JPH02276237A - Lamination of charged beam resist - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application) The present invention relates to a method for laminating a charged beam resist that enables reliable discharge of charges accumulated in a sample during charged beam exposure.

(Prior art) A method of drawing patterns on sensitive resin (hereinafter referred to as charged beam resist) using a charged beam, especially an electron beam, has been researched and developed and is widely used in the production of photomasks for semiconductor manufacturing. .

Furthermore, development is progressing toward practical application of a direct electron beam writing method in which a charged beam resist on a semiconductor wafer is directly irradiated with an electron beam to draw a pattern.

By the way, when an insulating film is irradiated with a charged beam, charges are accumulated (charge-up) in the insulating film. This accumulated charge distorts the range of the charged beam for drawing, causing a problem that a desired pattern cannot be drawn with high precision. In order to solve this problem, Japanese Patent Application Laid-Open No. 57-10603
Publication No. 4, JP-A-58-106831, JP-A-6
Methods disclosed in JP-A No. 0-53023, JP-A-60-74521, etc. have been attempted. All of these methods are methods of forming a conductive thin film on the resist or modifying the resist surface into a conductive film.

Among the above-mentioned publications, FIG. 2(a) of JP-A No. 58-106831 describes that an aluminum film as a workpiece is deposited on a silicon substrate having a silicon oxide film opening on the upper surface. has been done.

This aluminum film is an aluminum film to be processed, and therefore, the openings cannot be provided in squares where semiconductor devices are not formed.

Here, let's consider a specific path for discharging charges. A sample is usually inserted into a jig called a cassette, and a conductive pin attached to the cassette is brought into contact with a conductive thin film on the sample, whereby charges are discharged to the outside via the conductive pin.

Therefore, the degree of contact between the conductive pin and the conductive thin film, that is, the degree of electrical connection, is an important point in preventing the above-mentioned charge accumulation.

However, the methods disclosed in the above-mentioned publications form a conductive thin film on an organic film such as a charged beam resist or a photoresist.

For this reason, when inserting a sample into a cassette and trying to bring the conductive pin into contact with the conductive thin film, due to the fragility of the organic film under this conductive thin film, when the conductive pin is brought into contact with Due to the movement of the sample after
The conductive thin film also collapses together with the organic film.

As a result, the contact between the conductive thin film and the conductive pin becomes incomplete, and the electrical connection is broken, resulting in the problem that the accumulated charge is not discharged.

Here, among the above publications, JP-A-57-106034
Taking the method disclosed in the above publication as an example, the above problems can be solved in the second
This will be explained with a diagram.

According to this publication, as shown in Figure 2 (A), first,
A desired substrate 11 on which a pattern is to be formed is prepared.

Next, as shown in FIG. 2(B), a photoresist layer 12, a conductive layer 13, and a charged particle beam resist 14 are laminated in this order on the substrate 11 to form a laminated layer U. As shown in Figure 2 (C), charged particle beam 1
5 to the irradiation area 16 of the charged particle beam resist 14.

The subsequent steps described in this publication are not related to the problem that will be pointed out now, and will therefore be omitted.

(Problems to be Solved by the Invention) However, the problem of this Japanese Patent Application Laid-Open No. 57-106034 lies in the process shown in FIG. 2(C).

That is, when attempting to irradiate the charged particle beam 15, specifically, the substrate 11 is inserted into a cassette,
As shown in FIG. 2(D), the conductive pin 17 is connected to the charged particle beam resist 14, the conductive layer 13 and the photoresist N12.
Be set through the.

At this time, the conductive layer 13 contacts the conductive pin 17 and the contact portion 18.
electrically connected.

However, the photoresist layer 12 is generally fragile and may collapse when the conductive pin 17 is penetrated or by unexpected movement of the substrate 11 after the conductive pin 17 is penetrated.

For this reason, as shown in FIG. 2(E), the conductive layer 13 formed on the photoresist layer 12 also collapses, and the contact portion with the conductive pin 17 cannot be formed or becomes incomplete. .

Therefore, the electrical connection is not maintained and the accumulated charge cannot be discharged to the outside.

As described above, the essential problem with the methods disclosed in any of the above-mentioned publications is that the conductive thin film in the portion in contact with the conductive pin is formed on a fragile organic material.

This invention solves the problems of the above-mentioned prior art.
The present invention provides a charge beam resist stacking method that solves problems such as incomplete and uncertain contact between the conductive thin film and the conductive pins due to the fragility of the organic material under the conductive thin film.

(Means for Solving the Problems) The present invention provides a method for laminating a charged beam resist.
A process is introduced in which the thin film laminated on the semiconductor substrate and the portion where the conductive pin of the spacer contacts the semiconductor substrate are removed to expose the semiconductor substrate, and then a conductive thin film is deposited on the entire surface.

(Function) According to the present invention, as described above, in the charged beam resist stacking method, the conductive thin film at the position where the conductive pin contacts directly contacts the surface of the semiconductor substrate. Therefore, even if the conductive thin film collapses due to strong contact of the conductive pin with the semiconductor substrate, the conductive thin film is in contact with the semiconductor substrate in other parts, and the conductive pin will not be able to maintain conduction with the semiconductor substrate. You can do it.

Therefore, the above problem can be eliminated.

(Example) Hereinafter, a method for laminating a charged beam resist according to the present invention will be explained based on the drawings. FIG. 1(A) to FIG. 1(F) are process cross-sectional views of one embodiment.

First, as shown in FIG. 1A, a sample in which a silicon oxide film 22 is formed as a thin film on a semiconductor substrate 21 is prepared.

Next, as shown in FIG. 1(B), the silicon oxide film 22
A photoresist film 23 (OFP
R: manufactured by Tokyo Ohka Co., Ltd.) is applied.

Thereafter, as shown in FIG. 1 (C1), the photoresist film 23 and the silicon oxide film 2 are placed in the positions where the conductive pins, such as the squares where the semiconductor device is not formed, of the semiconductor substrate 21 should contact.
2 is removed by means such as laser irradiation to form an opening 24 exposing the semiconductor substrate 21.

The size of this opening 24 is determined in consideration of the thickness of the conductive pin and the positional accuracy when inserting the semiconductor substrate 21 into a cassette (not shown).

Next, as shown in FIG. 1(D), a conductive thin film 25 is deposited on the entire surface of the substrate.

Next, as shown in FIG. 1(E), a charged beam resist film 26 (SAL601: negative type resist manufactured by Silaplay Co., Ltd.) is applied to the entire surface of the substrate, completing preparations for the charged beam exposure.

Insert the semiconductor substrate prepared as above into the cassette,
When the conductive pin 27 is brought into contact, as shown in FIG. 1(F), the conductive pin 27 comes into contact with the conductive thin film 25 directly adhered to the semiconductor substrate 21.

As a result, the charge accumulated in the semiconductor substrate is transferred to the conductive pin 2.
7 and be discharged to ground.

In the above embodiment, the silicon oxide film 22 was used as an example of the thin film on the semiconductor substrate 21, but the silicon oxide film 22 is not limited to the silicon oxide film 22 (materials used in semiconductor manufacturing, such as silicon nitride). That's fine.

Further, although the photoresist film 23 has been described as an example of the material under the conductive thin film 25, other known materials may be used without departing from the spirit of the present invention.

Further, in the above embodiment, the opening 24 may be formed by laser irradiation (and can be formed easily).

Furthermore, the conductive thin film 25 may be formed under the photoresist film 23.

(Effects of the Invention) As described above in detail, according to the present invention, the conductive thin film is brought into direct contact with the semiconductor substrate at the position where the conductive pin contacts, so that the conductive pin can be attached to the rigid semiconductor substrate. The conductive thin film does not collapse even if it is brought into strong contact with the conductive pin, and a reliable electrical connection with the conductive pin can be achieved.

Further, even if the conductive thin film were to collapse, since the conductive thin film is in contact with the semiconductor substrate at other parts of the opening, electrical connection with the conductive pins can be maintained through the semiconductor substrate.

Therefore, electrical connection with the conduction pin is ensured, and accumulated charges can be reliably discharged.

Accordingly, highly accurate pattern drawing becomes possible.

[Brief explanation of drawings]

1(A) to 1(F) are process cross-sectional views of an embodiment of the charged beam resist lamination method of the present invention, and FIG. 2(A) to 2(E) are process sectional views of a conventional patterning method. It is a process cross-sectional view of the method. 21... Semiconductor substrate, 22... Silicon oxide film, 2
3... Photoresist film, 24... Opening, 25...
Conductive thin film, 26...Charged beam resist film, 27 Conductive pin. Cross-sectional view of the present invention Fig. 1 Crucible bundle p

Claims (1)

[Claims] (a) forming a spacer through a thin film formed on a semiconductor substrate; (b) removing a portion of the spacer and the thin film where the conductive pin contacts; A method for laminating a charged beam resist comprising the steps of: partially exposing the spacer; and (c) depositing a conductive thin film over the entire surface of the semiconductor substrate on the lower or upper surface of the spacer.