JP6715368B2 - Wiring circuit board - Google Patents

Description

The present invention relates to a printed circuit board used for a flexure for a head suspension.

In recent years, in order to further increase the density and improve the reliability of hard disk drives (HDD), in addition to conventional read/write elements for magnetic heads, fly height control heaters, hard disk interface (HDI) sensors, etc. In addition to the above functions, additional functions such as energy assisted recording are being considered, and the number of products with more than 10 terminals has increased, including the ground terminal.

Further, in the present HDD, a slider called Femto slider “Femto Slider” having a width of only about 0.7 mm is used. In reality, it is necessary to connect more than 10 terminals of the slider and the suspension arranged inside the 0.7 mm width without short-circuiting each other.

Here, the connection between the terminals of the slider and the suspension is often performed by reflow using micro solder balls as in Patent Documents 1 to 5.

17A and 17B are schematic cross-sectional views showing the terminal connection on the head side of the flexure by the reflow of the micro solder balls, where FIG. 17A is a relatively large size and FIG. 17B is a relatively small size.

As shown in FIGS. 17A and 17B, a micro solder ball 109 is placed in a valley between the terminal portion 103 of the slider 101 and the terminal portion 107 of the flexure 105, and the fillet 111 is reflowed. The terminal portions 103 and 107 are formed and soldered.

Here, when the number of terminals 107 is relatively small, for example, when the number of terminals for reading and writing is four, the terminals 103 and 107 can be made relatively large. As the 109, a large one can be used, and the fillet 111 can be formed to have a sufficient thickness.

However, when the number of terminal portions 107 is relatively large, such as 10 in order to support multiple functions, the terminal portions 103 and 107 are used in a small size as shown in FIG. 17B. The solder ball 109 also becomes relatively small, and the fillet 111 is also thin, so that it cannot be formed to have a sufficient thickness. For this reason, there is a problem that the rate of causing defective coupling between the terminal portions 103 and 107 increases.

On the tail side, there is a similar problem due to the fact that the solder balls are connected to the terminal portions with the main flexure and the solder balls become smaller.

In the positioning piezoelectric element, the terminals of the flexure are bonded to the conductive paste, and a smaller amount of the conductive paste may cause defective bonding.

In the aerial wiring part, that is, in the structure in which the wiring layer passes through the opening of the metal supporting layer, it is difficult to achieve both thinning of the electrical insulation layer and flattening of the wiring layer in the aerial wiring part, and stabilization of rigidity There was a problem that it was difficult.

In the structure in which the positioning reference hole used for image processing is formed in the wiring layer, the reference hole and its peripheral portion fall into the electrical insulation layer side and become a bent shape, resulting in an unnecessary edge for image processing. There was also the problem of doing.

In any case, there is a problem of the position of the terminal portion, the aerial wiring portion, the reference hole, and the peripheral portion thereof in the layer thickness direction, and in order to correct such a position, it is solved by machining as in Patent Document 6. There are also methods.

FIG. 18(A) is a cross-sectional view of an essential part in which a space between terminals is reduced by raising the metal supporting layer to increase the distance between terminals, and FIG. It is a principal part sectional view which reduced the space|interval.

18A and 18B are examples in which the position of the terminal portion 107 is changed and brought closer to the terminal portion 103 of the slider 101 by bending the terminal portion 107 together with the metal supporting layer 113 by machining. In this example, the space between the terminal portions is reduced, and a fillet having a sufficient thickness can be formed.

However, in the mechanical bending process including the metal supporting layer 113, the variation of the bending angle tends to be large, which causes the variation of the thickness of the fillet, which causes the problem of affecting the solder joint quality.

The influence of variations due to the mechanical bending process including the metal supporting layer 113 is also a cause of quality deterioration in the aerial wiring portion, the reference hole, and the peripheral portion thereof in addition to the solder joining of the terminal portion.

US07239484B2 publication US0784545B2 publication US08213121B2 publication US08295011B2 publication US8295012B1 Publication JP, 2005-251262, A

The problem to be solved is that there is a problem due to the position in the layer thickness direction of the terminal part, etc.There is also a method to solve it by machining including the metal support layer, but there is variation due to machining, which affects quality. The point to do.

The present invention, in order to improve the problems caused by the position of the terminal portion in the layer thickness direction and to enable stabilization of steel property, a metal supporting layer forming a substrate and a metal supporting layer laminated on the surface of the metal supporting layer. Wiring comprising a formed electric insulation layer, and a wiring layer having a general portion laminated on the surface of the electric insulation layer and arranged, and a terminal portion coupled to the general portion for electrically connecting to the outside In the circuit board, the wiring layer includes a step portion in a layer thickness direction in which the terminal portion is projected to the surface by a step of a layer having a raised structure with respect to the general portion, and the terminal portion includes the metal supporting layer and The tip of the opening faces the electric insulating layer in a plane including the step portion, and the step portion is formed to be thinner than the thickness of the main body of the electric insulating layer and protrudes into the opening of the electric insulating layer. The back surface of the terminal portion is supported by, and the front surface of the terminal portion is solder-bonded to the terminal portion of the slider .

Since the printed circuit board of the present invention has the above-mentioned configuration, there is no variation in the bending angle due to the bending of the metal supporting layer due to the step portion in the layer thickness direction, and the surface of the terminal portion is provided with respect to the general portion of the wiring layer. By projecting, the problem of the position of the terminal portion in the layer thickness direction can be improved. Moreover, it is possible to increase the flat surface of the terminal portion and stabilize the rigidity.

It is a plan view seen from the flexure side of the head suspension. (Example 1) FIG. 7 is a schematic enlarged cross-sectional view of a main part showing the connection of the terminal part on the head part side of the flexure. (Example 1) It is each principal part sectional drawing which shows the manufacturing process of a flexure in a schematic list in relation with a comparative example. (Example 1) FIG. 3A is a comparative example, and FIG. 3B is an enlarged cross-sectional view of an example, showing a comparison in the second row of FIG. (Example 1) FIG. 3A is a comparative example, and FIG. 3B is an enlarged cross-sectional view of an example, showing comparison of the third row in FIG. (Example 1) FIG. 4A is a comparative example and FIG. 4B is an enlarged cross-sectional view of an example, showing a comparison in the fourth row of FIG. (Example 1) FIG. 5A is a comparative example, and FIG. 4B is an enlarged cross-sectional view of an example, showing a comparison at the fifth level in FIG. 3. (Example 1) FIG. 6A is a comparative example, and FIG. 6B is an enlarged cross-sectional view of an example, showing a comparison in the sixth row of FIG. (Example 1) FIG. 4 is an explanatory diagram showing a comparison of first to third steps according to an example of details of the steps of FIG. 3. (Example 1) FIG. 8 is an explanatory diagram showing a comparison between a fourth step and a fifth step according to an example of details of the step in FIG. 3. (Example 1) FIG. 9 is an explanatory diagram showing a comparison of sixth to eighth steps according to an example of details of the steps in FIG. 3. (Example 1) The coupling structure on the upper surface of the tongue portion is shown, (A) is a cross-sectional view of a main part of a comparative example, (B) is a cross-sectional view of a main part of Example 1 according to a modified example in which the terminal parts are brought close to each other, (C) is FIG. 9 is a cross-sectional view of a main part of a first embodiment according to a modification in which the slider height is increased. (Example 1) (A) is a cross-sectional view of a main part of a comparative example, (B) is a cross-sectional view of a main part of Example 1 according to a modified example in which the terminal parts are brought close to each other, and (C) is It is a principal part sectional view of Example 1 which concerns on the modification which raised the slider height. (Example 1) It is a principal part sectional view which shows the flying lead of a tail part. (Example 2) 3A and 3B show an aerial wiring part, FIG. 3A being a comparative example, and FIG. 3B being a sectional view of an example. (Example 3) The reference hole for positioning is shown, (A) is a comparative example, (B) is sectional drawing of an Example. (Example 4) FIG. 3 is a schematic cross-sectional view showing a terminal connection on the head portion side of a flexure without a raised structure, where (A) is a large size and (B) is a small size. (Conventional example) (A) is a cross-sectional view of a main part in which the spacing between terminals is reduced by raising the metal support layer to increase the spacing between terminals, and (B) shows the spacing between terminals by folding including the metal support layer. FIG. (Conventional example)

The purpose of improving the problem caused by the position of the terminal portion in the layer thickness direction to improve quality regardless of the metal supporting layer is to improve the quality of the metal supporting layer forming the substrate and the surface of the metal supporting layer. An electric insulating layer formed by stacking, and a wiring layer having a general portion laminated and arranged on the surface of the electric insulating layer and a terminal portion connected to the general portion for conducting connection to the outside are provided. In the printed circuit board, the wiring layer includes a step portion in a layer thickness direction in which a step of the terminal portion is formed with respect to the general portion to protrude toward a front surface side, and the terminal portion includes the metal support. The tip side faces the openings of the layers and the electric insulating layer, and the step is realized by being supported by the tongue of the electric insulating layer formed to be thinner than the thickness of the main body of the electric insulating layer.

In addition, a metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and connected to the general portion A wiring circuit board having a wiring layer having a terminal portion for conducting connection to the outside, wherein the terminal portion faces the opening side of the metal supporting layer and the electrically insulating layer on the front end side, and the terminal portion is This is realized by the fact that the base of the opening facing the opening is supported by the tongue of the electric insulating layer formed to be thinner than the main body of the electric insulating layer.

In addition, a metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and connected to the general portion A wiring circuit board comprising: a wiring layer having a terminal portion for conducting connection to the outside, wherein the wiring layer projects the terminal portion to the surface side by forming a layer step with respect to the general portion. A step portion in the layer thickness direction, the terminal portion passes through an opening penetrating the metal supporting layer and the electric insulating layer, and the base portions of the step portion and the terminal portion are supported by the metal supporting layer and the electric insulating layer. It was realized by being done.

In addition, a metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and connected to the general portion A wiring circuit board having a wiring layer having a terminal portion for conducting connection to the outside, wherein the wiring layer includes an aerial wiring portion flattened with respect to the general portion, and the aerial wiring portion is It was realized by being supported by a thin portion formed to be thinner than the main body of the electric insulation layer.

In addition, a metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and connected to the general portion A wiring circuit board having a wiring layer having a terminal portion for conducting connection to the outside, wherein the wiring layer has a reference hole forming portion in which a reference hole for image processing is formed, flat with respect to the general portion. The reference hole forming portion is realized by being supported by a tongue portion formed to be thinner than the thickness of the main body of the electric insulating layer.

[Overview of head suspension]
FIG. 1 is a plan view of the head suspension as viewed from the flexure side according to the first embodiment. In the following description, the turning radius direction of the head suspension is the longitudinal direction or the front-back direction, the direction orthogonal thereto is the width direction, and the turning axis direction is the thickness direction or the layer thickness direction or the vertical direction.

As shown in FIG. 1, the head suspension 1 includes a base plate 3, a load beam 5, and a flexure 7, and a positioning actuator 9.

The base plate 3 is a component that is attached to the carriage side for turning drive and is driven to turn about an axis, and has a boss portion 11 for mounting. The base plate 3 can be attached to the carriage (not shown) side by ball staking by the boss portion 11. A positioning actuator 9 is integrally attached to the base plate 3.

The positioning actuator 9 is capable of displacing a head portion described later in the sway direction with respect to the base plate 3 side, and a piezoelectric element 15 is attached to the actuator plate 13. The rear portion of the actuator plate 13 is superposed on the base plate 3 and integrally joined by laser spot welding or the like. The load beam 5 is integrally connected to the front end of the actuator plate 13 by laser spot welding or the like.

The load beam 5 integrally includes a rigid body portion 21 and spring portions 23a and 23b. The base end side of the rigid body portion 21 is supported by the front end of the actuator plate 13 via the spring portions 23a and 23b, and information is written, A load is applied to the head portion 25, which is a movable portion on the front end side for reading. The flexure 7 is attached to the rigid body portion 21.

The flexure 7 constitutes a printed circuit board in the present embodiment, and the flexure 7 is provided with a slider 27 on the front end side, and the slider 27 is provided with a reading/writing element, a fly height control heater, and a hard disk. Functions such as an interface (HDI) sensor are incorporated to configure the head unit 25. Each terminal of the slider 27 for reading and writing, a heater for controlling fly height, a hard disk interface (HDI) sensor, etc. is connected to each terminal of the wiring of the flexure 7 by soldering. The flexure 7 extends through the positioning actuator 9 to the tail portion side of the base plate 3 side.

In the positioning actuator 9, the actuator connection terminal portion 29 of the flexure 7 is conductively connected to the common electrode of the piezoelectric element 15 by a conductive paste.

Therefore, the head suspension 1 is incorporated into a hard disk drive by being attached to the carriage (not shown) side via the boss portion 11, is driven to rotate by the voice coil motor on the carriage side, and is driven by the slider 27. The head unit 25 moves on the hard disk, and the head unit 25 can write and read information on the hard disk.

[Terminal on the head side]
FIG. 2 is a schematic enlarged cross-sectional view of a main part showing the connection of terminals on the head side of the flexure according to the first embodiment.

As shown in FIG. 2, in the flexure 7, the base insulating layer 33 as an electric insulating layer is laminated on the surface of the conductive thin plate 31, and the wiring layer 35 is formed on the surface of the base insulating layer 33 with a predetermined wiring pattern of copper. The wiring layer 35 is laminated, and the wiring layer 35 is covered with a cover insulating layer 37. The wiring pattern is, for example, a thick line extending in FIG. 1 from the head portion 25 side to the tail portion. In FIG. 1, the tail portion side of the flexure 7 is omitted.

The conductive thin plate 31 is formed of a thin stainless steel rolled plate (SST) having a spring property and constitutes a metal supporting layer which forms a substrate, and its thickness is formed to about 10 to 25 μm. The insulating base layer 33 is laminated on the surface of the conductive thin plate 31, which is a metal supporting layer, using, for example, polyimide, and has a thickness of about 5 to 10 μm. The wiring layer 35 is laminated on the surface of the electric insulating layer 33 by, for example, copper plating, and has a thickness of about 5 to 15 μm. The wiring layer 35 has a general portion 35a and a terminal portion 35b.

The general portion 35a of the wiring layer 35 is arranged so as to extend from the head portion 25 side to the tail portion as shown in FIG. 1, and the terminal portion 35b is connected to the general portion 35a to make conductive connection to the outside. The terminal portion of the portion 25 is electrically connected to the slider 27.

The insulating cover layer 37 is made of, for example, polyimide and covers the general portion 35 a of the wiring layer 35. The general portion 35a is a portion covered with the insulating cover layer 37 in this embodiment, but may be any portion that is not the terminal portion 35b in comparison with the terminal portion 35b.

The terminal portion 35b is formed at the tip of the general portion 35a. In the present embodiment, the terminal portion 35b is formed as a flying lead, gold plating 39 is applied to the front and back surfaces, and terminal surfaces are formed on both front and back surfaces. In this embodiment, the flying lead means a terminal portion which is not supported by the conductive thin plate 31 and the base insulating layer 33 by passing over the openings of the conductive thin plate 31 and the base insulating layer 33. .. Further, the gold plating 39 is drawn relatively thick in the drawing for the sake of expression, but in reality, it is plated very thinly. Further, the gold plating 39 can be omitted.

The wiring layer 35 is provided with a raised structure 41 in the layer thickness direction in the terminal portion 35b which is a predetermined function portion that exhibits a desired function. The raised structure 41 is a layer thickness direction portion in which a part of the wiring layer 35 is projected to the surface side with respect to the general portion 35a or is flush with the general portion 35a regardless of the conductive thin plate 31 which is a metal supporting layer. This means the structure of the terminal portion 35 b of 35.

The raised structure 41 of the present embodiment has a protruding form, and does not include the insulating base layer 33 regardless of the conductive thin plate 31, and is configured only by the terminal portion 35b. In this raised structure 41, the terminal portion 35b is arranged above the general portion 35a in a stepwise manner so as to project toward the surface side. The stepped portion between the general portion 35a and the terminal portion 35b is a right angle in the figure, but in reality, the transition occurs due to the inclination.

Since the conductive thin plate 31 is not involved in the raised structure 41, the conventional raised machining is unnecessary for the raised structure 41, and the precision of the raised structure 41 is improved.

Here, the fact that the conductive thin plate 31, which is a metal supporting layer, is not involved in the raised structure 41 means that the conductive thin plate 31 forms a part of the raised structure 41 by bending by machining in the portion provided with the raised structure 41. It means that there is no.

As shown in FIG. 2, the lower side in the layer thickness direction of the terminal portion 35b provided with the raised structure 41 is the opening 45, and the conductive thin plate 31 and the insulating base layer 33 are not present. However, even if the opening 45 does not exist and the conductive thin plate 31 and the insulating base layer 33 are present on the lower side in the layer thickness direction of the terminal portion 35b, the bending of the conductive thin plate 31 in the raised structure 41 of the terminal portion 35b is performed. This is also included unless mechanical processing such as.

Even if the conductive thin plate 31 has a machined portion other than the raised structure 41, it does not have to be related to the raised structure 41. The insulating base layer 33 and the like are not involved in the raised structure 41 because they are not mechanically processed, so there is no problem.

It should be noted that the raised structure in the layer thickness direction in which the predetermined function part is on the same plane as the general part 35a of the wiring layer 35 is considered not to be a lift at first glance. However, as in the configuration disclosed in Japanese Patent Application Laid-Open No. 2001-350272, in which the etching time is shortened by using the insulating base layer (base layer) made of photosensitive polyimide, the terminal portion is depressed toward the conductive thin plate (support substrate) side. To improve the structure that tends to move away from the slider with, and to adjust the position by lifting the terminal part from the depression (raising) so that the terminal part is flush with the general part of the wiring layer It has technical significance.

A specific example of the same plane form will be described later.

Due to the raised structure 41 of the terminal portion 35b, the gap between the terminal portion 43 of the slider 27 and the terminal portion 35b can be reduced, and an appropriate weld fillet can be formed.

A plurality of, for example, about 10 terminal portions 35b are formed. The terminal portion 35b is formed to be wider in the width direction than the general portion 35a. The terminal portion 35b may be formed to have the same wiring width as the general portion 35a. In some cases, the terminal portion 35b may be smaller than the wiring width of the general portion 35a.

The terminal portion 35b faces the opening 45 of the conductive thin plate 31 and the insulating base layer 33. The opening 45 is composed of openings 45a and 45b from the conductive thin plate 31 to the middle portion of the insulating base layer 33 in the layer thickness direction, and an opening 45c from the middle of the insulating base layer 33 in the layer thickness direction to the surface. .. The shapes and sizes of the openings 45a, 45b, 45c are not particularly limited as long as the flying leads can be realized, but in the present embodiment, the openings 45a, 45b are formed to have the same size, and the opening 45c is The tongue portion 33b protruding stepwise with respect to the opening 45b is formed to be relatively smaller than the openings 45a and 45b. On the tongue portion 33b, the terminal portion 35b starts to be raised. The depth of the opening 45b on the insulating base layer 33 side is set to about 2 to 5 μm with respect to the thickness of the insulating base layer 33 to about 5 to 10 μm. However, the depth of the opening 45b can be variously changed according to design requirements.

The slider 27, which is a functional component of the head unit 25, is, for example, a Femto slider or the like, and has, for example, about 10 terminal units 43 according to the built-in reading and writing elements, the fly height control heater, the HDI sensor, and the like. The groups are arranged side by side in the width direction on the front surface 27a of the slider 27.

As shown in FIG. 2, the respective terminal portions 35b of the flexure 7 and the respective terminal portions 43 of the slider 27 are arranged so as to intersect with each other and face each other so as to be substantially orthogonal in cross section.

A fillet 49 is formed between each terminal portion 35b and each terminal portion 43 by solder fusion bonding with a solder ball 47. The fillet 49 extends over the entire vertical width of the terminal portion 43, and extends from the tip to the stepped portion on the terminal portion 35b, and the width and thickness of the fillet 49 are sufficiently formed between the terminal portions 35b and 43.

[Method for manufacturing printed circuit board]
FIG. 3 is a cross-sectional view of a main part schematically showing a flexure manufacturing process in relation to a comparative example, and FIGS. 4 to 8 show comparisons of the second to sixth stages of FIG. 3, respectively (A). A comparative example, (B) is an enlarged cross-sectional view of the embodiment. Note that the conductive thin plate 31, the electrical insulating layer 33, and the like of the flexure 7 are semi-finished products, unlike the final shape in the process of manufacturing in FIG. 3, but for convenience of explanation, the name as the flexure 7 is used as it is.

3, in the method for manufacturing a wired circuit board according to the embodiment of the present invention, an electrically insulating layer is formed on the conductive thin plate 31 which is a metal supporting layer as in the step of the first row and the second row of the right column of FIG. Before forming a certain base insulating layer 33, the raised layer 51 of FIG. 3 for forming the raised structure 41 of FIG. 2 was added to the conductive thin plate 31.

The material of the raised layer 51 is arbitrary as long as it can be raised, but it is preferable to use an insulating material having a shorter etching time than the insulating base layer 33, copper, nickel, or chromium, or a combination thereof.

The setting range of the raised layer 51 is partially set at a position corresponding to the terminal portion 35b, but is not particularly limited as long as the terminal portion 35b can be the raised structure 41.

As shown in FIG. 5B (the third row in the right column in FIG. 3), the insulating base layer 33 has a raised portion 33a as shown in FIG. 4B (the second column in the right column in FIG. 3). The wiring layer 35 is formed. Therefore, it is possible to form the raised structure 41 in which the terminal portion 35b is raised relative to the general portion 35a.

The openings 45 are formed by the etching of FIGS. 6B and 7B (the fourth row and the fifth row in the right column of FIG. 3). The opening 45 penetrates the conductive thin plate 31 and the insulating base layer 33 and removes the raised layer 51.

Therefore, the tongue portion 33b protruding into the opening 45 remains in the insulating base layer 33, and supports the step portion 35c between the general portion 35a of the wiring layer 35 and the terminal portion 35b. The tongue portion 33b is formed by etching to be thinner than the main body of the insulating base layer 33. In this embodiment, the insulating base layer 33 is related to the raised structure 41 by the support of the step portion 35c by the tongue portion 33b. The insulating cover layer 37 is formed together with the formation of the opening 45.

As shown in FIG. 8B (the sixth column on the right in FIG. 3), the terminal portion 35b is used as a flying lead facing the opening 45, and the raised structure 41 of the terminal portion 35 is formed regardless of the conductive thin plate 31. You can

On the other hand, in the comparative example in the left column of FIG. 3, A is added to the reference numeral in the right column, and description will be given while omitting duplication. In FIG. 4A and FIG. 5A, the left column 2 in FIG. There is no raised layer 51 shown in the right column of the corresponding step (e.g., the third step).

In the comparative example, when the opening 45A is formed by etching as shown in FIG. 6A (fourth row in the left column in FIG. 3) and FIG. 7A (fifth row in the left column in FIG. 3) In order to shorten the time, the photosensitive polyimide of the insulating base layer 33A is used, and the portion 33Aa is formed corresponding to the position where the opening 45A is formed as shown in FIG. 4A (the second column on the left side of FIG. 3). Formed thin by exposure.

Therefore, as shown in FIG. 4A (second column in the left column of FIG. 3 ), FIG. 5A (third column in the left column in FIG. 3) is applied to the base insulating layer 33A in which the thin portion 33Aa is formed. Since the wiring layer 35A is formed as shown in FIG. 8, when the terminal portion 35Ab is used as a flying lead facing the opening 45A as shown in FIG. It becomes a stepped shape that falls to the layer 33A side.

The tongue portion 33Ab protruding into the opening 45A remains in the insulating base layer 33A, but does not support the step portion 35Ac between the general portion 35Aa of the wiring layer 35A and the terminal portion 35Ab.

As described above, according to the method for manufacturing a printed circuit board of the embodiment of the present invention, the flexure 7 including the raised structure 41 without the conductive thin plate 31 in the terminal portion 35b can be reliably manufactured without machining. it can.

That is, in the flexure 7 manufactured by the method for manufacturing a wired circuit board according to the embodiment of the present invention, the terminal portion 35b is projected to the surface side more than the general portion 35a as compared with the comparative example, and the flexure 7 of the flexure 7 is formed as shown in FIG. The gap between the terminal portion 35b and the terminal portion 43 of the slider 27 is reduced to easily form a fillet having a sufficient thickness.

[Process details]
9 to 11 are views for explaining an example of the details of the process of FIG. 3, FIG. 9 is an explanatory diagram showing a comparison from the first process to the third process, and FIG. 10 is a fourth process, FIG. 11 is an explanatory diagram showing comparison of 5 steps, and FIG. 11 is an explanatory diagram showing comparison of 6th step to 8th step. It is also possible to adopt another example of forming the raised structure 41 as the details of the process of FIG.

9 to 11, the manufacturing process of Example 1 will be described in comparison with the comparative example. For convenience of explanation, the name of the flexure 7 is used as it is during processing, as in the case of FIGS. 3 to 8. In the comparative example in the left column, A is added to the reference symbol in the right column. The same applies to the explanation. 9 to 11 show the details of the manufacturing process, and a part of the structure is substantially the same as that of FIGS. 2 to 8 although it is different.

In the manufacturing method of this embodiment, after forming the raised layer 51, the base insulating layer 33, the wiring layer 35, and the cover insulating layer 37 are sequentially laminated on the conductive thin plate 31 in a shape following the flexure 7, and finally the conductive layer is formed. The flexible thin plate 31 is shaped to follow the flexure 7. As a result, even if the structure of the flexure 7 is complicated, it is possible to deal with it.

(First step)
As shown in FIG. 9, in the first step, strip-shaped conductive thin plates 31 and 31A having a predetermined width are prepared for both Example 1 and Comparative Example.

(Second step)
In the second step, in Example 1, the sputter layer 51a and the step layer 51b are partially laminated as the raised layer 51 on the corresponding portions of the prepared conductive thin plate 31. Chromium and copper are used for the sputter layer 51a, and copper is used for the step layer 51b.

Specifically, in the second step of Example 1, first, a chromium and copper sputtered layer 51a is formed on the entire surface of the conductive thin plate 31 by sputtering as shown by a chain double-dashed line, and then a resist is formed. Are partially opened, and a step layer 51b is formed on the portion by copper plating. At this time, the height of the raised layer 51 is adjusted by the height of the step layer 51b. Next, the resist is peeled off, etching is performed to remove the portion indicated by the chain double-dashed line, and the sputter layer 51a is formed.

On the other hand, in the comparative example, there is no second step, and the first step is followed by the third step.

(Third step)
In the third step of Example 1, photosensitive polyimide is applied, exposed and cured using a photomask, and a part of the base insulating layer 33 is formed while forming the base insulating layer 33 following the shape of the flexure 7 in FIG. 33a is raised.

In the comparative example as well, photosensitive polyimide is applied and exposed and cured, but by adjusting the exposure, the portion 3Aa of the insulating base layer 33A is made thinner than the other portions to shorten the etching time described later. Also in the second step of Example 1, the raised layer 51 allows the portion 33a of the insulating layer 33 to be raised while being thinner than the other portions.

(Fourth step)
As shown in FIG. 10, in the fourth step of Example 1 and Comparative Example, sputter layers 53 and 53A of chromium and copper were formed on the insulating base layers 33 and 33A, and a resist was formed in a predetermined pattern on the sputter layers 53 and 53A. The wiring layers 35 and 35A are formed by plating so as to follow the shape of the flexure 7 in FIG. Then, the resist is peeled off, and an unnecessary sputtered layer is removed by etching.

(Fifth step)
In the fifth step of Example 1 and Comparative Example, the electroless nickel plating layers 55 and 55A are applied, the insulating cover layers 37 and 37A are formed so as to cover the wiring layers 35 and 35A, and the electroless nickel plating layer 55 is formed. , 55A unnecessary portions are deleted.

(Sixth step)
As shown in FIG. 11, in the sixth step of Example 1, the opening 45 is formed by etching the conductive thin plate 31, the sputter layer 51a and the step layer 51b of the raised layer 51, the insulating base layer 33, and the sputter layer 53. .. At this time, an etching solution that simultaneously etches copper and chromium, an etching solution that simultaneously etches copper, chromium, and stainless steel can be used as appropriate. Different etching liquids are used for etching the base insulating layer 33. At this time, since the raised layer 51 is already removed, the etching time of the insulating base layer 33 can be shortened. By this etching, the terminal portion 35b is shaped so as to face the opening 45 by the raised structure 41.

In the sixth step of the comparative example, the conductive thin plate 31A, the insulating base layer 33A and the sputtered layer 53A are similarly etched to form the opening 45A. In this comparative example, since the portion 33Aa of the insulating base layer 33A is thinned by exposure in the third step, the removal of the portion 33Aa by etching can be shortened. However, the terminal portion 35Ab is not raised and has a form in which the terminal portion 35Ab falls toward the conductive thin plate 31A side at the opening 45A.

(Seventh step)
In the seventh step of Example 1 and Comparative Example, a resist is formed, and after nickel underlayer plating, gold plating 39, 39A is applied by gold plating to cover the front and back surfaces of the terminal portions 35b, 35Ab, and the resist is peeled off.

(Eighth step)
In the eighth step of Example 1 and Comparative Example, a resist is formed, and the outer shapes of the conductive thin plates 31 and 31A are finally formed by etching in accordance with the outer shape of the flexure 7 in FIG. There is no change in the structure of the terminal portions 35b and 35Ab, and the eighth step is the same as the seventh step in FIG.

As described above, by performing the first to eighth steps of FIGS. 9 to 11, in the flexure 7 of the first embodiment, the raised structure 41 of the terminal portion 35b is formed regardless of the mechanical processing such as bending of the conductive thin plate 31. In contrast to this, in the comparative example, although the terminal portion 35b can be formed regardless of the mechanical processing such as bending of the conductive thin plate 31A, the terminal portion 35Ab is electrically conductive in the opening 45A. The structure is such that it falls to the thin plate 31A side.

[Effect of Example 1]
As described above, the flexure 7 according to the first embodiment of the present invention is arranged by wiring the conductive thin plate 31, the insulating base layer 33 laminated on the surface of the conductive thin plate 31, and the insulating base layer 33. The wiring layer 35 includes a general portion 35a and a wiring layer 35 having a terminal portion 35b coupled to the general portion 35a and electrically connected to an external slider 27. On the other hand, the terminal portion 35b was provided with the raised structure 41 in the layer thickness direction which is projected to the front surface side, regardless of the conductive thin plate 31.

Therefore, the terminal portion 35b is not affected by mechanical processing such as bending of the conductive thin plate 31, the positional accuracy of the terminal portion 35b does not vary, and the accurate raised structure 41 can be obtained.

As a result, each terminal portion 35b of the flexure 7 and each terminal portion 43 of the slider 27 become smaller due to the progress of miniaturization, and even if the solder balls 47 used have to be made relatively small, the structure of the raised structure 41 is reduced. Due to the presence, each terminal portion 35b of the flexure 7 can be brought close to each terminal portion 43 of the slider 27 as shown in FIG. Therefore, even when the small solder balls 47 are used for soldering, the fillet 49 can be formed to have a sufficient width and thickness, and the reliability of connection can be improved.

In addition, in the method for manufacturing the flexure 7 according to the first embodiment of the present invention, the raising layer 51 for forming the raising structure 41 is formed before the base insulating layer 33 is formed on the conductive thin plate 31 at the position where the terminal portion 35b is formed. It was added to the conductive thin plate 31.

Therefore, the raised layer 41 can be reliably and easily formed without machining. Further, the raised layer 41 can be made of a material that can shorten the etching time as compared with the gradation polyimide of the base insulating layer 33, and the etching time of the base insulating layer 33 can also be shortened.

If the raising layer 51 is made of copper, chromium, or the like and an etching solution that can etch the conductive thin plate 31 made of stainless steel is used, the etching time of only the raising layer 51 can be omitted.

[Modification]
12A and 12B show a coupling structure on the upper surface of the tongue portion. FIG. 12A is a cross-sectional view of a main portion of a comparative example, and FIG. FIG. 9C is a cross-sectional view of a main part of the first embodiment according to the modification in which the slider height is increased. In addition, the reference numerals of the first embodiment are used for the modified examples, and the same reference numerals or the same reference numerals are attached to the constituent portions corresponding to the constituent portions of the first embodiment for description in the comparative example, and the duplicate description is omitted. ..

FIG. 12 shows a tongue portion top bond type. In this type, the terminal portion 35Bb is arranged not under the end portion of the slider 27 but under the lower surface, and is soldered by mounting the slider 27 from above.

The flexure 7B of the comparative example of FIG. 12(A) has the same manufacturing method as that of the flexure 7A of the comparative example described in Example 1, and the soldering portion of the terminal portion 35Bb is depressed and the distance to the lower surface of the slider 27 is decreased. Is getting bigger.

In the modified example of FIGS. 12B and 12C, the terminal portion 35b is provided with the raised structure 41. 12B and 12C show a portion in which two different terminal portions 35b are symmetrically arranged.

In FIG. 12B, the general portion 35a and the terminal portion 35b are formed so as to be flat and continuous, and the tongue portion 33b supports the base portion of the terminal portion 35b. In FIG. 12C, the terminal portion 35b has a step portion 35c and projects toward the front side with respect to the general portion 35a. The step portion 35c is offset with respect to the tongue portion 33b and is positioned corresponding to above the opening edge portion of the conductive thin plate 31. A protrusion 37a of the insulating cover layer 37 is formed above the step 35c and supports the slider 27.

In the modification of FIGS. 12B and 12C, in the manufacturing method for providing the raised structure 41 of the terminal portion 35b, the same steps as described above are performed, and the gradation polyimide base is provided for each terminal portion 35b. When forming the insulating layer 33, a portion that protrudes as a stepped portion in the insulating base layer 33 is formed by a raised layer.

That is, a raised layer (not shown) is formed on the conductive thin plate 31 before the base insulating layer 33 is formed, gradation polyimide is applied, and the stepped portion of the base insulating layer 33 is removed by etching. The raised layer will be present before etching.

At this time, the shape of the terminal portion 35b in FIGS. 12B and 12C can be selectively formed by adjusting the height of the raised layer.

In this modification, the terminal portion 35b is closer to the lower surface of the slider 27 than in the comparative example as shown in FIG. 12B, or the distance between the terminal portion 35b and the lower surface of the slider 27 is as shown in FIG. 12C. Although the same as the comparative example, the mounting height of the slider 27 could be increased.

13A shows a coupling structure on the upper surface of the tongue portion, FIG. 13A is a cross-sectional view of a main portion of a comparative example, and FIG. 13B is a cross-sectional view of a main portion of a first embodiment according to a modified example in which the terminal portions are brought close to each other. FIG. 9C is a cross-sectional view of a main part of the first embodiment according to the modification in which the slider height is increased. In addition, the reference numerals of Example 1 are used for the modified examples, and the components corresponding to those of Example 1 are described with the same reference numerals or the same reference numerals with C for the comparative example, and the duplicate description is omitted. ..

Similar to FIG. 12, FIG. 13 shows a coupling structure on the upper surface of the tongue portion. In addition, the reference numerals of Example 1 are used for the modified examples, and the components corresponding to those of Example 1 are described with the same reference numerals or the same reference numerals with C for the comparative example, and the duplicate description is omitted. ..

The flexure 7C of the comparative example of FIG. 13(A) has a terminal portion 35Cb in which the wiring layer 35C is partially exposed through a hole of the insulating cover layer 37C, and the terminal portion 35Cb is the lower surface of the slider 27 facing it. Connected to the terminal part of. In such a structure, in order to reduce the distance between the terminal portion 35Cb and the lower surface of the slider 27, the cover insulating layer 37C is thinned or the gold plating 39C is thickened. However, the insulating cover layer 37C needs to have a thickness of approximately 3 μm to maintain its function, and the gold plating 39C needs to have a thickness of approximately 1 μm in order to suppress an increase in cost. Therefore, the distance between the terminal portion 35Cb and the terminal portion 35Cb with respect to the lower surface of the slider 27 is about 2 μm, and it is difficult to adjust the distance more than this.

In the modified example of FIG. 13B, the terminal portion 35b is provided with the raised structure 41 so that the distance between the terminal portion 35b and the lower surface of the slider 27 can be adjusted.

Specifically, the raised layer 51 is provided in the range of the opening of the insulating cover layer 37 in a plan view, the insulating base layer 33 has a stepped portion having a protruding shape, and the terminal portion 35b is accordingly a general portion. The protrusion 35 a is projected into the opening of the insulating cover layer 37. The surface of the terminal portion 35b is plated with gold 39 to bring the terminal portion 35b into contact with the lower surface of the slider 27.

As shown in FIG. 13C, the raised layer 51 has a shape that extends inside and outside the range of the opening of the insulating cover layer 37 in a plan view, so that the distance between the terminal portion 35b and the lower surface of the slider 27 is different from that of the comparative example. Although the same, the mounting height of the slider 27 can be increased.

In the modification of FIGS. 13B and 13C, in the manufacturing method for providing the raised structure 41 of the terminal portion 35b, the same steps as described above are performed, and the raised layer 51 is formed on the conductive thin plate 31, Gradation polyimide may be applied to form the raised structure 41 of the terminal portion 35b through the insulating base layer 33.

The structure in which the raised layer 51 is provided as shown in FIG. 13B can be applied when the terminal portion 35b in FIG. 2 is not a flying lead but a pad type. The pad-type terminal portion 35b means a terminal portion in which the terminal portion 35b is supported by the conductive thin plate 31 and the insulating base layer 33 as shown in FIG. 13B. Such a pad type terminal portion 35b is formed by, for example, performing the seventh step without performing the sixth step of FIG. 11 after performing the fifth step of FIG. It can be realized by applying.

[Other]
The wired circuit board is not limited to the flexure 7 as long as the later-described raised structure can be applied, and can be applied to other electric components. The same applies to the other examples.

The raised structure can be provided in another predetermined function part, for example, the actuator connection terminal part 29 as the terminal part of the flexure 7 is provided with the raised structure, and the actuator connection terminal part 29 is provided with a piezoelectric material by, for example, silver paste. The element 15 can be paste-bonded and can be paste-bonded with less silver paste while suppressing bonding failure.

FIG. 14 is a cross-sectional view of relevant parts showing a flying lead of a tail portion according to the second embodiment. It should be noted that the description will be given using the reference numerals of the first embodiment, and redundant description will be omitted.

As shown in FIG. 14, the wiring layer 35 of the tail portion 7 a has a flying lead 59 passing through the opening 57 penetrating the conductive thin plate 31 and the insulating base layer 33. The flying lead passes over the openings 57 of the conductive thin plate 31 and the insulating base layer 33, as in the first embodiment, so that the terminal portion not supported by the conductive thin plate 31 and the insulating base layer 33 is removed. means. The flying leads 59 have gold plating 61 on the front and back, and have a raised structure 41.

14, in the manufacturing method for providing the raised structure 41 of the flying leads 59, the same steps as described above are performed, and a raised layer (not shown) is formed on the conductive thin plate 31 before the base insulating layer 33 is formed. Then, the gradation polyimide is applied and hardened, and then the flying lead 59 of the raised structure 41 is formed in the opening 57 by etching or the like.

Therefore, in this embodiment, the height of the flying lead 59 with respect to the terminal portion of the main flexure can be adjusted, and proper soldering can be performed.

15A and 15B show an aerial wiring portion according to the third embodiment, FIG. 15A is a comparative example, and FIG. 15B is a sectional view of the embodiment. In addition, the reference numerals of the first embodiment are used for the third embodiment, and the same reference numerals or the same reference numerals are attached to the constituent portions corresponding to the constituent portions of the first embodiment for description in the comparative example, and the duplicate description is omitted. To do.

As shown in FIG. 15A, in the aerial wiring part 67D of the comparative example, the surface of the base insulating layer 33D in the aerial wiring part 67D is shaved by exposure, and the aerial wiring part 67D is depressed toward the conductive thin plate 31D. .. In the present embodiment, the aerial wiring portion is a portion of the insulating base layer 33, the wiring layer 35, and the insulating cover layer 37 that is not supported by the conductive thin plate 31, and means a portion other than the terminal portion.

In the flexure 7 of the third embodiment shown in FIG. 15B, the aerial wiring portion 67 has a raised structure 41 as a predetermined function portion. In the aerial wiring portion 67 of the present embodiment, the thin portion 33c of the base insulating layer 33 is wholly supported, the wiring layer 35 is laminated on the flat surface of the thin portion 33c, and the cover insulating layer 37 is formed on the flat surface. It is stacked.

In FIG. 15B, in the manufacturing method in which the aerial wiring part 67 includes the raised structure 41, the same steps as described above are performed, and the raised layer (not shown) is a conductive thin plate before the base insulating layer 33 is formed. Then, the base insulating layer 33 is additionally formed on the base 31 and then the gradation insulating polyimide is applied and cured to form the base insulating layer 33. The conductive thin plate 31 and the base insulating layer 33 are etched to remove the raised layer to form the thin portion 33c. By doing so, the aerial wiring portion 67 includes the raised structure 41 that flattens the aerial wiring portion 67 with respect to the general portion 35a.

By thus forming the aerial wiring part 67 to be flat with respect to the general part 35a, the rigidity of the flexure 7 can be stabilized.

16A and 16B show a reference hole for positioning according to the fourth embodiment, FIG. 16A is a comparative example, and FIG. 16B is a sectional view of the embodiment. In addition, the reference numerals of Example 1 are used for Example 4, and the same reference numerals or the same reference numerals are used for the components corresponding to those of Example 1 for the comparative example, and the description is omitted, and the duplicate description is omitted. To do.

In recent years, image processing is generally used to position a slider for high accuracy. Conventionally, a reference hole made of a stainless conductive thin plate has been used as a reference hole for this image processing. However, the reference hole formed in the wiring layer is used because it causes a positional error between the terminal portion and the stainless conductive thin plate.

In the flexure 7E of FIG. 16(A), the wiring layer 35E has a reference hole 71E for image processing, and the surface of the insulating base layer 33E is shaved by exposure to form the reference hole 71E, and then the wiring layer 35E is formed. The back surface of the insulating base layer 33E is removed by etching before or after forming the holes to be the reference holes 71E in the wiring layer 35E. As a result, the reference hole forming portion 73E in which the reference hole 71E is formed falls to the conductive thin plate 31 side. Due to this drop, a plurality of unnecessary edges are formed on the front and back sides of the reference hole forming portion 73E at the points P, Q, and R in FIG. 16(A).

Due to the plurality of edges, the edges are recognized during image processing, which is a cause of erroneous recognition.

In the flexure 7 of Example 4 of FIG. 16B, the reference hole forming portion 73 as the predetermined functional portion in which the wiring layer 35 has the reference hole 71 for image processing is provided with the raised structure 41.

In FIG. 16B, in the manufacturing method in which the reference hole forming portion 73 includes the raised structure 41, the same steps as described above are performed, and the raised layer (not shown) has conductivity before the base insulating layer 33 is formed. The insulating base layer 33 is additionally set on the thin plate 31, and then the gradation polyimide is applied and cured to form the insulating base layer 33. After that, the reference hole forming portion 73 of the raised structure 41 that is flattened with respect to the general portion 35a is formed by exposing the front surface and etching the back surface.

Therefore, as is clear from a comparison between FIGS. 16A and 16B, in the reference hole forming portion 73 of the raised structure 41, an unnecessary edge does not occur around the reference hole 71, and it is False recognition can be suppressed.

1 head suspension 7 flexure (wiring circuit board)
27 Slider 31 Conductive thin plate (metal support layer)
33 Base insulation layer (electrical insulation layer)
35 Wiring layer 35a General part 35b Terminal part (predetermined function part)
41 raised structure 51 raised layers 59, 67 aerial wiring part (predetermined function part)
71 reference hole 73 reference hole forming portion (predetermined function portion)

Claims (5)

A metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and routed to the outside connected to the general portion. A wiring circuit board having a wiring layer having a terminal portion for conducting connection of
The wiring layer includes a step portion in the layer thickness direction that causes the terminal portion to project to the surface by a step of the layer having a raised structure with respect to the general portion,
The terminal portion has a front end that faces a plane including the step in the openings of the metal supporting layer and the electric insulating layer,
The stepped portion has a back surface of the terminal portion supported by a tongue portion projecting into the opening of the electrical insulating layer formed to be thinner than a main body of the electrical insulating layer,
The terminal portion, the surface is soldered to the terminal portion of the slider ,
A printed circuit board characterized by the above. A metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and routed to the outside connected to the general portion. A wiring circuit board having a wiring layer having a terminal portion for conducting connection of
The terminal portion projects toward the surface by the flat continuation of the raised structure with respect to the general portion or by having a stepped portion of the raised structure with respect to the general portion and the tip faces the openings of the metal supporting layer and the electrical insulating layer. ,
The back surface of the terminal portion is supported by a tongue portion projecting into the opening of the electrical insulating layer, the base portion facing the opening being formed thinner than the thickness of the main body of the electrical insulating layer in the opening portion,
The terminal portion, the surface is soldered to the terminal portion of the lower surface of the slider ,
A printed circuit board characterized by the above. A metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated and arranged on the surface of the electric insulating layer, and an outside connected to the general portion. A wiring circuit board having a wiring layer having a terminal portion for conducting connection of
The wiring layer is provided with flying leads having stepped portions on both sides in the layer thickness direction which are projected to the surface by a step of the layer having a raised structure with respect to the general portion,
The flying lead passes through an opening penetrating the metal supporting layer and the electrically insulating layer,
The stepped portions on both sides of the flying lead and the base portion of the terminal portion have their back surfaces supported by the metal supporting layer and the electrical insulating layer,
A sputter layer is provided between the back surface of the step and the base on both sides of the flying lead and the electrical insulating layer.
A printed circuit board characterized by the above. A metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and routed to the outside connected to the general portion. A wiring circuit board having a wiring layer having a terminal portion for conducting connection of
The wiring layer extends from a portion supported by the metal supporting layer to a portion supported by the metal supporting layer through the air not supported by the metal supporting layer and has a flattened structure with respect to the general portion. Equipped with an aerial wiring section,
The aerial wiring portion, the back surface is supported by a thin portion formed to be thinner than the thickness of the body of the electrical insulating layer,
The main body of the electrically insulating layer projects from the portion supported by the metal supporting layer into the air not supported by the metal supporting layer to support the thin portion.
A printed circuit board characterized by the above. A metal supporting layer forming a substrate, an electric insulating layer laminated on the surface of the metal supporting layer, a general portion laminated on the surface of the electric insulating layer and routed to the outside connected to the general portion. A wiring circuit board having a wiring layer having a terminal portion for conducting connection of
The wiring layer has a reference hole forming portion having a reference hole for image processing formed flat with respect to the general portion,
The reference hole forming portion is supported by a tongue portion formed to be thinner than the thickness of the main body of the electric insulating layer,
A printed circuit board characterized by the above.

Images