JP2005111349A - Apparatus for film formation and method of forming film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for film formation which can be widely used under any conditions and eliminates thick parts of film produced on edges of the film during application of a liquid to arbitrary parts of the film with an application head having slit-shaped openings so as to extend the effective area of the film. <P>SOLUTION: The apparatus is for application of a liquid onto a target board and comprises a first means of specifying geometrical information on the board, including the shape of the surface to be applied, the shape of outer periphery, sizes, etc., a second means of specifying an application auxiliary member in response to the specified geometrical information, a third means of engaging the specified auxiliary member in the board, a fourth means of applying the liquid onto the board integrated with the auxiliary member, a fifth means of drying and solidifying the liquid film applied onto the board and a sixth means of separating the auxiliary member from the board with the liquid film dried and solidified. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a coating film forming method and apparatus for forming a thin film by applying a liquid material on an arbitrary substrate.

  When a liquid material is applied to an area on an arbitrary substrate, if the volatile component contained in the liquid material is left in a natural state or is volatilized at high speed by applying heat energy or the like, the thickness is increased at the end of the application area. The phenomenon of becoming a film (hereinafter referred to as a thick film edge) may appear. When the thickness deviates from the allowable range, the inside of the thick film portion must be an effective region, and the use efficiency of the coated substrate and the coated material is deteriorated, resulting in an increase in process cost. .

  In addition, when a photolitho resist material or the like is applied, and then exposure and development using a mask is performed, if the thickness of the thick film portion and the flat portion is large, exposure with a required accuracy may not be realized. In such a case, a process such as cutting the thick film portion may be added, and the process cost will similarly increase. Measures to prevent this thick film edge from occurring include: “Multiple coating”, “Supplying auxiliary liquid with low viscosity to the edge”, “Applying electric field to the edge”, “ There is an example in which "sonic wave application" or the like is applied.

JP 2002-204996 A

  In the thick film edge phenomenon, the volatilization rate of the volatile component contained in the coating material is large in the entire coating region, particularly at the edge, so the surface tension increases in the middle and the surrounding materials gather there. It is known to occur because of this. When the coating film thickness per one time is reduced, the difference in volatilization rate between the central part and the end part becomes small, and it becomes difficult to become the thick film end part. Therefore, if a necessary film thickness is realized by applying a plurality of times, the effective area of the film thickness can be expanded. However, this method has a problem that the tact time is naturally increased.

  When applying, a method of preventing thickening by supplying an auxiliary liquid having a low viscosity to the end may be considered, which has the advantage of reducing the in-plane flow due to the surface tension gradient. It is necessary to select an auxiliary solution that does not affect the membrane quality itself. In addition, there is a method of applying an electric field or an ultrasonic wave as a method of not increasing the surface tension even when the volatilization progresses. However, an apparatus for generating an electric field or an ultrasonic wave is necessary, and the process cost increases.

  As described above, various means for solving the thick film edge phenomenon are considered, but there are methods that cannot be used depending on the target coating substrate and coating material, and there are also secondary and tertiary methods. There are also ways in which process costs are increased due to the need for processes.

  The present invention has been made in view of the above problems, and the intended process can be used universally in any situation, and the slit-shaped opening can be formed by a method that suppresses the process cost as much as possible. A coating film forming apparatus and a coating film forming method capable of eliminating a thick film portion at an end portion of a coating region that appears when a liquid material is applied to an arbitrary region by a coating head having the coating head and expanding an effective region of the film forming unit It is to provide.

  The components volatilized from the applied material diffuse into the atmosphere, but there is only a degree of freedom in the normal direction in the central part of the application area, while it is widely spread outside the area near the edge of the application area. In order to have a degree of freedom, it is essential that the diffusion rate at the end is increased in a static state where there is no forced flow in the atmosphere. Therefore, the volatilization rate at the edge of the application region increases.

  On the other hand, as the volatilization progresses (the solid content concentration increases), the surface tension increases, so the end of the region where the volatilization rate is large becomes larger than the entire region, and a flow that collects in that region is generated. To do. This is the cause of the thick film edge phenomenon.

  That is, if the entire region including the coating region end can be volatilized uniformly, surface tension distribution does not occur in the middle of the region, and the thick film end phenomenon can be eliminated.

  In addition, if the liquid is applied to an area wider than the effective application area, there is no problem even if a thick film portion is generated. Further, when the entire coated surface of the coated substrate is an effective area, a device for expanding the coated area outside the surface can be considered (see Japanese Patent Application Laid-Open No. 2002-204996).

  However, when the coated substrate is a Si wafer or the like, the outer peripheral portion is often not subjected to secondary processing in the manufacturing process, and the variation in diameter is large. Therefore, since a member having a through hole with a diameter sufficiently larger than the assumed wafer diameter or a concave portion is arranged, when the gap with the coating substrate is large, liquid enters the gap, The end of the coated substrate may be a thick film.

  In order to solve the above-described problems, the present invention provides a coating film forming apparatus for applying a liquid on a substrate to be coated, means for specifying geometric information (coating surface shape, outer peripheral shape, dimensions, etc.) of the substrate to be coated. A means for specifying a coating auxiliary member according to the specified geometric shape information, a means for fitting the specified coating auxiliary member to the application target substrate, and a liquid on the application target substrate integrated with the coating auxiliary member. Means for applying, further means for drying and solidifying the liquid film applied on the substrate to be applied integral with the application auxiliary member, and means for separating the application auxiliary member from the application target member having the liquid film dried and solidified. It is characterized by comprising.

  In this case, the application assisting member has a hole or a recess having a shape similar to the outer peripheral shape of the application target substrate, and further has a surface that maintains continuity with the application target surface when the application target substrate is fitted. There is a feature that is.

  Further, the present invention specifies the geometric information (coating surface shape, outer peripheral shape, dimensions, etc.) of the substrate to be coated as a method of forming a coating film using the coating film forming apparatus, and according to the geometric shape information. After specifying the application auxiliary member, fitting the application auxiliary member to the application target substrate and forming the entire surface so as to maintain the continuity of the application surface of the application target substrate, applying the liquid, and further applying the application The liquid film applied on the substrate to be coated is dried and solidified while being integrated with the member, and the coating auxiliary member is separated from the member to be coated after the liquid film is dried and solidified.

  According to the present invention, when a thin film is formed by applying a liquid material to an arbitrary area by an application head having a slit-like opening, the degree of freedom in the diffusion direction of volatile components can be made uniform over the entire application area. In addition, the effective region can be expanded while suppressing the occurrence of the thick film edge phenomenon. As a result, it is possible to form a coating film with high film thickness accuracy with a minimum material cost.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

<Embodiment 1>
A schematic configuration of the entire coating film forming apparatus according to the present embodiment is shown in FIG.

  The coating film forming apparatus shown in FIG. 1 moves the coating head having the slit-shaped opening and the substrate to be coated from the coating head opening while relatively moving the coating head and the substrate to be coated perpendicular to the longitudinal direction of the coating head opening. An apparatus comprising: an application unit that performs application by discharging a liquid; and a drying unit that applies energy to the liquid applied to the application substrate to dry and solidify the device, and specifies the geometric shape information of the application substrate. And means for fitting an optimum application assisting member corresponding to the specified geometric information.

  FIG. 2 is a sectional view of only the coating device and the drying device in the entire apparatus shown in FIG. 1 as viewed from the relative movement direction of the coating head 12 and the coating substrate 9. Further, FIG. 8 shows a schematic configuration diagram of a coating head which is one of the components of the apparatus.

  First, the coating substrate 9 is arranged on the stage 31 and the geometric shape information is specified by the geometric shape recognition unit 32. The coated substrate in the present embodiment is a circular flat plate typified by a Si wafer or the like, and the average diameter and roundness are geometric shape information. As a method of recognizing the geometric shape of the coated substrate, the entire coated substrate is captured as image information by a CCD camera or the like (FIG. 11), and the information is calculated as a number of average diameter and roundness by software processing.

  Next, the coating substrate is moved to the fitting operation stage 34 by the robot arm 35 or the like (FIG. 9), and then the coating assisting member 1 specified based on the geometric information of the coating substrate is taken out from the stocker 33 (FIG. 12). Then, the coated substrate is fitted on the fitting stage 34 (FIG. 10).

  In this embodiment, assuming that the variation of the average diameter of the coated substrate is ± 0.5 mm with respect to the reference diameter of 150 mm, the coating auxiliary member for fitting the coated substrate in that range has a different inner diameter by 20 μm. Prepared. And based on the average diameter obtained by the geometric shape recognition part 32, and the value of roundness, the minimum internal diameter which can be fitted was specified, and the coating auxiliary member which has a hole of the internal diameter was specified.

  Thereafter, the coating substrate fitted with the coating auxiliary member is moved onto the coating stage 15 to start coating. The coating liquid is supplied from the coating liquid tank 25 to the coating head 12 by the metering pump 21. The metering pump 21 is a positive displacement pump such as a gear pump, a diaphragm pump, or a syringe pump. As another application liquid supply mechanism of the pump, a type in which the application liquid is pushed out by putting the application liquid tank 25 in a pressure vessel and supplying pressurized air to the pressure vessel by a pressure pump is also possible. .

  A filter 22 and an on-off valve 23 are provided in the path of the pipe 24 from the coating liquid tank 25 to the metering pump 21 as necessary. The coating liquid supplied to the coating head 12 from this coating liquid supply mechanism flows into the head from the inlet 7 at the center in the longitudinal direction of the side surface of the head 12, passes through the manifold 11, and then passes through the slit 6. It reaches the discharge port 5. Further, when discharged from the discharge port 5 to the outside of the head 12, the coating liquid forms beads and gradually increases, and eventually reaches the coating substrate 9.

  Thereafter, when the relative movement between the coating substrate 9 and the coating head 12 is started, the coating liquid supplied from the coating head 12 is deposited on the coating substrate 9 via the beads outside the discharge port 5 of the coating head 12. .

  Then, after applying to a predetermined area on the coating substrate 9, the supply of the coating liquid is stopped and the “coating step” is completed, and then the airflow generator 4 is moved to a position facing the coating substrate, and the surface of the coating substrate 9 An air flow is generated in a direction away from the normal direction. At this time, the air velocity and the air volume of the air current are controlled according to the situation. By generating a uniform updraft on the coated substrate, it is possible to realize a more uniform solvent volatilization distribution and to reduce the process cost by shortening the drying time.

  FIG. 3 shows this state in a longitudinal section of the coating head 12, and FIG. 4 shows a view seen from the normal direction of the coating substrate 9.

  In this Embodiment, the conveyance part 5 of the coating head 12 and the conveyance apparatus 2 of the airflow generation device 4 are arrange | positioned on the opposite side on both sides of the coating substrate 9 (refer FIG. 5-1 and FIG. 5-2). . Next, in order to shift to a “drying step” for removing volatile components such as a solvent, the coated substrate is moved to the drying unit 14 by the transport device 2 together with the airflow generator 4. This is shown in FIG. Then, the coating substrate 9 is heated by the heater 3 of the drying unit 14, and a volatile component such as a solvent contained in the coating material is controlled according to the situation by the air flow control function of the air flow generation device 4 while controlling the air speed and air volume. To dry and solidify. FIG. 7 is an image of the airflow generated by the airflow generation device 4 in the present embodiment, in which an airflow leaving the normal direction of the surface of the coating substrate 9 is depicted.

  As a result of performing the coating using the coating apparatus and the coating method according to the present embodiment described above, the inflow of the coating liquid into the gap between the coating auxiliary member and the coating substrate could be suppressed. The surface of the film was kept flat, and the uneven volatilization rate of the solvent could be suppressed. As a result, the film thickness distribution before applying the coating apparatus and the coating method according to the present embodiment was shown in FIG. 13, whereas the thick film edge phenomenon as shown in FIG. 14 (average value of measurement samples). The film thickness distribution in which the occurrence of the occurrence of the film was suppressed was obtained, and the effective coating area could be greatly expanded.

  The application conditions for obtaining this data are as follows.

Application speed: 5mm / sec
Discharge flow rate: 0.5 mm ³ / sec (per unit length in the coating head longitudinal direction)
Head-substrate distance: 130 μm
Coating solution viscosity: 4 Pa · sec
Coating liquid solid content concentration: 18.6 wt%
Airflow generator conditions: 50 mm / sec (exhaust)
Number of measurement samples: 100 (number of substrates) x 5 (measurement points)
<Embodiment 2>
FIG. 15 shows a schematic configuration of the entire coating film forming apparatus according to the second embodiment of the present invention.

  FIG. 15 shows a cross-sectional view of the coated substrate 9 viewed from the normal direction. The geometric shape of the coated substrate is recognized, the coating auxiliary member is specified based on the information, and the two are further fitted together. This embodiment is the same as the first embodiment, but the present embodiment is different in that the outer shape of the coating assisting member is circular and that a spin coater (FIG. 16) is used as the liquid coating device.

  Thus, also in the present embodiment, reduction of the thick film edge phenomenon is realized as in the first embodiment.

<Embodiment 3>
FIG. 17 shows a schematic configuration of the entire coating film forming apparatus according to Embodiment 3 of the present invention.

  FIG. 17 also shows a cross-sectional view of the coated substrate 9 viewed from the normal direction. Similar to the second embodiment, the geometric shape of the coated substrate is recognized, and the coating auxiliary member is specified based on the information. Although it is the same as that of Embodiment 1 until the two are fitted, in this embodiment, the application target surface of the application substrate is a curved surface, and the surface shape of the application assisting member is also corresponding to this. The point which becomes a phase so that it may become continuous with an application symmetrical surface after fitting, and the point which uses a dip coat device (Drawing 18) as a liquid application device differ from other embodiments.

  In addition, the geometric shape recognition apparatus is different from the other embodiments in that it has a function of recognizing the curved surface of the application target surface.

  Thus, also in the present embodiment, reduction of the thick film edge phenomenon is realized as in the first embodiment.

  The present invention is applicable to a coating film forming method and apparatus for forming a thin film by applying a liquid material on an arbitrary substrate.

BRIEF DESCRIPTION OF THE DRAWINGS It is a general view (sectional drawing seen from the normal line direction of the coating substrate) of the coating film forming apparatus which concerns on Embodiment 1 of this invention. It is sectional drawing (cross-sectional view of a coating head relative movement direction) of a coating device & drying apparatus. It is a motion (cross-sectional view of a coating head relative movement direction) of the airflow generation device in Embodiment 1 of the present invention. It is a motion (sectional drawing seen from the normal line direction of the application | coating board | substrate) of the airflow generation apparatus in Embodiment 1 of this invention. It is a figure which shows the coating head part of the coating film forming apparatus which concerns on Embodiment 1 of this invention. It is a figure which shows the airflow generation apparatus and conveyance part in Embodiment 1 of this invention. It is a figure which shows the motion of the airflow generation apparatus from the application part to the drying part by Embodiment 1 of this invention. It is an airflow image figure by Embodiment 1 of this invention. It is a coating head schematic diagram. It is a figure which shows the motion (from a geometric shape recognition stage to a fitting operation | work stage) of the coating substrate by Embodiment 1 of this invention. It is a figure which shows a motion (from a stocker to a fitting operation | work stage) of the coating auxiliary member by Embodiment 1 of this invention. It is a geometric shape recognition apparatus figure by Embodiment 1 of this invention. It is a coating auxiliary member stocker figure by Embodiment 1 of this invention. It is a conventional film thickness distribution graph. 2 is a film thickness distribution graph according to Example 1; It is a general view (sectional drawing seen from the normal line direction of the coating substrate) of the coating film forming apparatus which concerns on Embodiment 2 of this invention. It is a figure which shows the spin-coating apparatus by Embodiment 2 of this invention. It is a general view (sectional drawing seen from the normal line direction of the coating substrate) of the coating film forming apparatus which concerns on Embodiment 3 of this invention. It is a figure which shows the dip coating device which concerns on Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coating substrate tray 2 Conveyor device of airflow generator 3 Heater 4 Airflow generator 5 Discharge port 6 Slit 7 Inlet 8 Coating film 9 Coating substrate 10 Bead 11 Manifold 12 Coating head 13 Coating film forming device stage 14 Drying unit stage 15 Coating Part stage 16 Volatile component gas supply device 17 Airflow generator 18 Spin coating stage 19 Dip coating stage 21 Metering pump 23 On-off valve 24 Piping 25 Coating liquid tank 26 Spin coating liquid supply nozzle 27 Spin coating chamber 28 Spin coating rotating shaft 29 Dip liquid Layer 30 Dip application work arm 31 Geometric information recognition stage of application target substrate 32 Geometric information recognition device of application target substrate 33 Application auxiliary member stocker 34 Fitting operation stage of application target substrate and application auxiliary member 35 Application target Supporting jig fitting operation arm 36 coating the auxiliary member between the plate and the coating assisting member

Claims (7)

A coating film forming apparatus for coating a liquid on a substrate to be coated,
A means for specifying geometric shape information (application surface shape, outer peripheral shape, dimensions, etc.) of a substrate to be applied, a means for specifying a coating auxiliary member in accordance with the specified geometric shape information, and coating the specified coating auxiliary member A means for fitting to the target substrate, a means for applying a liquid to the application target substrate integrated with the application auxiliary member, and a liquid film applied on the application target substrate integrated with the application auxiliary member are dried and solidified. A coating film forming apparatus comprising: a means; and a device for separating the coating auxiliary member from the coating target member having the liquid film dried and solidified.   The coating film forming apparatus according to claim 1, wherein the coating auxiliary member has a surface that maintains the continuity of the coating surface of the substrate to be coated.   2. The coating according to claim 1, wherein the coating auxiliary member has a hole having a shape similar to the outer peripheral shape of the substrate to be coated, and a plurality of members having different ratios of the sizes of the holes are prepared. Film forming device.   2. The coating according to claim 1, wherein the coating auxiliary member has a concave portion having a shape similar to the outer peripheral shape of the substrate to be coated, and a plurality of members each having a different ratio of the size of the concave portion are prepared. Film forming device.   2. The coating film forming apparatus according to claim 1, wherein in the liquid coating unit and the liquid film drying and solidifying unit, an air flow generation unit is disposed at a position facing the substrate to be coated. A method of forming a coating film by a coating film forming apparatus,
Specify the geometric shape information (application surface shape, outer periphery shape, dimensions, etc.) of the application target substrate, specify the application auxiliary member according to the geometric shape information, and apply the application auxiliary member to the application target substrate for application. After the entire surface is formed so as to maintain the continuity of the application surface of the target substrate, the liquid is applied, and the liquid film applied on the application target substrate is dried and solidified while being integrated with the application auxiliary member. A coating film forming method, wherein the coating auxiliary member is separated from the coating target member whose liquid film is dried and solidified.   The airflow is generated by the airflow generating means according to claim 5 when applying the liquid to the application target substrate integrated with the application target substrate and drying and solidifying the applied liquid film. The coating film formation method of description.

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