JPH02115072A - Coating applicator - Google Patents

Abstract

PURPOSE:To prevent generation of a coating unevenness by equipping a means for monitoring the surface state of a platelike material to which coating liquid is applied and automatically controlling a coating liquid dropping control parameter according to the monitored information. CONSTITUTION:The initial treatment conditional information 12 of spin-on glass film thickness to be coated on a semiconductor wafer 2 is set in an overall controlling part 11. Then when the equipment is started, the number of revolution controlling value of the wafer 2 is set to a rotation controlling part 5 from the overall controlling part 11. The semiconductor wafer 2 is rotated at the prescribed number of rotations to calculate the uneven amount on the surface thereof. In this state, a differential level amount judging part 10 is controlled by the overall controlling part 11 and the wafer 2 is irradiated with light having constant quantity of light from a differential level measuring sensor 9. Simultaneously the quantity of light reflected from the wafer 2 is received and the uneven amount on the surface thereof is obtained on the basis of algorithm for calculating the uneven amount on the surface of the wafer. The optimum value of the number of revolutions of the wafer 2 is calculated on the basis of these information in the overall controlling part 11.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to coating technology, and in particular, applies a coating liquid to a plate-shaped object such as a semiconductor wafer or a magnetic disk while rotating the plate-shaped object. The present invention relates to a technology that is effective when used in spin coating techniques such as spin-on glass (SOG) coating equipment, photoresist coating equipment, and polyimide resin coating equipment.

[Conventional technology]

The conventional spin coating device is disclosed in Japanese Patent Application Laid-Open No. 52-1.23172,
JP-A-58-166721, JP-A-58-17181
As described in each publication No. 9, a coating liquid is dropped onto a semiconductor wafer and the wafer is rotated to form a coating film.

In this type of equipment, it is extremely important to prevent the occurrence of coating unevenness and improve coating film thickness accuracy, and measures such as processing temperature control, coating liquid viscosity control, and exhaust air speed control in the coating cup are taken as measures to achieve this. There is.

Furthermore, in order to remove the coating liquid that has gotten around to the back surface of the wafer, a removal method is used in which unnecessary coating film is removed using a solvent, as described in, for example, Japanese Patent Laid-Open No. 123172/1983. There is an example.

[Problem to be solved by the invention]

However, the conventional apparatus described above does not have a function to control coating liquid dropping control parameters such as coating liquid dropping amount, dropping speed, semiconductor wafer rotation speed during dropping, and dropping liquid spreading time for each semiconductor wafer to be coated.

For this reason, when semiconductor wafers having different wafer pattern step dimensions (irregularities) are mixedly processed using the conventional apparatus, they are processed under the same dropping processing conditions. As a result, the inventors have found that semiconductor wafers with large pattern step dimensions (irregularities) have a problem in that the amount of the coating liquid is insufficient to spread, resulting in uneven coating.

On the other hand, in semiconductor wafers with small pattern step dimensions (irregularities), the coating liquid spreads too much, causing a problem in that excess coating liquid flows around to the back surface of the wafer. In particular, if the coating liquid that has flowed around to the back surface of the wafer gets into the satin surface or uneven surface of the back surface of the wafer, it cannot be removed only by the removal method using a solvent described in Japanese Patent Application Laid-Open No. 52-123172.

In particular, as semiconductor products become more highly integrated, the size of micropatterns is reduced from 0.8 μm to 0.5 μm, and pattern step dimensions are becoming stricter due to the adoption of multilayer wiring processes, trench structure processes, etc. be.

In other words, when comparing the initial process and the final process,
The amount of change in unevenness on the surface of a semiconductor wafer tends to be extremely large.

On the other hand, regarding the photoresist coating process, in order to improve pattern processing accuracy, photoresist liquids with different coating characteristics have been developed, and a plurality of types of photoresist liquids are used in combination. As a result, the inventors have found that the amount of change in unevenness on the surface of the semiconductor wafer tends to become extremely large.

An object of the present invention is to provide a coating technique that can prevent the occurrence of coating unevenness and the leakage of unnecessary coating liquid to the back surface, even when plate-like objects with different surface conditions are mixedly treated.

The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[Means to solve the problem]

A brief overview of typical inventions disclosed in this application is as follows.

The coating apparatus of the present invention is provided with a monitor means for automatically monitoring the surface condition of the surface of a plate-like object such as a semiconductor wafer on which a coating film is formed, and the surface condition monitoring information of the surface of the plate-like object by this monitor means is used. Based on this, the coating liquid dropping control parameters and coating sequence control parameters are controlled.

[Effect]

According to the above-mentioned means, the surface condition of the surface of a plate-like object such as a semiconductor wafer, for example, the surface condition of the surface of the semiconductor wafer to be coated, is determined by a monitor for measuring the amount of unevenness before dropping the coating liquid onto the plate-like object. Measure the amount of unevenness.

Based on the results of this surface condition monitoring, the coating liquid dropping], the number of revolutions of the plate-like object during the coating liquid dropping, and the coating liquid dropping time are determined to obtain control information.

When forming a coating film, a predetermined amount of coating liquid is dropped over a predetermined period of time while rotating the plate-like object at a predetermined rotational speed based on the above control information, and then a coating film is formed on the plate-like object in a predetermined coating sequence. Ru.

In other words, the amount of the coating liquid dropped and the number of rotations of the plate-like object at the time of dropping are determined according to the surface condition such as the amount of unevenness on the surface of the plate-like object, so that the coating liquid is uniformly spread to the periphery of the plate-like object.
Moreover, the problem of unnecessarily causing the coating liquid to flow around the back surface of the plate-like object does not occur.

That is, the stretching speed of the dropped coating solution varies depending on the condition of the back surface of the plate-like object, for example, the amount of unevenness. The present invention takes advantage of this phenomenon, and controls the amount of coating liquid dropped, the wafer rotation speed during coating weight liquid dropping, the coating liquid stretching time, etc., in accordance with the amount of unevenness on the surface of a plate-shaped object. This corrects the change in the coating liquid stretching speed that occurs due to the change in the amount of surface unevenness. As a result, in the present invention, even if plate-shaped objects such as semiconductor wafers having different amounts of surface unevenness are mixedly processed, uneven coating does not occur and unnecessary coating liquid can be prevented from flowing around to the back surface of the semiconductor wafer.

〔Example〕

FIG. 1 is a cross-sectional view of a main part of a spin-on glass film coating apparatus which is an embodiment of the present invention.
This shows a state in which SOG) liquid is being dropped.

First, the configuration of the coating device of this example will be explained.
A semiconductor wafer 2 (plate-shaped object) on which a spin-on glass film is to be formed on the coating cup section 1 is vacuum-adsorbed to the spin chuck section 3. This spin chuck section 3 is connected to a motor 4, and is controlled by a rotation speed control section 5 so that the spin chuck section 3 can be rotated by the motor 4 at a predetermined rotation speed.

On the other hand, the dripping nozzle 6 is configured to drip a predetermined amount of the spin-on glass liquid 8 under the control of a dripping amount control section 7 .

Further, a step measuring sensor 9 (monitoring means) is provided which measures the amount of step as the amount of unevenness which is an example of the surface condition of the semiconductor wafer 2, and the sensor 9 is connected to the step amount determining section 10.

The step amount determination section 10, the drop amount control section 7, and the rotation speed control section 5 are connected to an overall control section 11.

The overall control unit 11 controls the dripping amount control unit 7 and the rotation speed control unit 5 based on the initial processing condition information 12, the level difference measurement sensor 9, and the monitor information of the level difference determination unit 10, and controls the dripping amount of the spin-on glass liquid 8, It is configured to perform rotation sequence control of the semiconductor wafer 2.

Here, the principle of monitoring the amount of surface unevenness of the semiconductor wafer 2 will be explained as an example with reference to a diagram of the principle of monitoring the amount of surface unevenness of the wafer shown in FIG.

In this principle diagram, a constant amount of light is irradiated while rotating the semiconductor wafer 2, and the amount of unevenness on the surface of the semiconductor wafer 2 is automatically monitored from the difference in optical reflection scene fluctuation. Specifically, the wafer surface unevenness amount coefficient value is determined from the difference in reflected light amount for light irradiated with the same amount of light, and the wafer surface unevenness amount is determined based on this value.

The algorithm for calculating the wafer surface unevenness coefficient value is α”(Er E,) x ΣE(Er
+ Ei ) / 2 α; Wafer surface unevenness coefficient ΣE; Projected light amount ET; Wafer pattern top reflected light amount E8; Wafer pattern bottom reflected light amount This algorithm is ΣE/ ((Et +Ea) /
2) determines the optical coefficients (reflectance, transmittance, absorption) of the wafer surface, and (ET-EB) determines the wafer surface unevenness ratio value. In total, the former is the wafer surface material (Aj!
, S i02. 3i, etc.), the wafer surface unevenness ratio value is corrected by the optical correction amount, and the wafer surface unevenness coefficient (α) is automatically obtained. Specifically, a certain amount of light is irradiated onto the semiconductor wafer 2 from the step measurement sensor 9, and the reflected light is received. The level difference determination section 10 automatically determines the amount of unevenness on the semiconductor wafer 2 using the above algorithm based on the amount of irradiated light and the amount of reflected light at this time.

Next, the operation of the coating apparatus of this embodiment will be explained.

First, initial processing condition information 12 regarding the thickness of the spin-on glass film to be applied onto the semiconductor wafer 2 is set in the overall control section 11 .

When the device is started after initial settings, the overall control unit 11
The semiconductor wafer 2 is rotated at a predetermined number of rotations in order for the rotation control unit 5 to determine the amount of unevenness on the surface of the semiconductor wafer 2 . In this state, the step amount determination unit 10 is controlled by the overall control unit 11,
A constant amount of light is emitted from the step measurement sensor 9.

At the same time, the amount of unevenness on the wafer surface is determined by the step amount determining section 10 based on the algorithm for receiving the amount of reflected light from the semiconductor wafer 2 and determining the amount of unevenness on the wafer surface described above. The obtained surface unevenness amount monitor or measurement information of the semiconductor weno\2 is fed back to the overall control section 11.

The overall control unit 11 determines the amount of spin-on glass liquid dropped, the dropped sl:'-)', and the rotational speed of the semiconductor wafer 2 at the time of dropping based on the unevenness measurement information of the semiconductor wafer 2 and the initial processing condition information 12. Find the optimal value.

Based on this optimal value of the dropping conditions, the overall control unit 11
The dripping amount control section 7 and the rotation speed control section 5 are controlled.

As a result, the rotation speed of the motor 4 is controlled by the rotation speed control section 5 according to the amount of unevenness of the semiconductor wafer 2.
is rotated at the optimum rotation speed. In this state, the dripping amount control unit 7
Then, a predetermined amount of the spin-on glass liquid 8 is dropped at an optimum dropping speed.

Thereafter, the semiconductor wafer 2 is controlled in a predetermined rotation sequence by the rotation speed control unit 5, and a spin-on glass film having a predetermined thickness with high precision is formed on the semiconductor wafer 2. As a result, it is possible to prevent uneven coating and the phenomenon that unnecessary spin-on glass liquid 8 flows around the back surface of semiconductor wafer 2.

As above, the invention made by the present inventor has been specifically explained based on examples, but the present invention is not limited to the above-mentioned examples, and various modifications can be made without departing from the gist of the invention. Needless to say, there is no °J.

For example, in addition to the photoresist coating device, the coating device of the present invention may also include a dopant coating device, a polymide coating device,
It can also be applied as a wet spin etching device.

Additionally, as a means of measuring the amount of unevenness on the surface of a semiconductor wafer, it is possible to measure the amount of unevenness on the surface of a semiconductor wafer by emitting irradiation light in a pulsed manner and determining the optical path length from the time difference in which the reflected light returns to the light receiving part. It is.

Furthermore, it is also possible to monitor other surface conditions than the amount of unevenness (step amount).

[Application field]

In the above description, the invention made by the present inventor was mainly applied to a semiconductor wafer manufacturing apparatus, which is the background field of application, but the invention is not limited thereto.

For example, it is effective when applied to the application of a coating liquid to a plate-shaped object in a magnetic disk manufacturing device, a liquid crystal manufacturing device, a cathode ray tube manufacturing device, etc.

〔Effect of the invention〕

Among the inventions disclosed in this application, the effects obtained by typical inventions are briefly described below.

(1)9 In the present invention, the surface condition (for example, the amount of unevenness) of the plate-like object to be coated by rotation is automatically measured, and the amount of the coating liquid dropped, the speed of the drop, and the plate-like object at the time of dripping are determined according to the measurement results. Dripping control parameters such as rotation speed and rotation time are automatically controlled. As a result, the surface condition of the plate to be coated (
For example, even if materials with different amounts of unevenness are mixed, there will be no problem of uneven coating or unnecessary coating liquid going around to the back surface of the plate, and a uniform and accurate coating film can be formed on the surface of the plate.

(2) When the present invention is applied to a spin-on glass coating device, a photoresist coating device, etc., which are semiconductor wafer manufacturing equipment, highly accurate film thickness of the spin-on glass film or photoresist can be obtained without causing coating unevenness.

At the same time, it is possible to prevent unnecessary spin-on glass liquid (photoresist liquid) from flowing around to the back surface of the semiconductor wafer. This solves the problem that during semiconductor wafer handling, unnecessary spin-on glass liquid (photoresist liquid) that has gotten around to the back side of the semiconductor wafer is transferred to the handling section or cracked during handling and acts as a foreign substance. As a result, pattern defects caused by foreign matter can be prevented.
Product yield of semiconductor products can be improved. At the same time, it becomes possible to mass produce ultra-LSI semiconductor products having fine element pattern dimensions in the submicron class.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a main part of a spin-on glass film coating apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing the principle of monitoring the amount of unevenness on a wafer surface. DESCRIPTION OF SYMBOLS 1... Coating cup part, 2... Semiconductor wafer (plate-like object), 3 - Motor, 5... Nozzle, 7... On-glass liquid, means), 10 - System clamp part, 12... Spin chuck Section, 4...Rotation speed control section, 6...Drop/Drop amount control section, 8...Spin 9...Level difference measurement sensor (monitor...Level difference amount determination section, 11...All... ...Initial processing condition information.

Claims (1)

[Claims] 1. An apparatus that applies a coating liquid to the surface of a plate-like object by rotating the plate-like object, and monitors the surface condition of the surface of the plate-like object to which the coating liquid is applied. What is claimed is: 1. A coating apparatus comprising a monitor means, and automatically controlling coating liquid droplet control parameters and coating sequence control parameters in accordance with surface condition monitor information from the monitor means. 2. The coating apparatus according to claim 1, wherein the monitoring means monitors the amount of unevenness on the surface of the plate-like object as the surface condition. 3. As the coating liquid dropping control parameters, the coating liquid dropping amount, the coating liquid dropping speed, the coating liquid dropping time, and the rotational speed of the plate-like object during coating liquid dropping are controlled independently or in combination. The coating device described. 4. The coating apparatus according to claim 1, wherein the coating sequence control parameters include a combination of plate-like object rotation speed and plate-like object rotation time.