JP3973588B2 - Substrate processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a substrate processing method. More specifically, the present invention is particularly suitable for cleaning a substrate of a liquid crystal display device or a large photomask substrate used for manufacturing a liquid crystal display device, and the like (hereinafter referred to as a watermark) It is related with the washing | cleaning processing method of the board | substrate which can suppress effectively.
[0002]
[Prior art]
Conventionally, in manufacturing a photomask substrate such as an LSI photomask or a large-sized photomask for manufacturing a liquid crystal device, the substrate is exposed to various contaminations during the manufacturing process. Therefore, cleaning is performed during the manufacturing process or in the final product. ing. As this cleaning method, a dip type cleaning method has been used so far. FIG. 3 is an explanatory diagram showing an example of a conventional cleaning method using a dip method for a photomask substrate. In the conventional dip type cleaning method, as shown in FIG. 3, an apparatus in which a cleaning liquid tank, a rinsing tank and a drying tank are arranged in series is used. First, the photomask substrate is used as a cleaning liquid tank and a rinsing tank. After sequentially immersing in the vertical direction to perform washing treatment and rinsing treatment, drying treatment is performed in a drying tank. In addition, the kind of chemical | medical solution used in these tanks, the rinse, and the drying method are performed in various combinations.
[0003]
This method is suitable for high throughput because a plurality of substrates can be processed at a time when the mask size is small, such as an LSI photomask, but in the case of a large photomask as described above, There is a problem that each tank is enlarged and a large amount of chemicals are required. Furthermore, in recent years, photomasks for liquid crystal display devices are becoming larger and more accurate, and cleaning with a clean cleaning liquid in a large chemical tank requires a large amount of chemical liquid as described above. Actually, it has become difficult to perform clean cleaning using a dip method.
[0004]
Therefore, in recent years, a single wafer type spin cleaning method has attracted attention and has been developed. This single wafer spin cleaning method is a method in which a photomask substrate or the like is held on a rotating substrate holding member, and cleaning, rinsing, and drying are continuously performed while rotating. That is, first, while rotating the substrate held horizontally in the processing chamber, supplying a cleaning liquid as a processing liquid to the substrate, cleaning the substrate, rinsing with pure water, etc., and then the substrate at a high speed for a predetermined period. A drying step of rotating and drying. According to this method, compared to the above-described dip method, a series of processes can be performed in the same processing chamber, so that the apparatus can be miniaturized, cleaning liquid can be reduced, and cleaning time can be shortened. .
[0005]
However, the single-wafer spin cleaning method as described above has a problem that a watermark tends to occur on the substrate after spin drying. When this watermark is generated, the quality of the pattern formed on the substrate is inevitably deteriorated, so that it is necessary to perform re-cleaning. In order to prevent the generation of the watermark, various attempts have been made on the apparatus, for example, to devise an exhaust method during drying.
[0006]
More recently, liquid crystal display panels tend to be larger, and liquid crystal display panel substrates and photomask substrates for manufacturing liquid crystal display panels tend to be larger. That is, a liquid crystal display panel substrate or a photomask substrate for manufacturing a liquid crystal display panel has no standard in size and must handle various sizes of substrates. Under such circumstances, as the substrate holding means of the spin cleaning machine, for example, a regulation pin for regulating the side surface portion of the substrate and a support pin for supporting the lower surface of the substrate so that a plurality of types of substrates can be held. A substrate holding member whose position is variable is disclosed (for example, see Patent Document 1).
[0007]
However, in such a conventional substrate holding member, as shown in the schematic side view of FIG. 4, the support pins 14 a exist near the outer periphery of the substrate 15, and the support pins 14 b also exist near the center of the substrate 15. As a result, the chemical used for cleaning stays in the gap where the support pin and the support pin stand upright, and the chemical that has entered during high-speed rotation in the subsequent drying process scatters and reattaches to the back surface of the substrate. There is a problem in that a watermark that appears to be due to the cleaning liquid is formed on the back surface of the substrate. In FIG. 4, reference numeral 11 denotes a rotating shaft, 12 denotes a chuck, and 13 denotes a regulating pin for suppressing horizontal movement of the substrate 15.
[0008]
[Patent Document 1]
Japanese Patent Laid-Open No. 11-307501
[Problems to be solved by the invention]
The present invention solves such problems of the prior art, and is particularly suitable for cleaning a substrate of a liquid crystal display device and a large photomask substrate used for manufacturing a liquid crystal display device. An object of the present invention is to provide a substrate cleaning method capable of effectively suppressing the watermark generated on the substrate.
[0010]
[Means for Solving the Problems]
As a result of intensive studies to achieve the above object, the present inventor has a step of cleaning a substrate with a processing liquid and a subsequent step of drying the substrate while rotating the substrate. In this case, it is found that the object can be achieved by providing a swing-off process step for rotating the substrate at a rotation speed larger than the rotation speed of the substrate in the drying process between the two processes. The present invention has been completed.
[0011]
That is, the present invention
(1) A method for processing any substrate selected from a photomask substrate, a liquid crystal display substrate, a glass substrate, and a photomask blank substrate,
While rotating the substrate held horizontally in the processing chamber, a cleaning process for performing a chemical treatment on the substrate surface and then rinsing ,
In a substrate processing method having a drying step including a step of drying while rotating the substrate,
After the washing step and before the drying step,
Substrate and having a shaking process rotates the substrate rotation speed per unit time the drying engineering as good Ri even size and comb, the <br/> further comprising the step of applying a rinse treatment after shaking step Processing method,
(2) The substrate processing method according to (1), further including a step of scrub cleaning after the swing-off processing step and before the rinsing step.
(3) The substrate processing method according to (1) or (2), wherein the substrate is a rectangular substrate.
(4) The substrate processing method according to (1), (2) or (3), wherein the substrate is a photomask substrate ,
( 5) The substrate processing method according to any one of (1) to (4), wherein the number of rotations in the swing-off process step is 100 rpm or more larger than the number of rotations in the drying step.
(6) The substrate processing method according to any one of (1) to (5), wherein the rinse treatment is performed with pure water.
(7) The processing of the substrate is performed using a spin cleaning machine, and the spin cleaning machine has a substrate holding member that supports the lower surface of the substrate with a plurality of support pins. The substrate processing method of any one of these, and
(8) Provided is a photomask substrate manufacturing method, wherein the substrate is processed during the manufacturing process by the method described in any one of (1) to (7) above. .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
In the substrate processing method of the present invention, the drying step is performed between the step of supplying and cleaning the processing liquid onto the substrate held horizontally in the processing chamber and the step of drying the substrate while rotating the substrate thereafter. A swing-off process step is performed in which the substrate is rotated at a rotational speed greater than the rotational speed of the substrate.
[0013]
The substrate holding member for holding the substrate is not particularly limited, but the substrate can be cleaned while the back surface of the cleaned substrate is kept clean before cleaning the substrate surface. It is preferable to be a substrate holding member that holds the back surface of the substrate with a space therebetween, and in order to prevent the central portion of the substrate (main device region) from becoming dirty, it is possible to hold the substrate at as few locations as possible in the peripheral portion of the substrate. preferable. In addition, it is preferable that the surface of the substrate holding member that faces the back surface of the substrate be as flat as possible so as to minimize the gap into which the chemical solution enters. Further, the four sides of the substrate may be supported, or the corners may be supported. By supporting the corners, it is possible to reduce the area where the liquid adheres to the substrate when the liquid that has entered the gap such as the support pins jumps out.
[0014]
FIG. 1 shows a side view (a) showing one side of a substrate holding member used for carrying out the method of the present invention, and an example of the mounted substrate to be processed. It is a top view (b).
As shown in FIG. 1, the substrate holding member includes a restriction pin 2 that suppresses horizontal movement of the substrate 1, a support pin 3 that supports the back surface of the substrate 1, and these restriction pin 2 and support pin 3. The chuck 5 is fixed. And the board | substrate 1 is hold | maintained at the board | substrate holding member by the said limitation pin 2 and the support pin 3 at the board | substrate holding member.
[0015]
Moreover, there is no restriction | limiting in particular about the shape of a board | substrate, Any of square shape, such as a square and a rectangle, or circular shape may be sufficient. Also, the type of the substrate is not particularly limited. For a photomask substrate, a substrate for a semiconductor element, a substrate for a display device such as a liquid crystal display device, or a glass substrate or a substrate being manufactured, for example, a photomask blank Also, the method of the present invention can be applied. As the substrate to which the method of the present invention is applied, a rectangular substrate is preferable, and a photomask substrate is preferable. It is particularly suitable for application in the final cleaning of the product. Further, for a large-sized rectangular substrate (for example, 300 mm or more on one side), the adhesion area of the chemical solution scattered from the substrate holding member becomes large. Therefore, it is most advantageous to apply the method of the present invention to a large-sized rectangular substrate.
[0016]
Moreover, although it is thought that there is an effect if the rotation speed of the swing-off process is larger than that in the drying process, it is more effective that there is a difference as much as possible. Specifically, it is preferable that there is a difference in the number of rotations of 100 rpm or more, more preferably 200 rpm or more from the drying step. The time for the swing-off process needs to be a time for which the effect of the swing-off process can be obtained. The time varies depending on the number of rotations (the smaller the number of rotations, the smaller the time), but it is preferable to perform the time for 10 seconds or more.
[0017]
Although the rotation speed in a drying process is suitably determined by the dimension of a board | substrate, it is preferable to carry out in the range of 100-3000 rpm. In particular, in the case of a large substrate having a side of 300 mm or more, it is preferable to rotate at 100 to 400 rpm from the viewpoint of performing drying so as not to generate a watermark.
Moreover, the shaking-off process and the rinsing process that is usually performed thereafter may be performed after the problematic chemical solution process and before the drying process, and a physical cleaning process such as scrub cleaning or ultrasonic cleaning may be inserted therebetween. .
Next, an example of a preferred embodiment of the substrate processing method of the present invention will be described.
[0018]
First, the substrate to be processed is held on the substrate holding member so that the back surface is horizontal upward. Next, while the substrate is rotated, the back surface of the substrate is subjected to scrub cleaning using, for example, an alkaline cleaning solution, and then the substrate is rotated while supplying a rinsing liquid to perform a rinsing process, and further a spin drying process is performed. Apply.
[0019]
Next, the substrate is held on the substrate holding member in the same manner as described above so that the surface is horizontal upward. Next, while the substrate is rotated, the surface of the substrate is treated with a chemical solution using sulfuric acid or the like, and then the rinse solution is supplied while the substrate is rotated to perform the rinsing process. Thereafter, the substrate is rotated at a rotational speed that is preferably 100 rpm or higher, more preferably 200 rpm or higher than the rotational speed in the next drying step, and the swing-off process is performed.
After this swing-off process, scrub cleaning is further performed, followed by a rinse process, and finally a spin drying process. In this way, a cleaning substrate in which the generation of watermarks on the back surface is suppressed is obtained. Note that pure water is usually used as the rinse liquid.
[0020]
[Action]
According to the present invention, the chemical liquid collected in the gaps such as the support pins of the substrate holding member by the chemical solution cleaning is intentionally released from the gaps such as the support pins of the substrate holding member by rotating in advance at a rotation speed larger than that of spin drying. By allowing the chemical solution to jump out, the chemical solution that jumps out at the time of spin drying can be removed in advance from the gap between the substrate holding members. And the chemical | medical solution which jumped out by washing | cleaning after that can be washed away. As a result, even if high-speed rotation processing is performed in the drying process, the chemical solution that pops out in the drying process at a rotation speed lower than the rotation speed of the swing-off process can be reduced in the gaps such as the support pins of the substrate holding member. The chemical solution can be prevented from adhering to the back surface of the substrate.
[0021]
【Example】
EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by this example.
(1) Backside Cleaning / Drying Process A rectangular large photomask substrate (390 × 610 mm) having a light-shielding film pattern formed on a transparent substrate, as shown in FIG. It was held on a holding member. Specifically, the substrate 1 is held on the substrate holding member by the support pins 3 that support the back surface of the substrate 1 and the regulation pins 2 for suppressing the movement of the substrate 1 in the horizontal direction.
[0022]
Thus, the outer peripheral part of the substrate was held by the substrate holding member, and first, scrub cleaning was performed on the back surface of the substrate. Scrub cleaning was performed by scanning the brush on the substrate while supplying the alkaline cleaning liquid while rotating the substrate. Next, pure water was supplied while rotating the substrate to perform a rinsing treatment, and then spin drying was performed.
(2) Surface cleaning and drying step Next, the surface of the substrate was held in the same manner as in (1) above, and the surface of the substrate was cleaned. Specifically, cleaning was performed by the following method.
[0023]
First, while supplying sulfuric acid to the substrate, it was rotated at a rotation speed (for example, 20 rpm) so that the sulfuric acid spreads on the substrate, and then a chemical solution treatment was performed, followed by a rinsing treatment with pure water.
Thereafter, the substrate was rotated for 90 seconds at a rotation speed of 500 rpm (swing-off process).
Next, after scrub cleaning, a rinse treatment was performed.
Finally, a spin drying process was performed. The spin drying process was performed at 300 rpm for 300 seconds.
[0024]
As described above, by performing the swing-off process, it was possible to prevent the sulfuric acid that has entered the gaps of the substrate holding member from being scattered by the sulfuric acid treatment and adhering to the back surface of the substrate during drying.
In the same manner as in the comparative example, after performing the back surface cleaning / drying step, the front surface cleaning / drying step was performed in the same manner as in the above example, except that the swing-off process was not performed in the front surface cleaning / drying step. Went. As a result, as shown in FIG. 2, a watermark that was probably caused by the adhesion of sulfuric acid was confirmed by visual inspection near the corner of the back surface of the substrate.
[0025]
FIG. 2 is an explanatory diagram (a) showing the cause of the occurrence of a watermark at the corner on the back side of the substrate, and a plan view (b) of the back side of the substrate showing the state of occurrence of the watermark. As shown in FIG. 2 (a), the chemical solution 4 that has entered the gap surrounded by the substrate 1, the chuck 5, the regulating pin 2, and the support pin 3 scatters in the direction of the arrow during drying. As shown, the watermark 6 is generated at the corner on the back side of the substrate 1.
In this embodiment, the case where sulfuric acid cleaning is performed as the chemical solution treatment is illustrated, but the present invention is also effective for other chemical solutions such as an alkaline chemical solution.
[0026]
【The invention's effect】
According to the present invention, it is possible to suppress contamination of the back surface of the substrate during spin cleaning and drying of the substrate surface, and to prevent generation of a watermark or the like.
[Brief description of the drawings]
FIG. 1 is a side view showing an example of a state in which a substrate to be processed is mounted on a substrate holding member used for carrying out the method of the present invention, and shows an example of the mounted substrate to be processed. It is a top view (b).
FIGS. 2A and 2B are an explanatory diagram showing the cause of the occurrence of a watermark at the corner portion on the back surface of the substrate, and a plan view on the back surface side of the substrate showing an example of the state of occurrence of the watermark. FIGS.
FIG. 3 is an explanatory diagram showing an example of a conventional cleaning method using a dip method for a photomask substrate.
FIG. 4 is a schematic side view showing an example of a conventional substrate holding member.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Board | substrate 2 Restriction pin 3 which suppresses horizontal movement of a board | substrate 3 Support pin 4 which supports the back surface of a board | substrate 4 Chemical solution 5 Chuck 6 Water mark 11 Rotating shaft 12 Chuck 13 Restriction pin 14a for suppressing horizontal movement of a board | substrate 14b Support pins for supporting the back surface of the substrate 15

Claims (8)

A method for processing any substrate selected from a photomask substrate, a liquid crystal display substrate, a glass substrate and a photomask blank substrate,
While rotating the substrate held horizontally in the processing chamber, a cleaning process for performing a chemical treatment on the substrate surface and then rinsing ,
In a substrate processing method having a drying step including a step of drying while rotating the substrate,
After the washing step and before the drying step,
The substrate processing method characterized by comprising: a shake-off process the substrate is rotated a number of revolutions per unit time the drying engineering as also large comb Ri good, a step <br/> performing rinsing treatment after the shake-off process. The substrate processing method according to claim 1, further comprising a step of scrub cleaning after the swing-off processing step and before the rinsing step.   The substrate processing method according to claim 1, wherein the substrate is a rectangular substrate.   The substrate processing method according to claim 1, wherein the substrate is a photomask substrate.   5. The substrate processing method according to claim 1, wherein the rotation speed of the swing-off process step is 100 rpm or more larger than the rotation speed of the drying step. The substrate processing method according to claim 1, wherein each of the rinsing processes is performed with pure water. 7. The substrate according to claim 1, wherein the substrate is processed using a spin cleaning machine, and the spin cleaning machine includes a substrate holding member that supports the lower surface of the substrate with a plurality of support pins. The substrate processing method as described. A method of manufacturing a photomask substrate, wherein the substrate is processed during the manufacturing process by the method according to claim 1.

Images