JPS63123465A - Photosensitive resin application and its apparatus - Google Patents

Abstract

PURPOSE:To make the thickness of a resin coat on a sheet uniform by applying a photosensitive resin to the periphery by means of a centrifugal force generated by the rotation of a sheet and controlling resin viscosity through application of ultrasound. CONSTITUTION:A wafer 1 fixed through suction to the surface of a chuck 2 is permitted to rotate by a drive mechanism 4 as indicated by an arrow, and at the same time different frequencies preset by means of a frequency control circuit 6 are applied to the wafer 1 from three piezos 7a-7c of a high frequency supply mechanism 5. When a resist is permitted to drop the center of the wafer 1 from a nozzle 3 under this state, the resist is applied in a radial direction to the periphery on the plane of the wafer by means of a centrifugal force generated by the rotation of the wafer 1. The viscosity of the resin is in inverse proportion to the frequency level. Therefore, the viscosity of photosensitive resin is increased by lowering the level of a frequency applied to each piezo 7a-7c in such a manner that the lowering rate is increased proportionately to the periphery. Thus the viscosity of photosensitive resin on the periphery is increased and the coat thickness made uniform.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a photosensitive resin coating device for forming a polymer film such as a photosensitive resin on the flat surface of a thin plate body such as a semiconductor wafer, and particularly relates to The present invention relates to a photosensitive resin coating method and apparatus suitable for improving alignment detection accuracy of an optical stepper and transfer pattern width accuracy by uniformizing the resist film thickness over the entire plane surface of the body.

[Conventional technology]

A conventional photosensitive resin coating device is, for example, disclosed in Japanese Patent Application Laid-open No. 1986-13.
As described in No. 0830, a spinner holding plate that can rotate once is rotatably held on a part of the circumference of the spinner holding plate with a predetermined radius, and a semiconductor wafer is sucked so that the center coincides with each upper surface. 4. A plurality of spinners are provided, and the spinner holding plate is rotated to drop the resist agent onto the center of each semiconductor wafer, and then the spinner holding plate is rotated while the plurality of spinners are rotated. A structure has been proposed in which a resist agent is formed into a uniform film thickness on a semiconductor wafer by centrifugal force caused by the rotation of the resist agent.

[Problem that the invention seeks to solve]

The above-mentioned conventional technology does not take into account the fact that the centrifugal force of a rotating semiconductor wafer varies depending on the radius from the center of rotation, so the film thickness of the photosensitive resin becomes thinner and more uniform around the wafer's outer periphery where the centrifugal force is greater. There was a problem that it could not be converted into

SUMMARY OF THE INVENTION An object of the present invention is to provide a photosensitive resin coating method and an apparatus therefor, which make it possible to uniformize the thickness of a photosensitive resin coated on a wafer using a spinner.

[Means for solving problems]

The above purpose is to apply a photosensitive resin by dropping a photosensitive resin onto the flat surface of a thin plate body fixedly held by a rotating holding mechanism, and applying centrifugal force caused by the rotation of the thin plate body to transfer the photosensitive resin to the thin plate. This is achieved by applying the photosensitive resin in a radial direction toward the outer periphery on a plane of the body and applying ultrasonic waves to the thin plate to control the viscosity of the photosensitive resin.

Further, in the photosensitive resin coating device, the holding mechanism fixedly holds the thin plate upward, the supply mechanism supplies the photosensitive resin onto the plane of the thin plate, and the holding mechanism rotates within the plane of the thin plate. This is achieved by installing a drive mechanism and an ultrasonic supply mechanism that applies ultrasonic waves to the thin plate body to control the viscosity of the photosensitive resin.

[Effect]

When ultrasonic waves are applied to a photosensitive resin, which is a polymeric material, the viscosity of the photosensitive resin decreases, but the viscosity of the photosensitive resin decreases in inverse proportion to the frequency of the ultrasonic wave. There is a phenomenon in which the viscosity decreases.

The present invention utilizes this phenomenon. That is, when the photosensitive resin is applied onto the flat surface of the thin plate toward the outer periphery due to the centrifugal force caused by the rotation of the thin plate, the frequency decreases as it goes from the center to the outer periphery of the thin plate. The viscosity of the photosensitive resin on the flat surface of the thin plate body was controlled to increase as the viscosity of the photosensitive resin on the plane of the thin plate body increases from the center to the outer periphery of the thin plate body by applying a preset ultrasonic wave so as to The photosensitive resin can be coated with a uniform thickness on the flat surface of the thin plate.

〔Example〕

The drawings showing one embodiment of the present invention will be described below.

In the drawing, reference numeral 2 denotes a chuck which is a holding mechanism, and a thin plate wafer 1 is suctioned and fixed on the upper surface by a vacuum suction mechanism (not shown), and a drive mechanism is installed at the lower position so that the chuck 2 rotates in the direction of the arrow. Connected to 4. Reference numeral 3 denotes a nozzle which is a photosensitive resin supply mechanism and is configured to drop resist (not shown), which is a photosensitive resin, toward the center of the wafer 1 on a plane. Reference numeral 5 denotes a high frequency supply mechanism including a frequency control circuit 6 and a plurality of (three in the figure) piezos 7 arranged radially from the approximate center of the wafer 1.
a, 7b, and 7c, and supplies high frequencies of different frequencies to the wafer 1 from the frequency control circuit 6, which is set in advance so that the outer piezo 7c is the highest and the inner piezo 7a is the lowest. I'm doing it like I'm doing it.

Since the photosensitive resin device according to the present invention is constructed as described above, its operation will be explained first.

The wafer 1 suctioned and fixed on the chuck 2 is rotated in the direction of the arrow by the driver n4, and at the same time, the three piezos 7a, 7b, 7c of the high frequency supply mechanism 5 are set in advance in the frequency control circuit 6 toward the wafer 1. When the resist is dropped from the nozzle 3 toward the center of the wafer 1 while applying different frequencies, the resist is radially moved on the plane of the wafer 1 toward the outer periphery due to the centrifugal force caused by the rotation of the wafer 1. applied. Also 3 piezos 8a, 8b
.

The viscosity of the resist 1 is adjusted by different frequencies applied to the wafer 1 from 8c. That is, the inner piezo 8a
Since the frequency from the outer piezo 8c is the lowest, there is little change in the viscosity of the resist 1, but since the frequency from the outer piezo 8c is the highest, the viscosity of the resist 1 that has reached the vicinity of the outer periphery of the wafer 1 decreases.

Therefore, the viscosity of the resist 1 at the outer peripheral portion on the plane of the wafer 1 can be set high, so that the resist 1 can be coated on the plane of the wafer 1 with a uniform thickness.

Although the above embodiment shows a case where three piezo elements are set in the high frequency supply mechanism, the present invention is not limited to this, and one piezo element is moved in the radial direction of the wafer, and the wafer It is also possible to change the frequency of the high frequency wave from the piezo element depending on the radius of the piezo element.

〔Effect of the invention〕

According to the present invention, the photosensitive resin is applied toward the outer periphery of the flat surface of the thin plate by centrifugal force due to rotation of the thin plate, and ultrasonic waves are applied to the thin plate to control the viscosity of the photosensitive resin. However, since the photosensitive resin can be coated with a uniform thickness on the flat surface of the thin plate, the alignment detection accuracy of the optical stepper and the accuracy of the transfer pattern width can be improved.

[Brief explanation of the drawing]

The drawing is an explanatory diagram of a photosensitive resin coating apparatus showing an embodiment of the present invention. 1... Wafer, 2... Chuck, 3... Nozzle,
4... Drive mechanism, Dan... High frequency supply mechanism, 6...
Frequency control circuit, 7a, 7b, 7cm piezo. Representative Patent Attorney Tadashi Akimoto No changes to the content of the engraving of the actual drawings) Amended drawings (I'fl Dan 1: Wafer 2: 4-Nook 3:) Large Ru 4: Ear Fh Jigokuzo Danura M Me hairy Surplus talent λ 6: layer to skin 1st
1. Road 7: PIESO 1 Procedural Amendment Form) 1. Indication of the case 1985 Patent Application No. 268547 2. Name of the invention Photosensitive resin coating method and apparatus 3. Person making the amendment Relationship with the case Patent applicant address (residence) 4-6 Kanda Surugadai, Chiyoda-ku, Tokyo Name (510) Hitachi, Ltd. 4, Agent address Soma Nishi-Shinbashi Building Showa, 1-6-14 Nishi-Shinbashi, Minato-ku, Tokyo January 27, 1962 (1) "Drawings" on page 5, line 7 of the specification is amended to "Figure 1."

Claims (1)

[Scope of Claims] 1. A photosensitive resin coating method, which comprises coating a rotating plate with a photosensitive resin and applying ultrasonic waves to make the film thickness of the photosensitive resin uniform. 2. The photosensitive resin coating method according to claim 1, wherein the frequency of the applied ultrasonic waves is lowered from the center of the plate toward the outer periphery. 3. A holding mechanism that holds the plate fixedly; a supply mechanism that supplies photosensitive resin onto the plane of the plate; a drive mechanism that rotates the holding mechanism within the plane of the plate; 1. A photosensitive resin coating device, comprising an ultrasonic wave applying means for applying ultrasonic waves, and configured to make the film thickness of the photosensitive resin formed on the flat surface of the plate uniform. . 4. The photosensitive resin coating apparatus according to claim 3, wherein the ultrasonic wave applying means is configured to reduce the applied frequency from the center of the plate toward the outer periphery.