These and/or other aspects and advantages of the present general inventive concept will become apparent and more readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:
Reference will now be made in detail to the embodiments of the present general inventive concept, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiments are described below in order to explain the present general inventive concept by referring to the figures.
Hereinafter, an apparatus and method for measuring widthwise ejection uniformity of slit nozzle according to the present invention will be described in detail with reference to the accompanying drawings. The apparatus for measuring ejection uniformity according to the invention serves to measure ejection uniformity of photoresist to be ejected by the slit nozzle of the slit coater described in the related art. The descriptions of the slit coater will be omitted.
Referring to
As shown in
When liquid Lq to be ejected from the slit nozzle 110 reaches the top surface of the liquid distributor 200, the ejected liquid Lq flows downward along the shape of the liquid distributor 200. That is, as shown in
Preferably, the liquid distributor 200 is spaced at less than a predetermined distance from the ejection port 112 which is the lower end of the slit nozzle 110. When the distance is large, the liquid Lq ejected from the ejection port 112 of the slit nozzle 110 is lumped into droplets due to a surface tension. Then, the liquid Lq does not uniformly flow into the liquid distributor 200. As a result, the liquid distributor 200 cannot distribute the liquid uniformly. The distance differs in accordance with a type of liquid. When photoresist PR to be used in the slit coater is used as liquid, the distance is preferably set to less than 300 μm.
Meanwhile, when the liquid Lq to be ejected from the upper end of the liquid distributor 200 is uniformly distributed by the constant amount and then drops into the liquid measuring unit 300 through the liquid collecting section 240, it is preferable that the liquid does not remain on the liquid distributor 200 but all drops into the liquid measuring unit 300. For this, the liquid distributor 200 is preferably surface-treated so that hydrophobicity is provided on the surface of the liquid distributor 200. Then, the liquid Lq is not adhered on the liquid distributor 200. That is, the liquid distributor 200 is not wetted by the liquid Lq. For example, hydrophobic coating can be performed on the surface of the liquid distributor 200, or surface roughness can be reduced.
The liquid measuring unit 300 includes a plurality of liquid collecting containers 320 disposed under the liquid distributor 200, a plurality of measuring sensors 340 which support the respective liquid collecting containers 320 and measure an amount of liquid Lq to be collected by the respective liquid collecting containers 320, and a measuring unit 360 which is connected to each of the measuring sensors 340 and receives a signal therefrom so as to measure an amount of liquid Lq flowing in each of the liquid collecting containers 320 such that the uniformity of the ejected liquid Lq is measured. The measuring sensor 340 may include a mass sensor such as a load cell which detects the mass of the collected liquid Lq.
Each of the liquid collecting containers 320 has an opening formed in the upper portion thereof and is disposed under each of the liquid collecting sections 240. Preferably, the opening of the liquid collecting container 320 is formed to have a large diameter such that liquid Lq to drop from each of the liquid collecting sections 240 flows into the corresponding liquid collecting container 320. In a general case, liquid Lq ejected from the slit nozzle 100 is separated by the liquid separating section 220 and is collected into the liquid collecting section 240. Then, the collected liquid Lq drops into the liquid collecting container 320 from the lower end (peak) of the liquid collecting section 240. However, after liquid Lq is separated by the liquid separating section 220, the liquid Lq may not reach the peak but drop in the middle. Even in this case, the liquid collecting container 320 should collect the liquid Lq. Therefore, the opening of the liquid collecting container 320 is formed to have as a large diameter as possible.
Meanwhile, the liquid separating section 220 positioned to correspond to either end of the slit nozzle 110 needs to be examined. As shown in
The apparatus for measuring ejection uniformity according to the invention serves to measure the ejection uniformity of photoresist PR to be ejected by a slit coater which coats such a material as photoresist PR onto a glass substrate at a constant thickness. For this, the apparatus for measuring ejection uniformity according to the invention is disposed under the slit nozzle 110 which actually ejects photoresist PR. Then, the photoresist PR is ejected from the slit nozzle 110 such that the distribution of the photoresist PR according to the widthwise direction of the slit nozzle 110 is measured.
That is, in order to measure the uniformity of photoresist PR using the apparatus for measuring ejection uniformity, the photoresist PR can be used as liquid Lq. In this case, however, since the photoresist PR to be used in the apparatus for measuring ejection uniformity is expensive and should be discarded, a lot of cost is required. Further, if the ejected photoresist PR which is highly volatile is not evaporated uniformly in a widthwise direction of the slit nozzle 110, the apparatus for measuring ejection uniformity according to the invention cannot measure the uniformity of the photoresist PR with reliability. Therefore, as for liquid to be used in the apparatus for measuring ejection uniformity, it is preferable to use water which is easily obtained and is not volatile.
When an ejected amount of liquid Lq according to the widthwise direction of the slit nozzle 110 is measured for each interval, an absolute value and ejection behavior for each interval are not measured, but the distribution for each interval is relatively measured. Therefore, the photoresist PR or a material having the same physical property as the photoresist PR does not need to be used.
In order to measure the distribution of liquid Lq according to the widthwise direction of the slit nozzle 110 by using the ejection uniformity measuring apparatus constructed in such a manner, the slit nozzle 110 and the ejection uniformity measuring apparatus are fixedly installed so that the liquid distributor 200 is disposed in parallel under the ejection port 112 of the slit nozzle 110 while being spaced at a constant distance from the ejection port 112.
After that, water, not photoresist PR, is supplied to the photoresist supply section 115 through the second photoresist supply line 117 of the slit coater (refer to
As shown in
The measuring sensors 340 supporting the respective liquid collecting containers 320 detect an amount of liquid Lq collected in the liquid collected containers 320 so as to transmit an amount signal to the measuring unit 360. The measuring unit 360 calculates an amount of liquid Lq collected in each of the liquid collecting containers 320. Then, the measuring unit 360 calculates the distribution of liquid Lq so as to measure the uniformity of ejected liquid Lq according to the widthwise direction of the slit nozzle 110.
Preferably, the measuring of the uniformity of liquid Lq is repeatedly performed about ten times, in order to secure reliability. When the measuring is completed, the space of the ejection port 112 of the slit nozzle 110 is adjusted on the basis of the uniformity. The measuring of the uniformity of liquid and the adjusting of the space of the ejection port 112 are repeatedly performed until desirable uniformity of ejected liquid is obtained.
Meanwhile, when the liquid Lq separated from the liquid separating section 220 of the liquid distributor 200 drops down from the liquid distributor 200 while flowing toward the liquid collecting section 240, it is likely that the corresponding liquid collecting container 320 cannot collect all the liquid Lq. That is, it has been described that the opening of the liquid collecting container 320 is preferably formed to have as a large diameter as possible. However, since the liquid collecting containers 320 are adjacent to each other, there is a limit in enlarging the diameter of the opening. Therefore, under the liquid separating section 220, two of the liquid collecting containers 320 are disposed to be spaced at a predetermined distance from each other. Therefore, when liquid Lq drops from the liquid distributor 200 immediately after being separated by the ejection separating section 220, the liquid Lq is not collected by the liquid collecting container 320.
The liquid distributor 200a shown in
The guide projection 202 is formed to project at a predetermined distance under the liquid separating section 220 in a thickness direction of the liquid distributor 202a and to extend along the edge of the inverted-triangle protrusion. Preferably, the guide projection 202, of which the projection height is gradually reduced along the edge, is integrally formed in the body of the liquid distributor 202a or is separately formed and then attached to the body of the liquid distributor 202a. When the guide projection 202 is formed so that the projection height thereof is gradually reduced, liquid adhered on the guide projection 202 flows downward along the guide projection 202 into the body of the liquid distributor 202a, without staying on the guide projection 202. In
Further, such a guide projection 202 serves to enhance the strength of the liquid distributor 202a. In order that the liquid distributor is spaced in parallel at a predetermined distance from the ejection port 112 of the slit nozzle 110, the liquid distributor should be firmly fixed and maintained in a flat shape in a state where a predetermined tension is applied to both ends thereof. At this time, the liquid separating section 220 with a small height inevitably has a small strength. In order to accurately separate liquid Lq, it is preferable that the liquid separating section 220 is formed to have as a small height as possible. In terms of strength, however, the liquid separating section 220 needs to have a predetermined height. The guide projection 202 can reinforce the strength of the liquid separating section 220. Accordingly, the height of the liquid separating section 220 can be reduced so that liquid Lq can be further accurately separated.
On the other hand, another modification for enhancing the strength of the liquid separating section 220 and further accurately separating election liquid Lq is shown in
A liquid distributor 200b shown in
As shown in
In the above description, the distribution protrusion 204 is formed on the upper end surface of the liquid separating section 220. However, the distribution protrusion 204 may be formed to protrude at a predetermined distance in the thickness direction of the liquid distributor 200b. Further, the distribution protrusion 204 and the guide projection 202 shown in
Meanwhile, in order that liquid Lq is further accurately separated by the liquid separating section 220, another construction can be considered, in addition to the distribution protrusion 204 shown in
In the above-described embodiment, the upper end surface and the front and rear surfaces of the liquid distributor 200 are formed to meet each other. Therefore, when liquid Lq flows on the front and rear surfaces after being ejected onto the upper end surface of the liquid distributor 200, the liquid Lq may not smoothly flow. In order to solve such a problem, the upper end surface of the liquid distributor can be formed in various shapes. That is, an inclined surface is formed between the upper surface and the front and rear surfaces of the liquid distributor such that liquid Lq ejected on the upper end surface of the liquid distributor can easily flow on the front and rear surfaces. Like a liquid distributor 200c shown in
In addition to the above-described modifications, the upper end surface of the liquid distributor 200c shown in
According to the invention, the apparatus and method for measuring ejection uniformity of slit nozzle can simply and precisely measure the widthwise ejection uniformity of photoresist to be ejected onto the substrate by the slit nozzle.
Through the measuring of the ejection uniformity, the space of the ejection port of the slit nozzle can be further easily adjusted. Therefore, a preparation time required for coating a substrate by using a slit coater and the resultant overall process time can be reduced.
Further, since photoresist does not need to be used for measuring widthwise ejection uniformity of photoresist, expensive photoresist is not wasted. Accordingly, it is possible to reduce a disposal cost of photoresist to be discarded.
Although a few embodiments of the present general inventive concept have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the appended claims and their equivalents.
Number | Date | Country | Kind |
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10-2006-0046139 | May 2006 | KR | national |