阅读说明：本技术 一种涂布方法和涂布系统 (Coating method and coating system ) 是由 熊超超 李瑶 于 2020-05-25 设计创作，主要内容包括：本发明提供了一种涂布方法及涂布系统,其中,所述涂布方法包括：提供一基板,在所述基板之上滴第一液体；在所述第一液体之上滴与所述第一液体不互溶且密度大于所述第一液体的第二液体；旋转所述基板使所述第一液体在所述基板的表面扩散以及使所述第二液体在所述第一液体的表面扩散。本发明的涂布方法由于在第一液体之上滴有与第一液体不互溶且密度大于所述第一液体的第二液体的第二液体,旋转基板,第一液体在离心力的作用下会向基板的边缘扩散,第二液体则会在离心力的作用下在第一液体的表面扩散,第一液体的表面由于受到第二液体的挤压作用,扩散后第一液体的中心至边缘区域的厚度将会更加的均匀。(The invention provides a coating method and a coating system, wherein the coating method comprises the following steps: providing a substrate, and dripping a first liquid on the substrate; dropping a second liquid, immiscible with and having a density greater than the first liquid, over the first liquid; rotating the substrate causes the first liquid to spread across the surface of the substrate and the second liquid to spread across the surface of the first liquid. According to the coating method, the second liquid which is immiscible with the first liquid and is higher than the first liquid in density is dripped on the first liquid, the substrate is rotated, the first liquid can diffuse towards the edge of the substrate under the action of centrifugal force, the second liquid can diffuse on the surface of the first liquid under the action of centrifugal force, and the thickness of the diffused first liquid from the center to the edge area is more uniform due to the extrusion effect of the second liquid on the surface of the first liquid.)

1. A coating method, comprising:

providing a substrate, and dripping a first liquid on the substrate;

dropping a second liquid on the first liquid, wherein the first liquid and the second liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

rotating the substrate causes the first liquid to spread across the surface of the substrate and the second liquid to spread across the surface of the first liquid.

2. The coating method of claim 1, wherein after dropping a first liquid over the substrate and before dropping a second liquid over the first liquid, further comprising:

rotating the substrate causes the first liquid to spread to a first area on the surface of the substrate.

3. Coating method according to claim 1 or 2, characterized in that it further comprises:

removing the second liquid from the surface of the first liquid.

4. Coating method according to claim 3, wherein said removing of said second liquid from the surface of said first liquid comprises:

and baking the first liquid and the second liquid to volatilize the second liquid from the surface of the first liquid.

5. Coating method according to claim 1, characterized in that the boiling point of the first liquid is greater than the boiling point of the second liquid.

6. Coating method according to claim 1, characterized in that the first liquid comprises a photoresist.

7. Coating process according to claim 1, characterized in that the second liquid comprises perfluorooctane, tetrahydrofuran and methyl ethyl ketone.

8. A coating system, comprising:

a substrate;

a first liquid injection device for dropping a first liquid onto the substrate;

second liquid injection means for dropping a second liquid onto the substrate; the second liquid and the first liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

and the substrate rotating device is used for driving the substrate to rotate so as to enable the first liquid to be diffused on the surface of the substrate and enable the second liquid to be diffused on the surface of the first liquid.

9. The coating system of claim 8, further comprising:

and the substrate baking device is used for baking the first liquid and the second liquid.

10. The coating system of claim 8, wherein the first liquid comprises photoresist and the second liquid comprises perfluorooctane, tetrahydrofuran, and methyl ethyl ketone.

Technical Field

The invention relates to the field of semiconductor manufacturing, in particular to a coating method and a coating system.

Background

In the semiconductor manufacturing process, photoresist is often required to be coated on a substrate, when the photoresist is coated on the substrate, the substrate is firstly fixedly arranged on a bearing surface of a turntable, then a certain amount of photoresist is sprayed on a central area of the surface of the substrate by a nozzle, then the turntable is controlled to rotate to drive the substrate to rotate around the center of the substrate, and in the rotating process of the substrate, the photoresist positioned in the central area of the surface of the substrate is diffused to a peripheral area under the action of centrifugal force, and finally the photoresist layer is formed on the surface of the substrate.

However, in the process of realizing the photoresist diffusion, the viscosity of the photoresist is usually high, so that the thickness of the photoresist after coating on the substrate is not uniform, thereby affecting the quality of the manufactured semiconductor product.

Accordingly, the prior art is yet to be developed and improved.

Disclosure of Invention

In view of the above-mentioned shortcomings of the prior art, the present application aims to provide a coating method and a coating system, which aim to solve the technical problem that the product quality is affected by the non-uniform thickness of the photoresist after coating in the conventional coating method.

In one aspect, the present invention provides a coating method comprising:

providing a substrate, and dripping a first liquid on the substrate;

dropping a second liquid on the first liquid, wherein the first liquid and the second liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

rotating the substrate causes the first liquid to spread across the surface of the substrate and the second liquid to spread across the surface of the first liquid.

In the above-mentioned realization process, because the second liquid that has the immiscible with first liquid drips on first liquid, and the density of first liquid is greater than the density of second liquid, the second liquid just can be located on first liquid all the time like this, rotatory base plate, first liquid can be to the marginal diffusion of base plate under the effect of centrifugal force, the second liquid then can be at the surperficial diffusion of first liquid under the effect of centrifugal force, the surface of first liquid is owing to receive the squeezing action of second liquid, center to marginal area's thickness will be more homogeneous.

Optionally, the dropping a first liquid on the substrate and before dropping a second liquid on the first liquid further comprises:

rotating the substrate causes the first liquid to spread to a first area on the surface of the substrate.

In the above implementation process, in order to make the second liquid drop on the first liquid, before dropping the second liquid, the surface of the first liquid can be enlarged to the first area by rotating the substrate, so that the surface area of the first liquid is larger, and the second liquid is more convenient to drop.

Optionally, the coating method further comprises:

removing the second liquid from the surface of the first liquid.

In the implementation process, since the second liquid has the function of pressing the surface of the first liquid by gravity after the first liquid is spread in a rotating manner to make the thickness of the first liquid uniform, the second liquid needs to be removed after the first liquid is spread.

Optionally, the removing the second liquid from the surface of the first liquid comprises:

and baking the first liquid and the second liquid to volatilize the second liquid from the surface of the first liquid.

In the implementation process, the second liquid is removed in a baking evaporation mode in the process of removing the second liquid on the surface of the first liquid, and the second liquid is located on the surface of the first liquid, so that the second liquid evaporates after the first liquid is evaporated in the baking process, and the removal of the second liquid can be accurately controlled by controlling the evaporation time.

Optionally, the boiling point of the first liquid is greater than the boiling point of the second liquid.

In the implementation process, the boiling point of the first liquid is greater than that of the second liquid, so that the second liquid can be removed by controlling the temperature to be greater than that of the second liquid and less than that of the first liquid, the evaporation time is not required to be accurately controlled in the process, and the operation is more convenient.

Optionally, the first liquid comprises photoresist.

In the implementation process, the photoresist has high viscosity, so that the thickness of the central region and the thickness of the edge region are different when the photoresist is diffused on the substrate, and the diffused thickness of the photoresist needs to be adjusted, thereby improving the quality of products.

Optionally, the second liquid comprises perfluorooctane, tetrahydrofuran, and methyl ethyl ketone.

In the implementation process, as the perfluorooctane, the tetrahydrofuran and the methyl ethyl ketone are common materials in semiconductor manufacturing, the perfluorooctane, the tetrahydrofuran and the methyl ethyl ketone are easy to obtain, have small boiling points and are easier to remove by an evaporation mode.

In another aspect, based on the same inventive concept, the present invention also provides a coating system, including:

a substrate;

a first liquid injection device for dropping a first liquid onto the substrate;

second liquid injection means for dropping a second liquid onto the substrate; the second liquid and the first liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

and the substrate rotating device is used for driving the substrate to rotate so as to enable the first liquid to be diffused on the surface of the substrate and enable the second liquid to be diffused on the surface of the first liquid.

In the implementation process, the first liquid is dripped onto the substrate through the first liquid injection device, the second liquid is dripped onto the substrate through the second liquid injection device, then the substrate is rotated through the substrate rotating device to enable the first liquid to be diffused on the surface of the substrate and the second liquid to be diffused on the surface of the first liquid, and the gravity of the second liquid is used for extruding the surface of the first liquid to enable the thickness of the first liquid to be more uniform.

Optionally, the coating system further comprises:

and the substrate baking device is used for baking the first liquid and the second liquid.

In the implementation process, the first liquid and the second liquid are diffused on the substrate and then placed into the substrate baking device for baking, so that the second liquid can be evaporated and removed from the surface of the first liquid, and the process of removing the second liquid is convenient.

Optionally, the first liquid comprises photoresist and the second liquid comprises perfluorooctane, tetrahydrofuran, and methyl ethyl ketone.

In the implementation process, the coating system is used for controlling the thickness of the photoresist coating, the second liquid adopts perfluorooctane, tetrahydrofuran and methyl ethyl ketone, has good adaptability with the photoresist, is easy to remove, and can play a good role in enabling the photoresist coating to be more uniform.

Drawings

FIG. 1 is a flow chart of a coating method according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a substrate after dropping a first liquid according to an embodiment of the invention;

FIG. 3 is a schematic diagram of a substrate after dropping a first liquid and a second liquid according to one embodiment of the invention;

FIG. 4 is a schematic view of a substrate after diffusion of a first liquid and a second liquid according to one embodiment of the invention;

fig. 5 is a schematic structural diagram of a coating system according to an embodiment of the invention.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

In the existing photoresist spin coating process, photoresist is firstly dropped on a substrate, and then spin-coating is carried out, so that the process is easy to have the condition that the thickness difference between the photoresist film at the center and the photoresist film at the edge is large. The concrete expression is as follows: in the rotating process, the photoresist extends from the center of the substrate to the edge of the substrate due to the action of the rotating centrifugal force, but the central part of the substrate is adhered with more photoresist, so that the thickness of the central area of the substrate is inevitably larger than that of the edge of the substrate in the rotating distribution process, the photoresist is unevenly distributed on the substrate, and the yield of subsequent photoetching and other processes is influenced.

Based on this, the present invention intends to provide a solution to the above technical problem, the details of which will be explained in the following embodiments.

Referring to fig. 1, the present invention provides a coating method comprising:

s100, providing a substrate, and dripping first liquid on the substrate;

s200, dropping a second liquid on the first liquid, wherein the first liquid and the second liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

s300, rotating the substrate to enable the first liquid to be diffused on the surface of the substrate and the second liquid to be diffused on the surface of the first liquid, and pressing the surface of the first liquid through the second liquid to enable the thickness of the first liquid to be uniform.

In the coating method of the present invention, since the second liquid immiscible with the first liquid is dropped on the first liquid and the density of the first liquid is higher than that of the second liquid, the second liquid can be always located on the first liquid, referring to fig. 2, the first liquid 20 is only dropped on the substrate 10, the thickness of the center and the edge of the first liquid 20 is not uniform, and the first liquid 20 also has the defect of non-uniform thickness of the edge center and the edge on the substrate 10 after being spread, referring to fig. 3, the second liquid 30 incompatible with the first liquid 10 is dropped on the surface of the first liquid 20, the second liquid 30 dropped on the surface of the first liquid 10 can form a partial recess on the surface of the first liquid 10 by gravity, the thickness of the center of the first liquid 10 is reduced, and then the substrate 10 is rotated, the first liquid 10 can be spread to the edge of the substrate 10 by centrifugal force, the second liquid 30 will spread on the surface of the first liquid 10 under the action of centrifugal force, and as shown in fig. 4, the thickness of the spread first liquid 10 from the center to the edge area will be more uniform due to the squeezing action of the second liquid 30 on the surface of the first liquid 10.

In some embodiments, the first liquid is dripped on the center of the surface of the substrate, so that the substrate is rotated, the first liquid spreads from the center of the substrate to the periphery, and the distribution on the substrate is more uniform. In some embodiments, the second liquid is dripped in the center of the surface of the first liquid, so that the second liquid is also more evenly distributed in the first liquid.

In some embodiments, the method of rotating the substrate includes rotating the substrate clockwise at a first speed for a first predetermined time and then rotating the substrate counterclockwise at a second speed for a second predetermined time, wherein the first speed is greater than the second speed. Thus, the thickness of the first liquid from the center to the edge area can be more balanced by the action of the centrifugal force in the forward and reverse directions.

In some embodiments, the dropping a first liquid over the substrate and before dropping a second liquid over the first liquid further comprises:

s110, rotating the substrate to enable the first liquid to be diffused to a first area on the surface of the substrate.

In order to facilitate the second liquid to be dripped on the first liquid, the surface of the first liquid can be enlarged to the first area by rotating the substrate before dripping the second liquid, so that the surface area of the first liquid is larger, and the dripping of the second liquid is more convenient.

In some embodiments, the first area is 1/3-3/3 of the total area of the substrate, such as 1/3, 2/3 and 3/3, which is not limited herein. The first area may be sized to be 1/3 of the total area of the substrate in order that the first liquid does not overflow the edge of the substrate when the substrate is spun a second time.

In some embodiments, the size of the first area is 1 to 3 times, such as 1.5 times, 2 times, 2.5 times and 3 times, the size of the initial area of the second liquid, and the invention is not limited herein, but for the convenience of the second liquid dropping on the first liquid and exerting better squeezing effect on the first liquid, for example, the size of the first area may be set to be 1.2 times the size of the initial area of the second liquid.

Referring to fig. 1, in certain embodiments, the coating method further comprises:

s400, removing the second liquid on the surface of the first liquid.

Since the second liquid has the function of pressing the surface of the first liquid by gravity after the first liquid is spread in a rotating manner to make the thickness of the first liquid uniform, the second liquid needs to be removed after the first liquid is spread.

In certain embodiments, the removing the second liquid from the surface of the first liquid comprises:

and baking the first liquid and the second liquid to volatilize the second liquid from the surface of the first liquid.

In the process of removing the second liquid on the surface of the first liquid, the second liquid is removed in a baking evaporation mode, and the second liquid is located on the surface of the first liquid, so that the second liquid evaporates after the first liquid is evaporated in the baking process, and the removal of the second liquid can be accurately controlled by controlling the evaporation time.

In other embodiments, the removing the second liquid from the surface of the first liquid further comprises:

and performing adsorption removal or laser ablation removal on the second liquid. For example, after the first liquid is spread on the substrate, the second liquid may be sucked away from the surface of the first liquid by an adsorption device or may be ablated by a laser device.

In certain embodiments, the second liquid comprises a volatile liquid. Need not to handle the second liquid like this, the second liquid can be followed the automatic volatilization of the surface of first liquid by oneself, and the process of getting rid of the second liquid is simpler like this.

In certain embodiments, the boiling point of the first liquid is greater than the boiling point of the second liquid.

In the implementation process, the boiling point of the first liquid is greater than that of the second liquid, so that the second liquid can be removed by controlling the temperature to be greater than that of the second liquid and less than that of the first liquid, the evaporation time is not required to be accurately controlled in the process, and the operation is more convenient.

In certain embodiments, the surface tension of the first liquid is less than the surface tension of the substrate and the surface tension of the second liquid is less than the surface tension of the first liquid, such that the first liquid spreads more easily over the substrate and the second liquid spreads more easily over the surface of the first liquid.

In some embodiments, the first liquid comprises photoresist.

In some embodiments, the first liquid further includes a liquid with a high viscosity, such as a resin, and the like.

In certain embodiments, the second liquid comprises perfluorooctane, tetrahydrofuran, and methyl ethyl ketone.

The perfluorooctane, the tetrahydrofuran and the methyl ethyl ketone are common materials in semiconductor manufacturing, are easy to obtain, have small boiling points and are easy to remove by evaporation.

Further, referring to fig. 5, based on the same inventive concept, the present invention also provides a coating system including:

a substrate;

a first liquid injection device for dropping a first liquid onto the substrate;

second liquid injection means for dropping a second liquid onto the substrate; the second liquid and the first liquid are mutually insoluble, and the density of the first liquid is greater than that of the second liquid;

and the substrate rotating device is used for driving the substrate to rotate so as to enable the first liquid to be diffused on the surface of the substrate and enable the second liquid to be diffused on the surface of the first liquid.

According to the coating system, the first liquid is dripped onto the substrate through the first liquid injection device, the second liquid is dripped onto the substrate through the second liquid injection device, then the substrate is rotated through the substrate rotating device, so that the first liquid is diffused on the surface of the substrate and the second liquid is diffused on the surface of the first liquid, and the thickness of the first liquid can be more uniform by pressing the surface of the first liquid through the gravity of the second liquid.

In certain embodiments, the coating system further comprises:

and the substrate baking device is used for baking the first liquid and the second liquid.

According to the coating system, the first liquid and the second liquid are spread on the substrate and then placed into the substrate baking device for baking, so that the second liquid can be evaporated and removed from the surface of the first liquid, and the process of removing the second liquid is convenient.

In certain embodiments, the first liquid comprises photoresist and the second liquid comprises perfluorooctane, tetrahydrofuran, and methyl ethyl ketone.

The coating system is used for controlling the thickness of photoresist coating, and the second liquid adopts perfluorooctane, tetrahydrofuran and methyl ethyl ketone, has good adaptability with the photoresist, is easy to remove, and can play a good role in enabling the photoresist coating to be more uniform.

In summary, the present invention provides a coating method and a coating system, wherein the coating method includes: providing a substrate, and dripping a first liquid on the substrate; dropping a second liquid over the first liquid; the substrate is rotated to enable the first liquid to be diffused on the surface of the substrate and the second liquid to be diffused on the surface of the first liquid, in the coating method, the second liquid which is not dissolved with the first liquid is dripped on the first liquid, and the density of the first liquid is higher than that of the second liquid, so that the second liquid can be always positioned on the first liquid, the substrate is rotated, the first liquid can be diffused to the edge of the substrate under the action of centrifugal force, the second liquid can be diffused on the surface of the first liquid under the action of centrifugal force, and the thickness of the first liquid after diffusion can be more uniform due to the extrusion effect of the second liquid on the surface of the first liquid.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.