Patent Application
20240215155
The present invention relates to an assembly sheet and a method for producing an assembly sheet.
Conventionally, an assembly sheet having a plurality of suspension boards with a circuit, a frame body supporting the plurality of suspension boards with a circuit, and a reinforcement portion (reinforcement insulating layer and reinforcement conductive layer) disposed on the frame body has been known (ref: for example, Patent Document 1 below).
In the assembly sheet described in Patent Document 1, there is a demand that the frame body is further reinforced.
The present invention provides an assembly sheet capable of achieving further reinforcement of a frame, and a method for producing an assembly sheet.
The present invention [1] includes an assembly sheet including a wiring circuit board having a support layer, an insulating layer disposed on one surface of the support layer in a thickness direction, and a conductive pattern disposed on one surface of the insulating layer in the thickness direction: a frame supporting the wiring circuit board; and a reinforcement portion disposed on the frame in the thickness direction and reinforcing the frame, wherein the reinforcement portion has a first layer made of a metal, and a second layer disposed on the first layer in the thickness direction and made of a metal.
According to such a configuration, the reinforcement portion has the first layer made of the metal and the second layer made of the metal.
Therefore, it is possible to increase a thickness of the metal layer in the reinforcement portion.
As a result, it is possible to achieve further reinforcement of the frame.
The present invention [2] includes the assembly sheet of the above-described [1], wherein the reinforcement portion is disposed on one surface of the frame in the thickness direction.
The present invention [3] includes the assembly sheet of the above-described [2] further including a second reinforcement portion disposed on the other surface of the frame in the thickness direction.
According to such a configuration, it is possible to provide the reinforcement portion on both surfaces of the frame.
As a result, it is possible to further reinforce the frame.
The present invention [4] includes the assembly sheet of any one of the above-described [1] to [3], wherein at least a portion of the conductive pattern is thinner than the reinforcement portion in the thickness direction.
According to such a configuration, it is possible to form the reinforcement portion, while improving a degree of freedom in design of the conductive pattern.
The present invention [5] includes the assembly sheet of any one of the above-described [1] to [3], wherein the conductive pattern has a terminal and a wiring connected to the terminal; at least a portion of the wiring has a first conductive layer made of a metal, and a second conductive layer made of a metal and having at least a portion being in contact with the first conductive layer; the first layer of the reinforcement portion is made of the same metal as the first conductive layer; and the second layer of the reinforcement portion is made of the same metal as the second conductive layer.
According to such a configuration, it is possible to form the reinforcement portion by using a step of forming the first conductive layer and a step of forming the second conductive layer.
Therefore, it is possible to improve the degree of freedom in the design of the conductive pattern, and to form the reinforcement portion, while suppressing an increase in the number of steps.
The present invention [6] includes the assembly sheet of any one of the above-described [1] to [3], wherein the conductive pattern has a first wiring made of a metal, a second wiring made of a metal and disposed away from the first wiring, and a second insulating layer disposed between the first wiring and the second wiring: the first layer of the reinforcement portion is made of the same metal as the first wiring; and the second layer of the reinforcement portion is made of the same metal as the second wiring.
According to such a configuration, it is possible to form the reinforcement portion by using a step of forming the first wiring and a step of forming the second wiring.
Therefore, it is possible to improve the degree of freedom in the design of the conductive pattern, and to form the reinforcement portion, while suppressing the increase in the number of steps.
The present invention [7] includes the assembly sheet of any one of the above-described [1] to [6], wherein the frame is made of a metal foil having a thickness of 50 μm or less.
According to such a configuration, when a frame made of a thin metal foil is provided, it is possible to achieve the further reinforcement of the frame.
The present invention [8] includes the assembly sheet of the above-described [7], wherein when a thickness of the frame is 100%, the thickness of the reinforcement portion is 50% or more and 300% or less.
The present invention [9] includes a method for producing an assembly sheet, the assembly sheet of any one of the above-described [1] to [8], including a patterning step of forming an insulating layer, a conductive pattern, and a reinforcement portion on a metal foil drawn from a first roll as a roll of the metal foil to produce a second roll having the plurality of assembly sheets, and a cutting step of cutting each of the plurality of assembly sheets from the second roll.
According to such a configuration, it is possible to form the reinforcement portion in a state where the metal foil is stretched between the first roll and the second roll.
Therefore, it is possible to suppress the occurrence of wrinkles in the assembly sheet by the reinforcement portion when the cut assembly sheet is handled.
As a result, it is possible to improve handleability of the cut assembly sheet.
The present invention includes the method for producing an assembly sheet of the above-described [9] further including a plating step of plating a terminal of the conductive pattern of the cut assembly sheet.
According to such a configuration, it is possible to suppress the occurrence of the wrinkles in the assembly sheet during the plating step.
According to the assembly sheet and the method for producing an assembly sheet of the present invention, it is possible to achieve further reinforcement of a frame.
As shown in
The plurality of wiring circuit boards 2 are disposed spaced from each other in the second direction, while disposed spaced from each other in the first direction. Each of the plurality of wiring circuit boards 2 has the same structure. Therefore, one of the wiring circuit boards 2 of the plurality of wiring circuit boards 2 is described, and descriptions of the other wiring circuit boards 2 are omitted.
The wiring circuit board 2 extends in the first direction and the second direction. In this embodiment, the wiring circuit board 2 has a generally rectangular shape. A shape of the wiring circuit board 2 is not limited.
As shown in
The support layer 11 supports the base insulating layer 12, the conductive pattern 13, and the cover insulating layer 14. In this embodiment, the support layer 11 is made of a metal foil. Examples of a metal include stainless steel and copper alloys.
A thickness of the metal foil, that is, the thickness of the support layer 11 is, for example, 50 μm or less, preferably 30 μm or less, and for example, 10 μm or more, preferably 15 μm or more.
The base insulating layer 12 is disposed on the support layer 11 in a thickness direction of the assembly sheet 1. The thickness direction is perpendicular to the first direction and the second direction. Specifically, the base insulating layer 12 is disposed on a one-surface S1 of the support layer 11 in the thickness direction. The base insulating layer 12 is disposed between the support layer 11 and the conductive pattern 13 in the thickness direction. The base insulating layer 12 insulates the support layer 11 from the conductive pattern 13. The base insulating layer 12 is made of a resin. An example of the resin includes polyimide.
The thickness of the base insulating layer 12 is, for example, 30 μm or less, preferably 15 μm or less, and for example, 1 μm or more, preferably 3 μm or more.
The conductive pattern 13 is disposed on the base insulating layer 12 in the thickness direction. Specifically, the conductive pattern 13 is disposed on a one-surface S11 of the base insulating layer 12 in the thickness direction. The conductive pattern 13 is disposed on the opposite side to the support layer 11 with respect to the base insulating layer 12 in the thickness direction. The conductive pattern 13 is made of a metal. An example of the metal includes copper. A shape of the conductive pattern 13 is not limited.
In this embodiment, as shown in
The terminals 131A, 131B, 131C, and 131D are disposed in one end portion of the wiring circuit board 2 in the second direction. In this embodiment, the terminals 131A, 131B, 131C, and 131D are disposed spaced from each other in the first direction. Each of the terminals 131A, 131B, 131C, and 131D has a square land shape.
As shown in
The conductive layer 1311 is a main body portion of the terminal 131A. The conductive layer 1311 is disposed on the one-surface S11 of the base insulating layer 12 in the thickness direction.
The thickness of the conductive layer 1311 is, for example, 3 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.
The plating layer 1312 covers the surface of the conductive layer 1311. The plating layer 1312 suppresses corrosion of the conductive layer 1311. The plating layer 1312 is made of the metal. Examples of the metal include nickel, gold, and tin. The plating layer 1312 may consist of one layer or may consist of a plurality of layers. When the plating layer 1312 consists of the plurality of layers, each of the plurality of layers may be made of metals different from each other.
The thickness of the plating layer 1312 is, for example, 0.1 μm or more, preferably 0.2 μm or more, and for example, 5 μm or less, preferably 4 μm or less.
A thickness T1 of the terminal 131A is the sum of the thickness of the conductive layer 1311 and the thickness of the plating layer 1312. The thickness T1 of the terminal 131A is thinner than a thickness T12 of the reinforcement portion 4. That is, a portion of the conductive pattern 13 is thinner than the reinforcement portion 4 in the thickness direction. The thickness T12 of the reinforcement portion 4 is described later.
The thickness T1 of the terminal 131A is, for example, 6 μm or more, preferably 8 μm or more, and for example, 100 μm or less, preferably 60 μm or less.
The terminals 131B, 131C, and 131D have the same structure as the terminal 131A. Therefore, the descriptions of the terminals 131B, 131C, and 131D are omitted.
As shown in
The terminals 132A, 132B, 132C, and 132D have the same structure as the terminal 131A. Therefore, the descriptions of the terminals 132A, 132B, 132C, and 132D are omitted.
One end of the wiring 133A is connected to the terminal 131A. The other end of the wiring 133A is connected to the terminal 132A. The wiring 133A electrically connects the terminal 131A to the terminal 132A.
One end of the wiring 133B is connected to the terminal 131B. The other end of the wiring 133B is connected to the terminal 132B. The wiring 133B electrically connects the terminal 131B to the terminal 132B.
One end of the wiring 133C is connected to the terminal 131C. The other end of the wiring 133C is connected to the terminal 132C. The wiring 133C electrically connects the terminal 131C to the terminal 132C.
One end of the wiring 133D is connected to the terminal 131D. The other end of the wiring 133D is connected to the terminal 132D. The wiring 133D electrically connects the terminal 131D to the terminal 132D.
In this embodiment, as shown in
The first conductive layer 1331 is disposed on the one-surface S11 of the base insulating layer 12 in the thickness direction. In this embodiment, the first conductive layer 1331 is made of the same metal as the conductive layer 1311 of the terminal 131A. The thickness of the first conductive layer 1331 is, for example, 3 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.
The second conductive layer 1332 is disposed on the first conductive layer 1331 in the thickness direction. At least a portion of the second conductive layer 1332 is in contact with the first conductive layer 1331. In other words, the second conductive layer 1332 is electrically connected to the first conductive layer 1331. The thickness of the second conductive layer 1332 is, for example, 3 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.
In the following descriptions, each of the plurality of terminals 131A, 131B, 131C, and 131D is referred to as a terminal 131; each of the plurality of terminals 132A, 132B, 132C, and 132D is referred to as a terminal 132; and each of the plurality of wirings 133A, 133B, 133C, and 133D is referred to as a wiring 133.
As shown in
The thickness of the cover insulating layer 14 is, for example, 30 μm or less, preferably 15 μm or less, and for example, 1 μm or more, preferably 3 μm or more.
The frame 3 is disposed on the outer periphery of the assembly sheet 1. The frame 3 surrounds the plurality of wiring circuit boards 2. In this embodiment, the frame 3 has a frame shape. Specifically, the frame 3 has a first frame 3A, a second frame 3B, a third frame 3C, and a fourth frame 3D.
The first frame 3A is disposed in one end portion of the assembly sheet 1 in the first direction. The first frame 3A extends in the second direction.
The second frame 3B is disposed in the other end portion of the assembly sheet 1 in the first direction. The second frame 3B is disposed away from the first frame 3A in the first direction. The plurality of wiring circuit boards 2 are disposed between the first frame 3A and the second frame 3B in the first direction. The second frame 3B extends in the second direction.
The third frame 3C is disposed in one end portion of the assembly sheet 1 in the second direction. The third frame 3C extends in the first direction. One end portion of the third frame 3C in the first direction is connected to one end portion of the first frame 3A in the second direction. The other end portion of the third frame 3C in the first direction is connected to one end portion of the second frame 3B in the second direction.
The fourth frame 3D is disposed in the other end portion of the assembly sheet 1 in the second direction. The fourth frame 3D is disposed away from the third frame 3C in the second direction. The plurality of wiring circuit boards 2 are disposed between the third frame 3C and the fourth frame 3D in the second direction. The fourth frame 3D extends in the first direction. One end portion of the fourth frame 3D in the first direction is connected to the other end portion of the first frame 3A in the second direction. The other end portion of the fourth frame 3D in the first direction is connected to the other end portion of the second frame 3B in the second direction.
As shown in
Since the thickness of the metal foil is the above-described upper limit value or less, rigidity of the frame 3 is low. Therefore, when the assembly sheet 1 is handled, there is a possibility that wrinkles occur in the assembly sheet 1. Therefore, handling of the assembly sheet 1 is difficult.
Examples of a case of the difficult handling of the assembly sheet 1 include a case of carrying the assembly sheet 1, and a plating step in the method for producing the assembly sheet 1 to be described later.
Further, in this embodiment, the assembly sheet 1 has a cut-out 5 between the frame 3 and the wiring circuit board 2, and the two wiring circuit boards 2. Therefore, the rigidity of the entire assembly sheet 1 is further low. Therefore, the handling of the assembly sheet 1 is more difficult.
The assembly sheet 1 has a connecting portion 6A which connects the frame 3 to the wiring circuit board 2, and a connecting portion 6B which connects the two wiring circuit boards 2 to each other. The plurality of wiring circuit boards 2 are supported by the frame 3 via the connecting portion 6A, while being connected to each other via the connecting portion 6B.
As shown in
The first reinforcement portion 4A is disposed on the first frame 3A. The first reinforcement portion 4A reinforces the first frame 3A. The first reinforcement portion 4A extends in the second direction. In other words, the first reinforcement portion 4A extends in a direction in which the first frame 3A extends.
The second reinforcement portion 4B is disposed on the second frame 3B. The second reinforcement portion 4B reinforces the second frame 3B. The second reinforcement portion 4B extends in the second direction. In other words, the second reinforcement portion 4B extends in a direction in which the second frame 3B extends.
The third reinforcement portion 4C is disposed on the third frame 3C. The third reinforcement portion 4C reinforces the third frame 3C. The third reinforcement portion 4C extends in the first direction. In other words, the third reinforcement portion 4C extends in a direction in which the third frame 3C extends. One end portion of the third reinforcement portion 4C in the first direction is connected to one end portion of the first reinforcement portion 4A in the second direction. The other end portion of the third reinforcement portion 4C in the first direction is connected to one end portion of the second reinforcement portion 4B in the second direction.
The fourth reinforcement portion 4D is disposed on the fourth frame 3D. The fourth reinforcement portion 4D reinforces the fourth frame 3D. The fourth reinforcement portion 4D extends in the first direction. In other words, the fourth reinforcement portion 4D extends in a direction in which the fourth frame 3D extends. One end portion of the fourth reinforcement portion 4D in the first direction is connected to the other end portion of the first reinforcement portion 4A in the second direction. The other end portion of the fourth reinforcement portion 4D in the first direction is connected to the other end portion of the second reinforcement portion 4B in the second direction.
As shown in
The first layer 41 is disposed on the frame 3 in the thickness direction. Specifically, the first layer 41 is disposed on the one-surface S21 of the frame 3 in the thickness direction. The first layer 41 is made of the metal. The first layer 41 is preferably made of the same metal as the first conductive layer 1331 of the wiring 133A of the wiring circuit board 2. When the first layer 41 and the first conductive layer 1331 are the same metal, it is possible to form the first layer 41 by using a step of forming the first conductive layer 1331.
The thickness of the first layer 41 is, for example, 3 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.
The second layer 42 is disposed on the first layer 41 in the thickness direction. The second layer 42 is made of the metal. The second layer 42 is preferably made of the same metal as the second conductive layer 1332 of the wiring 133A of the wiring circuit board 2. When the second layer 42 and the second conductive layer 1332 are the same metal, it is possible to form the second layer 42 by using a step of forming the second conductive layer 1332.
The thickness of the second layer 42 is, for example, 3 μm or more, preferably 5 μm or more, and for example, 50 μm or less, preferably 30 μm or less.
The thickness T12 of the reinforcement portion 4 is the sum of the thickness of the first layer 41 and the thickness of the second layer 42. The thickness of the reinforcement portion 4 is, for example, 6 μm or more, preferably 10 μm or more, and for example, 100 μm or less, preferably 60 μm or less.
When the thickness T11 of the frame 3 is 100%, the thickness T12 of the reinforcement portion 4 is, for example, 50% or more, preferably 80% or more, more preferably 100% or more, further more preferably 110% or more, and for example, 300% or less, preferably 250% or less, more preferably 200% or less.
When the thickness T12 of the reinforcement portion 4 in a case where the thickness T11 of the frame 3 is 100% is the above-described lower limit value or more, it is possible to further improve the strength of the frame 3. When the thickness T12 of the reinforcement portion 4 in a case where the thickness T11 of the frame 3 is 100% is the above-described upper limit value or less, it is possible to form the reinforcement portion 4 by using a step of forming the conductive pattern 13.
The total sum of the thickness T11 of the frame 3 and the thickness T12 of the reinforcement portion 4 is, for example, 16 μm or more, preferably 25 μm or more, more preferably 50 μm or more, and for example, 200 μm or less, preferably 150 μm or less.
Next, a method for producing the above-described assembly sheet 1 is described.
In this embodiment, the assembly sheet 1 is produced by a semi-additive method. The assembly sheet 1 may be also produced by an additive method. The method for producing the assembly sheet 1 includes a patterning step (ref:
As shown in
Specifically, in order to form the base insulating layer 12, first, a solution (varnish) of a photosensitive resin is coated on the metal foil M and dried to form a coating film of the photosensitive resin. Next, the coating film of the photosensitive resin is exposed to light and developed.
Thus, as shown in
The conductive pattern 13 and the reinforcement portion 4 are formed by electrolytic plating.
In order to form the conductive pattern 13 and the reinforcement portion 4 by the electrolytic plating, first, a seed layer is formed on the surfaces of the base insulating layer 12 and the metal foil M. The seed layer is, for example, formed by sputtering. Examples of a material for the seed layer include chromium, copper, nickel, titanium, and alloys of these.
Next, a plating resist is attached onto the base insulating layer 12 and the metal foil M, and the plating resist is exposed to light, while portions where the conductive layer 1311 (ref:
Next, the exposed plating resist is developed. Then, the plating resist of the shielded portion is removed, and the seed layer is exposed to the portions where the conductive layer 1311, the first conductive layer 1331, and the first layer 41 are formed. The plating resist of the exposed portion, that is, the portions where the conductive layer 1311, the first conductive layer 1331, and the first layer 41 are not formed remains.
Next, the conductive layer 1311, the first conductive layer 1331, and the first layer 41 are formed on the exposed seed layer by the electrolytic plating. After the electrolytic plating is completed, the plating resist is peeled. Thereafter, the seed layer exposed by peeling the plating resist is removed by etching.
Thus, as shown in
Next, as shown in
Next, as shown in
Next, as shown in
As described above, the second roll R2 having the plurality of assembly sheets 1 is produced.
Next, after the patterning step, the cutting step is carried out.
As shown in
Next, after the cutting step, the plating step is carried out.
In the plating step, the conductive layers 1311 of all of the terminals 131 and the conductive layers 1311 of all of the terminals 132 of the cut assembly sheet 1 are plated. In the plating step, the conductive layer 1311 is plated by electroless plating. Thus, the plating layer 1312 (ref:
Specifically, as shown in
At this time, the frame 3 of the cut assembly sheet 1 is reinforced by the reinforcement portion 4. Therefore, it is possible to suppress the occurrence of the wrinkles in the assembly sheet 1 during the plating step.
(1) According to the assembly sheet 1, as shown in
Therefore, it is possible to increase the thickness of the metal layer in the reinforcement portion 4.
As a result, it is possible to achieve further reinforcement of the frame 3.
(2) According to the assembly sheet 1, as shown in
Therefore, it is possible to form the reinforcement portion 4, while improving a degree of freedom in design of the conductive pattern 13.
(3) According to the assembly sheet 1, as shown in
Therefore, it is possible to form the reinforcement portion 4 by using a step of forming the first conductive layer 1331 and a step of forming the second conductive layer 1332.
As a result, it is possible to improve the degree of freedom in the design of the conductive pattern 13, and to form the reinforcement portion 4, while suppressing an increase in the number of steps.
(4) According to the assembly sheet 1, the frame 3 is made of the metal foil having a thickness of 50 μm or less.
Thus, according to the assembly sheet 1, when the frame 3 made of the thin metal foil is provided, it is possible to achieve the further reinforcement of the frame 3.
(5) According to the method for producing the assembly sheet 1, as shown in
Therefore, as shown in
As a result, it is possible to improve handleability of the cut assembly sheet 1.
(6) According to the method for producing the assembly sheet 1, as shown in
The frame 3 of the cut assembly sheet 1 is reinforced by the reinforcement portion 4.
Therefore, it is possible to suppress the occurrence of the wrinkles in the assembly sheet 1 during the plating step.
Next, modified examples are described with reference to
According to such a configuration, it is possible to provide the reinforcement portions (the reinforcement portion 4 and the second reinforcement portion 20) on both surfaces of the frame 3.
As a result, it is possible to further reinforce the frame 3.
Further, the reinforcement portion 30 may also have a fourth layer 302 made of the same resin as the cover insulating layer 14.
The first wiring 401 is disposed on the base insulating layer 12. The first wiring 401 is formed by the electrolytic plating in the same manner as the above-described first conductive layer 1331.
The second wiring 402 is disposed away from the first wiring 401. In other words, the second wiring 402 is not electrically conducted to the first wiring 401. The second wiring 402 is disposed on the intermediate insulating layer 403. The second wiring 402 is formed by the electrolytic plating in the same manner as the above-described second conductive layer 1332.
The intermediate insulating layer 403 is disposed between the first wiring 401 and the second wiring 402. The intermediate insulating layer 403 insulates the first wiring 401 from the second wiring 402. The intermediate insulating layer 403 is formed on the first wiring 401 and the base insulating layer 12 in the same manner as the base insulating layer 12.
The first layer 41 may be also made of the same metal as the first wiring 401. The second layer 42 may be also made of the same metal as the second wiring 402.
According to such a configuration, it is possible to form the reinforcement portion 4 by using a step of forming the first wiring 401 and a step of forming the second wiring 402.
Therefore, it is possible to improve the degree of freedom in the design of the conductive pattern 13, and to form the reinforcement portion 4, while suppressing an increase in the number of steps.
(7) As shown in
(8) As shown in
(9) The above-described embodiment and each modified example can be used in combination.
While the illustrative embodiments of the present invention are provided in the above description, such is for illustrative purpose only and it is not to be construed as limiting the scope of the present invention. Modification and variation of the present invention that will be obvious to those skilled in the art is to be covered by the following claims.
The assembly sheet of the present invention and the method for producing an assembly sheet of the present invention are used in production of a wiring circuit board.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-074403 | Apr 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/002939 | 1/26/2022 | WO |
