JP2854748B2 - Method of forming resist pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a resist pattern using a resist silylation process.

[0002]

2. Description of the Related Art When a film or a substrate to be processed is patterned by using a resist, a resist silylation process is used for complicated patterning due to a problem of an etching selectivity between the resist and the film or the substrate to be processed. I have.

FIG. 3 shows a resist pattern forming step having a conventional resist silylation process.

First, a silylation resist 5 is applied to a film 2 to be processed formed on a substrate 1 (FIG. 3 (a)), and a predetermined pattern of ultraviolet rays is irradiated (FIG. 3 (b)).
A silylating agent such as (hexamethyldisilazane) is diffused into the silylation resist 5 to silylate the UV-irradiated portion to form a resist silylation layer 6 (FIG. 3C).

Next, portions other than the silylated portion are etched by dry etching, and O ₂ dry development is performed (FIG. 3D).

In the resist silylation process, since the resist silylation layer 6 cannot be seen, a line width inspection and a line width inspection are performed based on the resist shape after dry development (resist pattern formation).
An inspection of alignment accuracy was being performed.

[0007]

In the above method, when a pattern defect is found in the development inspection,
It is also preferable from the viewpoint of cost reduction that the resist having the pattern defect is removed and the resist silylation is performed again using the film 2 to be processed or the substrate 1 such as the same wafer.

However, since the Si—O bond is formed by the silylation, it is difficult to remove only the resist silylated layer 6. In order to cut off the Si—O bond, highly ionic etching is required, and the underlying layer is etched. Therefore, if the determination becomes inappropriate, rework cannot be performed without damaging the surface of the underlying layer.

Accordingly, an object of the present invention is to provide a means for performing rework without damaging the surface of a base by performing an inspection during etching.

[0010]

According to the present invention, there is provided a resist pattern forming method for forming a resist pattern on a film or a substrate by a resist silylation process. A first step of providing an etching stopper directly or via a resist, and a step of forming a resist for silylation on the etching stopper from the surface of the film to be processed or the substrate.
After applying the coating so as to be 10% or more of the total film thickness up to the surface of the resist for silylation and exposing it in a predetermined pattern, the second step of silylating the exposed region, and dry etching the surface of the etching stopper After exposing,
A third step of performing a shape inspection of the resist silylation layer formed in the second step, and removing the resist silylation layer and the unreacted resist for silylation for those failing the inspection; Repeat second and third steps, or the resist silylation layer, the silylated resist unreacted, after removing the etching stopper and said resist, said first step, second step and third the third step, repeatedly, for those that have passed the inspection,
Removing the etching stopper or dry-etching the resist after removing the etching stopper.

[0011]

By using the above-mentioned forming method, even if a defect is found by the development inspection, the film to be processed or the substrate can be regenerated, and the resist silylation process can be used repeatedly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail based on an embodiment.

FIG. 1 shows a resist pattern forming step when a three-layer structure of a resist layer 3, an etching stopper 4 and a silylation resist layer 5 is formed on a film to be processed according to one embodiment of the present invention. FIG. 2 is a sectional view before exposure when a two-layer structure of an etching stopper 4 and a silylation resist layer 5 is formed on a film 2 to be processed according to one embodiment of the present invention. In the present invention, a silylation resist may be used in addition to a resist generally used as the resist layer 3.

First, on a film to be processed 2 formed on a substrate 1, a resist generally used, for example, [RG30
0B (manufactured by Hitachi Chemical Co., Ltd.)] and baked to form a resist layer 3 on which an etching stopper 4 such as a SOG film or low-temperature CVD is formed.
A silicon oxide film or silicon nitride film with a thickness of 100
Deposit up to 1000 °. As an etching stopper,
Any silicon oxide film or silicon nitride film that can be deposited on a resist is applicable.

Then, as a silylation resist layer 5,
For example, [PLASMASK200G-C (manufactured by Nippon Synthetic Rubber)] is applied and baked, so that the total thickness of the resist layer 5 for silylation (the resist layer 3 and the etch
Three-layer structure of a stopping stopper 4 and a silylation resist layer 5
In the case of fabrication, the total film thickness of these three layers, etching stock
In the case of a two-layer structure of par 4 and silylation resist layer 5
Is 10% or more of the total thickness of these two layers) (FIG. 1A). Here, the reason why it is set to 10% or more is that below this, the accuracy of the development inspection is not high. Further, the total of the film thicknesses is usually 15000 to 200
It is about 00 °. As shown in FIG. 2, an etching stopper 4 is formed directly on the film 2 to be processed without the intervention of the resist layer 3.
May be formed.

Next, ultraviolet rays are applied to the silylation resist layer 5 using a Cr mask (not shown) (FIG. 1).
(B)). This step may be the same as for a normal negative resist.

Next, the substrate was kept in a hexamethyldisilazane atmosphere on a hot plate at about 160 ° C. for 3 to 4 minutes to form the above-mentioned exposed area on the resist silylated layer 6 (FIG. 1C). .

Next, using the resist silylation layer 6 obtained in the above process as a mask, the unreacted silylation resist layer 5 is dry-etched using O ₂ gas as an etching gas at a plasma generation output of 200 W and a pressure of 20 mTorr. Then, the surface of the etching stopper 4 is exposed (FIG. 1D). At this stage, an alignment inspection using an optical microscope and a line width detection using an SEM are performed as a development inspection.

As a result of the development inspection, those which passed the test were subjected to wet etching with an aqueous solution of hydrofluoric acid at 20 ° C. for several seconds to remove the etching stopper 4 and then to dry-etch the resist layer 3 to complete the resist mask. Then, as shown in FIG. 1E, the normal etching of the film to be processed 2 is performed.

If the result of development is rejected, Cl
_{Using the two} gases as an etching gas, reactive ion etching was performed at a plasma generation output of 70 W and a pressure of 8 mTorr to remove the resist silylated layer 6 (FIG. 1).
(F)) Next, the unreacted silylation resist layer 5 is removed, a silylation resist layer is formed again, and the exposure, silylation and etching steps are repeated. After the etching stopper 4 and the resist film 3 are also removed, the above steps may be repeated (FIGS. 1A to 1D).

In the above embodiment, the step of forming a resist pattern for etching the film to be processed 2 has been described.
The present invention is also applicable to the formation of a resist pattern for etching the substrate 1.

[0022]

As described in detail above, by using the present invention, the patterning of the resist is completed by stopping the patterning in the middle by the etching stopper, performing the development inspection, and confirming the pass, and completing the patterning of the resist. In the case of rejection, the resist silylation process can be reworked because the silylated layer can be removed without damaging the film to be etched or the substrate surface when the resist silylated layer is removed by reactive etching.

[Brief description of the drawings]

FIG. 1 is a manufacturing process diagram of one embodiment of the present invention.

FIG. 2 is a sectional view of another embodiment of the present invention before exposure.

FIG. 3 is a diagram showing a conventional resist silylation process.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 film to be processed 3 resist layer 4 etching stopper 5 resist layer for silylation 6 resist silylation layer

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Hiroyuki Kawano 22-22 Nagaikecho, Abeno-ku, Osaka-shi, Osaka Inside Sharp Corporation (56) References Patent 2716293 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) H01L 21/027 H01L 21/3065

Claims (1)

(57) [Claims] 1. A resist pattern forming method for forming a resist pattern on a film or substrate to be processed by a resist silylation process, wherein a first step of providing an etching stopper directly or via a resist on the film or substrate to be processed. And a thickness of the silylation resist on the etching stopper, the thickness of the silylation resist from the surface of the film to be processed or the surface of the substrate.
A second step of applying the coating so as to be 10% or more of the total film thickness up to the resist surface , exposing it in a predetermined pattern, and then silylating the exposed area; and exposing the etching stopper surface by dry etching. A third step of performing a shape inspection of the resist silylation layer formed in the second step; and removing the resist silylation layer and the unreacted resist for silylation for those failing the inspection; Repeating the second step and the third step, or after removing the resist silylation layer, unreacted resist for silylation, the etching stopper and the resist,
The first step, the second step, and the third step are repeated, and for those that pass the inspection, after removing the etching stopper or removing the etching stopper,
A fourth step of dry-etching the resist.