WO2012073377A1

WO2012073377A1 - Spin-coat device

Info

Publication number: WO2012073377A1
Application number: PCT/JP2010/071680
Authority: WO
Inventors: 昌男柏田
Original assignee: Kashiwada Masao
Priority date: 2010-12-03
Filing date: 2010-12-03
Publication date: 2012-06-07

Abstract

In order to improve the uniformity of a coating film formed by spin-coating, a spin-coat device is provided comprising: a vacuum container; a substrate holder for holding a wafer substrate so that a coated surface thereof faces upward, the substrate holder being installed on the inside of the vacuum container; a spinning mechanism for spinning the substrate holder so that the wafer substrate spins approximately horizontally; a liquid supplier for supplying a liquid that includes a coating material from above the center of the wafer substrate to the coated surface; and a shield for cutting off the flow of the liquid or its vapor that is generated by the spinning of the wafer substrate, the shield being arranged to concentrically surround the wafer substrate.

Description

Spin coat equipment

The present invention relates to a spin coater for spin coating a coating film such as a photoresist film used in a microfabrication process of a semiconductor device. In particular, the present invention relates to a spin coater that can improve the uniformity of a coating film formed by spin coating.

As is well known, a photoresist film in a semiconductor device manufacturing process is formed by spin coating. For example, Patent Document 1 discloses that a chamber, a means for depressurizing the inside of the chamber, a means for applying an organic resin on a semiconductor wafer in the chamber, and a uniform film thickness of the organic resin applied by rotating the semiconductor wafer. A spin coater comprising: It is said that a high-quality electronic device (semiconductor device) can be manufactured by the spin coater without generating bubbles in the organic resin film.

JP 2003-168638 A

Although the above-described conventional technology can suppress bubbles in the photoresist film (organic resin film), there is a strong demand for miniaturization of semiconductor devices or an increase in substrate area, in order to meet these demands. For this, it is necessary to make the film thickness of the photoresist film more uniform. An object of the present invention is to improve the uniformity of a coating film formed by spin coating.

In order to solve the above problems, in the first aspect of the present invention, a vacuum vessel, a substrate folder installed inside the vacuum vessel and holding a wafer-like substrate so that a coating surface is on, and the wafer A rotating mechanism that rotates the substrate folder so that the substrate rotates substantially horizontally, a liquid supply unit that supplies a liquid material containing a coating material from above the center of the wafer substrate toward the coating surface, and the wafer And a shielding body arranged to concentrically surround the substrate and blocking the flow of the liquid material or the vaporized material generated by the rotation of the wafer substrate to the outside.

In the spin coater described above, the shield rotates together with the substrate folder, and a clearance or a hole for letting out the liquid substance or its vaporized substance that receives the action of the centrifugal force generated by the rotation from the inside to the outside of the shield. You may have. The lower part of the shield and the outer periphery of the substrate folder may be in contact with each other so that a downward flow of the liquid substance or its vaporized substance is inhibited. Moreover, you may have the ridge overhang | projected inside in the upper part of the said shield.

The above spin coating apparatus may further include a cleaning liquid supply unit that supplies a cleaning liquid from the center of the substrate folder toward the back surface of the wafer-like substrate. Moreover, you may further have the gas supply part which supplies a dry gas in the said vacuum vessel. Furthermore, you may further have a heating means to heat the said coating surface of the said wafer-like board | substrate.

Note that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

An outline of the spin coater 100 is shown. 1 is a cross-sectional view showing a spin coater 100 in more detail. 5 is a flowchart showing an example of a coating process using the spin coater 100.

Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

FIG. 1 shows an outline of the spin coater 100. In FIG. 1, the upper part shows a top view, and the lower part is a cross-sectional view. The spin coater 100 includes a vacuum container 102 that can keep the inside in a reduced pressure state, a substrate folder 104 that holds the wafer-like substrate 120, and a rotation mechanism 106 that rotates the substrate folder 104 so that the wafer-like substrate 120 rotates substantially horizontally. The liquid material supply unit 108 and the shield 110 supply a liquid material containing a coating material from the upper center of the wafer-shaped substrate 120 toward the coating surface 120a.

The wafer-like substrate 120 has a coating surface 120a, and a coating material such as an organic material such as a photoresist is coated on the coating surface 120a. The substrate folder 104 is installed inside the vacuum container 102. The substrate folder 104 holds the wafer-like substrate 120 so that the coating surface 120a is on top. The coating material is a material that is applied to the coating surface 120a, and an organic material such as a photoresist can be exemplified. When the coating material is an organic material, the liquid material contains an organic solvent.

In the spin coater 100, the wafer-like substrate 120 rotates with the rotation of the substrate folder 104, as in the other spin coaters. The liquid material supplied to the central portion of the wafer-like substrate 120 is caused to flow in the circumferential direction of the wafer-like substrate 120 by the action of the centrifugal force accompanying the rotation. That is, the coating substance contained in the liquid material is applied (spin coated) while rotating the wafer-like substrate 120. And in the spin coater 100, the said application | coating (spin coat) is implemented in a pressure-reduced atmosphere. In the reduced pressure state, air or the like that hinders the movement of the liquid material is reduced, and the liquid material is quickly flown in the circumferential direction of the wafer-like substrate 120.

The spin coat apparatus 100 further includes a shield 110. The shield 110 is disposed so as to surround the wafer-like substrate 120 concentrically, and blocks the flow 130 of the liquid material or the vaporized material generated by the rotation of the wafer-like substrate 120 to the outside.

As described above, the liquid material is caused to flow in the circumferential direction by the centrifugal force generated by the rotation of the wafer-like substrate 120. However, the liquid material itself or a vaporized material from the liquid material alone or together creates a flow 130. It has been empirically found that when there is nothing to block the flow 130, the thickness of the coating material in the vicinity of the periphery of the wafer-like substrate 120 becomes thin. However, since the spin coater 100 has the shield 110, a stay portion 132 of the flow 130 is formed between the wafer-like substrate 120 and the shield 110, and a region having a high pressure is formed locally. As a result, the film thickness of the coating substance in the vicinity of the periphery of the wafer-like substrate 120 is increased, and the film thickness uniformity over the entire wafer-like substrate 120 is improved.

The shield 110 has an upper shield 110a and a lower shield 110b, and a gap G is formed between the upper shield 110a and the lower shield 110b. When the shield 110 rotates together with the substrate folder 104, the liquid substance or its vaporized substance (flow 130) staying in the stay part 132 is released from the gap G to the outside under the action of the centrifugal force generated by the rotation. The flow 130 released to the outside of the shield 110 is discharged out of the vacuum vessel 102.

The shield 110 does not need to be separated into an upper part and a lower part, and may be formed integrally. In this case, a hole may be opened in the shield 110 instead of the gap G. Further, it is not always necessary to rotate the shield 110, but by rotating the shield 110, the liquid material staying in the shield 110 can be discharged to the outside through the gap G by the action of centrifugal force. In addition, the generation of particles due to the staying liquid can be prevented.

The lower part of the shield 110 (lower shield 110b) and the outer periphery of the substrate folder 104 may be in contact with each other. In this case, the downward flow 130 is obstructed, and the retention portion 132 is more effectively formed. As a result, the film thickness uniformity of the coating substance can be improved.

A ridge 110c projecting inward may be formed on the upper part of the shield 110 (upper shield 110a). In this case, the upward flow 130 is obstructed, and the stay part 132 is more effectively formed. As a result, the film thickness uniformity of the coating substance can be improved.

Although it can be estimated that the rotational speed of the wafer-shaped substrate 120, the rotational speed of the shield 110, and the distance of the gap G have a strong relationship with each other, it is appropriately determined in consideration of other parameters such as the viscosity of the liquid material. You can select any value.

FIG. 2 is a cross-sectional view showing the spin coater 100 in more detail. In addition to the vacuum container 102, the substrate folder 104, the rotation mechanism 106, the liquid material supply unit 108, and the shield 110, the spin coater 100 includes a cleaning liquid supply unit 140, a gas supply unit 150, a heating unit 160, a vacuum mechanism 170, and the like. A waste liquid treatment mechanism 180 is provided.

The vacuum vessel 102 has a vessel body 102a and a lid 102b. The space between the container main body 102a and the lid 102b is sealed by the packing 102c, and kept in a reduced pressure state by exhausting by the vacuum mechanism 170. As long as the container main body 102a and the lid | cover 102b have the mechanical strength which can endure a pressure-reduced state, and the chemical stability which can endure the chemical action from an organic solvent etc., the material is arbitrary. Examples of the material of the container body 102a and the lid 102b include metals such as iron, stainless steel, and aluminum, or organic resins such as vinyl chloride and acrylic.

The substrate folder 104 has a base plate 104a and pins 104b fixed to the base plate 104a. The base plate 104a is rotated by the rotation mechanism 106, and the pin 104b has a horizontal surface and a protrusion at the tip. The back surface of the peripheral end portion of the wafer-like substrate 120 is supported by the horizontal surfaces of the plurality of pins 104b, and the circumferential slip of the wafer-like substrate 120 is suppressed by the protrusions of the plurality of pins 104b.

The rotation mechanism 106 includes a rotation motor 106a, a shaft 106b, and a bearing 106c. The shaft 106b is fixed to the base plate 104a, and the bearing 106c supports the shaft 106b. The rotation motor 106a rotationally drives the shaft 106b. A servomotor can be exemplified as the rotation motor 106a. The rotational force of the shaft 106b is transmitted to the base plate 104a, and the wafer-like substrate 120 supported by the pins 104b rotates with the rotation of the base plate 104a.

The liquid supply unit 108 includes a nozzle 108a and a manifold 108b. The nozzle 108a injects the supplied liquid material. The nozzle 108a can be appropriately designed according to the injection direction and the injection speed of the liquid material. The manifold 108b allows the path of the liquid material and the path of other supplies such as dry gas to be shared.

The shield 110 includes a spacer 110d for forming a gap G between the upper shield 110a and the lower shield 110b in addition to the upper shield 110a, the lower shield 110b, and the flange 110c of the upper shield 110a. The distance of the gap G formed by the spacer 110d can be designed as appropriate. The lower shield 110b is fixed to the base plate 104a. Therefore, the entire shield 110 is also rotationally driven by the rotation mechanism 106.

Note that the shield 110 is not necessarily rotated. However, in this case, the advantage of discharging the liquid material staying inside the shield 110 by centrifugal force cannot be enjoyed. Further, it is not necessary that the lower portion of the shield 110 is fixed to the base plate 104a or integrally formed. Alternatively, the collar 110c of the upper shield 110a need not be formed. However, in these cases, the effect of forming the stay part 132 of the liquid 130 or the vaporized substance flow 130 may be reduced.

The cleaning liquid supply unit 140 supplies the cleaning liquid from the central part of the substrate folder 104 toward the back surface 120b of the wafer-like substrate 120. The cleaning liquid supply unit 140 includes a cleaning liquid nozzle 140a and an infusion tube 140b. The infusion tube 140b penetrates the inside of the shaft 106b and transports the cleaning liquid to the cleaning liquid nozzle 140a. The cleaning liquid nozzle 140 a injects the cleaning liquid toward the back surface 120 b of the wafer-like substrate 120. The cleaning liquid nozzle 140a can be appropriately designed according to the injection direction and the injection speed of the cleaning liquid. Examples of the cleaning liquid include water such as pure water and ozone water, and organic solvents such as isopropyl alcohol.

By having the cleaning liquid supply unit 140, the wafer-like substrate 120 can be cleaned before the coating substance is applied, and defects in the coating film due to particles and the like can be reduced. In many cases, particles adhere to the back surface 120b of the wafer-like substrate 120, and the spin coater 100 of this embodiment applies the coating substance in a reduced pressure environment. Since particles easily scatter in a reduced pressure environment, it is particularly effective in the spin coater 100 of this embodiment to include a means for cleaning the back surface 120b of the wafer-like substrate 120 before the coating process.

The gas supply unit 150 supplies dry gas into the vacuum vessel 102. An example of the dry gas is high-temperature nitrogen gas. Thereby, the organic solvent etc. which remain | survive in a coating film can be discharged | emitted rapidly. In addition, the cleaning liquid can be quickly dried after the cleaning process.

The heating means 160 heats the coating surface 120a of the wafer-like substrate 120. An example of the heating means 160 is an infrared heater such as a halogen lamp. Thus, when the coating film is a photoresist, the spin coating apparatus 100 can perform processing up to the step of pre-baking the photoresist film. As a result, the manufacturing process of the semiconductor device can be made efficient.

The vacuum mechanism 170 has a vacuum pump 170a and an exhaust pipe 170b. Examples of the vacuum pump 170a include an oil rotary pump and a mechanical booster pump. The material of the exhaust pipe 170b is the same as that of the container main body 102a and the lid 102b.

The waste liquid treatment mechanism 180 has a gas-liquid separator 180a and a drain tank 180b. The gas-liquid separator 180a separates the gas and liquid flowing through the exhaust pipe 170b. The drainage tank 180b temporarily stores the liquid separated by the gas-liquid separator 180a as drainage.

FIG. 3 is a flowchart showing an example of a coating process using the spin coater 100.

First, the lid 102 b of the vacuum container 102 is opened, and the wafer-like substrate 120 is loaded into the substrate folder 104. A loader / unloader equipped with a robot arm may be used for loading. Thereafter, the lid 102b is closed and the vacuum pump 170a is operated, or the vacuum valve disposed between the vacuum pump 170a and the vacuum vessel 102 is opened, and the inside of the vacuum vessel 102 is brought into a reduced pressure state (step 302).

Next, the rotation motor 106a is operated to start the rotation of the wafer-like substrate 120 (step 304). Thereafter, the back surface 120b of the wafer-like substrate 120 is cleaned (step 306). The back surface 120b is cleaned by opening the valve VL3 and supplying a cleaning liquid from the nozzle 140a. After a predetermined time elapses, the valve VL3 is closed and the supply of the cleaning liquid is stopped, and then the wafer-like substrate 120 is dried (step 308). The wafer-like substrate 120 is dried by opening the valve VL2 and supplying a drying gas.

After a predetermined time has elapsed, the valve VL2 is closed to stop the supply of the dry gas, and then the liquid material is supplied to the coating surface 120a of the wafer-like substrate 120 (step 310). The liquid material is supplied by opening the valve VL1 and closing the valve VL1 after a predetermined time has elapsed. Thereafter, the wafer-like substrate 120 is dried as in Step 308 (Step 312), and the rotation motor 106a is stopped to stop the rotation of the wafer-like substrate 120 (Step 314).

Further, the application surface 120a is heated by the heating means 160, and the application substance on the application surface is pre-baked (step 316). Thereafter, the vacuum pump 170a is stopped, or the vacuum valve disposed between the vacuum pump 170a and the vacuum vessel 102 is closed, and the inside of the vacuum vessel 102 is brought into an atmospheric pressure state. Thereafter, the wafer-like substrate 120 is unloaded (step 318).

Note that the cleaning in step 306 and the drying in step 308 are not essential. In addition, the drying in step 312 may be omitted if the liquid to be supplied has high volatility. Further, the pre-baking in step 316 is not essential.

The steps of cleaning in step 306, drying in step 308, drying in step 312 and pre-baking in step 316 may be performed in a state where the wafer-like substrate 120 is rotated or stopped, in a reduced pressure state. Or you may carry out in any state of an atmospheric pressure state. The supply of the liquid material in step 310 does not require the wafer-like substrate 120 to be rotated at the start stage and does not need to be in a reduced pressure state. The pressure may be reduced after the supply of the liquid material is started, or the rotation may be started after the supply of the liquid material is started.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

The execution order of each process such as operations, procedures, steps, and stages in the apparatus and method shown in the claims, the description, and the drawings is particularly specified as “before”, “prior”, etc. It should be noted that it can be implemented in any order except. Even if it is described using “first”, “next”, and the like for the sake of convenience regarding the operation flow in the claims, the description, and the drawings, it does not mean that the operation is essential in this order.

DESCRIPTION OF SYMBOLS 100 ... Spin coater, 102 ... Vacuum container, 102a ... Container body, 102b ... Lid, 102c ... Packing, 104 ... Substrate folder, 104a ... Base plate, 104b ... Pin, 106 ... Rotation mechanism, 106a ... Rotation motor, 106b ... Shaft 106c ... Bearing, 108 ... Liquid material supply unit, 108a ... Nozzle, 108b ... Manifold, 110 ... Shielding body, 110a ... Upper shielding body, 110b ... Lower shielding body, 110c ... Saddle, 110d ... Spacer, 120 ... Wafer substrate 120a ... coating surface, 120b ... back surface, 130 ... flow, 132 ... staying part, 140 ... cleaning liquid supply part, 140a ... cleaning liquid nozzle, 140b ... infusion tube, 150 ... gas supply part, 160 ... heating means, 170 ... vacuum mechanism , 170a ... vacuum pump, 170b ... exhaust pipe, 180 ... waste liquid treatment mechanism 180a ... gas-liquid separator, 180b ... drainage tank, G ... gap, VL1 ... valve, VL2 ... valve, VL3 ... valve.

Claims

A vacuum vessel;
A substrate folder that is installed inside the vacuum vessel and holds the wafer-like substrate so that the coating surface is on top,
A rotation mechanism for rotating the substrate folder so that the wafer-like substrate rotates substantially horizontally;
A liquid material supply unit for supplying a liquid material containing a coating material from above the center of the wafer-shaped substrate toward the coating surface;
A shield that concentrically surrounds the wafer-like substrate, and shields the flow of the liquid material or its vaporized material generated by rotation of the wafer-like substrate to the outside;
A spin coater having:
The said shielding body has a clearance gap or a hole which rotates with the said substrate folder, and escapes the said liquid substance or the vaporized material which receives the effect | action of the centrifugal force produced by the said rotation from the inner side of the said shielding body. Spin coating equipment.
The spin coater according to claim 2, wherein the lower part of the shield and the outer periphery of the substrate folder are in contact with each other, so that the downward flow of the liquid substance or its vaporized substance is inhibited.
The spin coater according to claim 2, further comprising a ridge projecting inwardly on an upper portion of the shield.
The spin coater according to any one of claims 1 to 4, further comprising a cleaning liquid supply unit configured to supply a cleaning liquid from a central portion of the substrate folder toward a back surface of the wafer-like substrate.
The spin coater according to any one of claims 1 to 5, further comprising a gas supply unit that supplies a dry gas into the vacuum vessel.
The spin coater according to any one of claims 1 to 6, further comprising a heating unit that heats the coating surface of the wafer-like substrate.