JP2010182749A - Alignment mark and forming method thereof - Google Patents

Abstract

An alignment mark position reading accuracy is improved.
An alignment mark in which a plating power supply film is formed on a surface of a substrate, a photoresist pattern is formed on the plating power supply film, and then patterned by electroplating, and a method for producing the alignment mark. . The alignment mark is provided around a portion of the mark main body 15 so as not to form the plating power supply film 13 so as to adjust the resistance at the time of plating power supply, thereby adjusting the thickness of the plating layer serving as the mark main body 15 And a plating power supply non-film forming region 16 to be controlled. In forming the mark main body 15, an alignment mark is formed by forming a region where the plating power supply film non-formation region 16 is formed around the mark main body 15 and the plating power supply film 13 is not formed. It is provided and the resistance at the time of plating power feeding is adjusted to control the film thickness of the plating layer serving as the mark body 15.
[Selection] Figure 1

Description

  The present invention relates to an alignment mark that is patterned on the surface of a printed wiring board or the like.

  In a printed wiring board manufacturing process or the like, an alignment mark is provided on a board in order to specify a position of the board when component mounting or the like is performed after the board is manufactured. This alignment mark is usually formed on the surface of the substrate by plating. By forming the alignment mark by plating, a step is generated between the surface of the alignment mark and the surface of the substrate. Then, the surface of the substrate is photographed with a camera, and a step between the surface of the alignment mark and the surface of the substrate is identified as a difference in contrast by image processing, and the position of the alignment mark is specified. Thereby, the position of the substrate, the position of the circuit on the substrate surface, and the like are specified based on the specified alignment mark.

  In this manner, the position of the board, the position of the circuit on the board surface, and the like are specified based on the alignment mark, and components are mounted on the printed wiring board.

  Examples of such alignment marks will be described with reference to FIGS.

  As shown in FIGS. 2 and 3, the alignment mark 1 is mainly composed of an antireflection film 3 provided on the substrate 2 and a mark portion 4 provided on the antireflection film 3.

  In creating the mark portion 4, it is important to make the plating film thickness uniform within the surface, but depending on the pattern, it may be difficult to control the plating film thickness within the surface. If the plating film thickness of the mark part 4 becomes thicker than necessary, the edge part of the mark part 4 may be tapered and the contrast of the edge part may be unclear.

  An example of a method for creating the alignment mark 1 will be described with reference to FIGS.

  On the substrate 2 shown in FIGS. 4A and 5A, an insulating material (polyimide) to be the antireflection film 3 is formed as shown in FIGS. 4B and 5B. Next, a sputtered film 5 for plating power feeding is formed on the substrate 2 and the antireflection film 3 as shown in FIGS. 4C and 5C, and shown in FIGS. 4D and 5D. Thus, a photoresist pattern 6 is formed. At this time, a necessary laminated pattern is simultaneously formed. Next, electroplating is performed. As a result, a plating layer 7 is formed along the photoresist pattern 6 as shown in FIGS. 4 (e) and 5 (e).

  Thereafter, the photoresist pattern 6 is removed as shown in FIGS. 4 (f) and 5 (f), and the plating power supply sputtering film 3 is removed as shown in FIGS. 4 (g) and 5 (g). The alignment mark 1 is completed as shown in FIGS. At this time, a pattern to be a wiring is created at the same time.

  Examples of the alignment mark 1 include those described in Patent Document 1 and Patent Document 2.

JP 2002-246743 A JP 2007-258374 A

  By the way, when the alignment mark 1 is formed by plating, it may be difficult to recognize depending on the height of the plating layer. In the case of the mark portion 4 of the alignment mark 1 shown in FIG. 2, the plating layer becomes too high and the edge portion 8 becomes tapered, so that it is difficult to identify. That is, the contrast of the edge portion 8 becomes unclear and it is difficult to identify the alignment mark 1 and the alignment mark 1 cannot be read accurately.

  When the plating for forming the alignment mark 1 becomes thick, there may be a taper on the upper side and the lower side of the plating as in the edge portion 8 of the mark portion 4 shown in FIG. When the edge portion 8 is tapered, it is difficult to recognize the mark portion 4 when processing the image photographed by the camera when the position is recognized using the mark portion 4. Specifically, if the edge portion 8 of the mark portion 4 is tapered, the image processing recognizes somewhere in the tapered portion t as an edge, so that the position of the edge portion 8 fluctuates and an error occurs. Will occur. That is, the contrast of the taper portion t which is the edge portion 8 becomes unclear and a plurality of edge portions appear, and each time the alignment mark 1 is read, a different portion is recognized as the edge portion 8 and an error occurs. . As a result, there is a problem that the alignment mark position reading accuracy is lowered.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an alignment mark that can improve alignment mark position reading accuracy and a method for producing the alignment mark.

  In order to solve the above problems, the alignment mark according to the present invention is formed by forming a plating power supply film on the surface of the substrate, then forming a photoresist pattern on the plating power supply film, and then patterning by electroplating. An alignment mark, a mark body formed on the surface of the substrate, and an area formed around the mark body, where a portion where the film for plating power feeding is not formed is provided in part. A plating power feeding film non-formation region for controlling the film thickness of the plating layer serving as the mark body by adjusting the resistance at the time is provided.

  The method for creating an alignment mark according to the present invention is to create an alignment mark by forming a plating power supply film on the surface of a substrate, then forming a photoresist pattern on the plating power supply film, and then patterning by electroplating. In order to form the alignment mark main body at a predetermined position on the substrate, when a plating power feeding film is provided around the mark main body forming portion at the position, the plating power feeding is provided around the position. Adjusting the resistance at the time of plating power feeding by forming a film non-formation region and forming a region where the plating power feeding film is not formed in part, thereby controlling the thickness of the plating layer serving as the mark body Features.

  When forming the mark main body, the plating power supply film non-formation region is formed and the resistance at the time of plating power supply is adjusted to control the thickness of the plating film. Can be prevented. As a result, alignment mark position reading accuracy can be improved.

It is a schematic diagram which shows the cross section of the alignment mark which concerns on embodiment of this invention, and the plane and side surface of a mark main body. It is a schematic diagram which shows the cross section of the conventional alignment mark, and the plane and side surface of a mark main body. It is a top view which shows the conventional alignment mark. It is process drawing which shows the preparation method of the conventional alignment mark in a cross-sectional state. It is process drawing which shows the preparation method of the conventional alignment mark in a planar state. It is a top view which shows the alignment mark which concerns on embodiment of this invention. It is process drawing which shows the preparation method of the alignment mark which concerns on embodiment of this invention in a cross-sectional state. It is process drawing which shows the preparation method of the alignment mark which concerns on embodiment of this invention in a planar state. It is a top view which shows a 1st modification. It is a top view which shows the 2nd modification.

  Hereinafter, an alignment mark and a method for producing the same according to an embodiment of the present invention will be described with reference to the accompanying drawings. The alignment mark of the present embodiment is provided on the surface of a substrate that needs to be accurately specified, such as a printed wiring board. The position of the alignment mark is recognized by photographing the alignment mark with a camera and processing the image, and the position of the substrate, the position of the circuit on the substrate, and the like are specified based on the position of the alignment mark. The alignment mark of this embodiment can be applied to all such substrates.

  The alignment mark according to the present embodiment is a mark that is patterned by electroplating. In the case of electroplating, the thickness of the plated layer varies depending on the amount of power supplied. For this reason, the amount of power supplied is adjusted by appropriately providing a resistance portion, and the film thickness of the plating layer is controlled.

  As shown in FIGS. 1 and 6, the alignment mark 11 according to this embodiment mainly includes a substrate 12, a plating power supply film 13, an antireflection film 14, a mark body 15, and a plating power supply film non-formation region. 16. 1A is a cross-sectional view taken along the line AA in FIG. 6, FIG. 1B is a cross-sectional view taken along the line BB in FIG. 6, and FIG. FIG.

  The substrate 12 is a substrate such as a printed wiring board.

  The plating power supply film 13 is a film serving as an electrode to which ions constituting the plating layer adhere when the plating layer is formed by electroplating. The plating power supply film 13 is formed by, for example, a sputtering method using a sputtering phenomenon. In this sputtering method, it is generally known that a phenomenon in which a sputtered film is not formed due to insufficient coverage (a film formation state at the stepped portion) occurs at a stepped portion. Using this, the plating power supply film 13 is formed while forming the plating power supply film non-forming region 16 described later.

  When the plating power supply film 13 is formed by the sputtering method, if the sputtered particles collide with the plating power supply film non-forming region 16, the coverage may be insufficient. That is, when the film is not formed in the plating power supply film non-formation region 16 and the plating power supply film non-formation region 16 is formed high, the coverage is insufficient due to the step between the upper end and the base end. The phenomenon that the film is not formed occurs. As a result, no film is formed on the side wall of the plating power supply film non-forming region 16, and the film formed in the plating power supply film non-forming region 16 is separated from the plating power supply film 13. As a result, the portion of the plating power supply film non-forming region 16 does not function as the plating power supply film 13 but becomes a resistance portion. Utilizing this, the plating power supply film 13 having the resistance portion is formed. The plating power supply film 13 is formed on the surface of the substrate 12 and the antireflection film 14.

  The antireflection film 14 is a film material that serves as a base for supporting the mark main body 15, and is formed in a quadrangular trapezoidal shape. The antireflection film 14 is formed of a resin such as polyimide. Thereby, the antireflection film 14 increases the contrast with the mark body 15 formed on the antireflection film 14 when processing an image taken by the camera.

  The mark main body 15 is a mark serving as a reference for alignment. The mark main body 15 is formed at a set position of the substrate 12 and is used for alignment of the substrate 12, alignment of circuits in the substrate 12, and the like. When performing alignment or the like of the substrate 12, the mark main body 15 is specified, and the position of the substrate 12 and the position of the circuit in the substrate 12 are specified based on the mark main body 15.

  The mark body 15 is required to have an edge portion so that the mark body 15 can be accurately recognized by the camera. For this reason, it is desirable that the mark main body 15 be formed thin. This is because when the mark main body 15 is thick, the edge portion is tapered as described above as a problem of the prior art. For this reason, the mark main body 15 is composed of a plated layer, and the thickness of the plated layer is adjusted by changing the amount of power supply.

  The plating power supply film non-formation region 16 is an area formed around the mark main body 15, and the resistance at the time of plating power supply is adjusted by providing a part where the plating power supply film 13 is not formed. This is a resistance portion for controlling the film thickness of the plating layer that becomes the mark main body 15. The plating power supply film non-formation region 16 is provided so as to surround the periphery of the formation portion of the mark main body 15. Specifically, it is composed of four convex portions 17 formed along each side of the rectangular antireflection film 14. The four elongated protrusions 17 are formed by deleting the corners of the streaky protrusions formed in a square ring shape.

  The plating power supply film non-formation region 16 is formed simultaneously with the antireflection film 14. Specifically, first, four elongated base portions 17A (see FIG. 7A) having the same height as the antireflection film 14 are formed using a resin such as polyimide as the first step, and then as the second step. Then, a synthetic resin is further laminated on each base portion 17A and raised to form the convex portion 17. The height of each convex portion 17 constituting the plating power supply film non-formation region 16 is such that when the sputter film is formed by the sputtering method, the coverage is insufficient at the upper end and the base end, and the sputter film is not formed on the side wall. Set to be. Sputtered films are not formed on the side walls of the four convex portions 17 and are electrically separated from the plating power supply film 13, so that the four convex portions 17 constitute resistance portions. The convex portions 17 as the resistance portions reduce the amount of power supplied by the plating power supply film 13 in the antireflection film 14 portion, and the plated layer formed on the antireflection film 14 becomes thin and stabilized. That is, the mark body 15 and the outer mark portion 18 on the outer periphery thereof are thinned and stabilized. As a result, the upper end portion and the base end portion of the edge portion are not tapered, and the sharp edge portion becomes sharp and the recognition of the mark main body 15 is stabilized. Thus, the alignment mark 11 with a clear edge is obtained by reducing the plating film thickness of the alignment mark 11.

  The amount of power supply is adjusted by changing the resistance values by changing the four convex portions 17. That is, the power supply amount is adjusted by controlling the resistance value by changing the installation positions and sizes of the four convex portions 17 and changing the distance between them.

[How to create alignment marks]
Next, a method for creating alignment marks will be described.

  In the method of creating an alignment mark of this embodiment, a plating power supply film 13 is formed on the surface of the substrate 12, a photoresist pattern is formed on the plating power supply film 13, and the thickness of the alignment mark is increased by electroplating. In this method, a pattern is formed while adjusting. In this method of creating an alignment mark, in order to form the alignment mark body at a predetermined position on the substrate 12, when the plating power supply film 13 is provided around the formation portion of the mark body 15 at the position, The plating power supply film non-formation region 16 is formed around the position, and the region where the plating power supply film 13 is not formed is provided in part to adjust the resistance during plating power supply, thereby forming the mark body 15. Control the thickness of the plating layer.

  Four convex portions 17 are used as the plating power supply film non-forming region 16 in which a region where the plating power supply film 13 is not formed is provided in part. A region where the plating power supply film 13 is not formed in a set range is formed by using the four convex portions 17 surrounding the periphery of the formation portion of the mark body 15. The resistance at the time of plating power feeding is adjusted according to the size of the plating power feeding film non-forming region 16 where the plating power feeding film 13 is not formed. Specifically, the plating power supply film 13 is formed of a sputtered film by sputtering, and the sputtered film is cut at the upper end and the base end by a step in the plating power supply film non-forming region 16. That is, the created sputtered film is cut due to insufficient coverage in the plating power supply film non-forming region 16.

  Thereby, when the sputtered film is formed by the sputtering method, the sputtered film is cut off at the upper end and the base end of the plating power supply film non-forming region 16 so that no current flows. The plating power supply film non-formation region 16 where no current flows is used as a resistance portion. By appropriately adjusting the dimension of the plating power supply film non-forming region 16 as the resistance portion, the resistance value is changed to adjust the resistance at the time of plating power supply. This resistance reduces the amount of power supplied to the alignment mark portion at the mark body 15, thereby reducing the amount of deposition of plating. Thereby, the film thickness of the plating layer of the mark main body 15 is made thinner than other portions. After electroplating, the photoresist and the sputtered film are removed to complete the alignment mark.

  At this time, patterns necessary for wiring are created simultaneously. In patterns other than the alignment mark, since the amount of power supply is normal, a necessary plating film thickness can be obtained.

  A specific method for creating an alignment mark will be described with reference to FIGS. 7A is a side view of the substrate 12, FIG. 8A is a plan view of the substrate 12, FIG. 7B is a cross-sectional view taken along line AA in FIG. 8B, and FIG. 8B is a cross-sectional view taken along line BB in FIG. 8B, FIGS. 7D and 7E are cross-sectional views taken along line AA and BB in FIG. 8C, and so on. 7 (f) to (o) are cross-sectional views taken along lines AA and BB in FIGS. 8 (d) to (h). For example, the dimensions in FIGS. 7B and 7C are originally different. FIG. 7B is a dimension on the AA line of FIG. FIG.7 (c) is a dimension on the BB line of FIG.8 (b). For this reason, although both have different dimensions, they are the same here for convenience of explanation.

  First, the antireflection film 14 and the convex portion 17 are formed on the substrate 12 of FIGS. 7A and 8A with a synthetic resin such as polyimide as shown in FIGS. 7B, 7C, and 8B. The base portions 17A are respectively formed. The base portion 17A is the first step and is formed at the same height as the antireflection film 14.

  Next, as shown in FIGS. 7D, 7E and 8C, the four ridges 17 are formed by laminating the synthetic resin as the second stage on each of the base parts 17A as the first stage. The convex portion 17 is formed at a level difference that is high enough to prevent the sputtered film from being formed on the side wall due to insufficient coverage between the upper end and the base end. The four projections 17 form a plating power supply non-film formation region 16.

  Next, as shown in FIGS. 7F, 7G, and 8D, the plating power supply film 13 is formed on the entire substrate 12, the antireflection film 14, and the plating power supply film non-forming region 16 by sputtering. A sputtered film is formed. At this time, like the portions X and Y in FIG. 7 (f), the plating power supply film 13 is cut due to the step of the plating power supply film non-forming region 16, and this portion becomes a resistance during electroplating. Part.

  Next, as shown in FIGS. 7H, 7I, and 8E, a pattern 19 for forming the mark main body 15 and the like is formed using a photoresist. In pattern formation using a photoresist, a uniform film is formed over the entire portion of the formed pattern regardless of the level difference.

  Next, electroplating is performed as shown in FIGS. 7 (j) (k) and 8 (f). At this time, a voltage is applied to the plating power supply film 13 to form an electrode to which ions constituting the plating layer adhere. At this time, since the plating power supply film 13 is cut in the plating power supply film non-forming region 16, the power supply amount of the mark body 15 surrounded by the plating power supply film non-forming region 16 is limited, The plating layer becomes thinner. That is, since the amount of power supply is not limited outside the plating power supply film non-forming region 16, the plating layer has a normal thickness. On the other hand, on the inner side of the plating power supply film non-forming region 16 where the mark main body 15 is located, the power supply amount is limited, and the thickness of the plating layer becomes thinner than the outer side. The thickness of the plating layer inside the plating power supply film non-formation region 16 is formed such that the edge portion cannot be tapered. The film thickness of the plated layer that cannot be tapered at the edge portion varies depending on various conditions such as the size of the mark body 15, so that the actual mark body 15 is experimentally formed with a plurality of different thicknesses, and the most desirable thickness Is identified. That is, the size of the plating power supply film non-formation region 16 is variously changed to change the power supply amount at the time of electroplating, and a plurality of plating layers are experimentally formed to specify the most desirable thickness.

  Next, the photoresist is removed as shown in FIGS. 7 (l) (m) and 8 (g), and the plating power supply film 13 is used as shown in FIGS. 7 (n) (o) and 8 (h). Is removed to form the alignment mark 11 of FIG. The alignment mark 11 has a mark body 15 with a sharp edge.

[effect]
Since the plating power supply film non-formation region 16 is provided and the dimensions thereof are changed as appropriate to adjust the resistance value at the time of plating power supply, the thickness of the plating layer of the alignment mark 11 can be easily controlled. it can. As a result, it is possible to form an alignment mark 11 having a sharp contrast without a taper at the edge portion.

  In addition, the alignment mark 11 can be accurately recognized by forming the alignment mark 11 as described above. That is, by photographing the alignment mark 11 with a camera and processing the image, it is possible to recognize the alignment mark 11 with a sharp contrast of the edge portion, and to improve the alignment mark position reading accuracy.

  As a result, the alignment accuracy of the substrate 12 can be improved during exposure of the printed wiring board.

  The alignment mark of the present invention can be used for all members whose positions need to be specified by camera image processing.

  Further, in the embodiment, the plating power supply film 13 is formed by the sputtering method, and the plating power supply film non-forming region 16 is provided with a height difference at which the sputtered film is cut at the upper end and the base end. However, the present invention is not limited to this, and any means that can partially provide a region where the plating power feeding film 13 is not formed can be used. For example, after the plating power supply film is formed on the entire surface without increasing the plating power supply film non-forming region, a step of removing the plating power supply film in the portion of the plating power supply film non-forming region may be provided. . Also, when forming a plating power supply film, a part of the substrate surface is masked to create a region where no film is formed, or after the plating power supply film is solidified, a part is removed by etching or the like. May be. In this case, the plating power supply film is not limited to the sputtering method, and other methods such as a CVD method may be used.

  In the above embodiment, the plating power feeding film non-formation region 16 is configured by the four convex portions 17 surrounding the formation portion of the mark main body 15. However, the present invention is not limited to this, and the formation of the mark main body 15 is performed. Any convex portion that surrounds the portion and is partially cut off may be used. For example, as shown in FIG. 9, the plating power feeding film non-forming region 21 may be formed in an annular shape by cutting two places to greatly reduce the power feeding amount. At this time, the amount of power supply is adjusted by providing one or three or more cut portions. The amount of power supply may be adjusted by changing the width of the two cut portions.

  In addition to this, as shown in FIG. 10, four rectangular convex portions 22 may be provided. The plating power supply film non-formation region 16 may be any shape provided around the mark body 15 and capable of adjusting the power supply amount to the mark body 15. Thereby, there can exist an effect | action and effect similar to the said embodiment.

  11: alignment mark, 12: substrate, 13: plating power supply film, 14: antireflection film, 15: mark main body, 16: plating power supply film non-formation region, 17: convex portion, 21: plating power supply film non-formation Region 22: convex portion.

Claims (6)

An alignment mark formed by forming a plating power supply film on the surface of the substrate, then forming a photoresist pattern on the plating power supply film, and then patterning by electroplating,
A mark body formed on the surface of the substrate;
The thickness of the plating layer that becomes the mark body by adjusting the resistance at the time of plating power feeding by providing a part of the area around the mark body where the plating power feeding film is not formed. An alignment mark comprising a plating power feeding film non-formation region for controlling The alignment mark according to claim 1,
An alignment mark, wherein the plating power supply film non-formation region is constituted by a convex portion surrounding the mark main body formation portion and partially cut off. In the alignment mark according to claim 1 or 2,
The plating power supply film is formed by a sputtering method, and the plating power supply film non-forming region has a height at which the sputtering film is not formed due to insufficient coverage at the upper end and the base end when the sputtering film is formed by the sputtering method. An alignment mark characterized by a step. Forming a plating power supply film on the surface of the substrate, then forming a photoresist pattern on the plating power supply film, and then forming an alignment mark by electroplating;
In order to form the alignment mark main body at a predetermined position on the substrate, when a plating power feeding film is provided around the mark main body forming portion at the position, a plating power feeding film non-forming region is formed around the position. An alignment mark formed by adjusting a resistance at the time of plating power feeding by providing a part of the region where the plating power feeding film is not formed, thereby controlling the film thickness of the plating layer serving as the mark body How to create In the creation method of the alignment mark of Claim 4,
As the plating power supply film non-formation region, by using a convex portion surrounding the mark main body forming portion and partially cut off, a region where the plating power supply film is not formed is provided in part so that the plating power supply is not performed. A method for producing an alignment mark, characterized by adjusting a resistance of the substrate. In the creation method of the alignment mark of Claim 4 or 5,
The plating power feeding film is formed by a sputtering method, and the plating power feeding film non-formation region is formed at a height step where the sputtering film is not formed due to insufficient coverage, and when the sputtering film is formed by the sputtering method. Forming an alignment mark characterized by adjusting the resistance at the time of plating power feeding by using the plating power feeding film non-forming region where the sputter film is not formed due to a lack of coverage at a step of the plating power feeding film non-forming region as a resistance portion Method.

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