JP2017213783A - Mesh integrated type metal mask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mesh integrated type metal mask capable of achieving both of securing sufficient adhesiveness of mesh and metal mask and reducing position lag of patterns.SOLUTION: There is provided a mesh integrated type metal mask consisted by a frame body, a mesh stretched to the frame body and of which a part consists of metals, and a metal mask having a printing pattern open hole contacting with the mesh and conjugated by a plating metal coating, maximum dimension of the metal mask to maximum dimension of an inner side opening part of the frame body is 60% or less and opening of the mesh around the metal mask is filled.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a mesh-integrated metal mask.

  The mesh-integrated metal mask is used for screen printing of internal electrodes of chip-shaped electronic components such as multilayer ceramic capacitors and inductors.

  Patent Document 1 discloses a mesh-integrated metal in which a metal mask having a large number of openings patterned into a desired printing pattern by electroforming is electrodeposited (integrated) on a conductive mesh. A mask manufacturing method is disclosed. This is superior in chemical resistance and wear resistance compared to a mesh formed with a mask made of photosensitive resin, etc., has a very small dimensional change due to squeegee printing pressure, and has a relatively high accuracy. Printing can be expected.

  On the other hand, with the recent trend of downsizing and increasing the density of electronic components, multilayer ceramic capacitors are required to have a small size and large capacity. In order to reduce the size and increase the capacity, the number of dielectric layers to be stacked is further increased, and the thickness of the dielectric layers per layer has been further reduced. Accordingly, the internal electrode pattern is made thinner and higher by screen printing. It has been required to print with positional accuracy and high dimensional accuracy.

  Patent Document 1 and Patent Document 2 disclose a method of manufacturing a mesh-integrated metal mask for thin films. FIG. 7 is a schematic explanatory view of a general manufacturing method of a mesh-integrated metal mask. As shown in FIG. 7A, an electroforming mother die 71 having conductivity is prepared. As shown in FIG. 7B, an insulating pattern 72 is formed on the electroforming mother die 71 with an insulating film such as a resist. Form. The shape of the insulating pattern 72 is made to correspond to the opening of the mesh-integrated metal mask obtained, in other words, the shape of the pattern to be formed by printing. Next, as shown in FIG. 3C, a metal mask 73 is formed by a plating technique such as nickel plating. At this time, the plating pattern is prevented from being generated at the location of the insulating pattern 72 and becomes an opening in the metal mask 73. Thereafter, as shown in FIG. 4D, the conductive mesh 74 stretched on the frame is pressed onto the metal mask 73 to integrate them by plating such as nickel plating. The integrated metal mask 73 and mesh 74 are peeled off from the electroforming mother die 71 to obtain a mesh integrated metal mask 70 (FIG. 5E). As described above, in the mesh-integrated metal mask 70, the opening 75 is formed at a location corresponding to the insulating pattern 72.

JP-A-8-183151 JP 2010-42567 A

  As described above, when joining the metal mask to the conductive mesh, it is necessary to press the electroforming mother die and the metal mask (electrodeposition layer) with tension applied to the mesh. At this time, since the metal mask is bonded in a state where the mesh is stretched, if the electroforming mother mold is peeled off from the metal mask after bonding, the elongation of the mesh due to pressing is relieved, and the metal mask itself is also deformed at the same time. End up. As a result, positional deviation occurs in the pattern formed on the metal mask, and a high-accuracy screen mask cannot be manufactured. In particular, when the metal mask is thin, such as a mask used for printing the internal electrode and dielectric layer of the multilayer ceramic capacitor, the positional deviation of this pattern is large and its stability is low.

  As described above, when the electroforming mother die and the metal mask (electrodeposition layer) are pressed against the mesh while the mesh is pressed, the mesh is greatly stretched as the pressing is increased, and as a result, the positional deviation of the pattern is increased. On the other hand, if the pressing is weak, the mesh and the metal mask are not sufficiently adhered, which causes poor bonding. In view of the above, an object of the present invention is to provide a mesh-integrated metal mask capable of ensuring both sufficient adhesion between the mesh and the metal mask and reducing the positional deviation of the pattern.

  According to the present invention, a metal mask having a frame, a mesh stretched on the frame, at least a part of which is made of metal, and a printed pattern through-hole that is in contact with the mesh and joined by a plated metal film The longest dimension of the metal mask with respect to the longest dimension of the inner opening of the frame is 60% or less, and the mesh openings around the metal mask are sealed. A mesh-integrated metal mask is provided.

  According to the present invention, the adhesion between the mesh and the metal mask is sufficient, and the pattern displacement amount and the dimensional deviation amount can be reduced.

It is a schematic cross section of the integration process of a metal mask and a mesh. It is a model top view of a mesh integrated type metal mask. The pressure distribution which arises at the time of integration of a metal mask and a mesh is shown. The calculation result regarding the distribution of the load to the mesh generated when the metal mask and the mesh are integrated is shown. It is a schematic explanatory drawing about the position shift and dimension shift of a pattern. The pattern and dimensional deviation are shown. It is model explanatory drawing of the general manufacturing method of a mesh integrated type metal mask. The table shows the metal mask dimensional conditions, pattern positional deviation amounts, and dimensional deviation amounts of the examples and comparative examples. The pattern positional deviation amount and the dimensional deviation amount are illustrated. It is a schematic cross section of a mesh-integrated metal mask.

  The present invention will be described in detail with appropriate reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and in the drawings, the characteristic portions of the invention may be emphasized and expressed, so that the accuracy of the scale is not necessarily guaranteed in each part of the drawings. Not.

  FIG. 1 is a schematic cross-sectional view of an integration process of a metal mask and a mesh. FIG. 1A is a schematic cross-sectional view in the case of manufacturing the mesh-integrated metal mask of the present invention. A state in which a metal mask 13 is formed on the electroformed mother die 14 on which the insulating pattern 12 is formed and the mesh 11 stretched on the frame body is pressed is depicted. According to the present invention, since the size of the metal mask 13 is substantially equal to the print pattern area, sufficient adhesion between the mesh 11 and the metal mask 13 can be achieved simply by pressing the mesh 11 against the metal mask 13 with a weak force. For this reason, the elongation of the mesh 11 due to the pressing is reduced, and as a result, the positional deviation is reduced. In particular, an advantage can be found in that the load applied to the mesh 11 in the region indicated by the symbol I, in other words, in the vicinity of the end portion of the electroforming mother die 14 is not excessive.

  Here, the print pattern area is defined as an area where an opening having a predetermined position and shape is formed in the metal mask. That the size of the metal mask is equal to the print pattern area means that openings for the print pattern are provided at predetermined positions and shapes over almost the entire area of the metal mask.

  FIG. 1B is a schematic cross-sectional view in the case of manufacturing a mesh-integrated metal mask in the prior art. The metal mask 17 is formed on the electroforming mother die 19 on which the insulating pattern 18 is formed, and the state in which the mesh 16 stretched on the frame is pressed is depicted. In the case of the prior art, the size of the metal mask 17 is larger than the print pattern area, and the metal mask 17 exists around the periphery of the area where the insulating pattern 18 is formed. In this case, the mesh 16 and the metal mask 17 must be integrated over a relatively large area with respect to the area of the print pattern area, and a relatively strong pressing force is required for the integration. For this reason, the elongation of the mesh 16 due to the pressing increases, and as a result, the positional deviation increases. In particular, the load on the mesh 16 in the region indicated by reference numeral II, in other words, in the vicinity of the end of the electroformed mother die 19, becomes excessive.

  Among the ends of the electroforming mother die 19, the load is particularly large in the corner portion of the electroforming mother die 19, that is, in the vicinity of the corner of the frame. Therefore, by chamfering the corner portion of the electroforming mother die 19, either one or both of the vertical and horizontal sides of the electroforming mother die 19 are reduced, and either the vertical or horizontal side of the metal mask 17 is reduced. The same effect as described above can be obtained by making the length of one or both substantially equal to the length of the print pattern area.

  Conventionally, in the metal mask for screen printing, the range in which the squeegee and the scraper move is made of metal. However, the present inventors have proposed that if the metal mask bonded to the mesh is very thin, the print pattern area It has been newly found that even if only metal is used as a metal, there is no problem in printing, in other words, printing performance equivalent to that of a normal product can be obtained.

  FIG. 2 is a schematic plan view of a mesh-integrated metal mask. FIG. 2A shows a mesh-integrated metal mask according to the present invention. FIG. 2C shows another example of a mesh-integrated metal mask according to the present invention. In both examples, the region indicated by reference numeral 21 near the center is a region of the metal mask integrated with the mesh. A sealing portion 22 is provided around the metal mask 21.

  The role of the sealing portion 22 is to prevent the printing paste from adhering to a portion other than the printing material under the screen through the opening of the mesh. As long as the role can be fulfilled, the material of the sealing portion 22 is not particularly limited, and a photosensitive emulsion emulsion, a photosensitive resin, or an adhesive is preferably used. The sealing portion may be less than the thickness of the mesh or may be exposed from the mesh surface by several μm.

  In normal printing, a sufficient amount of printing paste is temporarily stored in an area circumscribing one side of the printing pattern area, and this is spread evenly in the printing pattern area with a scraper and printed with a squeegee. Imprint the pattern opening. Since there are variety in the number of squeegees, the number of scrapers, and the moving directions of squeegees and scrapers, in some cases, the area for temporarily storing the print paste may be circumscribed at both ends of the print pattern area. is there. In this paper, the area where the sufficient amount of printing paste is temporarily stored is called the paste supply unit and holding unit because of its function. The mesh-integrated metal mask of the present invention includes a paste supply unit and a holding unit, and the paste supply unit and the holding unit do not include a metal mask. The prior art can be referred to as appropriate for the structure and manufacturing method of the paste supply unit and the holding unit.

  FIG. 2B shows a mesh-integrated metal mask in the prior art. An area indicated by reference numeral 26 represents a metal mask integrated with a mesh. The surrounding area 27 holds a metal mask in which a mesh that has been sealed is integrated with the mesh. The conventional mesh-integrated metal mask also has a paste supply unit and a holding unit, and the paste supply unit and the holding unit are configured with a metal mask.

  According to the present invention, the thickness of the sealing portion can be determined as appropriate in relation to the thickness of the mesh. In a preferred embodiment, the sealing portion does not exceed the mesh thickness. In this case, the thickness of the metal mask is preferably 10 μm or less, more preferably 5 μm or less. If the thickness of the sealing part does not exceed the thickness of the mesh and the thickness of the metal mask is within the above range, the squeegee and scraper will be affected by the step at the boundary between the sealing part and the metal mask part during printing. The advantage of being able to move without being expected is expected (FIG. 10A). It is difficult to apply a force to the mesh due to the squeegee near the end of the metal, distortion is unlikely to occur, the plate life is not reduced due to metal peeling, and there is less concern about the life reduction due to accelerated wear of the squeegee angle.

  As another aspect, there is a case where the sealing portion is thicker than the mesh and exposed as a film of several μm from the mesh surface. In this case, the difference between the thickness exposed from the mesh surface of the mesh portion and the thickness of the metal mask is preferably as small as possible. Specifically, the difference is 10 μm or less (FIG. 10B). FIG. 10C). Here, reference numeral 101 represents a sealing portion, reference numeral 102 represents a metal mask, and reference numeral 103 represents a mesh. The difference between the thickness exposed from the mesh surface of the mesh portion and the thickness of the metal mask is small, in other words, there are few “steps”, and the force on the mesh due to the squeegee near the metal edge. It is difficult to cause distortion, distortion is unlikely to occur, plate life is less likely to be reduced due to metal peeling, and there is less concern about life reduction due to accelerated wear on the squeegee angle.

  Note that it is also a preferable aspect that the sealing portion is thicker than the mesh and the metal mask is thicker than the thickness exposed from the mesh surface of the sealing portion. In this case, more preferably, the difference between the thickness of the metal mask and the thickness exposed from the mesh surface of the sealing portion is 5 μm or less (FIG. 10C).

  The table described below FIG. 10C summarizes the thickness of the metal mask, the thickness of the sealing portion, the difference between the two thicknesses, and the life of the screen. Judgment criteria for the lifetime are shown at the bottom of FIG.

  According to the present invention, the ratio of the longest dimension of the metal mask to the longest dimension inside the frame is preferably 60% or less, and more preferably 50% or less. Here, the “frame body” is a holding body that holds the screen and stretches the mesh. The “longest dimension” inside the frame means the longest dimension of the stretched mesh, and this longest dimension usually refers to the length of the diagonal line. In the case of a square or rectangular metal mask, the “longest dimension” of the metal mask is usually the length of the diagonal line, but this is not limited depending on the shape of the metal mask. Since the relationship of the longest dimension is 60% or less, there is an advantage that the average value of the amount of pattern position deviation can be reduced to about 1/2 of the conventional example as shown in FIGS. Further, when the relationship of the longest dimension is 50% or less, an advantage that the pattern positional deviation amount is within ± 10 μm is expected from FIGS. 8 and 9.

  According to the present invention, the length of the metal mask is preferably 60% or less with respect to the inner length of the frame. The “length” inside the frame means the length of the stretched mesh in the vertical or horizontal direction, and the “length” of the metal mask means the length of the vertical or horizontal part of the metal mask. To do. Since the relationship of these “lengths” is 60% or less, an advantage that the average value of the dimensional deviation amount in that direction is about 1/2 of the conventional example is expected from FIGS.

  Furthermore, according to the present invention, the area of the metal mask is preferably 40% or less with respect to the area inside the frame. The “area” inside the frame means the area of the stretched mesh, and the “area” of the metal mask means the entire area including the printed pattern through hole portion formed in the metal mask. Since the relationship of these “areas” is 40% or less, an advantage that the average value of the amount of pattern positional deviation can be reduced to about 1/2 of the conventional example from FIGS. 8 and 9 is expected.

  According to the present invention, the length of at least one side of the outer periphery of the metal mask is preferably within 120% of the length of at least one side of the outer periphery of the print pattern area. Here, the “length” of the print pattern area means a vertical or horizontal length of a rectangular outer peripheral portion that can include all of the print pattern through holes formed in the metal mask. Since the relationship of the “length” is within the above range, the metal mask and the mesh can be integrated with each other so that the minimum length of the metal mask with respect to the length of the pattern area can be obtained. 1 is expected to be integrated with less distortion.

  FIG. 3 shows a pressure distribution generated when the metal mask and the mesh are integrated. The pressure generated during the integration is measured by a pressure sensor, and the pressure value is expressed as a relative value in terms of color intensity. FIG. 3A shows the pressure distribution when the metal mask and the mesh are integrated in the prior art. The pressure at the center of the metal mask is relatively small, and it can be said that this is the minimum pressure sufficient to integrate the metal mask and the mesh. In that case, a relatively large pressure is generated at the edge of the metal mask, and a particularly large pressure is generated at the corner of the metal mask, particularly at the corners, and a large load is applied to the mesh. It is inferred that

  FIG. 3B shows a pressure distribution when the metal mask and the mesh according to the present invention are integrated. What is characteristic is that the pressure is relatively low and the variation is small at the end of the metal mask. Therefore, even if the pressing pressure between the mesh and the metal mask is increased, an excessive load on the mesh in the vicinity of the end portion is unlikely to occur. Therefore, sufficient integration is promoted by pressing the mesh and the metal mask with a large pressure. At the same time, distortion of the mesh can be reduced. FIG. 3C shows another example of the pressure distribution when the metal mask and the mesh according to the present invention are integrated. What is characteristic is that the pressure is relatively low at the corners of the metal mask and there is little variation. Therefore, even in this case, even if the pressing pressure between the mesh and the metal mask is increased, an excessive load on the mesh in the vicinity of the corner is unlikely to occur. And the mesh distortion can be reduced.

  FIG. 4 shows a calculation result regarding a load distribution on the mesh generated when the metal mask and the mesh are integrated. FIG. 4A shows a load distribution when the metal mask and the mesh are integrated in the prior art. A relatively large load was generated at the end of the metal mask, and a calculation result that the distortion of the mesh increased was obtained. FIG. 4B shows a load distribution when the metal mask and the mesh according to the present invention are integrated. Unlike the case of FIG. 4A, the calculation shows that the load is relatively low and the mesh distortion is small at the end of the metal mask. FIG. 4C shows another example of the load distribution when the metal mask and the mesh according to the present invention are integrated. Unlike the case of FIG. 4A, the calculation shows that the load is relatively low and the mesh distortion is small at the corners of the metal mask.

FIG. 5 is a schematic explanatory view of pattern positional deviation and dimensional deviation.
The positional deviation in FIG. 5A is defined as a positive direction, and the positional deviation in FIG. 5B is defined as a negative direction. The positional deviation of the pattern area 51 in FIG. A dotted line with reference numeral 52 is a design value of the pattern area and shows a case where the positional deviation is zero. Similarly, the positional deviation of the pattern area 51 in FIG. The meaning content of the dotted line of the reference numeral 52 is the same as in the case of FIG. In both figures, the distortion of the pattern area shape is expressed. Due to the strong and non-uniform pressing, the elongation of the mesh at the time of joining is large and the positional deviation increases when the balance is lost.

  FIG. 5C shows the deviation of the pattern area dimension from the design value in the prior art. FIG. 5D shows a deviation of the pattern area dimension from the design value in the present invention. Reference numeral 51 is a schematic diagram of an actually measured pattern area, and a dotted line indicated by reference numeral 52 indicates a design value. In the prior art, as shown in FIG. 5C, the pressing amount is large, the elongation of the mesh at the time of joining becomes large, and the pattern dimension on the metal mask becomes small. In the present invention, as shown in FIG. 5D, since the pressing amount at the time of joining can be reduced, the pattern dimension becomes large and the dimensional deviation from the design value is small.

  5E and 5F schematically show the relationship between the deformation of the mesh and the positional deviation of the pattern. As shown in FIG. 5E, the metal mask 55 and the mesh 56 are integrated using a pressing jig 57 or the like. At this time, since the pattern is fixed in a state where the mesh 56 is deformed, if the jig 57 is removed and the substrate is peeled off from the metal mask 55 as shown in FIG.

  FIG. 6 shows pattern and dimension deviations. 6A shows the positional deviation of the pattern, FIG. 6B shows the dimensional deviation in the X direction, and FIG. 6C shows the dimensional deviation in the Y direction. The horizontal axis of each graph is the sample number. In each graph, the measurement values of the mesh-integrated metal mask according to the related art and the product of the present invention are plotted. The mesh-integrated metal mask of the present invention uses a frame whose inner and outer openings are 716 mm in length and width, and whose diagonal is 1013 mm. The thickness of the metal mask is 5 μm, the thickness of the mesh is 20 μm, The thickness of the metal mask is less than 1 μm, the vertical and horizontal dimensions of the metal mask are each 320 mm, the diagonal is the maximum dimension of the metal mask of 452 mm, and the ratio of the longest dimension of the metal mask to the longest dimension inside the frame is 45%. The ratio of the mask length to the print pattern area length is 107%. The mesh-integrated metal mask of another example of the present invention uses the same frame, has a shape in which the corners of the metal mask are cut off, the thickness is 5 μm, the mesh thickness is 20 μm, and the thickness of the sealing portion. Is less than 1 μm, the vertical and horizontal maximum dimensions of the metal mask are 500 mm each, the length of one side of the right triangle of the square cut-out portion is 80 mm, the longest dimension of the metal mask is 605 mm, and the metal relative to the longest dimension inside the frame The ratio of the longest dimension of the mask is 60%, and the ratio of the length of the metal mask to the print pattern area length is 167%. The material of the sealing portion is an emulsion emulsion. In the conventional mesh-integrated metal mask, the same frame is used, and the vertical and horizontal dimensions of the metal mask are each 500 mm. Therefore, the ratio of the longest dimension of the metal mask to the longest dimension inside the frame is 70%. The ratio of the length of the metal mask to the length of the printed pattern area was 167%. The plot of ▲ is the measured value in the mesh-integrated metal mask of the prior art, the plot of ■ is the measured value in the mesh-integrated metal mask of the present invention, and the plot of ◆ is in the mesh-integrated metal mask of another example of the present invention. Represents the measured value. As shown in FIGS. 6A to 6C, in the mesh-integrated metal mask according to the present invention, the positional deviation and dimensional deviation of the pattern were smaller than those of the conventional product.

  Similarly, FIG. 8 shows a result of an experiment performed by changing the size and shape of the metal mask, and FIG. 9 shows a graph of the result. If the longest dimension of the frame and the longest dimension of the metal mask are 60% or less, the advantage that the average value of the pattern position deviation amount can be reduced to about 1/2 of the conventional example is expected from FIGS. Further, when the relationship of the longest dimension is 50% or less, an advantage that the pattern positional deviation amount is within ± 10 μm is expected from FIGS. 8 and 9.

  The length of at least one side in the vertical and horizontal directions of the outer periphery of the metal mask is 60% or less with respect to the length of one side in the same direction as the length of the metal mask in the inner opening of the frame. Further, the average value of the amount of dimensional deviation in that direction becomes about 1/2 of the conventional example.

  When the area of the metal mask is 40% or less with respect to the area of the inner opening of the frame body, the average value of the amount of pattern displacement can be reduced to about 1/2 of the conventional example from FIGS. Benefits are expected.

In FIG. 8A, the condition 12 is 500 mm in length and width, but has four corners each chamfered (cut off) by a right triangle of 80 mm on each side. Condition 8 is that the ratio of the length of one side is within the scope of the present invention, but does not correspond to the practice of the present invention because it does not satisfy the ratio of the longest part. In FIG. 8B, it is considered that the X and Y directions do not have the same direction shift amount because the mesh is inclined by 30 degrees with respect to the frame.

Claims (10)

  A mesh, comprising a frame, a mesh stretched on the frame, at least part of which is made of metal, and a metal mask having a printed pattern through hole that is in contact with the mesh and joined by a plated metal film. A body-type metal mask, wherein the longest dimension of the metal mask with respect to the longest dimension of the inner opening of the frame is 60% or less, and the mesh-integrated metal in which openings of the mesh around the metal mask are sealed mask.   2. The mesh-integrated metal mask according to claim 1, wherein the metal mask has a thickness of 10 μm or less and the sealing portion is flush with or lower than the surface of the metal mask.   2. The mesh-integrated type according to claim 1, wherein the mesh portion is thicker than the mesh, and the difference between the thickness of the portion exposed from the mesh surface of the mesh portion and the thickness of the metal mask is 10 μm or less. Metal mask.   The mesh-integrated metal mask according to claim 3, wherein a thickness of the metal mask is thicker than a thickness of a portion exposed from the mesh surface of the sealing portion.   The mesh-integrated metal mask according to claim 4, wherein a difference between a thickness of the metal mask and a thickness of a portion exposed from the mesh surface of the sealing portion is 5 µm or less.   6. The mesh-integrated metal mask according to claim 1, wherein the diagonal length of the metal mask is 60% or less with respect to the diagonal length of the inner opening of the frame body.   The length of at least one side of the outer periphery of the metal mask is 60% or less with respect to the length of one side in the same direction as the length of the metal mask of the inner opening of the frame. The mesh-integrated metal mask according to any one of 5.   The mesh-integrated metal mask according to any one of claims 1 to 5, wherein an area of the metal mask is less than 40% with respect to an area of an inner opening of the frame.   The length of at least one side in the vertical and horizontal directions of the outer periphery of the metal mask is 120% or less with respect to the length of the print pattern area having the print pattern through hole. Mesh integrated metal mask.   The mesh-integrated metal mask according to any one of claims 1 to 8, wherein the sealing portion is configured using a photosensitive emulsion emulsion, a photosensitive resin, or an adhesive.