JP2012111985A - Vapor deposition mask and thin film pattern-forming method using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vapor deposition mask with which the position deviation of a thin film pattern and the blur of pattern edge are prevented and which does not cause a defect such as a flaw in the substrate surface, in a thin film pattern forming step using a vapor deposition mask for forming a deposited layer in a selected area of the substrate surface from a vapor phase, and to provide a thin film pattern-forming method using the same.SOLUTION: The vapor deposition mask 11 uses a flexible sticking film 110 in which a material, covering parts to be non-deposition areas and brought into close contact with whole surface of a base material 10 is composed of a flexible film 111. After bringing the flexible sticking film 110 into close contact with the whole surface on the film deposition side of the base material 10 by using the vapor deposition mask 11, the flexible sticking film 110 covering areas where a desired deposition layer 13 is formed is selectively removed. Thereafter, a film deposition step is carried out to form the deposition layer 13, and finally, the flexible sticking film 110 left on the base material surface is removed.

Description

  The present invention relates to a vapor deposition mask for performing pattern formation simultaneously with film formation in a thin film manufacturing method such as sputtering.

  A general manufacturing process of a color filter (hereinafter abbreviated as CF) used for multi-color display of a flat panel display such as a liquid crystal display device is performed by patterning a black matrix (hereinafter abbreviated as BM) on a transparent substrate such as glass. After forming, a transparent counter electrode is formed on the upper surface of the main part of the CF in which colored transparent pixels of the three primary colors such as red (R), green (G), and blue (B) are regularly arranged between BMs in a plane. A transparent conductive thin film made of ITO (indium tin oxide) is formed by sputtering or the like. The ITO film is basically unnecessary in areas other than the CF pixel area, and in order to prevent the occurrence of problems in the subsequent panel manufacturing process, a vacuum is conventionally applied so that the ITO film is not applied to the non-pixel area. Similar to the vapor deposition mask that has been used in the vapor deposition method, a deposition layer is formed from a gas phase in a selective region of the substrate surface by masking means for performing pattern formation simultaneously with film formation.

  In the example of forming the counter electrode in the CF manufacturing process by the ITO sputtering method using the vapor deposition mask as described above, in particular, the liquid crystal display method of the LCD is a vertical electric field display represented by the TN type, and the pixel driving method is TFT. This is often the case in active matrix driving represented by (thin film transistor). As shown in FIG. 2A, a frame obtained by processing only a region desired to be formed into a mask opening 22 on a ferromagnetic metal plate such as a SUS material or a 42 alloy material having a thickness of about 0.5 mm. A vapor deposition mask (metal mask) 21 is arranged on one side of the base material 20 on the CF substrate surface side, and is closely fixed by a magnet holder 29 containing a magnet from the back surface of the base material, and then on the mask opening 22 side. An ITO sputtering film is formed. After the film formation, the combination of the three metal masks 21, the base material 20, and the magnet holder 29 is released to obtain a CF substrate having an ITO deposited layer formed only in a desired pixel region.

  The metal mask is formed so as to cover a non-pixel region, that is, a frame portion formed of a black matrix material outside the pixel surface and a cutting region between multi-faced CF pieces. Many shapes. In recent years, multi-faced CF pieces have been increasingly used to reduce manufacturing costs, and particularly in products for small panels for portable terminals, there is a tendency to further increase the number of CF pieces to be multi-faced on a large substrate. In order to increase the number of CF pieces per sheet, not only the size of the CF master substrate is increased, but also the direction of narrowing the width of the cutting area that separates the pieces is progressing. Then it is getting very thin.

  When a film is formed in a state where the substrate surface is covered with the conventional vapor deposition mask (metal mask) shown in FIG. 2A, there are several problems. One is that when the three plates of the metal mask 21, the substrate 20, and the magnet holder 29 are combined, the metal mask is likely to be displaced from the correct position of the substrate. Improvements have been made by automating handling to increase the accuracy of alignment, but errors of 0.3 to 0.6 mm are likely to occur.

  Further, depending on how the force is applied when the metal mask is mounted, the floating due to poor adhesion may occur in some places. FIG. 2B is a cross-sectional view illustrating an example of a state in which a deposition layer is formed in the opening of the vapor deposition mask (metal mask). When the metal mask 21 is lifted as shown in the figure, the cross-sectional shape of the deposited layer 23 becomes smooth, and the edge blur where the pattern shape of the obtained ITO film becomes unclear is large with a width of about 1 mm. appear. In particular, in the portion where the frame width of the metal mask is narrow, the boundary region with the ITO pattern corresponding to the adjacent opening portion may even disappear.

  Furthermore, when the metal mask is mounted, scratches of these patterns are caused by rubbing a part of the metal mask against various marks such as a frame portion and alignment marks already formed on the surface of the base material by the black matrix material. It may cause peeling and other defects and new dirt.

  In order to improve the problem due to rubbing, as shown in Patent Document 1, a step is formed by half etching at the end of the opening of the metal mask so as not to contact the pattern already formed by the black matrix material. Was proposed. However, as shown in the cross-sectional view of FIG. 2C, the deposited layer 33 is an example in which the deposited layer is formed in the opening of the evaporation mask (metal mask) 31 that is half-etched to a depth of about 0.2 mm. As a result, the cross-sectional shape of the ITO film becomes smooth, resulting in blurring of the edge that makes the pattern shape of the ITO film unclear.

  Further, Patent Document 1 leaves the photoresist used when producing the metal mask as it is, and prevents the hard surface of the metal mask from directly contacting the pattern already formed by the black matrix material. It was proposed to avoid it. After that, various methods of coating the metal mask surface with resin have been proposed, but these improvements are also incomplete in preventing edge blurring and scratches, and the coated resin is peeled off. With the generation of particles during film formation, problems such as a new increase in pinhole defects in the film occurred.

JP-A-10-39289

  The present invention is proposed in view of the above-mentioned problems, and the problem to be solved by the present invention is a thin film using a vapor deposition mask for forming a deposition layer from a vapor phase in a selective region of a substrate surface. An object of the present invention is to provide a vapor deposition mask that does not cause a positional shift of a thin film pattern or a blur of a pattern edge in a pattern forming process and does not cause defects such as scratches on a substrate surface, and a thin film pattern forming method using the same.

  As a means for solving the above-mentioned problems, the invention according to claim 1 is an evaporation mask for forming a deposition layer from a gas phase in a selective region on the surface of a substrate, and should be a non-deposition region. A vapor deposition mask characterized in that a flexible adhesive film made of a flexible film is used as a material that covers a portion and is in close contact with a substrate surface.

  The invention according to claim 2 is the vapor deposition mask according to claim 1, wherein the flexible film is made of a plastic film having a thickness of 0.01 to 0.1 mm.

  The invention according to claim 3 is the vapor deposition mask according to claim 2, wherein the plastic film is made of polyimide.

  Moreover, invention of Claim 4 has an adhesion layer in the side which adheres the said flexible sticking film with the base-material surface, It is a vapor deposition mask in any one of Claims 1-3 characterized by the above-mentioned. .

The invention according to claim 5 is the vapor deposition mask according to claim 4, wherein the adhesive layer uses a silicone-based adhesive.

  In addition, the invention according to claim 6 is the desired deposition layer after the flexible adhesive film used for the vapor deposition mask according to any one of claims 1 to 5 is adhered to the entire surface of the substrate on the film forming side. The flexible adhesive film covering the area where the film is to be formed is selectively removed, and then a film forming process is performed to form a deposited layer, and finally the flexible adhesive film left on the substrate surface is removed. A thin film pattern forming method characterized in that:

  Further, the invention according to claim 7 is based on electrostatic force as a method for bringing the flexible adhesive film used for the vapor deposition mask into close contact with the entire surface of the substrate on the film forming side. This is a pattern forming method.

  In the invention according to claim 8, as a method for selectively removing the flexible adhesive film covering the region where the desired deposition layer is to be formed, the periphery of the region is cut by a laser beam or an electron beam. 8. The thin film pattern forming method according to claim 6, wherein the entire region is mechanically peeled off after the removal.

  The invention according to claim 9 is characterized in that the desired deposition layer is an ITO (indium tin oxide) thin film as a counter transparent electrode for a liquid crystal display device, and the film forming step is a sputtering method. The thin film pattern forming method according to claim 6.

  According to the present invention, a thin film pattern is formed by using a vapor deposition mask using a flexible adhesive film made of a flexible film as a material that covers a portion to be a non-deposition region and adheres closely to a substrate surface. In the process, it is possible to provide a vapor deposition mask that does not cause a positional shift of the thin film pattern and a blur of the pattern edge and does not give a defect such as a scratch to the substrate surface, and a thin film pattern forming method using the same. In particular, according to the ninth aspect, the ITO thin film pattern as the counter transparent electrode on the liquid crystal display device CF can be satisfactorily provided by the sputtering method.

It is a schematic diagram for demonstrating an example of the principal part at the time of forming a thin film pattern with the vapor deposition mask of this invention, Comprising: (a) is a perspective view which shows the covering state of the base-material surface by a vapor deposition mask, (b) These are sectional drawings which show the state in which the deposition layer was formed in the opening part of a vapor deposition mask. It is a schematic diagram for demonstrating the example of the principal part in the case of forming a thin film pattern with the conventional vapor deposition mask, Comprising: (a) is a perspective view which shows the covering state of the base-material surface by a vapor deposition mask, (b) It is sectional drawing which shows an example of the state in which the deposition layer was formed in the opening part of a vapor deposition mask, (c) is sectional drawing which shows another example of the state in which the deposition layer was formed in the opening part of a vapor deposition mask. It is a perspective schematic diagram for demonstrating the condition which changed the material which should be used as the vapor deposition mask of this invention from the accommodation state to the use state, Comprising: (a) shows the unwinding state of material, (b) is sticking of material Indicates the attached state. It is a perspective schematic diagram for demonstrating the cutting process process for forming the vapor deposition mask of this invention, Comprising: (a) is a cutting line formation process, (b) peels a film selectively along a cutting line. Step (c) shows a state in which a deposition mask is prepared on the substrate. It is the cross-sectional schematic diagram which showed an example of the process of forming a thin film pattern with the vapor deposition mask of this invention by the process order for the opposing transparent electrode formation of a color filter by (a)-(f).

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a schematic view for explaining an example of a main part in the case of forming a thin film pattern with the vapor deposition mask of the present invention, wherein (a) is a perspective view showing a covering state of a substrate surface with the vapor deposition mask. (B) is sectional drawing which shows the state in which the deposition layer was formed in the opening part of a vapor deposition mask.
A vapor deposition mask 11 of the present invention is a vapor deposition mask for forming a deposition layer 13 from a gas phase, having a mask opening 12 in a selective region on the surface of a substrate, and covering a portion to be a non-deposition region. Thus, the material to be brought into close contact with the surface of the substrate 10 is a flexible adhesive film 110 made of a flexible film 111.

  As the flexible film 111, a plastic film having a thickness of 0.01 to 0.1 mm is suitable. It is easy to store and transport in the state of a film wound around a roll, which will be described later, and has a thickness that can be easily processed even when it is attached to a flat substrate surface as a vapor deposition mask.

  Further, as a specific material for the plastic film, a material that is excellent in heat resistance, such as polyimide, has a low thermal shrinkage rate, has a high elastic modulus, and is hardly distorted is particularly preferable. Of course, when performing a certain heat treatment in the film forming process, even if the heat treatment is not performed in the film forming process, it is difficult to influence the degassing and desorption of adsorbed moisture in the vacuum chamber. This is because deformation at the time of application to the surface of the base material or processing for forming a mask opening can be suppressed.

  Moreover, by having the adhesive layer 112 on the side where the flexible adhesive film 110 is in close contact with the substrate surface, the flexible adhesive film can be easily attached to the substrate surface. The flexible adhesive film 110 may be one in which the adhesive layer 112 is formed on one surface of the flexible film 111 as described above. However, as will be described later, the electrostatic charging process is flexible in the process immediately before the application. What was given to the property film 111 may be sufficient, and is not limited.

  When the adhesive layer 112 is used for the flexible adhesive film 110, depending on the surface conditions of the flexible film 111 and the base material 10, and depending on the use processing conditions of the front and rear processes including the vacuum film formation process. Thus, an optimum pressure-sensitive adhesive can be designed and selected in consideration of the balance between adhesiveness and peelability. In particular, a silicone-based adhesive obtained by adding a silicone resin as a tackifier to an elastomer made of silicone rubber is uniformly applied to the flexible film 111 in advance as an adhesive layer 112, so that it can be used stably even in a vacuum, A flexible adhesive film 110 having a relatively wide application temperature range and appropriate adhesiveness can be obtained.

  Next, a specific method for forming a thin film pattern using the vapor deposition mask of the present invention will be described. In particular, FIG. 5 mainly illustrates an example in which an ITO thin film pattern as a counter transparent electrode on a liquid crystal display device CF is manufactured by a sputtering method, but is not necessarily limited thereto.

  FIG. 3 is a schematic perspective view for explaining a state in which the material to be used as the vapor deposition mask of the present invention is shifted from the housed state to the in-use state, where (a) shows the unwound state of the material, and (b) Indicates the pasted state of the material. The roll-shaped vapor deposition mask material 114 wound around the roll core 115 represents the original storage state of the flexible adhesive film 110 described above, and can be obtained by appropriate web operation means such as roll rotation and tension control. Then, the vapor deposition mask material 113 in the unwound state is pulled out. Next, this material is pulled out to the required length, and is applied to the surface of the base material 10 uniformly using the film application roll 116, etc., and the end of the application portion is cut, thereby allowing flexibility. An individual is obtained in a state where the adhesive film 110 is in close contact with the entire surface of the substrate 10 on the film formation side.

  As a method for bringing the flexible adhesive film 110 into close contact with the entire surface of the substrate 10 on the film forming side, the flexible film 111 itself constituting the flexible adhesive film 110 is not limited to relying on the adhesiveness of the adhesive layer 112 described above. It is also possible to carry out the charging process in the process immediately before the application to the film and to apply it by electrostatic force. As the charging treatment, a method using friction or a method accompanied by surface modification of the base material by various discharge treatments can be used. However, it is necessary to individually devise to avoid the adverse effect of dust collection such as foreign matter. It should be noted that this means is limited to the application to a plastic film having high electrical insulation on the surface, and it goes without saying that it is not applicable when the flexible film 111 has a conductive metal or the like as a material. Yes.

  FIG. 4 is a schematic perspective view for explaining a cutting process for forming the vapor deposition mask of the present invention, wherein (a) is a cutting line forming process and (b) is selectively along the cutting line. The step of peeling the film, (c) shows a state in which a deposition mask is prepared on the substrate.

  As a method for forming the cutting line, it is possible to mechanically cut with a blade having a blade. However, a processing means using a laser beam or an electron beam is useful for the precision and stability of the process. For example, in FIG. 4 (a), light focused in a beam shape from the processing laser light source 14 is accurately irradiated to the cutting portion 15 of the flexible adhesive film 110, and irradiated along the predetermined cutting line 16. By moving the point, the entire circumference of the cutting line indicated by the broken line can be processed. In addition, when processing with laser light or the like, it becomes easy to turn on / off irradiation and control the processing intensity with pulses. Therefore, even when a CF pattern region such as a frame on the substrate is used as the base of the irradiation point, Can be minimized.

  In addition, although it is not cut | disconnected completely among the said predetermined cutting lines 16, a certain amount of cuts can be formed in the flexible adhesive film 110 previously. If the film expansion / contraction control and the adhesion accuracy to the base material can be increased, the process load in the cutting process in this process can be reduced, and the vapor deposition mask material in the roll state described in FIG. A cutting pattern having the above-mentioned certain degree of cut can be provided in advance.

  After processing the entire circumference of the cutting line, the step of selectively peeling the release film 121 for mask opening along the cutting line is (b), and the peeling method mechanically causes a part of the cutting edge, There is a method of peeling the entire continuous region starting from that point, and a method of pulling that part by providing an adhesion point with the peeling jig on the back of the release film 121 for mask opening. This is possible by applying a tensile force that exceeds the adhesive strength with the substrate. To moderately weaken the adhesive strength with the base material at the time of peeling, weaving it into the material design of the adhesive, or giving special conditions such as temperature and vibration to the place at the time of peeling to assist, or the adhesive In the case of the flexible adhesive film 110 that can be attached by electrostatic force without using the film, it is possible by selectively removing static electricity.

  As a result of the above process, the flexible adhesive film covering the region where the desired deposited layer is to be formed can be selectively removed, and as shown in FIG. The vapor deposition mask 11 having 12 is prepared, and it is possible to shift to a film forming process for forming a deposited layer.

  FIG. 5 is a schematic cross-sectional view showing (a) to (f) an example of a process of forming a thin film pattern using the vapor deposition mask of the present invention in the order of processes for forming the counter transparent electrode of the color filter. In particular, an example of a type in which the flexible adhesive film 110 is formed by applying the adhesive layer 112 to the flexible film 111 will be described in more detail.

  FIG. 5A shows a state in which the CF substrate already formed on the base material 10, that is, the black matrix 5, the frame portion 51, and the colored pixels 6, 7, and 8 are attached together with the flexible adhesive film 110. Show. Here, the black matrix 5 and the frame portion 51 are formed of a photosensitive resin containing a black pigment, and the colored pixels 6, 7, and 8 are made of a photosensitive resin containing red, green, and blue transparent colored pigments, respectively. It is a pixel pattern arranged repeatedly. Further, as the flexible adhesive film 110, a Teflon (registered trademark) (substance name: polytetrafluoroethylene) film having a thickness of several tens of μm obtained by applying a silicone-based adhesive to a thickness of several μm can be used.

  4B, as described with reference to FIG. 4, the position and strength of the cut portion 15 of the flexible adhesive film 110 are precisely irradiated with light focused in a beam form from the processing laser light source 14 to be flexible. The outer periphery of the region to be the mask opening is processed so as to minimize the damage to the upper surface of the frame 51 while penetrating the adhesive film 110.

  Next, as shown in (c), the release film 121 for mask opening corresponding to the flexible adhesive film in the portion of the CF that is on the CF in the region that should be the isolated mask opening is processed by removing the outer periphery. To do. In the figure, the entire mask opening release film 121 is shown as being peeled off in the direction indicated by the block arrow at a stretch in the form of a flat plate, but it is flexible in a direction of approximately 180 degrees triggered by the cut portion processed in (b). Alternatively, a method may be used in which a predetermined region of the flexible adhesive film 110 in which the adhesive film 111 and the adhesive layer 112 are integrated is peeled from the CF substrate side.

  Next, the film forming process shown in FIG. As a film forming apparatus, a transfer film forming type magnetron sputtering apparatus is used. For example, sputtering is performed from an ITO target in an atmosphere of 0.35 Pa in which a small amount of oxygen gas is mixed with argon gas, and transparent with a uniform thickness of 140 nm. An electrode (ITO film) 9 can be formed.

  Finally, as shown in (e), the flexible adhesive film 110 left on the substrate surface is removed from the CF substrate together with the ITO film thereon as shown by a block arrow. As a result, as shown in (f), the transparent electrode (ITO film) 9 can be satisfactorily formed only at the correct selected position on the CF substrate without blurring of the edge.

  In general, a good thin film pattern can be formed at any place on the substrate using the vapor deposition mask of the present invention in the same manner as described above.

5 ... Black matrix 6, 7, 8 ... Colored pixel 9 ... Transparent electrode (ITO film)
10, 20, 30 ... base material 11 ... vapor deposition mask 12, 22 ... mask openings 13, 23, 33 ... deposition layer 14 ... laser light source 15 ... cutting location 16 ...・ Cutting lines 21, 31 ... Evaporation mask (metal mask)
29 ... Magnet holder 51 ... Frame portion 110 ... Flexible adhesive film 111 ... Flexible film 112 ... Adhesive layer 113 ... Deposition mask material (unwinding state)
114 ... Evaporation mask material (roll state)
115: Roll core 116 ... Roll for film application 121 ... Release film for mask opening

Claims (9)

  A vapor deposition mask for forming a deposition layer from a gas phase in a selective region on a substrate surface, and a material that covers a portion to be a non-deposition region and adheres closely to the substrate surface may be a flexible film. A vapor deposition mask characterized by being a flexible adhesive film.   The said flexible film consists of a 0.01-0.1-mm-thick plastic film, The vapor deposition mask of Claim 1 characterized by the above-mentioned.   The vapor deposition mask according to claim 2, wherein the plastic film is made of polyimide.   The vapor deposition mask according to any one of claims 1 to 3, further comprising an adhesive layer on a side where the flexible adhesive film is in close contact with the substrate surface.   The vapor deposition mask according to claim 4, wherein the adhesive layer uses a silicone-based adhesive.   The flexible sticking which covers the area | region which should form a desired deposition layer, after making the flexible sticking film used for the vapor deposition mask in any one of Claims 1-5 adhere to the film-forming side whole surface of a base material A method of forming a thin film pattern, comprising selectively removing a film, and thereafter performing a film forming step of forming a deposited layer, and finally removing a flexible adhesive film left on the surface of the substrate.   The thin film pattern forming method according to claim 6, wherein the flexible adhesive film used for the vapor deposition mask is brought into close contact with the entire surface of the substrate on the film forming side by electrostatic force.   As a method for selectively removing the flexible adhesive film covering the region where the desired deposited layer is to be formed, the entire peripheral region is mechanically peeled after the peripheral portion of the corresponding region is cut with a laser beam or an electron beam. The thin film pattern forming method according to claim 6, wherein the thin film pattern is removed.   9. The desired deposition layer is an ITO (indium tin oxide) thin film as a counter transparent electrode for a liquid crystal display device, and the film forming step is a sputtering method. Thin film pattern forming method.