JP6539616B2 - Mesh integrated metal mask - Google Patents

Description

  The present invention relates to a mesh integrated metal mask.

  The mesh integrated metal mask is used, for example, for screen printing of internal electrodes of chip-like 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 and formed into a desired print pattern by electroforming is electrodeposited (integrated) on a conductive mesh. A method of making a mask is disclosed. According to this, it is excellent in chemical resistance and abrasion resistance as compared with those in which a mask made of photosensitive resin or the like is formed on the mesh, and the dimensional change due to the squeegee pressure is extremely small, and the sharpness is relatively high. Printing can be expected.

  On the other hand, with the recent trend of miniaturization and densification of electronic parts, the multilayer ceramic capacitor is required to be miniaturized and increased in capacity. In order to reduce the size and increase the capacity, it is progressing to further increase the number of dielectric layers to be laminated and to make the dielectric layer per layer thinner, and accordingly, the internal electrode pattern is made thin and high by screen printing. Printing with high positional accuracy and high dimensional accuracy has been required.

  Patent Document 1 and Patent Document 2 disclose a method of manufacturing a mesh-integrated metal mask as thin film compatible. FIG. 7 is a schematic explanatory view of a general manufacturing method of the mesh integrated metal mask. As shown in FIG. 7A, an electroforming matrix 71 having conductivity is prepared, and as shown in FIG. 7B, an insulating pattern 72 is formed of an insulating film such as a resist on the electroforming matrix 71. Form The shape of the insulating pattern 72 corresponds to the opening in the resultant mesh-integrated metal mask, in other words, the shape of the pattern to be formed by printing. Next, as shown in FIG. 6C, a metal mask 73 is formed by a plating technique such as nickel plating. At this time, the portions of the insulating pattern 72 are prevented from being plated and become openings in the metal mask 73. Thereafter, as shown in FIG. 6D, the conductive mesh 74 stretched on the frame is pressed onto the metal mask 73 to integrate the both by plating such as nickel plating. The integrated metal mask 73 and the mesh 74 are peeled off from the electroforming matrix 71 to obtain a mesh integrated metal mask 70 (FIG. 6E). As described above, in the mesh integrated metal mask 70, the opening 75 is formed at a position corresponding to the insulating pattern 72.

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

  As described above, when bonding a metal mask to a conductive mesh, it is necessary to apply tension to the mesh and press the metal mask (electrodeposited layer) against the mesh. At this time, since the metal mask is bonded in a state where the mesh is stretched, when the electroforming matrix is peeled from the metal mask after bonding, the elongation of the mesh due to pressing is relaxed, and the metal mask itself is deformed at the same time I will. As a result, positional deviation occurs in the pattern formed on the metal mask, making it impossible to manufacture a screen mask with high accuracy. 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 the stability thereof is also low.

  As described above, when the electroforming matrix and the metal mask (electrodeposited layer) are tensioned and pressed onto the mesh, the stronger the pressing, the larger the mesh is stretched, and as a result, the positional deviation of the pattern becomes larger. On the contrary, if the pressing is weak, the adhesion between the mesh and the metal mask is insufficient, which causes a bonding failure. In view of the above, it is an object of the present invention to provide a mesh-integrated metal mask that can achieve both sufficient adhesion of a mesh and a metal mask, and reduce positional deviation of a pattern.

  According to the present invention, a metal mask having a frame, a mesh which is stretched on the frame and at least a part of which is a metal, and a printed pattern through hole which is in contact with the mesh and which is 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 opening around the metal mask is sealed An integrated mesh metal mask is provided.

  According to the present invention, the adhesion between the mesh and the metal mask is sufficient, and the positional displacement amount and dimensional displacement amount of the pattern 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 in unification of a metal mask and a mesh is shown. The calculation result regarding the distribution of the load to the mesh which arises at the time of unification of a metal mask and a mesh is shown. It is model explanatory drawing about the positional offset and dimension shift of a pattern. Indicates deviations in patterns and dimensions. It is model explanatory drawing of the general manufacturing method of a mesh integrated metal mask. The metal mask dimension conditions, the pattern positional deviation amount, and the dimensional deviation amount of the example and the comparative example are shown in the table. The pattern positional deviation amount and the dimensional deviation amount are illustrated. It is a schematic cross section of a mesh integrated type metal mask.

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

  FIG. 1 is a schematic cross-sectional view of a process of integrating 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. The metal mask 13 is formed on the electroforming matrix 14 on which the insulating pattern 12 is formed, and a state in which the mesh 11 stretched on the frame is pressed is depicted. According to the present invention, since the size of the metal mask 13 is substantially equal to the printing pattern area, sufficient adhesion between the mesh 11 and the metal mask 13 can be achieved only by pressing the mesh 11 against the metal mask 13 with a weak force. For this reason, the elongation of the mesh 11 by pressing becomes small, and as a result, the positional deviation becomes small. In particular, an advantage can be found in that the load on the mesh 11 in the region indicated by the symbol I, in other words, near the end of the electroformed matrix 14 does not become excessive.

  Here, the printing pattern area is defined as an area where an opening of a predetermined position and shape is formed in the metal mask. The fact 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 substantially the entire area of the metal mask.

  FIG. 1 (B) is a schematic cross-sectional view in the case of manufacturing a mesh-integrated metal mask in the prior art. A metal mask 17 is formed on the electroforming matrix 19 on which the insulating pattern 18 is formed, and a 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 printed pattern area, and the metal mask 17 is present over the area including the area in which 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 in the integration. For this reason, the elongation of the mesh 16 due to the pressing becomes large, and as a result, the positional deviation becomes large. In particular, the load on the mesh 16 in the region indicated by the symbol II, in other words, in the vicinity of the end of the electroformed matrix 19 becomes excessive.

  Among the end portions of the electroformed matrix 19, particularly, the load at the corner portion of the electroformed matrix 19, that is, in the vicinity of the corner of the frame is large. Therefore, by chamfering the corner portion of the electroforming matrix 19 largely, one or both of the longitudinal and lateral sides of the electroforming matrix 19 can be reduced, and either the longitudinal or lateral side of the metal mask 17 can be reduced. The same effect as described above can be obtained by making one or both lengths 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, but the present inventors have found that if the metal mask joined to the mesh is very thin, the printed pattern area It is newly found that even if only metal is not a 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 the mesh-integrated metal mask. FIG. 2A shows a mesh-integrated metal mask according to the present invention. FIG. 2C is another example of the mesh integrated metal mask according to the present invention. In both examples, the area indicated by reference numeral 21 near the center is the area of the metal mask integrated with the mesh. A sealing portion 22 is provided around the metal mask 21.

  The role of the blinding portion 22 is to prevent the printing paste from adhering to the portion other than the substrate under the screen through the opening of the mesh. The material of the filling portion 22 is not particularly limited as long as it can play the above role, and preferably, a photosensitive emulsion, photosensitive resin or adhesive is used. The blind portion may be smaller than the thickness of the mesh or may be exposed by several μm from the mesh surface.

  In ordinary printing, a sufficient amount of printing paste is temporarily stored in an area circumscribed to one side of the printing pattern area, and this is spread evenly in a printing pattern area with a scraper and printed with a squeegee. We will imprint in the pattern opening. Because there is a variety in the number of squeegees, the number of scrapers, and the movement directions of the squeegee and the scrapers, in some cases, the area for temporarily storing 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 a paste supply unit and a holding unit from the function thereof. In the mesh-integrated metal mask of the present invention, a paste supply unit and a holding unit exist, and no metal mask is formed in the paste supply unit and the holding unit. The prior art can be appropriately referred to 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 the mesh. The surrounding area 27 carries a metal mask in which the plugged mesh is integral with the mesh. Although a paste supply unit and a holding unit are also present in the mesh integrated metal mask of the conventional example, a metal mask is configured in the paste supply unit and the holding unit.

  According to the present invention, the thickness of the sealing portion can be appropriately determined in relation to the thickness of the mesh. In a preferred embodiment, the sealing portion does not exceed the thickness of the mesh. 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 filling portion does not exceed the thickness of the mesh and the thickness of the metal mask is within the above range, the squeegee or scraper is affected by the step between the filling portion and the metal mask portion during printing. The advantage of being able to move without moving is anticipated (FIG. 10 (A)). It is difficult to apply a force to the mesh due to squeegeeing near the metal end, strain is not easily generated, reduction of plate life due to peeling of metal hardly occurs, and concern about reduction of life due to accelerated wear of squeegee angle is also reduced.

  As another aspect, the sealing portion may be thicker than the mesh and exposed as a several μm film from the mesh surface. In this case, it is preferable that the difference between the thickness exposed from the mesh surface of the sealing portion and the thickness of the metal mask be as small as possible, specifically, the difference is 10 μm or less (FIG. 10 (B), FIG. 10 (C). Here, reference numeral 101 represents a filling 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 filling portion and the thickness of the metal mask is small, in other words, the force on the mesh due to squeegeeing near the metal end due to the small “step” It is hard to take place, distortion is difficult to occur, plate life is not easily reduced due to metal peeling, and there is less concern about life reduction due to accelerated wear of the squeegee angle.

  It is a preferred embodiment 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. 10 (C)).

  The table described at the bottom of 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. The criterion for the life is described 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, more preferably 50% or less. Here, the “frame” is a holder that holds the screen and stretches the mesh. The "longest dimension" inside the frame means the longest dimension of the stretched mesh, which usually refers to the length of the diagonal. In the case of a square or rectangular metal mask, the “longest dimension” of the metal mask is usually the diagonal length, but this is not the case depending on the shape of the metal mask. Since the relationship of the longest dimension is 60% or less, an advantage can be expected from FIGS. Further, when the relation of the longest dimension is 50% or less, an advantage that the pattern displacement amount is within ± 10 μm can be expected from FIGS. 8 and 9.

  Further, 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 side or the horizontal side of the metal mask. Do. Since the relationship of these “lengths” is 60% or less, an advantage is expected from FIGS. 8 and 9 that the average value of the amount of dimensional deviation in that direction is about half that of the conventional example.

  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 mesh that has been stretched, and the "area" of the metal mask means the whole area including the part of the printed pattern through holes made in the metal mask. Since the relationship of these "areas" is 40% or less, the advantage that the average value of the pattern positional deviation amount can be reduced to about 1/2 that of the conventional example is expected from FIGS.

  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 the longitudinal or lateral length of the outer peripheral portion of the quadrangle which can include all the print pattern through holes formed in the metal mask. If the “length” relationship is within the above range, the length of the metal mask can be minimized with respect to the length of the pattern area in the step of integrating the metal mask and the mesh. It is expected to be integrated with less distortion as in 1.

  FIG. 3 shows the pressure distribution that occurs upon integration of the metal mask and the mesh. The pressure generated in the integration is measured by a pressure sensor, and the pressure value is expressed as a relative value by color density. FIG. 3A shows a pressure distribution at the time of integration of the metal mask and the mesh in the prior art. The pressure is relatively small at the central portion of the metal mask, which is the minimum pressure sufficient for integration of the metal mask and the mesh. In that case, a relatively large pressure is generated at the end of the metal mask, and a particularly large pressure is generated particularly at the corner of the metal mask among the ends, and a large load is applied to the mesh. It is guessed that

  FIG. 3 (B) shows a pressure distribution at the time of integration of the metal mask and the mesh according to the present invention. It is characteristic that the pressure is relatively low and less variable 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 is unlikely to occur. Therefore, the mesh and the metal mask are pressed with a large pressure to promote sufficient integration. At the same time, the distortion of the mesh can be reduced. FIG. 3C shows another example of the pressure distribution at the time of integration of the metal mask and the mesh according to the present invention. It is characteristic that the pressure is relatively low and the variation is small at the corner edge of the metal mask. 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, so the mesh and the metal mask are pressed with a large pressure to achieve sufficient integration. While reducing the distortion of the mesh.

  FIG. 4 shows the calculation result on the distribution of the load on the mesh that occurs in the integration of the metal mask and the mesh. FIG. 4A shows a load distribution at the time of integration of the metal mask and the mesh in the prior art. A relatively large load is generated at the end of the metal mask, and the calculation result is obtained that the distortion of the mesh is increased. FIG. 4 (B) shows a load distribution at the time of integration of the metal mask and the mesh according to the present invention. Unlike the case of FIG. 4A, it was shown by calculation that the load is relatively low at the end of the metal mask and the distortion of the mesh is also small. FIG. 4C shows another example of the load distribution at the time of integration of the metal mask and the mesh according to the present invention. Unlike the case of FIG. 4A, it was shown by calculation that the load is relatively low at the corners of the metal mask and the distortion of the mesh is also small.

FIG. 5 is a schematic explanatory view of positional deviation and dimensional deviation of a pattern.
The positional deviation in FIG. 5A is defined as the positive direction, and the positional deviation in FIG. 5B is defined as the negative direction. The positional deviation of the pattern area 51 in FIG. The dotted line 52 is a design value of the pattern area and shows the case where the positional deviation is zero. Similarly, the positional deviation of the pattern area 51 in FIG. The meaning of the dotted line 52 is the same as that of FIG. 5 (A). In both figures, distortion of the pattern area shape is expressed. Due to the strong and uneven pressing, the mesh elongation at the time of bonding is large and the positional deviation is large when the balance is broken.

  FIG. 5C shows the deviation of the pattern area size from the design value in the prior art. FIG. 5D shows the deviation of the pattern area size from the design value in the present invention. The reference numeral 51 is a schematic view of a pattern area to be measured, and the dotted line indicated by the reference numeral 52 shows 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 bonding is large, and the pattern size on the metal mask is reduced. In the present invention, as shown in FIG. 5 (D), the pressing amount at the time of bonding can be reduced, so the pattern size becomes large and the dimensional deviation from the design value is small.

  FIG. 5E and FIG. 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, as shown in FIG. 5F, if the jig 57 is removed and the substrate is peeled off from the metal mask 55, the position of the pattern is shifted.

  FIG. 6 shows the deviation of patterns and dimensions. 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 a sample number. In each graph, measured values of the mesh-integrated metal mask according to the prior art and the embodiment of the present invention are plotted. The mesh integrated metal mask of the present invention uses a frame having an inner opening dimension of 716 mm in length and width and a diagonal dimension of 1013 mm, the thickness of the metal mask is 5 μm, the mesh thickness is 20 μm, and the meshed portion Thickness is less than 1 μm, the vertical and horizontal dimensions of the metal mask are 320 mm each, the diagonal is the maximum dimension of the metal mask 452 mm, and the ratio of the longest dimension of the metal mask to the longest dimension inside the frame is 45%; The length of the mask is 107% of the length of the print pattern area. Another example of the mesh integrated metal mask of the present invention uses the same frame, and has a shape in which the corners of the metal mask are cut off, and the thickness is 5 μm, the mesh thickness is 20 μm, and the thickness of the sealing portion Is less than 1 μm, the maximum dimension in the vertical and horizontal directions of the metal mask is 500 mm each, the length of one side of the right triangle of the square cutout is 80 mm, the longest dimension of the metal mask is 605 mm, the metal for 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 length of the printed pattern area is 167%. The material of the blind portion is an emulsion. In the mesh integrated metal mask in the prior art, since the same frame is used and the vertical and horizontal dimensions of the metal mask are each 500 mm, 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 print pattern area was 167%. The plot of は 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 the mesh integrated metal mask of another example of the present invention Represents a measured value. As shown in FIGS. 6A to 6C, in the mesh integrated metal mask according to the present invention, the positional deviation and the dimensional deviation of the pattern were smaller than those of the conventional product.

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

  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 at the inner opening of the frame, as shown in FIGS. Further, the average value of the amount of dimensional deviation in that direction is about half that of the conventional example.

  Since the area of the metal mask is 40% or less with respect to the area of the inner opening of the frame, the average value of the pattern positional deviation can be reduced to about 1/2 that of the conventional example, as shown in FIGS. An advantage is expected.

In FIG. 8A, the condition 12 is 500 mm in the vertical and horizontal directions, but it has a shape in which four corner portions are chamfered (cut off) by a right triangle having one side of 80 mm. Although the ratio of the length of one side of the condition 8 is within the scope of the present invention, it does not satisfy the implementation of the present invention because the ratio of the longest part is not satisfied. In FIG. 8B, it is considered that the reason that the X and Y directions do not become the same amount of direction shift is that the mesh is stretched at an angle of 30 degrees with respect to the frame.

Claims (10)

A mesh formed by a frame, a metal mask having a printed pattern through hole which is stretched on the frame and at least a part of which is made of metal and which is in contact with the mesh and which is in contact with the mesh It is a body-type metal mask, The thickness of the said metal mask is 5 micrometers or less, The length of the vertical and horizontal at least one side of the said metal mask is with respect to the length of the printing pattern area which has the said printing pattern through-hole A mesh integrated metal mask, which is 120% or less and in which openings of the mesh around the metal mask are sealed. Mesh-integrated metal mask according to claim 1, before Symbol th stop portion is lower the metal mask surface is flush or even more.   The mesh integral type according to claim 1, wherein the sealing portion is thicker than the thickness of the mesh, and the difference between the thickness of the portion of the sealing portion exposed from the mesh surface 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 integral type metal mask according to claim 4, wherein a difference between a thickness of the metal mask and a thickness of a portion of the filling portion exposed from the mesh surface is 5 μm or less.   The mesh integrated metal mask according to any one of claims 1 to 5, wherein a diagonal length of the metal mask is 60% or less with respect to a diagonal length of the 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 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. The mesh integrated metal mask as described in any one of 5.   The mesh integrated metal mask according to any one of claims 1 to 5, wherein the area of the metal mask is less than 40% of the area of the inner opening of the frame. The mesh integrated metal mask according to any one of claims 1 to 5, wherein the longest dimension of the metal mask is 60% or less of the longest dimension of the inner opening of the frame .   The mesh integrated metal mask according to any one of claims 1 to 8, wherein the filling portion is constituted of a photosensitive emulsion, photosensitive resin or adhesive.