JPH07302745A - Coating method and device - Google Patents

Abstract

PURPOSE:To provide the coating, technology capable of reducing the fringe part area of a photomask blanks while lessening the difference in film thickness for suppressing the creeping of resist in the side and rear surface of the blanks in the resist coating step especially in the manufactucture of semiconductor integrated circuit device. CONSTITUTION:Within the title spin coating device composed of a loader, a resist coating part, a soft baking part and an unloader part, a resist feeding nozzle 12 dripping resist 11 and another resist feeding nozzle 14 dripping resist solution 13 are provided above a coating cap 8 of the resist coating part 3. In such a constitution, the resist 11 and the resist solution 13 are dripped on the central parts of the blanks 7 fixed on a spin head 9 simultaneouly or at an arbitrary time interval.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coating technique by a rotary method, and particularly, in resist coating to a photomask blank used for forming a device pattern of a photomask or a wafer in the production of a semiconductor integrated circuit device, the photomask blank of the photomask blank is used. The present invention relates to a technique effective when applied to a coating method and apparatus capable of reducing a fringe area, reducing a difference in film thickness of a resist, and suppressing the wraparound of the resist on the side surface and the back surface of the photomask blank.

[0002]

2. Description of the Related Art For example, in the manufacture of semiconductor integrated circuit devices, a chemical amplification type photosensitive material (hereinafter referred to as "photosensitive material") having high resolution and high sensitivity in a photomask which is an original plate of a semiconductor integrated circuit has been used in accordance with miniaturization technology. (Registration) is being introduced. The main feature of the chemically amplified resist used for forming the device pattern of this photomask is a resist that utilizes a catalytic reaction, and a catalyst is generated with a small exposure amount, and many reactions are caused by this catalytic reaction. It is possible to increase sensitivity.

Now, a process of applying a resist to a photomask blank in manufacturing the photomask will be briefly described.

First, a photomask blank is formed by vapor-depositing a metal film on a precision-polished transparent glass substrate. After that, there is a step of applying a resist on the surface of the metal film, and as the applying method, an apparatus mainly having a rotation mechanism is used.After dropping the resist on the surface of this photomask blank, the blank is rotated. Let it coat.

Then, the resist applied on the surface of the photomask blank is subjected to a soft baking treatment to remove excess solvent in the resist. The photomask blank coated with this resist film is inserted into an exposure device (for example, an electron beam drawing device), and a device pattern is drawn on the surface of the resist film by an electron beam.

After that, a chemically amplified resist is mainly required to be baked after exposure (hereinafter referred to as PEB processing). After the PEB treatment, the resist film is developed, the developed resist film is used as a cover, the metal film is etched to form a light-shielding pattern, and then the unnecessary resist film is removed.

The above is a brief outline of the process steps in coating a resist on a photomask blank, and a photomask is manufactured using this method.

Regarding the resist coating technique, for example, the Institute of Electronics and Communication Engineers, 1984, 1
"LSI Handbook" published on January 30, P253-P
263 exposure technology.

[0009]

However, the present inventor has found that the above-mentioned technique has the following problems. In other words, as a result of examining the above-mentioned technology, since most of the blanks used for the photomask are rectangular, a fringe portion is formed at the corner after coating, which does not occur in a circular wafer, and the backside, which is a common problem with the wafer. The wraparound of the resist occurs (Figs. 5 (a) and 5 (b)).

The former fringe portion cannot be used as the exposure region of the device pattern because the resist film thickness is much thicker than the central portion, and the phenomenon that it is not developed even if it is used occurs. The latter part of the resist that wraps around on the back surface is peeled off during the process treatment, and the peeled off becomes a foreign matter, which wraps around on the front surface and causes a deterioration in the appearance quality of the device pattern. Further, the above phenomenon causes a problem that the yield of the photomask is reduced.

Therefore, an object of the present invention is to solve these problems and improve the coating accuracy in the coating process, and particularly to a photomask blank used for forming a device pattern of a photomask or a wafer in the manufacture of a semiconductor integrated circuit device. In the resist coating, a coating method and apparatus capable of reducing the area of fringes generated at the corners of the blank and reducing the difference in the resist film thickness to suppress the wraparound of the resist on the side surface and the back surface of the blank. To provide.

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

[0013]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows.

That is, the coating method of the present invention is applied to a coating method by a rotation method for coating a coating material on an object to be coated, and a plurality of coating materials are dropped at the same time or at an arbitrary time lag. It is a thing.

In this case, the object to be coated is applied to a photomask blank used for forming a device pattern of a photomask or a wafer in the manufacture of a semiconductor integrated circuit device, and a resist material and a resist solvent are used as the coating material. It is adapted to be applied.

Further, the coating apparatus of the present invention comprises a first supply mechanism for dropping a resist material as a coating material and a second supply mechanism for dropping a resist solvent onto a photomask blank as an object to be coated. And the resist material is dropped from the first supply mechanism to the central portion of the photomask blank or to an arbitrary position, and the resist solvent is dropped to the periphery thereof from the second supply mechanism at the same time or with an arbitrary time difference. To do.

[0017]

According to the above-mentioned coating method and apparatus, a plurality of coating materials are dropped onto an object to be coated at the same time or at an arbitrary time difference, so that the coating conditions can be controlled by utilizing the properties of the respective coating materials. It is possible to optimize and improve the coating accuracy in the coating step.

For example, when the resist material is applied to the photomask blanks, the resist material is dropped from the first supply mechanism and the resist solvent is dropped from the second supply mechanism at the same time or at an arbitrary time difference. This resist solvent promotes the spread of the resist material,
It is possible to reduce the area of fringes that occur at the four corners of the blank.

In the photomask blank,
The difference in film thickness between the fringe portion and the central portion of the resist can be reduced, and the wraparound of the resist on the side surface and the back surface of the blank can be suppressed, so that the appearance quality of the photomask can be improved.

In this case, the resist material is applied to the central portion or an arbitrary position of the photomask blank, and a resist solvent is applied to the periphery of the photomask blank at the same time or with an arbitrary time difference. This can be done by dropping the material or, conversely, dropping the resist material to spread the resist material to some extent and then dropping the resist solvent.

Thus, in the spin coating method in which a plurality of coating materials are dropped onto the object to be coated at the same time or at an arbitrary time difference, and in the coating apparatus equipped with the supply mechanism for dropping the plurality of coating materials. The appearance quality of the photomask after coating can be improved, and the yield of the photomask can be further improved.

[0022]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a front view showing the whole coating apparatus which is an embodiment of the present invention, FIG. 2 is a sectional view showing a resist coating section in the coating apparatus of this embodiment, and FIG. 3 is a coating material for blanks. Fig.4 (a), (b)
FIG. 4A is a plan view and a cross-sectional view showing a state of blanks after coating.

First, the structure of the coating apparatus of this embodiment will be described with reference to FIG.

The coating apparatus of this embodiment is, for example, a rotary coating apparatus that coats a coating material on a rotating object to be coated. The rotary coating apparatus is housed inside the clean bench 1 and has a loader section. 2, a resist coating section 3, a soft bake section 4, and an unloader section 5, and overall control is performed by an operation from a clean bench control panel 6 provided on the top of the clean bench 1.

The loader unit 2 includes, for example, an IC and an LSI.
Is a portion for supplying blanks (objects to be coated) 7 of a photomask of a photosensitive material used for device pattern formation, and the blanks 7 set in the loader section 2 are taken out one by one to be applied to the resist coating section. 3 is transported.

The resist coating section 3 is a section for coating a resist material on the blanks 7. For example, as shown in FIG. 2, a spin head 9 whose rotation is controlled is provided in the center of the coating cup 8. The rotation control of the spin head 9 is performed by an operation from the spin control panel 10.

Above the coating cup 8, for example, a resist supply nozzle (first supply mechanism) 12 for dropping a chemically amplified resist (coating material) 11 and a resist solvent (coating material) 13 are dropped. A resist solvent supply nozzle (second supply mechanism) 14 is provided, and for example, the resist supply nozzle 12 is disposed in the substantially central portion so as to be movable with respect to the spin head 9, and the resist solvent supply nozzle 14 is also movable in the periphery. It is arranged at almost two places of the section. Furthermore, the inside of the coating cup 8 can be exhausted through an exhaust duct 15.

In the resist coating section 3, the blanks 7 conveyed from the loader section 2 are spin heads 9.
The resist 11 is fixed onto the blank 7 from the resist supply nozzle 12 and the resist solvent 13 is dropped from the resist solvent supply nozzle 14 at the same time or at an arbitrary time lag, and after coating by rotation control, the soft bake portion is applied. 4 is transported.

The soft bake part 4 is a part for removing excess solvent in the resist 11, and the temperature control of the bake oven 16 for removing this solvent is performed by an operation from the bake control panel 17. In the soft bake unit 4, the blanks 7 conveyed from the resist coating unit 3 are soft-baked in the baking furnace 16 by temperature control and then conveyed to the unloader unit 5.

The unloader section 5 is a blank 7 after coating.
Is the part for discharging the
The blanks 7 conveyed from the soft bake unit 4 are 1
Stored one by one.

Since a series of operations from the resist coating to the soft bake in this spin coater is performed in batch processing of a plurality of sheets in consideration of mass productivity, reproducibility of each sheet is important, Therefore, the monitoring monitor 18 is provided in the unloader unit 5 so that the manufacturing can be always performed under the condition that the influence of the coating accuracy is not impaired.

Next, regarding the operation of the present embodiment, an example of the overall work flow will be described first.

First, the blanks 7 of the photomask are set in the loader section 2, and in this case, the spin control panel 10 inputs the coating conditions such as the rotation speed of the spin head 9 of the resist coating section 3 in advance. And the loader unit 2
The blanks 7 taken out from are conveyed into the coating cup 8 of the resist coating section 3.

Further, the resist 11 is coated in the coating cup 8. Then, the blanks 7 on which the coating of the resist 11 has been completed are transferred to the baking oven 16 of the soft baking unit 4 which has been conditionally set by the baking control panel 17, and the soft baking process is performed.

After this soft bake processing, it is conveyed to the unloader section 5 and stored. In this case, in order to obtain reproducibility in these series of operations, the monitoring monitor 1 is always provided so that the manufacturing can be performed under the condition that the influence of the coating accuracy is not impaired.
The work is repeated while being monitored by 8.

Next, the spin coating method in the resist coating section 3 will be described in detail.

First, in the resist coating section 3, the blanks 7 are mounted on the spin head 9 in the coating cup 8. The blanks 7 are fixed on the spin head 9 by vacuum suction or mechanically (not shown).

Further, after fixing the blanks 7, the blanks 7 are rotated at low speed for each spin head 9. The resist supply nozzle 1 is placed on the blanks 7 rotating at a low speed.
2. The resist solvent supply nozzle 14 is moved to an arbitrary position, for example, the resist supply nozzle 12 is moved to the central portion of the blank 7 and the resist solvent supply nozzle 14 is moved to the periphery thereof.

Then, the resist 11 is dropped from the resist supply nozzle 12 and the resist solvent 13 is dropped from the resist solvent supply nozzle 14 simultaneously or at an arbitrary time lag. Particularly, the resist solvent 13 is dropped so as to surround the periphery of the resist 11 dropped on the blank 7 as shown in FIG.

For example, when the resist solvent 13 is dropped at an arbitrary time difference, the resist 11 is dropped after surrounding the surroundings by dropping the resist solvent 13, or conversely, the resist 11 is dropped and spread to some extent and then the resist solvent 13 is dropped. There is a method of dropping.

Further, a resist 11 is formed on the blanks 7.
And after dropping the resist solvent 13, the spin head 9
Each time, the blanks 7 are raised to an arbitrary number of revolutions and spin coated. At this time, the interior of the coating cup 8 is evacuated by the evacuation duct 15 with an arbitrary amount of air at the same time as or before the spin head 9 and the blanks 7 are rotated.

In this case, the spread of the resist 11 is promoted by the resist solvent 13 around the resist 11, so that the resist 11 easily spreads over the surface of the blank 7 as shown in FIG. 4 (a). As a result, the fringe portion 19 can be reduced, and the resist 1
1 is formed to have a uniform film thickness as shown in FIG. 4 (b), and the wraparound to the side surface and the back surface can be eliminated.

In this coating apparatus, in order to improve the coating accuracy, the shape and size of the coating cup 8, the atmosphere and exhaust control in the coating cup 8, the spin head 9
Needless to say, each condition such as rotation control is controlled to an optimum value, and optimization of each condition is a prerequisite.

Therefore, according to the coating apparatus of this embodiment, the resist supply nozzle 12 for dropping the resist 11 and the resist solvent supply nozzle 14 for dropping the resist solvent 13 are provided in the coating cup 8 of the resist coating section 3. By providing the resist 11 from the resist supply nozzle 12 and dropping the resist solvent 13 from the resist solvent supply nozzle 14 at the same time or with an arbitrary time difference, the area of the fringe portion 19 occurring at the corner portion of the blank 7 can be reduced. can do.

Further, the difference in film thickness of the resist 11 between the fringe portion 19 and the central portion of the blank 7 can be reduced, and the wraparound of the resist 11 on the side surface and the back surface of the blank 7 can be suppressed. In addition, it is possible to improve the appearance quality of the photomask and further improve the yield of the photomask.

Although the invention made by the present inventor has been specifically described based on the embodiments, the present invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, in the coating apparatus of the present embodiment, the resist supply nozzle 12 is arranged substantially at the center of the spin head 9 and the resist solvent supply nozzle 14 is arranged at two peripheral positions. I explained,
The present invention is not limited to the above-described embodiment, and modifications such as the case where the resist solvent supply nozzles are provided at four locations are possible, and the same applies when at least one resist supply nozzle and one resist solvent supply nozzle are provided at each location. The effect of can be obtained.

Further, in the above-mentioned embodiment, the case of applying to the technique of applying the resist 11 for the photomask to the blanks 7 of the photomask as the object to be coated has been described, but other materials are applied. It is also applicable to, for example, blanks used for forming a device pattern on a wafer.

Further, as the coating material, in addition to the chemically amplified resist 11, SOG (Spin-On-Glass) film can be applied widely, and a conductive film such as metal can also be applied. Is.

In the above description, the case where the invention made by the present inventor is mainly applied to the resist coating technique for a photomask in the manufacturing field of a semiconductor integrated circuit device, which is the field of application thereof, has been described, but the invention is not limited to this. However, the present invention can be applied not only to other materials but also to other materials, and is particularly applicable to other manufacturing processes that require coating technology.

[0052]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.
It is as follows.

(1). A plurality of coating materials are dropped onto the object to be coated at the same time or at an arbitrary time difference, so that the respective properties of the plurality of coating materials are utilized to apply the coating conditions to the object to be coated. Since it can be optimized, the coating accuracy in the coating step can be improved.

(2) In the above (1), when the object to be coated is a photomask blank used for forming a device pattern on a photomask or a wafer and the coating material is a resist material and a resist solvent, the photomask blanks are used. Resist material at the center or at any position,
The resist solvent can be spread at the same time or by giving an arbitrary time difference to the periphery of the resist solvent to promote the spread of the resist material. Therefore, it is possible to reduce the fringe area that occurs in the corner portion of the photomask blank. .

(3) According to the above (2), the spread of the resist material can be promoted by the resist solvent, so that the difference in the film thickness of the resist between the fringe portion and the central portion of the photomask blank can be reduced.

(4) According to the above (2), the spread of the resist material can be promoted by the resist solvent, so that the wraparound of the resist on the side surface and the back surface of the photomask blank can be suppressed.

(5). According to the above (2) to (4), particularly in the resist coating step in the manufacture of the semiconductor integrated circuit device,
It is possible to reduce the fringe area of the photomask blank, reduce the difference in the resist film thickness, and prevent the resist from wrapping around the side and back surfaces of the photomask blank, thus improving the appearance quality of the photomask after coating. In addition, the yield of the photomask and the yield in pattern formation can be improved.

[Brief description of drawings]

FIG. 1 is a front view showing the entire coating apparatus according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing a resist coating section in the coating apparatus of this embodiment.

FIG. 3 is a plan view showing a state in which a coating material is dropped onto blanks in the present example.

4A and 4B are a plan view and a cross-sectional view showing a state of blanks after coating in this example.

5A and 5B are a plan view and a cross-sectional view showing a state of blanks after coating in a coating apparatus which is an example of a conventional technique.

[Explanation of symbols]

 1 Clean Bench 2 Loader Section 3 Resist Coating Section 4 Soft Bake Section 5 Unloader Section 6 Clean Bench Control Panel 7 Blanks (Target Object) 8 Coating Cup 9 Spin Head 10 Spin Control Panel 11 Resist (Coating Material) 12 Resist Supply Nozzle (First Supply Mechanism) 13 Resist Solvent (Coating Material) 14 Resist Solvent Supply Nozzle (Second Supply Mechanism) 15 Exhaust Duct 16 Bake Furnace 17 Bake Control Panel 18 Monitoring Monitor 19 Fringe Portion

Continuation of front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03F 7/16 502

Claims (5)

[Claims] 1. A method for applying a coating material to an object to be coated by a rotating method, wherein a plurality of coating materials as the coating material are dropped simultaneously or at an arbitrary time lag. Application method. 2. The object to be coated is a photomask blank used for forming a device pattern of a photomask or a wafer in the manufacture of a semiconductor integrated circuit device, and the plurality of coating materials are applied to the photomask blank simultaneously or arbitrarily. The coating method according to claim 1, wherein the dropping is performed with a time difference of 2). 3. The resist material and a resist solvent are used as the coating material, the resist material is provided in the central portion of the photomask blank or at an arbitrary position, and the resist is provided in the central portion of the photomask blank or around the arbitrary position. The coating method according to claim 2, wherein the solvent is dropped at the same time or with an arbitrary time difference. 4. When the resist material and the resist solvent are dropped with an arbitrary time difference, the resist material is dropped after dropping the resist solvent, or the resist solvent is dropped after dropping the resist material. The coating method according to claim 3, wherein 5. A coating apparatus according to a rotation method for coating a coating material onto a coating object, wherein a resist material as the coating material is dropped onto a photomask blank as the coating object. No. 1 supply mechanism and a second supply mechanism for dropping the resist solvent as the coating material onto the photomask blanks, and from the first supply mechanism to the central portion of the photomask blanks or an arbitrary position. The resist material on the second
5. The coating apparatus, wherein the resist solvent is dropped from the supply mechanism to the central portion of the photomask blank or the periphery of an arbitrary position at the same time or with an arbitrary time difference.