Producing method of wiring circuit board and wiring circuit board assembly sheet

In a method for producing a wiring circuit board, a conductive pattern is formed using a plating resist formed by photolithography for sequentially moving one photomask in a first direction with respect to a dry film resist to be exposed a plurality of times. The conductive pattern has a conductive intermediate portion which is inclined. The one photomask has a third photo pattern. The third photo pattern includes a first photoline pattern and a second photo line pattern. A first portion of the first photoline pattern coincides with a second portion of the second photoline pattern when projected in the first direction.

CROSS REFERENCE TO RELATED APPLICATION

The present application claims priority from Japanese Patent Application No. 2019-203754 filed on Nov. 11, 2019, the contents of which are hereby incorporated by reference into this application.

TECHNICAL FIELD

The present invention relates to a method for producing a wiring circuit board, and a wiring circuit board assembly sheet.

BACKGROUND ART

Conventionally, a method for producing a flexible substrate for forming a wiring pattern in an insulating layer by a pattern forming method of an additive method or a subtractive method has been known.

For example, as a method for forming the wiring pattern by the subtractive method, a method in which an exposure mask having an opening portion of an equal length of a width of both end portions is provided on a photosensitive resist layer disposed on the surface of a metal layer so as to sequentially overlap end portions of the opening portion in a longitudinal direction, and the resist layer is repeatedly exposed has been proposed (ref: for example, Patent Document 1 below).

In Patent Document 1, the opening portion of the exposure mask has a linear shape when viewed from the top along the longitudinal direction, and has the same width over the longitudinal direction.

In Patent Document 1, by development after exposure, a resist pattern having a linear shape of the same width over the longitudinal direction is formed, and then, by etching the metal layer exposed from the resist pattern, a wiring pattern having a linear shape of the same width over the longitudinal direction is formed.

PRIOR ART DOCUMENT

Patent Document

SUMMARY OF THE INVENTION

Problems to be Solved by the Invention

However, a terminal pattern in addition to the wiring pattern may be formed in a conductive layer. The terminal pattern usually has a wider land shape than the wiring pattern from the viewpoint of improving the connection reliability with other electrical substrates. Then, in the method of Patent Document 1, when the exposure mask corresponding to the wire is sequentially overlapped to be disposed in the longitudinal direction, the wiring pattern can be formed, and the terminal pattern cannot be formed in the shape described above.

On the other hand, when the exposure mask corresponding to the terminal pattern is sequentially overlapped to be disposed in the longitudinal direction, the pattern terminal can be formed, and the wiring pattern cannot be formed, and moreover, since a terminal is usually disposed in the end portion of the wiring pattern, the wiring pattern is discontinuous in the longitudinal direction.

In view of the description above, it is devised to separately prepare an exposure mask corresponding to a wiring pattern and an exposure mask corresponding to a terminal pattern.

However, in this trial plan, in the exposure step, the photosensitive resist layer in the area corresponding to the wiring pattern is exposed through the exposure mask corresponding to the wiring pattern, then, the exposure mask is replaced, and thereafter, the photosensitive resist layer in the area corresponding to the terminal pattern is exposed through the exposure mask corresponding to the terminal pattern. Therefore, there is a problem that the number of components of a production device increases, and also, the replacement of the exposure mask becomes troublesome.

The present invention provides a method for producing a wiring circuit board which has a conductive one end portion and/or a conductive other end portion capable of having a different shape from a conductive intermediate portion, while the number of components of a production device decreases, and can easily form a conductive pattern having excellent reliability, and a wiring circuit board assembly sheet.

Solution to the Problems

The present invention (1) includes a method for producing a wiring circuit board including a conductive pattern and an insulating layer adjacent to the conductive pattern in a thickness direction including the steps of forming the insulating layer and forming the conductive pattern using a resist formed by photolithography for sequentially moving one photomask in a first direction with respect to a photoresist to be exposed a plurality of times, wherein the conductive pattern has a conductive one end portion, a conductive other end portion, and a conductive intermediate portion; the conductive intermediate portion extends in a second direction inclined with respect to the first direction; the one photomask has a first photo pattern corresponding to the conductive one end portion, a second photo pattern corresponding to the conductive other end portion, and a third photo pattern corresponding to the conductive intermediate portion; the third photo pattern includes a plurality of photoline patterns disposed adjacent to each other at spaced intervals in a third direction perpendicular to the second direction in the one photomask; the plurality of photoline patterns include a first end portion located in a first directional one end portion of the one photomask and a second end portion located in a first directional other end portion of the one photomask; and of the plurality of photoline patterns, a first portion included in a portion located in the first end portion of one photoline pattern coincides with a second portion included in a portion located in the second end portion of the other photoline pattern adjacent to one photoline pattern in the third direction when projected in the first direction.

In the method for producing a wiring circuit board, the first portion of one photoline pattern in the plurality of photoline patterns coincides with the second portion of the other photoline pattern when projected in the first direction. Therefore, the conductive intermediate portion can be continuous in the second direction. Further, even when the shape of the first photo pattern and/or the second photo pattern is different from the shape of the third photo pattern, since the first portion coincides with the second portion, the conductive intermediate portion also can be continuous in the second direction. As a result, it is possible to form the conductive pattern having the conductive one end portion and/or the conductive other end portion which can have a different shape from the conductive intermediate portion and having excellent reliability.

Further, since the one photomask is sequentially moved in the first direction to expose the photoresist a plurality of times, it is possible to easily form the conductive pattern described above, while the number of components of the production device is reduced.

The present invention (2) includes the method for producing a wiring circuit board described in (1), wherein in the step of forming the conductive pattern, in the photoresist, a portion facing the first end portion of the one photomask at the time of the n-th time (n is a natural number) exposure is overlapped with a portion facing the second end portion of the one photomask at the time of the [n+1]th time exposure.

However, in the photoresist used in the step of forming the conductive pattern, when the portion facing the first directional one end portion in the one photomask at the time of the n-th time exposure is not overlapped with the portion facing the first directional other end portion in the one photomask at the time of the [n+1]th time, there may be a case where the conductive intermediate portion easily becomes discontinuous, and the reliability of the conductive pattern is reduced.

On the other hand, in this producing method, since the two portions are overlapped, even when the one photomask is sequentially moved in the first direction, the two portions can be reliably continuous, therefore, the conductive intermediate portion is reliably continuous, and it is possible to suppress a decrease in reliability of the conductive pattern.

The present invention (3) includes the method for producing a wiring circuit board described in (1) or (2), wherein a length in the second direction of the conductive pattern is 300 mm or more.

In the photolithography for exposing the one photomask once, the conductive pattern having a short length in the second direction of below 300 mm can be formed, and there may be a case where the conductive pattern having a long length in the second direction of 300 mm or more cannot be formed.

However, in the method for producing a wiring circuit board, since the photolithography for sequentially moving the one photomask in the first direction to be exposed a plurality of times is carried out, it is possible to form the long conductive pattern having excellent reliability.

The present invention (4) includes the method for producing a wiring circuit board described in any one of (1) to (3), wherein in the step of forming the insulating layer, photolithography for sequentially moving one second photomask in the first direction with respect to a photosensitive precursor layer to be exposed a plurality of times is carried out; the insulating layer has an insulating one end portion corresponding to the conductive one end portion, an insulating other end portion corresponding to the conductive other end portion, and an insulating intermediate portion corresponding to the conductive intermediate portion; the insulating intermediate portion extends in the second direction; the one second photomask has a fourth photo pattern corresponding to the insulating one end portion, a fifth photo pattern corresponding to the insulating other end portion, and a sixth photo pattern corresponding to the insulating intermediate portion; in the one second photomask, the sixth photo pattern includes a plurality of photo patterns disposed adjacent to each other at spaced intervals in the third direction; the plurality of photo patterns include a third end portion located in a first directional one end portion of the one second photomask and a fourth end portion located in a first directional other end portion of the one second photomask; and of the plurality of photo patterns, a third portion included in a portion located in the third end portion of one photo pattern coincides with a fourth portion included in a portion located in the fourth end portion of the other photo pattern adjacent to one photo pattern in the third direction when projected in the first direction.

In the method for producing a wiring circuit board, in the plurality of photo patterns, the third portion included in the portion located in the third end portion of one photo pattern coincides with the fourth portion included in the portion located in the fourth end portion of the other photo pattern. Therefore, the insulating intermediate portion is continuous in the second direction. Further, even when the shape of the fourth photo pattern and/or the fifth photo pattern is different from the shape of the sixth photo pattern, and the shape of the insulating one end portion and/or the insulating other end portion is different from the shape of the insulating intermediate portion, since the third portion coincides with the fourth portion, the insulating intermediate portion can be also continuous in the second direction. As a result, it is possible to form the insulating layer having the insulating one end portion and/or the insulating other end portion which can have a different shape from the insulating intermediate portion and having excellent reliability.

Further, since the one second photomask is sequentially moved in the first direction to expose the photosensitive precursor layer a plurality of times, it is possible to easily form the insulating layer described above, while the number of components of the production device is reduced.

The present invention (5) includes the method for producing a wiring circuit board described in any one of (1) to (4) further including a step of forming an alignment mark in a boundary portion of sheet areas adjacent to each other in the first direction.

In this method, it is possible to accurately form the conductive pattern and/or the insulating layer.

The present invention (6) includes the method for producing a wiring circuit board described in (6), wherein prior to the step of forming the conductive pattern, a step of forming the alignment mark is carried out and in the step of forming the alignment mark, the two alignment marks sandwiching the boundary of the sheet areas adjacent to each other in the first direction therebetween are formed at one time.

However, when the two alignment marks sandwiching the boundary of the sheet areas therebetween are separately formed, there may be a case where the other alignment mark deviates from one alignment mark in a direction perpendicular to the first direction. Then, there may be a case where even when the photomask is aligned using one alignment mark, and then, the photomask is moved to be again aligned using the other alignment mark, the first portion and the second portion do not easily coincide.

However, in this method, since the two alignment marks are formed at one time, it is possible to suppress the deviation of the two alignment marks in the direction perpendicular to the first direction. Therefore, the first portion and the second portion can further more reliably coincide.

The present invention (7) includes a wiring circuit board assembly sheet including a support sheet extending in a first direction, a plurality of wiring circuit boards provided in the support sheet and including a conductive pattern extending in a second direction inclined with respect to the first direction, and a plurality of sheet areas having the conductive pattern of the same shape and sequentially partitioned in the first direction, wherein in each of the plurality of sheet areas, the conductive pattern has a conductive one end portion, a conductive other end portion, and a conductive intermediate portion; the plurality of conductive intermediate portions are disposed adjacent to each other at spaced intervals in a third direction perpendicular to the second direction; the plurality of conductive intermediate portions include a fifth end edge located in a first directional one end edge of the sheet area and a sixth end edge located in a first directional other end edge of the sheet area; and the fifth end edge of one conductive intermediate portion in one sheet area coincides with the sixth end edge of the other conductive intermediate portion adjacent to one conductive intermediate portion in the third direction in the other sheet area adjacent to one sheet area in the first direction.

In the wiring circuit board assembly sheet, since the conductive intermediate portion of the conductive pattern includes the fifth end edge and the sixth end edge, and the fifth end edge of one conductive intermediate portion coincides with the sixth end edge of the other conductive intermediate portion, the conductive intermediate portion can be reliably continuous over the plurality of sheet areas. Therefore, the conductive pattern has excellent reliability.

The present invention (8) includes the wiring circuit board assembly sheet described in (7), wherein an alignment mark is provided in a boundary portion of the sheet areas adjacent to each other in the first direction.

Since the wiring circuit board assembly sheet includes the alignment mark, the plurality of wiring circuit boards have excellent reliability.

Effect of the Invention

According to the method for producing a wiring circuit board of the present invention, it is possible to easily form the conductive pattern described above, while the number of components of the production device is reduced.

In the wiring circuit board assembly sheet of the present invention, the conductive pattern has excellent reliability.

EMBODIMENT OF THE INVENTION

One embodiment of a wiring circuit board assembly sheet and a method for producing a wiring circuit board of the present invention is described with reference toFIGS. 1 to 12. InFIG. 1, in order to clearly show the shape of a conductive pattern5(described later), a cover insulating layer6(described later) is omitted.

As shown inFIGS. 1 and 2D, a wiring circuit board assembly sheet1has a predetermined thickness, and is an elongated generally rectangular sheet when viewed from the top extending along a first direction perpendicular to a thickness direction. The wiring circuit board assembly sheet1may be wound so that both end edges in the first direction thereof (not shown) are close to each other. Further, the wiring circuit board assembly sheet1has width directional both end edges10facing each other in a width direction perpendicular to the thickness direction and the first direction. The wiring circuit board assembly sheet1includes one support sheet2, a plurality of wiring circuit boards3, and a plurality of alignment marks7.

The support sheet2has the same shape as the wiring circuit board assembly sheet1when viewed from the top. The support sheet2is not particularly limited as long as it can support (secure) the plurality of wiring circuit boards3from the other side in the thickness direction. An example of the support sheet2includes a sheet having toughness, flexibility, and rigidity. Examples of the support sheet2include a metal plate such as stainless steel plate, a resin sheet such as polyimide sheet, and paper. Further, the support sheet2is a single layer or a multilayer (laminate). A thickness of the support sheet2is not particularly limited, and is, for example, 5 μm or more, preferably 15 μm or more, and for example, 500 μm or less, preferably 200 μm or less.

The plurality of wiring circuit boards3are disposed on one surface in the thickness direction of the support sheet2. The plurality of wiring circuit boards3are arranged in alignment at spaced intervals in the first direction. Each of the plurality of wiring circuit boards3has a generally rectangular shape when viewed from the top that is long in a second direction inclined with respect to the first direction. An inclination angle of a second line (not shown) along the second direction with respect to a first line (not shown) along the first direction is, for example, 45 degrees or less, preferably, 30 degrees or less, more preferably, 20 degrees or less, further more preferably, 5 degrees or less, and for example, above 0 degree.

All of the plurality of wiring circuit boards3are overlapped when projected in the first direction.

The two wiring circuit boards3adjacent to each other in the first direction are disposed adjacent to each other at spaced intervals in a third direction. Specifically, the two wiring circuit boards3adjacent to each other in the first direction are partially overlapped when projected in the third direction. Specifically, when projected in the third direction, the other end portion and an intermediate portion in the second direction of one wiring circuit board3are overlapped with the other wiring circuit board3adjacent to one side in the third direction of one wiring circuit board3, and one end portion in the second direction of one wiring circuit board3is not overlapped with (deviates from) the other wiring circuit board3.

Each of the plurality of wiring circuit boards3includes the conductive pattern5. The conductive pattern5is disposed over the second direction in the wiring circuit board3. The conductive pattern5extends in the second direction. As shown inFIGS. 1 and 4C, the conductive pattern5includes a conductive one end portion21, a conductive other end portion22, and a conductive intermediate portion23in each of the plurality of wiring circuit boards3.

The conductive one end portion21is located in one end portion in the second direction of the conductive pattern5. The conductive one end portion21includes, for example, a one-side terminal. The plurality of one-side terminals are disposed adjacent to each other at spaced intervals in the third direction in the wiring circuit board3. Each of the plurality of one-side terminals has, for example, a generally rectangular land shape.

The conductive other end portion22is located in the other end portion in the second direction of the conductive pattern5. The conductive other end portion22includes, for example, an other-side terminal. The plurality of other-side terminals are disposed adjacent to each other at spaced intervals in the third direction in the wiring circuit board3. Each of the plurality of other-side terminals has, for example, a generally rectangular land shape.

The conductive intermediate portion23is located in the intermediate portion in the second direction of the conductive pattern5. The conductive intermediate portion23is located between the conductive one end portion21and the conductive intermediate portion23. The conductive intermediate portion23extends in the second direction. The conductive intermediate portion23includes a narrower wire than the one-side terminal and the other-side terminal. The wire is continuous to the one-side terminal and the other-side terminal. Thus, the wire connects the one-side terminal to the other-side terminal in the second direction. The plurality of wires are disposed adjacent to each other at spaced intervals in the third direction in the wiring circuit board3. The plurality of wires are parallel with each other. Each of the plurality of wires has a generally linear shape when viewed from the top along the second direction.

A length L0in the second direction of the conductive pattern5is, for example, 300 mm or more, preferably 600 mm or more, more preferably 1,000 mm or more, and for example, 10,000 mm or less. The length L0in the second direction of the conductive pattern5is a distance between one end edge of the conductive one end portion21and the other end edge of the conductive other end portion22. When the length L0in the second direction of the conductive pattern5is the above-described lower limit or more, it is suitable as an elongated wiring circuit board in which a transmission distance of electric signals or power supply currents is long.

A width of the wire in the conductive pattern5is, for example, 100 μm or less, preferably 90 μm or less, more preferably 80 μm or less, and for example, 5 μm or more. An interval between the wires adjacent to each other is, for example, 100 μm or less, preferably 90 μm or less, more preferably 80 μm or less, and for example, 5 μm or more. When the width and/or the interval are/is the above-described upper limit or less, it is suitable as the narrow wiring circuit board3.

As shown inFIG. 2D, the wiring circuit board3further includes the cover insulating layer6as one example of an insulating layer adjacent to each of one side and the other side in the thickness direction of the conductive pattern5, and a base insulating layer4as one example of an insulating layer. Specifically, the wiring circuit board3includes the base insulating layer4, the conductive pattern5described above disposed on one surface in the thickness direction of the base insulating layer4, and the cover insulating layer6disposed on one surface in the thickness direction of the base insulating layer4so as to expose the one-side terminal and the other-side terminal of the conductive pattern5and cover one surface in the thickness direction and both side surfaces in the third direction of the wire of the conductive pattern5.

The base insulating layer4is disposed on one surface in the thickness direction of the support sheet2. The base insulating layer4has the same outer shape as the wiring circuit board3. As shown inFIGS. 3B to 4C, the base insulating layer4integrally includes a base one end portion17as one example of an insulating one end portion including the conductive one end portion21when viewed from the top, a base other end portion18as one example of an insulating other end portion including the conductive other end portion22when viewed from the top, and a base intermediate portion19as one example of an insulating intermediate portion including the conductive intermediate portion23when viewed from the top. An example of a material for the base insulating layer4includes a resin having insulating properties such as polyimide. A thickness of the base insulating layer4is, for example, 3 μm or more and 50 μm or less.

An example of a material fir the conductive pattern5includes a conductor such as copper. A thickness of the conductive pattern5is, for example, 5 μm or more and 100 μm or less.

As shown inFIGS. 3B and 4D, the cover insulating layer6includes a cover one end portion25as one example of an insulating one end portion included in the base one end portion17when viewed from the top, a cover other end portion26as one example of an insulating other end portion included in the base other end portion18when viewed from the top, and a cover intermediate portion27as one example of an insulating intermediate portion included in the base intermediate portion19when viewed from the top. An example of a material for the cover insulating layer6includes a resin having insulating properties such as polyimide. A thickness of the cover insulating layer6is, for example, 3 μm or more and 50 μm or less.

As shown inFIG. 2D, the alignment mark7is disposed on one surface in the thickness direction of the support sheet2. Further as shown inFIGS. 1 and 3A, the plurality of alignment marks7are disposed in the vicinity of each of the width directional both end edges10.

Of the width directional both end edges10, the alignment mark7in the vicinity of a width directional one end edge10A has a mark set8including a first mark14and a second mark15which is closely disposed with the first mark14in the first direction. The plurality of mark sets8are disposed at spaced intervals in the first direction.

Of the width directional both end edges10, the alignment mark7in the vicinity of a width directional other end edge10B also has the mark set8including the first mark14and the second mark15which is closely disposed with the first mark14in the first direction. The plurality of mark sets8are disposed at spaced intervals in the first direction.

More specifically, in the one mark set8, the second mark15is oppositely disposed at a subtle interval to the first mark14. A distance L1between the first mark14and the second mark15in the one mark set8is, for example, 20 mm or less, preferably 10 mm or less, more preferably 5 mm or less, and for example, 0.5 mm or more.

The plurality of alignment marks7are disposed to be shifted toward both outer sides in the width direction of the plurality of wiring circuit boards3when projected in the first direction.

Further, one mark set8and the other mark set8adjacent thereto in the first direction are remoted. Specifically, a distance L2between the second mark15of one mark set8and the first mark14of the other mark set8is longer than the distance L1described above, and specifically, for example, 200 mm or more, preferably, 230 mm or more, more preferably, 280 mm or more, and for example, 600 mm or less. A ratio (L2/L1) of the distance L2to the distance L1is, for example, 10 or more, preferably, 25 or more, more preferably, 50 or more, and for example, 1200 or less.

A material for the alignment mark7is not particularly limited. Examples thereof include a resin and a conductor. Preferably, the same resin as the base insulating layer4is used.

As shown inFIG. 3A, in the wiring circuit board assembly sheet1, the one mark set8defines a boundary13of sheet areas9adjacent to each other in the first direction. The boundary13is along the width direction over the width directional both end edges10. Specifically, the boundary13is a line segment passing through the intermediate point of the line segment connecting the center of gravity of the first mark14to the center of gravity of the second mark15and parallel in the width direction. The boundary13is shown by a phantom line inFIG. 1andFIGS. 3A to 4D, and in the actual wiring circuit board assembly sheet1, the outer shape of the boundary13may not be clearly visually recognized.

Further, a peripheral region including the boundary13is referred to as a boundary portion16. The mark set8is located in the boundary portion16.

Then, by the two boundaries13spaced apart from each other in the first direction, the one sheet area9is partitioned. Further, the three or more boundaries13divide the plurality of sheet areas9. The plurality of sheet areas9are sequentially partitioned in the first direction.

Each of the plurality of sheet areas9has the width directional both end edges10, a first end edge11as one example of a fifth end edge connecting a first directional one end edge of the width directional both end edges10, and a second end edge12as one example of a sixth end edge connecting a first directional other end edge of the width directional both end edges10.

The width directional both end edges10included in the plurality of sheet areas9are the same as the width directional both end edges10of the wiring circuit board assembly sheet1.

The second end edge12of one sheet area9is the same as the first end edge11of the other sheet area9adjacent to the other side in the first direction of one sheet area9.

Then, as shown inFIGS. 1 and 4C, in the wiring circuit board assembly sheet1, one wiring circuit board3is disposed over the continuous plurality of (four) sheet areas9. The plurality of sheet areas9have the conductive pattern5of the same shape.

For example, the four sheet areas9described above are sequentially referred to as a first sheet area9A, a second sheet area9B, a third sheet area9C, and a fourth sheet area9D toward one side in the first direction. In this case, the conductive one end portion21in one conductive pattern5is disposed in the fourth sheet area9D. On the other hand, the conductive other end portion22in one conductive pattern5described above is disposed in the first sheet area9A. On the other hand, the conductive intermediate portion23in one conductive pattern5is disposed over the first sheet area9A to the fourth sheet area9D.

On the other hand, in the one sheet area9, the four conductive intermediate portions23adjacent to each other in the third direction are disposed. In the one sheet area9(specifically, each of the first sheet area9A to the fourth sheet area9D), a first conductive intermediate portion23A, a second conductive intermediate portion23B, a third conductive intermediate portion23C, and a fourth conductive intermediate portion23D are independently disposed. The first conductive intermediate portion23A, the second conductive intermediate portion23B, the third conductive intermediate portion23C, and the fourth conductive intermediate portion23D are sequentially disposed at spaced intervals toward one side in the third direction in the one sheet area9.

Further, the first conductive intermediate portion23A disposed in the one sheet area9is continuous to the conductive other end portion22. The fourth conductive intermediate portion23D disposed in the one sheet area9is continuous to the conductive one end portion21.

Then, the first end edge11of the first conductive intermediate portion23A in the first sheet area9A coincides with the second end edge12of the second conductive intermediate portion23B in the second sheet area9B. Thus, the first conductive intermediate portion23A of the first sheet area9A is continuous to the second conductive intermediate portion23B of the second sheet area9B in the second direction.

Further, the first end edge11of the second conductive intermediate portion23B in the second sheet area9B coincides with the second end edge12of the third conductive intermediate portion23C in the third sheet area9C. Thus, the second conductive intermediate portion23B of the second sheet area9B is continuous to the third conductive intermediate portion23C of the third sheet area9C in the second direction.

Furthermore, the first end edge11of the third conductive intermediate portion23C in the third sheet area9C coincides with the second end edge12of the fourth conductive intermediate portion23D in the fourth sheet area9D. Thus, the third conductive intermediate portion23C of the third sheet area9C is continuous to the fourth conductive intermediate portion23D of the fourth sheet area9D in the second direction.

Accordingly, the first conductive intermediate portion23A of the first sheet area9A, the second conductive intermediate portion23B of the second sheet area9B, the third conductive intermediate portion23C of the third sheet area9C, and the fourth conducive intermediate portion23D of the fourth sheet area9D are continuous in the second direction over the first sheet area9A to the fourth sheet area9D. Thus, the conductive intermediate portion23in the one wiring circuit board3is continuously disposed in the second direction over the continuous four sheet areas9.

As shown inFIG. 3B, the base intermediate portion19is also continuously disposed in the second direction over the continuous plurality of (four) sheet areas9in the plurality of (four) sheet areas9that are continuous in the second direction in the same manner as the conductive intermediate portion23. The plurality of sheet areas9have the base insulating layer4of the same shape. The base intermediate portion19includes a first base intermediate portion19A, a second base intermediate portion19B, a third base intermediate portion19C, and a fourth base intermediate portion19D each of which includes the first conductive intermediate portion23A, the second conductive intermediate portion23B, the third conductive intermediate portion23C, and the fourth conductive intermediate portion23D (ref:FIG. 4C), respectively.

Further, as shown inFIG. 4D, the cover intermediate portion27is continuously disposed in the second direction over the continuous plurality of (four) sheet areas9in the plurality of (four) sheet areas9that are continuous in the second direction in the same manner as the conductive intermediate portion23. The plurality of sheet areas9have the cover insulating layer6of the same shape. The cover intermediate portion27includes a first cover intermediate portion27A, a second cover intermediate portion27B, a third cover intermediate portion27C, and a fourth cover intermediate portion27D each of which is included in the first base intermediate portion19A, the second base intermediate portion19B, the third base intermediate portion19C, and the fourth base intermediate portion19D (ref:FIG. 4C), respectively.

Next, a method for producing the wiring circuit board assembly sheet1is described.

As shown inFIGS. 2A to 2D, the method includes a first step of preparing the support sheet2, a second step (ref:FIG. 2A) of forming the alignment mark7, a third step (ref:FIG. 2B) of forming the base insulating layer4, a fourth step (ref:FIG. 2C) of forming the conductive pattern5, and a fifth step (ref:FIG. 2D) of forming the cover insulating layer6. Further, the method for producing the wiring circuit board assembly sheet1is carried out by a roll-to-roll method.

In the first step, as shown inFIGS. 2A and 3A, the elongated support sheet2in the first direction is prepared.

Subsequently, in the second step, the alignment mark7is formed on one surface in the thickness direction of the support sheet2.

The method of forming the alignment mark7is not particularly limited. The alignment mark7is, for example, firmed by a photolithography method. Specifically, as shown inFIG. 5A, a photosensitive precursor layer24is disposed on the entire one surface in the thickness direction of the support sheet2, and subsequently, a photosensitive resin is exposed through an alignment photomask20to be then developed.

Specifically, as shown inFIGS. 5A to 5B, the one alignment photomask20is sequentially moved in the first direction to expose the photosensitive precursor layer24a plurality of times.

The alignment photomask20has a pattern corresponding to the mark set8. The mark set8is the one mark set8in the vicinity of one end edge in the width directional both end edges10, and the mark set8facing it in the width direction. The alignment photomask20has, for example, a generally rectangular outer shape when viewed from the top. For example, when the photosensitive precursor layer24is a negative type, the pattern of the alignment photomask20has a light transmitting pattern T corresponding to the mark set8and a light shielding pattern B corresponding to a portion other than the mark set8.

First, as shown inFIG. 5A, the one alignment photomask20is disposed on one side in the thickness direction of the photosensitive precursor layer24corresponding to one mark set8. Subsequently, only the photosensitive precursor layer24corresponding to the alignment photomask20is exposed through the alignment photomask20to form a latent image68(ref:FIG. 5B) corresponding to one mark set8in the photosensitive precursor layer24.

As shown by an arrow ofFIG. 5AandFIG. 5B, the alignment photomask20is subsequently moved (slid) to one side in the first direction with respect to the photosensitive precursor layer24, and is disposed on one side in the thickness direction of the photosensitive precursor layer24corresponding to the mark set8adjacent to one side in the first direction of one mark set8. At this time, for example, in the photosensitive precursor layer24, a portion20A facing one end portion in the first direction in the alignment photomask20at the time of the previous exposure is overlapped with a portion20B facing the other end portion in the first direction in the alignment photomask20at the time of the present exposure.

Subsequently, the photosensitive precursor layer24is exposed through the alignment photomask20after movement to form another latent image68. The movement of the alignment photomask20, the exposure of the photosensitive precursor layer24, and the formation of the latent image68described above are repeated.

Thereafter, the photosensitive precursor layer24is developed and if necessary heated.

Thus, as shown inFIG. 3A, the plurality of alignment marks7are formed on one surface in the thickness direction of the support sheet2.

Then, in the third step, as shown inFIG. 2B, the base insulating layer4is formed.

A method of forming the base insulating layer4is not particularly limited. The base insulating layer4is, for example, formed by a photolithography method. For example, as shown inFIGS. 6A to 7F, a photosensitive base precursor layer81as one example of a photosensitive precursor layer is disposed on one surface in the thickness direction of the support sheet2, and then, the photosensitive base precursor layer81is exposed through a base photomask31as one example of a second photomask to be then developed.

In order to dispose the photosensitive base precursor layer81on one surface in the thickness direction of the support sheet2, as shown inFIG. 7A, for example, a precursor composition of the above-described resin having photosensitivity is applied to one surface in the thickness direction of the support sheet2and if necessary, dried.

Subsequently, as shown inFIGS. 7B to 7E, the one base photomask31is prepared and sequentially moved in the first direction to expose the photosensitive base precursor layer81a plurality of times.

As shown inFIG. 6A, the base photomask31includes a first base photo pattern28as one example of a fourth photo pattern, a second base photo pattern29as one example of a fifth photo pattern, and a third base photo pattern30as one example of a sixth photo pattern.

Each of the first base photo pattern28, the second base photo pattern29, and the third base photo pattern30in the one base photomask31corresponds to each of the base one end portion17, the base other end portion18, and the base intermediate portion19in one sheet area9(ref:FIG. 3B), respectively. In the base photomask31, for example, when the photosensitive base precursor layer81is a negative type, it has the light transmitting pattern T corresponding to the base insulating layer4and the light shielding pattern B corresponding to a portion other than the base insulating layer4.

The third base photo pattern30includes a base photo pattern83as one example of a plurality of photo patterns disposed adjacent to each other at spaced intervals in the third direction in the one base photomask31. The plurality of base photo patterns83sequentially have a fourth base photo pattern32, a fifth base photo pattern33, a sixth base photo pattern34, and a seventh base photo pattern35toward one side in the third direction.

Each of the fourth base photo pattern32to the seventh base photo pattern35corresponds to each of the first base intermediate portion19A to the fourth base intermediate portion19D (ref:FIG. 3B).

Further, the base photomask31has, for example, a mask frame67having a generally rectangular shape when viewed from the top. The base photomask31includes a base mask one end portion31A as one example of a first directional one end portion, and a base mask other end portion31B as one example of a first directional other end portion at the inside of the mask frame67.

Then, in the plurality of base photo patterns83, a slide pattern obtained by sliding (subjected to parallel movement of) a base photo pattern first end portion36that is a portion located in the base mask one end portion31A of the fourth base photo pattern32to the other side in the first direction coincides with a base photo pattern second end portion37that is a portion located in the base mask other end portion31B of the fifth base photo pattern33.

The base photo pattern first end portion36includes a base first portion38. The base first portion38is located in the intermediate portion in the first direction in the base photo pattern first end portion36, and disposed over the entire width direction in the base photo pattern first end portion36. Specifically, the base first portion38is located in the central portion in the first direction of the base photo pattern first end portion36.

The base photo pattern second end portion37includes a base second portion39. The base second portion39is located in the intermediate portion in the first direction in the base photo pattern second end portion37, and disposed over the entire width direction in the base photo pattern second end portion37. Specifically, the base second portion39is located in the central portion in the first direction of the base photo pattern second end portion37.

Then, the base first portion38coincides with the base second portion39when projected in the first direction. That is, the position in the width direction of the base first portion38is the same as the position in the width direction of the base second portion39when projected in the first direction.

Further, a slide pattern obtained by sliding (subjected to parallel movement of) the base photo pattern first end portion36located in the base mask one end portion31A of the fifth base photo pattern33to the other side in the first direction coincides with the base photo pattern second end portion37located in the base mask other end portion31B of the sixth base photo pattern34. Each of the base photo pattern first end portion36of the fifth base photo pattern33and the base photo pattern second end portion37of the sixth base photo pattern34includes each of the base first portion38and the base second portion39, respectively. The base first portion38of the fifth base photo pattern33coincides with the base second portion39of the sixth base photo pattern34when projected in the first direction.

Furthermore, a slide pattern obtained by sliding (subjected to parallel movement of) the base photo pattern first end portion36located in the base mask one end portion31A of the sixth base photo pattern34to the other side in the first direction coincides with the base photo pattern second end portion37located in the base mask other end portion31B of the seventh base photo pattern35. Each of the base photo pattern first end portion36of the sixth base photo pattern34and the base photo pattern second end portion37of the seventh base photo pattern35includes each of the base first portion38and the base second portion39, respectively. The base first portion38of the sixth base photo pattern34coincides with the base second portion39of the seventh base photo pattern35when projected in the first direction.

In other words, of the plurality of base photo patterns83, a slide pattern obtained by sliding (subjected to parallel movement of) the base photo pattern first end portion36of one third base photo pattern30to one side in the first direction coincides with the base photo pattern second end portion37of the other third base photo pattern30adjacent to one side in the third direction of one third base photo pattern30.

In the third step, the base photomask31is disposed on one side in the thickness direction of the photosensitive base precursor layer81, while the base photomask31is aligned using the alignment mark7.

First, the base photomask31is disposed with respect to the photosensitive base precursor layer81corresponding to one sheet area9with the first mark14and the second mark15in one sheet area9as a reference.

Subsequently, only the photosensitive base precursor layer81corresponding to the base photomask31is exposed through the base photomask31to form the latent image68(ref:FIG. 6B) corresponding to the first base photo pattern28to the third base photo pattern30in the photosensitive base precursor layer81.

As shown by the arrow ofFIG. 6A,FIG. 6B, the arrow ofFIG. 7B, andFIG. 7C, the base photomask31is subsequently moved (slid) to one side in the first direction with respect to the photosensitive base precursor layer81, and disposed on one side in the thickness direction of the photosensitive base precursor layer81corresponding to the other sheet area9(for example, the second sheet area9B) adjacent to one side in the first direction of one sheet area9(for example, the first sheet area9A).

When the base photomask31is moved and disposed with respect to the photosensitive base precursor layer81, the base photomask31is disposed in the photosensitive base precursor layer81corresponding to the other sheet area9(for example, the second shed area9B) with the first mark14and the second mark15in the other sheet area9(for example, the second sheet area9B) as a reference.

Further, in the photosensitive base precursor layer81, a portion facing the base mask one end portion31A of the base photomask31at the time of the previous exposure is overlapped with a portion facing the base mask other end portion31B of the base photomask31at the time of the present exposure.

Then, in the photosensitive base precursor layer81, a portion corresponding to the base first portion38of the base photomask31at the time of the previous exposure coincides with a portion corresponding to the base second portion39of the base photomask31at the time of the present exposure.

Subsequently, the photosensitive base precursor layer81is exposed to form another latent image68through the base photomask31after movement.

Thereafter, as shown inFIGS. 7D to 7E, the movement of the base photomask31, the alignment of the base photomask31, the exposure of the photosensitive base precursor layer81, and the formation of the latent image68described above are repeated.

Thereafter, as shown inFIG. 7F, the photosensitive base precursor layer81is developed and if necessary, heated.

Thus, as shown inFIGS. 3B and 7F, the base insulating layer4including the base intermediate portion19continuous in the second direction over the plurality of sheet areas9is formed.

Then, as shown inFIG. 2C, in the fourth step, the conductive pattern5is formed. The conductive pattern5is formed on one surface in the thickness direction of the base insulating layer4.

As shown inFIGS. 10G to 10H, the conductive pattern5is formed using a plating resist50as one example of a resist. As shown inFIGS. 9B to 10G, the plating resist50is formed by photolithography in which one photomask40is sequentially moved in the first direction (ref:FIGS. 11A to 11B) to be exposed a plurality of times with respect to a photosensitive dry film resist60as one example of a photoresist.

In the fourth step, first, as shown inFIG. 9A, a seed film69is disposed on one surfaces in the thickness direction of the base insulating layer4, the alignment mark7, and the support sheet2. The seed film69is, for example, formed by sputtering. A material for the seed film69includes a conductor that is the same as the conductive pattern5(specifically, copper). A thickness of the seed film69is, for example, 10 nm or more, and for example, 1000 nm or less.

Then, in the fourth step, as shown inFIG. 9B, the photosensitive dry film resist60is laminated on one surface in the thickness direction of the seed film69.

Then, in the fourth step, as shown inFIGS. 8A and 9C, the photomask40is disposed on one side in the thickness direction of the dry film resist60.

The one photomask40has a first photo pattern41, a second photo pattern42, and a third photo pattern43. Each of the first photo pattern41to the third photo pattern43corresponds to each of the conductive one end portion21, the conductive other end portion22, and the conductive intermediate portion23in one sheet area9(ref:FIG. 4C). In the photomask40, for example, when the dry film resist60is a negative type, it has the light shielding pattern B corresponding to the conductive pattern5, and the light transmitting pattern T corresponding to a portion other than the conductive pattern5.

The third photo pattern43includes a plurality of photoline patterns44disposed adjacent to each other at spaced intervals in the third direction in the one photomask40. The plurality of photoline patterns44sequentially include a first photoline pattern46, a second photoline pattern47, a third photoline pattern48, and a fourth photoline pattern49toward one side in the third direction. Each of the first photoline pattern46to the fourth photoline pattern49corresponds to each of the first conductive intermediate portion23A to the fourth conductive intermediate portion23D, respectively (ref:FIG. 4C).

The photomask40includes, for example, the mask frame67having a generally rectangular shape when viewed from the top. The first photo pattern41to the third photo pattern43are provided in the mask frame67described above.

Further, the photomask40includes a first directional one end portion61, and a first directional other end portion62at the inside of the mask frame67. The first directional one end portion61and the first directional other end portion62are located in the vicinity of each of the inside of two sides45facing each other in the first direction in the frame of the photomask40.

A slide pattern obtained by sliding (subjected to parallel movement of) a first photoline pattern first end portion63located in the first directional one end portion61of the first photoline pattern46in the photomask40to the other side in the first direction coincides with a first photoline pattern second end portion64located in the first directional other end portion62of the second photoline pattern47.

The first photoline pattern first end portion63includes a first portion65. The first portion65is located at least in the intermediate portion in the first direction in the first photoline pattern first end portion63. Specifically, the first portion65is located in the central portion in the first direction of the first photoline pattern first end portion63.

The first photoline pattern second end portion64includes a second portion66. The second portion66is located at least in the intermediate portion in the first direction in the first photoline pattern second end portion64. Specifically, the second portion66is located in the central portion in the first direction of the first photoline pattern second end portion64.

Then, the first portion65coincides with the second portion66when projected in the first direction. That is, the position in the width direction of the first portion65is the same as the position in the width direction of the second portion66when projected in the first direction.

Further, a slide pattern obtained by sliding (subjected to parallel movement of) the first photoline pattern first end portion63located in the first directional one end portion61of the second photoline pattern47to the other side in the first direction coincides with the first photoline pattern second end portion64located in the first directional other end portion62of the third photoline pattern48. Each of the first photoline pattern first end portion63of the second photoline pattern47and the first photoline pattern second end portion64of the third photoline pattern48includes each of the first portion65and the second portion66, respectively. The first portion65of the second photoline pattern47coincides with the second portion66of the third photoline pattern48when projected in the first direction.

Furthermore, a slide pattern obtained by sliding (subjected to parallel movement of) the first photoline pattern first end portion63located in the first directional one end portion61of the third photoline pattern48to the other side in the first direction coincides with the first photoline pattern second end portion64located in the first directional other end portion62of the fourth photoline pattern49. Each of the first photoline pattern first end portion63of the third photoline pattern48and the first photoline pattern second end portion64of the fourth photoline pattern49includes each of the first portion65and the second portion66, respectively. The first portion65of the third photoline pattern48coincides with the second portion66of the fourth photoline pattern49when projected in the first direction.

In other words, of the plurality of photoline patterns44, a slide pattern obtained by sliding (subjected to parallel movement of) the first photoline pattern first end portion63of one plurality of photoline patterns44to the other side in the first direction coincides with the first photoline pattern second end portion64of the other plurality of photoline patterns44adjacent to one side in the third direction of one plurality of photoline patterns44.

In the fourth step, the photomask40is disposed on one side in the thickness direction of the dry film resist60, while the photomask40is aligned using the alignment mark7.

In the alignment of the photomask40using the alignment mark7, the photomask40is disposed with respect to the dry film resist60corresponding to one sheet area9with the first mark14and second mark15in one sheet area9as a reference.

Subsequently, only the dry film resist60corresponding to the photomask40is exposed through the photomask40to form the latent image68corresponding to the first photo pattern41to the third photo pattern43in the dry film resist60.

As shown by the arrow ofFIG. 8A,FIG. 8B, the arrow ofFIG. 9C, andFIG. 9D, the photomask40is subsequently moved (slid) to one side in the first direction with respect to the dry film resist60, and disposed on one side in the thickness direction of the dry film resist60corresponding to the other sheet area9(for example, the second sheet area9B) adjacent to one side in the first direction of one sheet area9(for example, the first sheet area9A).

When the photomask40is moved and disposed with respect to the dry film resist60, the photomask40is disposed in the dry film resist60corresponding to the other sheet area9(for example, the second sheet area9B) with the first mark14and the second mark15in the other sheet area9(for example, the second sheet area9B) as a reference.

Further, in the dry film resist60, a portion facing the first directional one end portion61of the photomask40at the time of the previous exposure is overlapped with a portion facing the first directional other end portion62of the photomask40at the time of the present exposure. Thus, an overlapped portion is present in the dry film resist60.

Then, in the dry film resist60, a portion corresponding to the first portion65of the photomask40at the time of the previous exposure coincides with a portion corresponding to the second portion66of the photomask40at the time of the present exposure.

As shown inFIG. 8B, the line segment passing through the central portion in the first direction of the overlapped portion becomes the boundary13.

Subsequently, the dry film resist60is exposed through the photomask40after movement to form another latent image68.

As shown inFIGS. 9D to 9E, the movement of the photomask40, the alignment of the photomask40, the exposure of the dry film resist60, and the formation of the latent image68described above are repeated.

In the fourth step, in the dry film resist60, a portion facing the first directional one end portion61of the one photomask40at the time of the n-th time (a is a natural number) exposure is overlapped with a portion facing the first directional other end portion62of the one photomask40at the time of the [n+1]th time exposure. A plurality of overlapped portions are present.

Thus, the plurality of boundaries13are partitioned by the plurality of overlapped portions, thereby defining the plurality of sheet areas9.

As shown inFIG. 10G, thereafter, the dry film resist60is developed and if necessary, heated to form the plating resist50in an inverted pattern of the conductive pattern5.

As shown inFIG. 10H, thereafter, the conductive pattern5is formed using the plating resist50by plating.

As shown inFIG. 10I, a clear boundary may be present, or as shown inFIG. 10H, the boundary may not be present between the conductive pattern5and the seed film69adjacent to the other side in the thickness direction thereof.

Subsequently, as shown inFIG. 10I, the plating resist50is removed, and subsequently, the seed film69exposed from the conductive pattern5is removed.

Thus, as shown inFIGS. 2C and 4C, the conductive pattern5including the conductive intermediate portion23continuous in the second direction over the plurality of sheet areas9is formed.

Thereafter, as shown inFIG. 2D, in the fifth step, the cover insulating layer6is formed. The cover insulating layer6is disposed on one surface in the thickness direction of the base insulating layer4so as to cover the wire of the conductive pattern5and expose the one-side terminal and the other-side terminal of the conductive pattern5.

A method of forming the cover insulating layer6is not particularly limited. The cover insulating layer6is, for example, formed by a photolithography method. For example, as shown inFIGS. 11A to 12F, a photosensitive cover precursor layer91is disposed on one surfaces in the thickness direction of the support sheet2, the base insulating layer4, the alignment mark7, and the conductive pattern5, and then, the photosensitive cover precursor layer91is exposed through a cover photomask52as one example of a second photomask to be then developed.

In order to dispose the photosensitive cover precursor layer91, as shown inFIG. 12A, for example, a precursor composition of the above-described resin having photosensitivity is applied to one surfaces in the thickness direction of the support sheet2, the base insulating layer4, the alignment mark7, and the conductive pattern5and if necessary, dried.

Subsequently, as shown inFIGS. 12B to 12E, the one cover photomask52is prepared and sequentially moved in the first direction (ref:FIGS. 11A to 11B) to expose the photosensitive cover precursor layer91a plurality of times.

As shown inFIG. 11A, the cover photomask52includes a first cover photo pattern53as one example of a fourth photo pattern, a second cover photo pattern54as one example of a fifth photo pattern, and a third cover photo pattern55as one example of a sixth photo pattern.

Each of the first cover photo pattern53, the second cover photo pattern54, and the third cover photo pattern55in the one cover photomask52corresponds to the cover one end portion25, the cover other end portion26, and the cover intermediate portion27, respectively in one sheet area9(ref:FIG. 4D). In the cover photomask52, for example, when the photosensitive cover precursor layer91is a negative type, it has the light transmitting pattern T corresponding to the cover insulating layer6and the light shielding pattern B corresponding to a portion other than the cover insulating layer6.

Further, the third cover photo pattern55includes a cover photo pattern51as one example of a plurality of photo patterns disposed adjacent to each other at spaced intervals in the third direction in the one cover photomask52. The plurality of cover photo patterns51sequentially have a fourth cover photo pattern56, a fifth cover photo pattern57, a sixth cover photo pattern58, and a seventh cover photo pattern59toward one side in the third direction.

Each of the fourth cover photo pattern56to the seventh cover photo pattern59corresponds to each of the first cover intermediate portion27A to the fourth cover intermediate portion27D (ref:FIG. 4D).

The cover photomask52has, for example, the mask frame67having a generally rectangular shape when viewed from the top. The cover photomask52includes a cover mask one end portion60A as one example of a first directional one end portion, and a cover mask other end portion60B as one example of a first directional other end portion at the inside of the mask frame67.

In the plurality of cover photo patterns51, a slide pattern obtained by sliding (subjected to parallel movement of) the cover photo pattern first end portion71that is a portion located in the cover mask one end portion60A of the fourth cover photo pattern56to the other side in the first direction corresponds to the cover photo pattern second end portion72that is a portion located in the cover mask other end portion60B of the fifth cover photo pattern57.

The cover photo pattern first end portion71includes a cover first portion73. The cover first portion73is located in the intermediate portion in the first direction in the cover photo pattern first end portion71, and disposed over the entire width direction in the cover photo pattern first end portion71. Specifically, the cover first portion73is located in the central portion in the first direction of the cover photo pattern first end portion71.

The cover photo pattern second end portion72includes a cover second portion74. The cover second portion74is located in the intermediate portion in the first direction in the cover photo pattern second end portion72, and disposed over the entire width direction in the cover photo pattern second end portion72. Specifically, the cover second portion74is located in the central portion in the first direction of the cover photo pattern second end portion72.

Then, the cover first portion73coincides with the cover second portion74when projected in the first direction. That is, the position in the width direction of the cover first portion73is the same as the position in the width direction of the cover second portion74when projected in the first direction.

Further, a slide pattern obtained by sliding (subjected to parallel movement of) the cover photo pattern first end portion71located in the cover mask one end portion60A of the fifth cover photo pattern57to the other side in the first direction coincides with the cover photo pattern second end portion72located in the cover mask other end portion60B of the sixth cover photo pattern58. Each of the cover photo pattern first end portion71of the fifth cover photo pattern57and the cover photo pattern second end portion72of the sixth cover photo pattern58includes each of the cover first portion73and the cover second portion74, respectively. The cover first portion73of the fifth cover photo pattern57coincides with the cover second portion74of the sixth cover photo pattern58when projected in the first direction.

Furthermore, a slide pattern obtained by sliding (subjected to parallel movement of) the cover photo pattern first end portion71located in the cover mask one end portion60A of the sixth cover photo pattern58to the other side in the first direction coincides with the cover photo pattern second end portion72located in the cover mask other end portion60B of the seventh cover photo pattern59. Each of the cover photo pattern first end portion71of the sixth cover photo pattern58and the cover photo pattern second end portion72of the seventh cover photo pattern59includes each of the cover first portion73and the cover second portion74, respectively. The cover first portion73of the sixth cover photo pattern58coincides with the cover second portion74of the seventh cover photo pattern59when projected in the first direction.

In other words, of the plurality of cover photo patterns51, a slide pattern obtained by sliding (subjected to parallel movement of) the cover photo pattern first end portion71of one plurality of cover photo patterns51to one side in the first direction coincides with the cover photo pattern second end portion72of the other plurality of cover photo patterns51adjacent to one side in the third direction of one plurality of cover photo patterns51.

In the fifth step, the cover photomask52is disposed on one side in the thickness direction of the photosensitive cover precursor layer91, while the cover photomask52is aligned using the alignment mark7.

First, the cover photomask52is disposed with respect to the photosensitive cover precursor layer91corresponding to one sheet area9with the first mark14and second mark15in one sheet area9as a reference.

Subsequently, only the photosensitive cover precursor layer91corresponding to the cover photomask52is exposed through the cover photomask52to form the latent image68corresponding to the first cover photo pattern53to the third cover photo pattern55in the photosensitive cover precursor layer91.

As shown by the arrow ofFIG. 11A,FIG. 11B, the arrow ofFIG. 12B, andFIG. 12C, the cover photomask52is subsequently moved (slid) to one side in the first direction with respect to the photosensitive cover precursor layer91, and disposed on one side in the thickness direction of the photosensitive cover precursor layer91corresponding to the other sheet area9(for example, the second sheet area9B) adjacent to one side in the first direction of one sheet area9(for example, the first sheet area9A).

When the cover photomask52is moved and disposed with respect to the photosensitive cover precursor layer91, the cover photomask52is disposed in the photosensitive cover precursor layer91corresponding to the other sheet area9(for example, the second sheet area9B) with the first mark14and the second mark15in the other sheet area9(for example, the second sheet area9B) as a reference.

Further in the photosensitive cover precursor layer91, a portion facing the cover mask one end portion60A of the cover photomask52at the time of the previous exposure is overlapped with a portion facing the cover mask other end portion60B of the cover photomask52at the time of the present exposure.

Further, in the photosensitive cover precursor layer91, the cover first portion73of the cover photomask52at the time of the previous exposure is at the same position as the cover second portion74of the cover photomask52at the time of the present exposure.

Subsequently, the photosensitive cover precursor layer91is exposed through the cover photomask52after movement to form another latent image68.

Thereafter, as shown inFIGS. 12D to 12E, the movement of the cover photomask52, the alignment of the cover photo mask52, the exposure of the photosensitive cover precursor layer91, and the formation of the latent image68described above are repeated.

As shown inFIG. 12F, thereafter, the photosensitive cover precursor layer91is developed and if necessary, heated.

Thus, as shown inFIG. 4D, the cover insulating layer6including the cover intermediate portion27continuous in the second direction is formed over the plurality of sheet areas9.

Thus, the plurality of wiring circuit boards3including the base insulating layer4, the conductive pattern5, and the cover insulating layer6are produced.

Thus, the wiring circuit board assembly sheet1including the plurality of alignment marks7and the plurality of wiring circuit boards3is obtained.

(Function and Effect of One Embodiment)

Then, in the producing method described above, as shown inFIG. 8A, each of the first portions65of the plurality of photoline patterns44coincides with each of the second portions66of the plurality of photoline patterns44when projected in the first direction. Therefore, as shown inFIG. 4C, the conductive intermediate portion23can be continuous in the second direction.

Further, in one embodiment, as shown inFIG. 8A, even when the shape of the first photo pattern41and the second photo pattern42are afferent from the shape of the third photo pattern43, as described above, since the first portion65coincides with the second portion66, as shown inFIG. 4C, the conductive intermediate portion23can be also continuous in the second direction. As a result, it is possible to form the conductive pattern5having excellent reliability, while the conductive one end portion21and the conductive other end portion22having a different shape from the conductive intermediate portion23are provided.

Further, since the one photomask40is sequentially moved in the first direction to expose the dry film resist60a plurality of times, it is possible to easily form the conductive pattern5described above, while the number of components of the production device is reduced.

However, in the dry film resist60, when a portion facing the first directional one end portion61of the one photomask40at the time of the n-th time exposure is not overlapped with a portion facing the first directional other end portion62of the one photomask40at the time of the [n+1]th time, there may be a case where the conductive intermediate portion23easily becomes discontinuous, and the reliability of the conductive pattern5is reduced.

On the other hand, in this producing method, as shown inFIGS. 8B, and 9C to 9F, since the first directional one end portion61and the first directional other end portion62described above are overlapped, even when the one photomask40is sequentially moved in the first direction, the conductive intermediate portion23can be continuous, and therefore, it is possible to suppress a decrease in reliability of the conductive pattern5.

The conductive pattern5having the short length L0in the second direction of below 300 mm can be formed by photolithography for exposing the one photomask40once. However, in the photolithography, there may be a case where the conductive pattern5having the long length L0in the second direction of 300 mm or more cannot be formed.

However, in the producing method, since the photolithography for sequentially moving the one photomask40in the first direction to be exposed a plurality of times is carried out, as described above, it is possible to form the conductive pattern5having the long length L0in the second direction, while having excellent reliability.

As shown inFIGS. 6A to 6B, in the third step of forming the base insulating, layer4, each of the base first portions38of the plurality of base photo patterns83coincides with each of the base second portions39of the plurality of base photo patterns83when projected in the first direction. Therefore, as shown inFIG. 3B, the base intermediate portion19can be continuous in the second direction.

As shown inFIG. 6A, even when the shape of the first base photo pattern28and the second base photo pattern29is different from the shape of the third base photo pattern30, as described above, since the base first portion38coincides with the base second portion39, as shown inFIG. 3B, the base intermediate portion19is also continuous in the second direction. As a result, it is possible to form the base insulating layer4having the base one end portion17and the base other end portion18which can have a different shape from the base intermediate portion19and having excellent reliability.

Further, since the one base photomask31is sequentially moved in the first direction to expose the photosensitive base precursor layer81a plurality of times, it is possible to easily form the base insulating layer4described above, while the number of components of the production device is reduced.

Further, as shown inFIGS. 11A to 11B, in the fifth step of forming the cover insulating layer6, each of the cover first portions73of the plurality of cover photo patterns51coincides with each of the cover second portions74of the plurality of third cover photo patterns55when projected in the first direction. Therefore, as shown inFIG. 4D, the cover intermediate portion27is continuous in the second direction. Further, in one embodiment, as shown inFIG. 11A, even when the shape of the first cover photo pattern53and the second cover photo pattern54is different from the shape of the third cover photo pattern55, as described above, since the cover first portion73coincides with the cover second portion74, as shown inFIG. 4D, the cover intermediate portion27is also continuous in the second direction. As a result, it is possible to form the cover insulating layer6having the cover one end portion25and the cover other end portion26which can have a different shape from the cover intermediate portion27and having excellent reliability.

Further, since the one cover photomask52is sequentially moved in the first direction to expose the photosensitive cover precursor layer91a plurality of times, it is possible to easily form the cover insulating layer6described above, while the number of components of the production device is reduced.

Further, as shown inFIG. 4C, in the wiring circuit board assembly sheet1, the conductive intermediate portion23of the conductive pattern5includes the first end edge11and the second end edge12, and the first end edge11of the conductive intermediate portion23of the first sheet area9A coincides with the second end edge12of the conductive intermediate portion23of the second sheet area9B. Therefore, the conductive intermediate portion23can be reliably continuous over the plurality of sheet areas9. Therefore, the conductive pattern5is excellent in reliability.

Since the wiring circuit board assembly sheet1includes the alignment mark7, it is excellent in reliability of the plurality of icing circuit boards3.

In each of the third step to the fifth step, since the alignment mark7is used, each of the base insulating layer4, the conductive pattern5, and the cover insulating layer6can be accurately formed.

MODIFIED EXAMPLES

In the following modified examples, the same reference numerals are provided for members and steps corresponding to each of those in the above-described one embodiment, and their detailed description is omitted. Each of the modified examples can achieve the same function and effect as that of one embodiment unless otherwise specified. Furthermore, one embodiment and the modified examples thereof can be appropriately used in combination.

As shown inFIG. 13A, in the photomask40used in the fourth step, both of the first photoline pattern first end portion63and the first photoline pattern second end portion64are a straight pattern75extending in the first direction. The straight portion75is parallel with the width directional both end edges10.

As shown inFIG. 13B, the conductive intermediate portion23of the conductive pattern5formed using the photomask40described above includes a straight portion77extending in the first direction. The straight portion77is located in the boundary portion16.

As shown inFIG. 14, in the photomask40, all of the slide patterns of the first photoline pattern first end portions63of the plurality of photoline patterns44may not coincide with all of the first photoline pattern second end portions64of the plurality of photoline patterns44.

In this case, for example, the first photoline pattern first end portion63is the straight portion77. The slide pattern obtained by subjecting the straight portion77to parallel movement to the other side in the first direction intersects the first photoline pattern second end portion64. However, the first portion65coincides with the second portion66at an intersection.

On the other hand, the slide pattern of the first photoline pattern first end portion63other than the first portion65does not coincide with the first photoline pattern second end portion64other than the second portion66and deviates in the second direction.

In this modified example, the boundary13passes through the intersection described above.

As shown inFIG. 15, the conductive intermediate portion23in one wiring circuit board3is disposed over the continuous three sheet areas9(the first sheet area9A, the second sheet area9B, and the third sheet area9C).

As shown inFIG. 16, the conductive intermediate portion23in one wiring circuit board3is disposed over the continuous two sheet areas9(the first sheet area9A and the second sheet area9B).

Further, though not shown, the conductive intermediate portion23in one wiring circuit board3may be disposed over the continuous five or more sheet areas9.

Although not shown, by using an elongated base sheet in the first direction as the support sheet2, the conductive pattern5and the cover insulating layer6are sequentially formed on one side in the thickness direction thereof, and then, by trimming the base sheet, it is also possible to form the base insulating layer4.

As shown inFIG. 15, it is also possible to dispose the mark set8in the intermediate portion (central portion) in the width direction of the support sheet2.

As shown inFIG. 17, the plurality of wiring circuit boards3disposed in alignment in the first direction may be in two rows at spaced intervals in the width direction. In the modified example, the alignment mark7is disposed in the vicinity of the width directional both end edges10, and in the central portion between the width directional both end edges10.

As shown inFIG. 18B, a shape and/or a dimension of the conductive intermediate portion23may vary toward one side in the second direction. For example, inFIG. 18, in the conductive intermediate portion23, a width of the wire becomes thicker toward one side in the second direction. Further, in the conductive intermediate portion23, an interval between the wires adjacent to each other becomes wider toward one side in the second direction.

As shown inFIG. 18B, a shape of the conductive one end portion21is different from that of the conductive other end portion22. The one-side terminals of the conductive one end portion21are disposed in alignment at spaced intervals to each other in the third direction. The terminals of the conductive other end portion22are disposed in alignment at spaced intervals to each other in the second direction and the third direction.

However, as shown inFIG. 18A, the slide pattern of the first photoline pattern first end portion63coincides with the first photoline pattern second end portion64. The first portion65is located in the same position as the second portion66when projected in the first direction.

As shown inFIG. 18B, both end edges in the width direction of the base one end portion17are continuous to both end edges in the width direction of the base intermediate portion19. The base other end portion18expands outwardly in the third direction with respect to the base intermediate portion19.

Further, though not shown, it is also possible to carry out the second step and the third step at the same time. In this case, in the third step, in the alignment of the base photomask31, the alignment mark7described above is not used.

As shown inFIG. 19, the conductive intermediate portion23may be curved in a generally S-shape when viewed from the top. Further, though not shown, the conductive intermediate portion23may have a folded shape.

Further, in one embodiment, the conductive pattern5is formed by an additive method. Alternatively, the conductive pattern5can be also formed by a subtractive method. In the subtractive method, a conductive sheet adheres to one surfaces in the thickness direction of the support sheet2and the base insulating layer4, and subsequently, the dry film resist60is disposed on one surface in the thickness direction of the conductive sheet. Thereafter, by photolithography in which the one photomask40is sequentially moved in the first direction to be exposed a plurality of times, an etching resist is formed in the same pattern as the conductive pattern5. Thereafter, by etching the conductive sheet exposed from the etching resist, the conductive pattern5is formed.

In addition, in the third step, the photosensitive base precursor layer81may be exposed a plurality of times using the plurality of base photomasks31. Furthermore, in the third step, by a method other than the photolithography, for example, the base insulating layer4formed in advance into a pattern having the base one end portion17, the base other end portion18, and the base intermediate portion19can also adhere to the support sheet2.

In addition, in the fifth step, the photosensitive cover precursor layer91may be exposed a plurality of times using the plurality of cover photomasks52. Furthermore, in the fifth step, by a method other than the photolithography, for example, the cover insulating layer6formed in advance into a pattern having the cover one end portion25, the cover other end portion26, and the cover intermediate portion27can also adhere to the base insulating layer4and the conductive pattern5.

Alternatively, it is also possible to shave the one-side portion in thickness direction of the support sheet2to form a recessed portion, or to form a through hole penetrating the support sheet2in the thickness direction to form the alignment mark7consisting of the through hole. The alignment mark7can be also formed by laser irradiation or ink printing (ink jet printing).

In the method for producing the wiring circuit board assembly sheet1, since the support sheet2is elongated, a roll-to-roll method is carried out, and a length in the first direction of an exposure device is usually shorter than that of the support sheet2, there may be a case where the plurality of alignment marks7cannot be formed by one exposure. Therefore, the alignment photomask20is sequentially moved toward one side in the first direction to be exposed a plurality of times.

In one embodiment, as shown inFIGS. 5A to 5B(orFIGS. 21A to 21Bto be described later), the latent image68corresponding to the first mark14and the second mark15sandwiching the boundary13therebetween is formed by one exposure using the one alignment photomask20.

On the other hand, in the modified example shown inFIGS. 20A to 20E, the latent image68corresponding to the first mark14and the second mark15sandwiching the boundary13therebetween is formed by separate exposures.

That is, in the modified example, first, as shown inFIG. 20A, the latent image68of the first mark14and the second mark15corresponding to one sheet area9(the first sheet area9A) is formed by exposure through the one alignment photomask20. Next, as shown inFIG. 20B, the alignment photomask20is slid with respect to the photosensitive precursor layer24corresponding to the other sheet area9(the second sheet area9B). Thereafter, the latent image68of the first mark14and the second mark15is formed on the photosensitive precursor layer24corresponding to the other sheet area9(the second sheet area9B) by exposure through the one alignment photomask20.

However, in the modified example, in the mark set8, the second mark15may deviate in the width direction with respect to the first mark14(occurrence of deviation G). Then, as shown inFIG. 20C, even when the photomask40is first aligned to expose the dry film resist60using the second mark15in one sheet area9(the first sheet area9A), and then, as shown inFIG. 20D, the photomask40is moved and aligned again with the dry film resist60to be exposed using the first mark14in the other sheet area9(the second sheet area9B), the first portion65and the second portion66do not easily coincide due to the deviation G described above. Then, as shown by an enlarged view ofFIG. 20E, the conductive intermediate portion23in one sheet area9(the first sheet area9A) may be not easily continuous to the conductive intermediate portion23in the other sheet area9(the second sheet area9B).

However, in one embodiment, as shown inFIGS. 5A to 5B, the latent image68corresponding to the first mark14and the second mark15sandwiching the boundary13therebetween is formed by one exposure, and as shown inFIGS. 21A to 21B, even when the first mark14and the second mark15corresponding to one sheet area9deviate in the width direction and the posture of the one photomask40is slightly rotated (ref: a thin arrow ofFIG. 21C), the latent image68corresponding to the first mark14and the second mark15sandwiching the boundary13therebetween is formed by one exposure, so that the above-described positional deviation can be suppressed. Consequently, as shown by the enlarged view ofFIG. 21E, the conductive intermediate portion23in one sheet area9(the first sheet area9A) and the conductive intermediate portion23in the other sheet area9(the second sheet area9B) can be reliably electrically conducted.

As shown inFIGS. 22A to 22B, the one alignment mark7may be provided in the boundary portion16at each of the both end portions in the width direction. In this modified example, for example, the alignment mark7is provided in the vicinity of one side in the first direction of the boundary13at the boundary portion16.

In the fourth step, the photomask40is disposed in the dry film resist60, while the alignment thereof is carried out using the alignment mark7.

DESCRIPTION OF SYMBOLS

1Wiring circuit board assembly sheet

3Wiring circuit board

11First end edge (one example of the fifth end edge)

12Second end edge (one example of the sixth end edge)

17Base one end portion (one example of insulating one end portion)

18Base other end portion (one example of insulating other end portion)

19Base intermediate portion (one example of insulating intermediate portion)

21Conductive one end portion

22Conductive other end portion

23Conductive intermediate portion

25Cover one end portion (one example of insulating one end portion)

26Cover other end portion (one example of insulating other end portion)

28First base photo pattern (one example of the fourth photo pattern)

29Second base photo pattern (one example of the fifth photo pattern)

30Third base photo pattern (one example of the sixth photo pattern)

31Base photo mask

31A Base mask one end portion

31B Base mask other end portion

32Fourth base photo pattern

33Fifth base photo pattern

34Sixth base photo pattern

35Seventh base photo pattern

36Base photo pattern first end portion

37Base photo pattern second end portion

38Base first portion

39Base second portion

41First photo pattern

42Second photo pattern

43Third photo pattern

44Plurality of photoline patterns

51Cover photo pattern (one example of photo pattern)

52Cover photo mask (one example of photo mask)

53First cover photo pattern

54Second cover photo pattern

55Third cover photo pattern

56Fourth corner photo pattern

57Fifth cover photo pattern

58Sixth cover photo pattern

59Seventh cover photo pattern

60Dry film resist

60A doper mask one end portion

60B Cover mask other end portion

61First directional one end portion

62First directional other end portion

63First photoline pattern first end portion

64First photoline pattern second end portion

71Cover photo pattern first end portion

72Cover photo pattern second end portion

73Cover first portion

74Cover second portion

81Photosensitive base precursor layer (one example of photosensitive precursor layer)

83Base photo pattern (one example of photo pattern)

91Photosensitive cover precursor layer (one example of photosensitive precursor layer)

L0Second directional length of conductive pattern