JP2008124280A - Coating method and coating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coating method and coating apparatus for coating an entire surface of a substrate with a coating solution in a substantially uniform thickness. <P>SOLUTION: The coating method of coating the surface of the substrate 1 with a coating solution 2 includes a solvent treatment process as a pretreatment process or an aftertreatment process for the coating process of applying the coating solution 2, in which a marginal part of the substrate 1 is selectively exposed to an atmosphere of a solvent 2a contained in the coating solution 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a coating method and a coating apparatus for coating a coating liquid on a substrate surface, and in particular, a coating method and a coating apparatus suitable for coating a coating liquid on a surface of a substrate provided with a recess (including a through hole). About.

  For example, as a coating method for applying a predetermined coating liquid (solvent) such as a resist material or an insulating material to a substrate such as a semiconductor wafer, a spin coating method is generally used. There is a problem that a large amount of coating solution (resist solution) is scattered from the peripheral portion of the substrate and is wasteful, and that the apparatus must be frequently cleaned as the coating solution is scattered.

  In addition, as a coating method, for example, the solution is caused to flow out from the tip of the nozzle by capillary action, and the solution is applied to the surface of the substrate. There is a method of applying a solution adhering to the application roll section onto a substrate (see, for example, Patent Documents 1 and 2). In such a coating method, since the coating liquid is not scattered, the coating liquid can be coated on the substrate without waste.

JP-A-6-343908 JP 7-47315 A

  However, for example, if a coating liquid is applied to a substrate having a recess (including a through hole) by such a coating method, there is a problem that “sinking” of the coating liquid occurs at the peripheral edge of the recess. . That is, there is a problem that the coating solution is retracted and a region where the coating solution is not attached is formed at the peripheral edge of the recess. Such a problem may also occur at the peripheral edge of the substrate, and is particularly likely to occur when a material having a relatively low viscosity is used.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a coating method and a coating apparatus capable of coating a coating liquid on the entire surface of a substrate with a substantially uniform thickness.

The present invention for solving the above-mentioned problems is a coating method for coating a coating liquid on a substrate surface, and an atmosphere of a solvent contained in the coating liquid as a pre-treatment process or a post-treatment process of the coating process for coating the coating liquid. And a solvent treatment step of selectively exposing the edge of the substrate.
In such a coating method of the present invention, sink marks of the coating solution at the edge of the substrate can be prevented or eliminated, and the coating solution can be applied to the entire surface of the substrate with a substantially uniform thickness. Further, since the edge portion of the substrate is selectively exposed to the solvent atmosphere, the coating liquid in other portions is not affected.

  Here, it is preferable that the solvent treatment step is performed as a pretreatment step and a posttreatment step of the coating step, respectively. Thereby, the sink of the coating liquid in the edge part of a board | substrate can be eliminated more reliably.

  In the case where the substrate is provided with a recess, it is preferable that a peripheral edge of the recess provided in the substrate is selectively exposed to the solvent atmosphere in the solvent treatment step. The sink of the coating liquid is likely to occur at the peripheral edge of the concave portion provided on the substrate (the edge of the substrate), but by performing the solvent treatment process, the sink of the coating liquid at the peripheral edge of the concave portion can be surely eliminated. Can do.

  Moreover, when the said coating liquid contains multiple types of solvent, it is preferable to selectively expose the edge part of the said board | substrate to the atmosphere of the 1 type of solvent contained in the said coating liquid in the said solvent treatment process. Thereby, the sink of a coating liquid can be prevented more reliably.

  Examples of the coating liquid include a photoresist. According to the present invention, the coating liquid that is a photoresist can be applied to the surface of the substrate with a uniform thickness.

Furthermore, the present invention is a coating apparatus that applies the coating liquid that has flowed out of the coating head onto the surface of the substrate held on the holding table, and the holding table can hold the substrate on the lower surface in the vertical direction, A solvent tank that is disposed so as to face the lower surface of the holding table in the vertical direction and stores a solvent contained in the coating solution, and an opening having a predetermined shape that is provided between the holding table and the solvent tank. And a mask member having the above.
In the coating apparatus of the present invention, a part of the substrate, for example, the edge of the substrate can be easily exposed to the solvent atmosphere stored in the solvent tank through the mask member. That is, the solvent vapor can be selectively attached to a part of the substrate. Thereby, the sink of the coating liquid generated at the edge of the substrate or the like can be prevented or eliminated, and the coating liquid can be applied to the entire surface of the substrate with a substantially uniform thickness. Further, since the edge portion of the substrate is selectively exposed to the solvent atmosphere, the coating liquid in other portions is not affected.

  Here, it is preferable to further include an opening / closing means provided between the solvent tank and the holding table and capable of opening and closing a space between the solvent tank and the holding table. By opening the opening / closing means only when the substrate is exposed to the solvent atmosphere, it is possible to prevent other portions of the substrate from being exposed to the solvent atmosphere.

  The mask member is preferably made of the same material as the substrate. Thereby, the temperature difference between the mask member and the substrate is reduced, and the vapor of the solvent can be better adhered to the substrate.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is a perspective view showing a schematic configuration of a slit coat type coating apparatus which is a coating apparatus according to an embodiment of the present invention, and FIG. 2 is a sectional view of an essential part thereof. The slit coating type coating apparatus 10 is an apparatus for forming a photoresist layer having a predetermined thickness by applying a photoresist liquid 2 as a coating liquid on the surface of a substrate 1. The coating head 30 provided on the substrate 1 side of the holding table 20, the storage means 40 for supplying the photoresist liquid 2 to the coating head 30, and the solvent tank 50 in which the predetermined solvent 2a contained in the photoresist liquid 2 is stored. And have. Although not shown, these components such as the holding table 20, the coating head 30, the storage means 40, and the solvent tank 50 are arranged in a predetermined sealed space.

  The substrate 1 to which the photoresist liquid 2 is applied by the slit coat type coating apparatus 10 is made of, for example, a silicon wafer in the present embodiment, and has a recess 1a from which at least a part in the thickness direction is removed. The concave portion 1a referred to here includes a through hole penetrating the substrate 1 in the thickness direction in addition to a groove from which a part of the substrate 1 in the thickness direction is removed. The substrate 1 exemplified in this embodiment is provided with a recess 1a that is a through hole penetrating in the thickness direction.

  The holding table 20 holds the substrate 1 on the lower surface in the vertical direction so that the surface thereof faces downward in the vertical direction. The method for holding the substrate 1 by the holding table 20 is not particularly limited, and examples thereof include a method using suction such as a vacuum pump. The holding table 20 is provided so as to be linearly reciprocable along the surface direction of the substrate 1 by a table driving means such as a driving motor (not shown).

  The coating head 30 has a slit-like nozzle opening 31 that opens upward in the vertical direction and flows out the photoresist solution 2 supplied from the storage means 40, and a liquid reservoir 32 that communicates with the nozzle opening 31. Further, the coating head 30 is held by a device body (not shown) so as to be movable in the vertical direction, and the distance between the tip of the coating head 30 and the surface of the substrate 1 is, for example, the kinematic viscosity of the photoresist liquid 2, the photoresist The liquid 2 is appropriately adjusted in consideration of various conditions such as wettability to the substrate 1.

  The storage unit 40 includes a storage tank 41 that holds the photoresist solution 2, and a supply pipe 42 that has one end connected to the coating head 30 and the other end connected to the storage tank 41. The stored photoresist solution 2 is supplied to the coating head 30 via the supply pipe 42.

  When the photoresist liquid 2 is supplied from the storage tank 41 of the storage means 40 to the coating head 30 through the supply pipe 42 and the photoresist liquid 2 is filled in the solution pool 32 of the coating head 30, the liquid pool portion. The photoresist liquid 2 in 32 rises to the tip of the nozzle opening 31 by capillary action. As a result, the slit-like nozzle opening 31 is uniformly filled with the photoresist liquid 2. Then, from this state, the coating head 30 is raised and the photoresist liquid 2 protruding from the nozzle opening 31 is brought into contact with the surface of the substrate 1. In this state, the holding table 20 and the coating head 30 are moved in the surface direction of the substrate 1. Move relative. For example, in this embodiment, the holding table 20 is linearly moved in the surface direction of the substrate 1 with the coating head 30 fixed. As a result, the photoresist liquid 2 continuously flows out from the nozzle opening 31 and is applied to the surface of the substrate 1, and a photoresist layer having a predetermined thickness is formed on the surface of the substrate 1.

  Further, on the substrate 1 side of the holding table 20, a coating head 30 and a storage unit 40 are provided, and in the present invention, a solvent tank 50 in which a predetermined solvent 2 a contained in the photoresist liquid 2 is stored is provided. Yes. In this embodiment, the solvent tank 50 is arranged on the rear side of the coating head 30 in the traveling direction of the holding table 20. The solvent tank 50 is open on the surface facing the substrate 1, that is, on the upper side in the vertical direction, and the solvent 2 a contained in the photoresist solution 2 is held therein. The solvent 2a stored in the solvent tank 50 is the solvent when the photoresist liquid 2 is composed of only one kind of solvent, and when the photoresist liquid 2 contains a plurality of kinds of solvents, these plural kinds of solvents are used. At least one of these solvents. In particular, when the photoresist liquid 2 contains a plurality of types of solvents, it is preferable to use only one of these types of solvents. Furthermore, it is desirable to use a solvent having low volatility. In addition, an opening / closing means 70 that can open and close a space between the solvent tank 50 and the holding table 20 is provided between the solvent tank 50 and the holding table 20. In the present embodiment, an opening / closing means 70 capable of opening and closing the opening is provided at the opening of the solvent tank 50, the solvent tank 50 is opened at a predetermined timing, and the substrate 1 is placed in an atmosphere of solvent 2a (solvent The atmosphere of the solvent 2a evaporated from the tank 50 can be exposed.

  In the space between the solvent tank 50 and the substrate 1, for example, a mask member 60 formed of a silicon substrate and having an opening 61 having a predetermined shape is disposed. The mask member 60 is arranged so that the distance from the substrate 1 is about several mm, for example, about 1 to 2 mm. Thereby, a part of the substrate 1 is selectively exposed to the atmosphere of the solvent 2a. The mask member 60 according to the present embodiment is provided with an opening 61 having a shape corresponding to the peripheral edge of the recess 1a of the substrate 1, and the peripheral edge of the recess 1a provided in the substrate 1 is selectively used as the solvent 2a. Be exposed to the atmosphere. Then, by exposing the surface of the substrate 1 to the atmosphere of the solvent 2a as described in detail below, sink marks of the photoresist liquid 2 applied to the substrate 1 can be eliminated.

  Hereinafter, the coating method of the present invention will be described in detail. FIG. 3 is a schematic view showing the operation of a slit coat type coating apparatus which is an example of a coating apparatus.

  First, as shown in FIG. 3A, the substrate 1 is fixed to the lower surface of the holding table 20, the coating head 30 is raised, and the distance between the surface of the substrate 1 and the tip surface of the nozzle opening 31 of the coating head 30 is set. Adjust so that it is at a predetermined interval. Specifically, the coating head 30 is raised so that the tip of the photoresist liquid 2 protruding from the nozzle opening 31 is positioned slightly higher than the position of the surface of the substrate 1. In this embodiment, the distance between the coating head 30 and the substrate 1 is adjusted by moving the coating head 30. Of course, the coating head 30 is fixed and the holding table 20 is moved. It may be.

  Next, as shown in FIG. 3B, the holding table 20 is linearly moved in the surface direction of the substrate 1, that is, in the horizontal direction by a table driving means (not shown), for example, at a speed of about 5 m / s. The photoresist liquid 2 protruding from the nozzle opening 31 of the coating head 30 comes into contact with the surface of the substrate 1 and the coating of the photoresist liquid 2 is started.

  After the application of the photoresist liquid 2 to the substrate 1 is started in this way, the photoresist liquid 2 is continuously transferred from the nozzle opening 31 by further moving the holding table 20 as shown in FIG. The photoresist liquid 2 is applied to the surface of the substrate 1 with a predetermined thickness. Note that while the photoresist solution 2 is applied to the substrate 1 in this way, the opening of the solvent tank 50 is closed by the opening / closing means 70.

  Here, at the stage where the coating process for applying the photoresist liquid 2 to the substrate 1 is completed in this way, as shown in FIG. 4, the photoresist liquid 2 is formed in a region corresponding to the peripheral edge of the concave portion 1 a of the substrate 1. A sink will occur. That is, the photoresist solution 2 attached to the peripheral portion of the concave portion 1a of the substrate 1 recedes, and a region where the photoresist solution 2 is not attached to the peripheral portion of the concave portion 1a is formed. Further, in the vicinity of the end portion of the photoresist solution 2 where sink marks have occurred, a portion having a thickness that gradually decreases toward the outside is formed. That is, the taper angle θ1 of the end face of the photoresist liquid 2 becomes considerably small.

  For this reason, in the present invention, after the coating step, a solvent treatment step of selectively exposing the peripheral portion of the concave portion 1a of the substrate 1 to the atmosphere of the solvent 2a is performed. Specifically, after applying the photoresist liquid 2 to the substrate 1 as described above, as shown in FIG. 5, the peripheral portion of the concave portion 1a of the substrate 1 and the opening 61 of the mask member 60 are opposed to each other. Then, the substrate 1 and the mask member 60 are aligned, and the opening / closing means 70 is opened in this state to open the solvent tank 50. Thereby, only the peripheral part of the recessed part 1a of the board | substrate 1 is selectively exposed to the atmosphere of the solvent 2a. That is, the vapor of the solvent 2 a flowing out from the solvent tank 50 passes through the opening 61 of the mask member 60 and selectively adheres to the peripheral edge of the recess 1 a of the substrate 1. At this time, it is preferable that the vicinity of the end portion of the photoresist solution 2 as well as the region where the photoresist solution 2 of the substrate 1 is not attached is exposed to the atmosphere of the solvent 2a.

  By carrying out the solvent treatment step in this way, the vapor of the solvent 2a adheres to the region of the substrate 1 where the photoresist solution 2 is not applied, and the wettability of this region is improved. Further, the thickness of the vicinity of the end portion of the photoresist solution 2 slightly increases due to the solvent 2a adhering to the end portion of the photoresist solution 2. With these actions, the photoresist liquid 2 is pulled toward the concave portion 1 a of the substrate 1. For example, when the thickness of the photoresist solution 2 is increased to about 100 nm to 500 nm, the photoresist solution 2 is pulled to the concave portion 1 a side of the substrate 1 by about 100 μm at the maximum. Thereby, sink marks of the photoresist liquid 2 are eliminated, and as shown in FIG. 6, the photoresist liquid 2 is applied to the entire surface including the vicinity of the end face of the concave portion 1a of the substrate 1 with a substantially uniform thickness. Further, the taper angle θ2 of the end surface of the photoresist liquid 2 is increased as compared with the taper angle θ1 before the substrate 1 is exposed to the solvent 2a.

  Further, as in the slit coat type coating apparatus 10 described above, the coating apparatus is exposed to the atmosphere of the solvent 2a through the mask member 60, so that the coating apparatus can be used even when the shape of the substrate 1 is changed. This can be handled relatively easily by changing only the mask member 60 without significantly remodeling 10. Further, the mask member 60 also serves to prevent foreign matters from adhering to the substrate 1. In the present embodiment, the mask member 60 is formed of a silicon substrate that is the same material as the substrate 1 and has a small temperature difference from the substrate 1, so that the solvent 2 a can be easily adhered to the substrate 1. Of course, the mask member 60 may be formed of other materials. Further, when the substrate 1 is exposed to the solvent 2a atmosphere through the mask member 60, the amount of the solvent 2a attached to the substrate 1 is adjusted by adjusting the temperature by heating or cooling the mask member 60. Also good.

  After carrying out the solvent treatment step in this way, the holding table 20 is moved to a predetermined position after the opening / closing means 70 is closed and the solvent tank 50 is sealed. Then, for example, the photoresist liquid 2 is dried by blowing nitrogen gas on the photoresist liquid 2. Thereby, the photoresist layer is satisfactorily formed with a substantially uniform thickness on the surface of the substrate 1. Note that the solvent tank 50 is kept open when the holding table 20 is moved because the area other than the peripheral edge of the recess 1a of the substrate 1 is exposed to the atmosphere of the solvent 2a, for example, the thickness of the photoresist liquid 2 This is not preferable because there is a possibility that a problem such as a change in height may occur.

  Although not shown, for example, a metal layer made of gold (Au) or the like is provided on the substrate 1, and the photoresist layer is used when patterning the metal layer to form a wiring pattern or the like. . As described above, the photoresist layer is formed with a substantially uniform thickness, so that the metal layer can be well patterned with high accuracy.

  Although one embodiment of the present invention has been described above, of course, the present invention is not limited to such an embodiment. For example, in this embodiment, after the coating process of applying the photoresist liquid 2 to the substrate 1 by the coating head 30, a solvent processing process is performed in which the peripheral edge of the recess 1a of the substrate 1 is selectively exposed to the atmosphere of the solvent 2a. However, the application process may be performed after the solvent treatment process. That is, the peripheral edge of the concave portion 1 a of the substrate 1 is selectively exposed to the atmosphere of the solvent 2 a so that the solvent 2 a is attached to the surface of the substrate 1 in advance, and then the photoresist liquid 2 is applied to the substrate 1 by the coating head 30. It may be. In this case, when the photoresist solution 2 is applied, the wettability of the peripheral portion of the concave portion 1a of the substrate 1 is improved as compared with other portions, so that the sink of the photoresist solution 2 is prevented from occurring. Can do. Of course, the solvent treatment step may be performed before and after the coating step, respectively. Thereby, sink marks of the photoresist liquid 2 can be more reliably eliminated.

  In the present embodiment, the example in which the sink of the photoresist liquid 2 in the peripheral edge portion of the recess 1 a provided in the substrate 1 is prevented has been described. However, according to the present invention, the substrate 1 such as the outer peripheral portion of the substrate 1 is Sinking of the photoresist liquid 2 generated at the edge can be prevented. Furthermore, in the present invention, for example, when the film thickness of the photoresist solution 2 applied to the substrate 1 is partially reduced due to the viscosity of the photoresist solution 2 or volatilization of the solvent, the film is formed by the above-described method. By selectively exposing the thinned portion to the atmosphere of the solvent 2a, the film thickness of the photoresist solution 2 can be made uniform.

  Furthermore, it goes without saying that the present invention can also be applied to the case where a coating solution other than the photoresist solution is applied to the substrate. Moreover, this invention is not limited to the slit coat type coating apparatus mentioned above, For example, it can apply also to other coating apparatuses, such as a roll coating apparatus.

It is a perspective view which shows schematic structure of the coating device which concerns on Embodiment 1 of this invention. It is principal part sectional drawing of the coating device which concerns on Embodiment 1 of this invention. It is the schematic which shows the coating method which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the state of the coating liquid after an application | coating process. It is the schematic which shows the coating method which concerns on Embodiment 1 of this invention. It is a schematic sectional drawing which shows the state of the coating liquid after a solvent processing process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Substrate, 1a Concave part, 2 Photoresist liquid, 10 Slit coat type coating device, 20 Holding table, 30 Coating head, 31 Nozzle opening, 40 Storage means, 50 Solvent tank, 60 Mask member, 70 Opening / closing means

Claims (8)

  An application method for applying a coating liquid to a substrate surface, wherein an edge of the substrate is selectively applied to an atmosphere of a solvent contained in the coating liquid as a pre-processing step or a post-processing step of the coating step of applying the coating solution. A coating method characterized by carrying out a solvent treatment step exposed to water.   The coating method according to claim 1, wherein the solvent treatment step is performed as a pretreatment step and a posttreatment step of the coating step.   3. The coating method according to claim 1, wherein in the solvent treatment step, a peripheral edge portion of a recess provided in the substrate is selectively exposed to the solvent atmosphere.   The edge part of the said board | substrate is selectively exposed to the atmosphere of the kind of solvent contained in the said coating liquid in the said solvent treatment process, when the said coating liquid contains multiple types of solvent. The coating method according to any one of the above.   The coating method according to claim 1, wherein the coating solution is a photoresist. A coating apparatus that applies a coating liquid that has flowed out of a coating head onto the surface of a substrate held on a holding table,
A solvent tank in which the holding table can hold the substrate on a lower surface in the vertical direction, and is disposed so as to face the lower surface in the vertical direction of the holding table, and stores a solvent contained in the coating liquid; A coating apparatus comprising a mask member provided between the holding table and the solvent tank and having an opening of a predetermined shape.   The coating apparatus according to claim 6, further comprising an opening / closing means provided between the solvent tank and the holding table and capable of opening and closing a space between the solvent tank and the holding table.   The coating apparatus according to claim 6 or 7, wherein the mask member is formed of the same material as the substrate.

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