JP5641994B2 - Coating apparatus and coating method - Google Patents

Description

  The present invention relates to a coating apparatus and a coating method, for example, a coating apparatus and a coating method for forming a coating film by coating a material on a coating target.

  There is a spiral coating method as a method for forming a circular film on a substrate in the field of semiconductors and the like. In this spiral coating method, a disk-shaped substrate is fixed on a circular rotary stage, the distance (gap) between the discharge surface of the coating nozzle and the substrate surface is maintained at a predetermined value, the rotary stage is rotated, and the flow rate is adjusted. While discharging the material from the coating nozzle with a controllable metering pump, the coating nozzle is moved linearly from the center of the substrate toward the outer periphery of the substrate, and a spiral coating pattern is drawn on the entire surface of the substrate. This is a method of forming (see, for example, Patent Document 1).

  In such a coating apparatus and a coating method using spiral coating, in order to control the film thickness shape of the edge portion, it is required to quickly reduce the residual pressure in the nozzle channel immediately before reaching the periphery of the edge.

JP 2010-279932 A

  The embodiment of the invention makes it possible to control the film thickness shape of the edge portion by quickly reducing the residual pressure in the nozzle flow path.

  The coating apparatus according to the embodiment includes a stage having a mounting surface on which a coating target is placed, a rotating mechanism that rotates the stage in a rotation direction along the mounting surface, and the coating target on the stage. An application nozzle that discharges and applies the material, a moving mechanism that relatively moves the stage and the application nozzle in a crossing direction intersecting the rotation direction along the placement surface, and a supply that supplies the material to the application nozzle A discharge section that discharges the material, a communication pipe that communicates the supply section, the application nozzle, and the discharge section, a switching mechanism that switches a flow of the material in the communication pipe, and discharge of the communication pipe A discharge height adjusting mechanism for adjusting the height of the side.

Schematic explanatory drawing which shows the structure of the coating device concerning one Embodiment. The flowchart which shows the control procedure of the coating device.

  Hereinafter, a coating apparatus and a coating method according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2. In the drawings, arrows X, Y, and Z indicate three directions orthogonal to each other. In each drawing, the configuration is appropriately enlarged, reduced, or omitted for explanation.

  The coating apparatus 1 is a stage 2 on which a wafer W as an application target is placed, a rotating mechanism 3 that rotates the stage 2 in a horizontal plane, and a material that is applied to the wafer W on the stage 2 by discharging material from the tip. A coating nozzle 4, a moving mechanism 5 that relatively moves the coating nozzle 4 and the stage 2 in the horizontal plane direction, a supply unit 7 that supplies the coating material to the coating nozzle 4, a discharge unit 8 that discharges the coating material, A communication tube 9 that forms a flow path that communicates these, an observation device 10 that observes the film surface of the coating film M on the wafer W, and a control unit 11 that controls each part are provided.

  The stage 2 is formed in a circular shape, for example, and is configured to be rotatable in a horizontal plane by the rotation mechanism 3. The stage 2 includes a suction mechanism that sucks the mounted wafer W, and the wafer W is fixed and held on the mounting surface 2a of the stage 2 by the suction mechanism. As this adsorption mechanism, for example, an air adsorption mechanism or the like is used.

  The rotation mechanism 3 is a mechanism that supports the stage 2 so as to be rotatable in a horizontal plane, and rotates the stage 2 in the horizontal plane by a drive source such as a motor with the stage center as a rotation center. As a result, the wafer W placed on the stage 2 rotates in a horizontal plane.

  The coating nozzle 4 is a nozzle that discharges a material to be the coating film M, and has a tip 4a. The coating nozzle 4 continuously discharges material from the tip 4 a by pressure, and applies the material to the wafer W on the stage 2.

  A supply unit 7 for supplying a material is connected to the application nozzle 4 via a supply-side flow path 9a of a communication tube 9 such as a tube or a pipe. The supply unit 7 includes a supply tank 7a for storing material, a supply pump 7b, a flow rate adjusting valve, and the like. The supply unit 7 is controlled by the control unit 11, and the material discharge amount from the application nozzle 4 is adjusted.

  Further, a discharge part 8 for discharging the material is connected to the application nozzle 4 via a discharge side flow path 9b of a communication pipe 9 such as a tube or a pipe. The discharge unit 8 includes a discharge tank 8a for storing material, a height adjusting mechanism 8b for adjusting the height of the discharge side port 9e of the communication pipe 9, and the like. The discharge unit 8 is controlled by the control unit 11, and the material is discharged from the coating nozzle 4.

  The height adjusting mechanism 8b moves, for example, the discharge tank 8a and the discharge side port 9e of the communication pipe 9 connected thereto in the Z-axis direction. By adjusting the position in the Z direction, the negative pressure of the flow path formed in the communication pipe 9 is adjusted.

  The communication pipe 9 is composed of, for example, a tube or a pipe, and communicates the coating nozzle 4 with the supply tank 7 a of the supply unit 7 and the discharge tank 8 a of the discharge unit 8. The communication pipe 9 is configured to include a supply-side flow path 9a, a discharge-side flow path 9b, and a common flow path 9d above the coating nozzle 4, and the supply-side and discharge-side flow paths are branched by a branching portion 9f. . A diaphragm type valve 9 c is provided in the discharge side flow path 9 b of the communication pipe 9. By the operation of the valve 9c, the discharge side channel 9b is opened and closed, and the material supply to the application nozzle 4 and the material discharge from the application nozzle 4 are switched. The end on the discharge side has a discharge side port 9e that opens into the discharge tank 8a. The discharge side opening 9e of the communication pipe 9 is disposed at a position lower than the tip 4a of the application nozzle 4. The height of the discharge side opening 9e is adjusted by the height adjusting mechanism 8b. In the application process, the material is supplied from the supply tank 7a to the application nozzle 4 through the supply side channel 9a and the common channel 9d by the operation of the supply pump 7b. When the application is completed, the material is discharged to the discharge tank 8a through the common flow path 9d and the discharge side flow path 9b due to the negative pressure in the communication pipe 9.

  The moving mechanism 5 supports the application nozzle 4 and moves it in the Z-axis direction, and the X-axis movement mechanism that supports the application nozzle 4 and moves it in the X-axis direction via the Z-axis movement mechanism 5a. 5b. The moving mechanism 5 positions the coating nozzle 4 above the stage 2 and moves the coating nozzle 4 relative to the stage 2. As the Z-axis moving mechanism 5a and the X-axis moving mechanism 5b, for example, a linear motor moving mechanism using a linear motor as a driving source, a feed screw moving mechanism using a motor as a driving source, or the like is used.

  The Z-axis moving mechanism 5a is provided with a distance measuring unit L such as a reflective laser sensor. The distance measuring unit L is moved in the X-axis direction by the X-axis moving mechanism 5b together with the Z-axis moving mechanism 5a, and measures the separation distance from the wafer W on the stage 2. Thereby, the surface roughness of the coated surface of the wafer W, that is, the height profile of the coated surface can be acquired.

  When spiral coating is performed by the coating apparatus 1, the coating nozzle 4 discharges material toward the wafer W on the rotating stage 2 while moving from the center of the wafer W toward the outer periphery in the X axis direction. The material is applied on the surface of the wafer W in a spiral shape.

  The observation apparatus 10 includes an observation image acquisition unit 10a that acquires an image of the coating film M of the wafer W placed on the stage 2, an image processing unit 10b that processes an image acquired by the observation image acquisition unit 10a, And a display unit 10c for displaying an image processed image and the like.

  The observation image acquisition unit 10a is provided above the stage 2 so that the entire surface of the wafer W on the stage 2 can be observed, and acquires an image of the entire surface of the coating film M on the wafer W. As the observation image acquisition unit 10a, for example, an imaging unit such as a CCD (Charge Coupled Device) camera or a sensor that detects reflected light by applying light to a material is used. For example, a liquid crystal display (LCD) or a cathode ray tube (CRT) is used as the display unit 10c.

  The image processing unit 10 b communicates with the control unit 11 and transmits an image processed image to the control unit 11. Based on the image transmitted from the image processing unit 10b and the relationship information between the film thickness and the shade (image density) stored in the storage unit, the control unit 11 generates omissions, foreign matter, the degree of film thickness variation, and the coating film. Determine the shape of M. Here, the image processing unit 10b is provided in the observation apparatus 10, but the present invention is not limited to this. For example, the image processing unit 10b may be provided in the control unit 11, and the control unit 11 may be provided in the image processing unit 10b. Alternatively, image processing may be performed.

  The control unit 11 includes a microcomputer that centrally controls each unit and a storage unit that stores various programs and various information. A memory, a hard disk drive (HDD), or the like is used as the storage unit. The control unit 11 controls the rotating mechanism 3 and the moving mechanism 5 based on various programs and various information (such as coating condition information), rotates the stage 2 on which the wafer W is placed, and controls the coating nozzle 4. While discharging the material from the tip 4a, the coating nozzle 4 is moved linearly from the center of the substrate (or the outer periphery of the substrate) toward the outer periphery of the substrate (or the center of the substrate) to draw a spiral coating locus on the entire surface of the substrate. Film formation is performed (spiral coating).

  Hereinafter, a film forming process (coating method) performed by the coating apparatus 1 will be described with reference to FIG. The control unit 11 of the coating apparatus 1 performs a film forming process based on various programs and various information (such as coating condition information).

  As shown in FIG. 2, first, initial operations such as return to origin and negative pressure control are performed (step S1). As negative pressure control, the control unit 11 operates the height adjusting mechanism 8b of the discharge unit 8 to set the discharge side port 9e to an appropriate height, thereby setting the negative pressure in the communication pipe 9 to an appropriate value. At this time, for example, based on the viscosity of the coating material, the discharge unit 8 is driven so as to obtain an appropriate negative pressure.

  Next, the wafer W, which is a substrate, is loaded onto the stage 2 by a transfer mechanism such as robot handling (step S2). The wafer W is fixed on the stage 2 by a suction mechanism. Thereafter, for example, using a height profile acquired before coating, a correction amount is calculated so that a vertical distance (gap) between the coating nozzle 4 and the coating surface of the wafer W becomes a set value, and the correction amount is calculated. Only the coating nozzle 4 is moved in the Z-axis direction by the Z-axis moving mechanism 5a. In this way, the gap between the coating nozzle 4 and the coating surface of the wafer W is adjusted to a desired gap (step S3).

  Next, a coating process is performed (step S4). In the coating process, the stage 2 is rotated by the rotating mechanism 3, and the wafer W on the stage 2 is rotating, so that the coating nozzle 4 moves from the origin position, which is the center of the wafer W, together with the Z-axis moving mechanism 5a to the X axis. The moving mechanism 5b moves in the X-axis direction, that is, from the center of the wafer W toward the outer periphery at a constant speed.

  At this time, the discharge side flow path 9b is closed and the supply pump 7b is operated to supply the coating material, whereby the coating nozzle 4 moves and continuously discharges the material from the tip 4a onto the coating surface of the wafer W. The material is applied in a spiral shape on the application surface (spiral application). Thereby, the coating film M is formed on the coating surface of the wafer W.

  Next, it is determined whether or not a predetermined position or a predetermined time just before the completion of application has been reached (step S5), and if it is determined that it is not the predetermined position or predetermined time immediately before the completion of application (step S5). NO), the coating process is continued.

  On the other hand, when it is determined that it is immediately before the application is completed (YES in step S5), the control unit 11 switches the open / close state of the diaphragm valve 9c and the supply by the supply pump 7b is stopped to stop the application. (Step S7). The position or time immediately before the completion of application is determined based on, for example, the viscosity of the material or the condition of the communication tube 9 and is set to be about several seconds before the completion of application or 1 to 2 mm before the application completion position.

  At this time, the discharge-side flow path 9b is opened and the supply pump 7b is stopped to stop the supply of the material and the application is stopped. Here, since the discharge side opening 9e of the communication pipe 9 forming the flow path is set lower than the tip 4a of the coating nozzle 4, a negative pressure is generated in the flow path due to the water head difference Δh. become. For this reason, the residual pressure of the coating material in the supply-side flow path is quickly reduced, and the desired edge of the coating film M can be formed.

  Thereafter, the coating nozzle 4 is raised by the Z-axis moving mechanism 5a (step S7). Then, the coating film M on the wafer W is observed, that is, inspected by the observation apparatus 10 (step S8), whether or not the coating film M is missing, whether there is a foreign substance in the coating film M, whether there is a film thickness abnormality, The shape or the like of the edge portion Me of the coating film M is monitored, and if necessary, a repair process for performing partial coating is performed, and the process ends.

  According to the present invention, the residual pressure in the supply flow path can be quickly reduced by arranging the discharge side port 9e lower than the tip 4a of the nozzle 4 to generate a negative pressure in the communication pipe 9. . Therefore, the edge shape can be easily controlled. Further, by adjusting the height of the discharge side port 9e with the height adjusting mechanism 8b, a negative pressure suitable for various conditions can be set, and the reduction speed of the residual pressure can be optimized.

  Further, since a diaphragm type valve is used as the switching mechanism, inconveniences such as air mixing and dust generation can be avoided as compared with, for example, a ball valve.

Although the embodiments of the present invention have been described, these embodiments are presented as examples, and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
[Appendix 1]
A stage having a placement surface on which the application object is placed;
A rotation mechanism for rotating the stage in a rotation direction along the placement surface;
An application nozzle for discharging and applying a material to the application object on the stage;
A moving mechanism for relatively moving the stage and the application nozzle along the placement surface in a crossing direction intersecting the rotation direction;
A supply unit for supplying a material to the application nozzle;
A discharge part for discharging the material;
A communication pipe communicating the supply unit, the application nozzle, and the discharge unit;
A switching mechanism for switching the material flow in the communication pipe;
A discharge height adjusting mechanism for adjusting the height of the discharge side of the communication pipe;
A coating apparatus comprising:
[Appendix 2]
While rotating the stage on which the coating object is placed by the rotating mechanism, the moving mechanism moves the stage and the coating nozzle relative to each other along the placement surface in the intersecting direction, and the coating nozzle The application apparatus according to [Appendix 1], further comprising: a controller that controls application of the material to the application object on the stage by controlling the switching mechanism and controlling the flow of the material. .
[Appendix 3]
The discharge side opening of the communication pipe is disposed at a position lower than the tip of the nozzle,
The switching mechanism is a diaphragm type valve provided in a flow path on the discharge side of the communication pipe,
The coating apparatus according to [Appendix 1] or [Appendix 2], wherein the supply state and the discharge state are switched by opening and closing the flow path.
[Appendix 4]
The control unit controls the discharge height adjusting mechanism to adjust a negative pressure generated by a difference between the height of the nozzle and the height of the opening on the discharge side of the communication pipe [Appendix 1] to [ The coating apparatus according to any one of Appendix 3].
[Appendix 5]
While rotating the stage on which the application object is placed, the application nozzle disposed opposite to the stage is relatively moved along the placement surface in the crossing direction, and the application nozzle on the stage is moved by the application nozzle. Applying the material,
The negative pressure of the flow path is adjusted by adjusting the height on the discharge side of the flow path that connects the supply nozzle, the discharge section that discharges the coating material, and the application nozzle. The coating method characterized by the above-mentioned.

W ... wafer, M ... coating film, L ... distance measuring part, .DELTA.h ... water head difference, Me ... edge part,
DESCRIPTION OF SYMBOLS 1 ... Coating device, 2 ... Stage, 2a ... Mounting surface, 3 ... Rotation mechanism, 4 ... Coating nozzle,
4a ... tip, 5 ... moving mechanism, 7 ... supply part, 7a ... supply tank, 7b ... supply pump,
DESCRIPTION OF SYMBOLS 8 ... Discharge part, 8a ... Discharge tank, 8b ... Height adjustment mechanism, 9 ... Communication pipe, 9a ... Supply side flow path, 9b ... Discharge side flow path, 9e ... Discharge side port, 9d ... Common flow path, 9f ... Branch part, 9c ... valve, 10 ... observation device, 11 ... control part.

Claims (5)

A stage having a placement surface on which the application object is placed;
A rotation mechanism for rotating the stage in a rotation direction along the placement surface;
An application nozzle for discharging and applying a material to the application object on the stage;
A moving mechanism for relatively moving the stage and the application nozzle along the placement surface in a crossing direction intersecting the rotation direction;
A supply unit for supplying a material to the application nozzle;
A discharge part for discharging the material;
A communication pipe communicating the supply unit, the application nozzle, and the discharge unit;
A switching mechanism for switching the material flow in the communication pipe;
A discharge height adjusting mechanism for adjusting the height of the discharge side of the communication pipe;
A coating apparatus comprising: While rotating the stage on which the coating object is placed by the rotating mechanism, the moving mechanism moves the stage and the coating nozzle relative to each other along the placement surface in the intersecting direction, and the coating nozzle The coating apparatus according to claim 1, further comprising: a control unit configured to control application of the material to an application target on the stage and to control the flow of the material by controlling the switching mechanism. The discharge side opening of the communication pipe is disposed at a position lower than the tip of the application nozzle,
The switching mechanism is a diaphragm type valve provided in a flow path on the discharge side of the communication pipe,
The coating apparatus according to claim 1, wherein the supply state and the discharge state are switched by opening and closing the flow path. According to claim 2, wherein the control unit to adjust the negative pressure generated by the height difference between the discharge side of the opening of the height and the communicating pipe of the coating nozzle by controlling the discharge height adjustment mechanism Coating device. While rotating the stage on which the application object is placed, the application nozzle disposed opposite to the stage is relatively moved along the placement surface in a crossing direction intersecting the rotation direction, and the application nozzle is used to move the application nozzle on the stage. While applying the material to the application object of
In the flow path for communicating the discharge portion for discharging said material and said coating nozzle and supply unit for supplying the material to the application nozzle, the high discharge side of the flow path with switches the flow of the material in the flow path The coating method characterized by adjusting negative pressure by adjusting thickness.

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