for example, silanol into which an organic functional group has been introduced is used as a raw material for the coated silicon oxide film.
SOG having a structure in which 5i-0-H bonds are reduced is used. In this way, protons are not taken into the SOG surface, and it is possible to prevent the resist from becoming constricted or remaining at the interface between the resist and the SOG.

[Example] Next, embodiments of the present invention will be described in detail.

Spin-coat a multilayer base material to a thickness of 1.5 μm on the substrate, and
Baking was performed in an oven at 00'C for 30 minutes or more in a nitrogen atmosphere. On top of this was spin-coated SOG having the following structural formula [■], in which half of the 5i02 units were 5i02 units in which one of the silicon bonds in the silanol was replaced with a methyl group, and baked.

The thickness of the SOG film formed at this time was 1,500 layers.

On top of this, a negative resist containing an acid generator was spin-coated to a thickness of 4000 mm.

FIG. 1(a) is a cross-sectional view of the multilayer resist structure obtained in this way, in which a lower organic film 2, an SOG film 3 containing an organic functional group, and a resist 4 containing an acid generator are disposed on a substrate 1. are formed sequentially.

Next, this is exposed to an electron beam, and after exposure, the beta is set to 1
The paste was applied on a hot plate for 2 minutes at 05°C, and developed with an alkaline aqueous solution.
C. Bake on hot plate for 1 minute. As a result, as shown in FIG. 1(b), the resist pattern was formed without any constrictions.

In addition to this example, any method for forming a multilayer resist pattern using a coating-type oxide film as an intermediate layer, which has sufficient resistance to serve as a mask during etching of the lower organic film and is inert to acids, can of course be used. Included in the present invention.

[Effect of the invention 1 As explained above, according to the present invention, the acid generated from the acid generator contained in the resist and the S
Prevents reaction with OG and allows pattern formation without constrictions or residue. Therefore, the method of the present invention exhibits outstanding effects as a method for forming fine patterns for electronic devices with high pattern transfer accuracy.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a multilayer resist for explaining the present invention in detail, and FIG. 2 is an inorganic SO containing silanol as a main component.
A cross-sectional view of a negative resist pattern containing an acid-generating substance on a G film, Figure 3 shows an inorganic type SO whose main component is Shiratsuru.
FIG. 2 is a cross-sectional view of a positive resist pattern containing an acid-generating substance on a G film. 1...Substrate 2, 32.42...Lower organic film 3...SOG film containing an organic functional group 4...Resist 34 containing an acid generator...Negative resist 35, 45... Inorganic SOG film 44...positive resist

Claims (1)

[Claims] (1) In a pattern forming method using a multilayer resist containing a substance that generates acid when exposed to light as the top layer and having an intermediate layer, the intermediate layer is coated silicon that is inert to the acid generated from the resist. A multilayer resist pattern forming method characterized by using an oxide film.