JP5609097B2 - Suspension substrate, suspension, suspension with head, hard disk drive, and method for manufacturing suspension substrate - Google Patents

Description

  The present invention relates to a suspension substrate used in, for example, a hard disk drive (HDD).

  Recently, there has been a growing demand for HDDs installed in various small devices such as portable applications, and accordingly, disks for information recording are required to be downsized and high in recording density. In order to read / write data from / to a track on a downsized (smaller diameter) disk, the disk rotation needs to be slowed down, and the relative speed (circumferential speed) of the disk to the magnetic head is slowed down. . For this reason, the suspension substrate needs to approach the disk with a weak force, and it is necessary to reduce the rigidity of the suspension substrate.

  In order to reduce the rigidity, studies are being made to reduce the portion of the highly rigid metal substrate. However, if the metal substrate portion is reduced, the suspension substrate is likely to warp. The cause of warping is considered to be the difference in thermal expansion coefficient between the metal substrate and the insulating layer and the difference in hygroscopic expansion coefficient between the insulating layer and the cover layer, and attempts have been made to control warpage from the viewpoint of material properties. (Patent Document 1).

JP 2008-310946 A

  As described in Patent Document 1, it is also an effective means to suppress warpage of the suspension substrate by controlling the physical properties of the material used for the insulating layer and the material used for the cover layer. However, if it is intended only to suppress warpage, it may not be possible to obtain predetermined physical properties required for the insulating layer and the cover layer. On the other hand, when priority is given to predetermined physical properties required for the insulating layer and the cover layer, there is a possibility that warpage of the suspension substrate cannot be sufficiently suppressed.

  The present invention has been made in view of the above circumstances, and it is a main object of the present invention to provide a suspension substrate in which warpage is suppressed from a viewpoint other than material physical properties.

  In order to solve the above problems, in the present invention, a gimbal part, an external connection board connection part, a wiring part for connecting the gimbal part and the external connection board connection part, and a wiring layer constituting the wiring part are provided. A suspension substrate having at least one cover layer, wherein the cover layer has one or more notches in the wiring portion.

  According to the present invention, since the cover layer has a cut portion, a suspension substrate with reduced warpage can be obtained. In the present invention, the cut portion can absorb a part of the expansion / contraction change of the cover layer. Thereby, the absolute value of the variation | change_quantity of the whole cover layer by expansion and contraction can be lowered | hung. As a result, stress can be reduced and warpage of the suspension substrate can be suppressed.

  In the above invention, the suspension substrate has a bending portion positioned between the gimbal portion and the external connection substrate connecting portion, and the wiring portion is located between the bending portion and the gimbal portion. It is preferable to have a longitudinal wiring area where the wiring layer exists along the longitudinal direction of the suspension substrate, and in the longitudinal wiring area, the cover layer has the cut portion. This is because the warp of the suspension substrate can be effectively suppressed by providing the cut portion in the cover layer in the longitudinal wiring region where the influence of the warp is most likely to appear.

  In the above invention, the cut portion is preferably a through cut portion that penetrates from one end portion of the cover layer to the other end portion in the width direction of the cover layer. This is because warpage of the suspension substrate can be effectively suppressed.

  In the said invention, it is preferable that the angle which the notch direction of the said penetration notch part makes and the length direction of the said cover layer is in the range of 30 degrees-90 degrees. This is because warpage of the suspension substrate can be effectively suppressed.

  In the above invention, it is preferable that the cut portion has an exposed portion where the wiring layer is exposed, and a wiring plating layer is formed on the exposed portion. This is because the warp of the suspension substrate can be effectively suppressed by providing the deep cut portion. Further, by providing a wiring plating layer on the exposed wiring layer, deterioration of the wiring layer can be suppressed.

  In the said invention, it is preferable that the thin layer whose thickness is smaller than the said cover layer is formed in the said notch part. This is because the warp of the suspension substrate can be effectively suppressed without providing the wiring plating portion.

  In the above invention, the wiring portion includes a first wiring layer and a second wiring layer, and the suspension substrate includes a metal substrate, a first insulating layer formed on the metal substrate, and the first insulating layer. It is preferable to have the first wiring layer and the second wiring layer formed on the layer, and the cover layer covering the first wiring layer and the second wiring layer.

  In the above invention, the cut portion includes the through cut portion and an inter-wire cut portion formed between the first wiring layer and the second wiring layer, and the through cut portion and the wiring It is preferable that the cut portions are connected to each other. This is because warpage of the suspension substrate can be effectively suppressed.

  In the above invention, the cut portion is formed in the width direction of the cover layer, the first cut portion formed on one end side of the cover layer and the second cut portion formed on the other end side of the cover layer. Preferably, the first cut portion and the second cut portion are arranged so as not to overlap each other in the width direction of the cover layer. By arranging in this way, it is possible to prevent the first wiring layer 3a and the second wiring layer 3b from being short-circuited by foreign substances while suppressing the warpage of the suspension substrate.

  In the above invention, the cut portion includes the first cut portion, the second cut portion, and an inter-wire cut portion formed between the first wiring layer and the second wiring layer, It is preferable that the first cut portion, the second cut portion, and the inter-wire cut portion are connected to each other. This is because warpage of the suspension substrate can be effectively suppressed.

  In the above invention, the wiring portion includes a first wiring layer and a second wiring layer, and the suspension substrate includes a metal substrate, a first insulating layer formed on the metal substrate, and the first insulating layer. The first wiring layer formed on the layer, the second insulating layer covering the first wiring layer, and the second insulating layer formed on the second insulating layer and overlapping with the first wiring layer in the thickness direction. It is preferable to have two wiring layers and the cover layer covering the second wiring layer.

  In the said invention, it is preferable to have one or two or more lower wiring layers between said 1st insulating layer and said 2nd insulating layer. This is because a suspension substrate with higher functionality can be obtained.

  In the said invention, it is preferable to have two or more said 1st wiring layers and said 2nd wiring layers, respectively. This is because a suspension substrate with higher functionality can be obtained.

  The present invention also provides a suspension including the above-described suspension substrate.

  According to the present invention, a suspension with less warpage can be obtained by using the above-described suspension substrate.

  According to the present invention, there is provided a suspension with a head including the above-described suspension and a magnetic head slider mounted on the suspension.

  According to the present invention, by using the suspension described above, a suspension with a head with less warpage can be obtained.

  The present invention also provides a hard disk drive including the suspension with a head described above.

  According to the present invention, a high-performance hard disk drive can be obtained by using the suspension with a head described above.

  In the present invention, the cover that covers at least one of the gimbal part, the external connection board connection part, the wiring part that connects the gimbal part and the external connection board connection part, and the wiring layer that constitutes the wiring part. And the cover layer is a method for manufacturing a suspension substrate having one or more cut portions, and a preparation step of preparing a processing member having the wiring portion; and A cover layer forming step for forming a cover layer covering at least one of the wirings constituting the wiring portion of the processing member; and a notch forming step for forming the notch with respect to the cover layer. A method for manufacturing a suspension substrate is provided.

  According to the present invention, it is possible to obtain a suspension substrate in which warpage is suppressed by providing a cut portion in the cover layer.

  In the present invention, there is an effect that warpage of the suspension substrate can be suppressed.

It is a schematic plan view which shows an example of the board | substrate for suspensions of this invention. It is AA sectional drawing of FIG. It is a schematic plan view which shows an example of the longitudinal direction wiring area | region in this invention. It is a schematic plan view which shows an example of the penetration notch part in this invention. FIG. 5 is a cross-sectional view of FIG. 4. It is a schematic plan view which shows the other example of the penetration notch part in this invention. It is explanatory drawing which shows an example of the determination method of the width | variety of a notch part in this invention. It is explanatory drawing explaining the wiring plating layer in this invention. It is explanatory drawing explaining the thin layer in this invention. It is explanatory drawing explaining the notch | incision part in this invention. It is explanatory drawing explaining the notch | incision part in this invention. It is explanatory drawing explaining the notch | incision part in this invention. It is explanatory drawing explaining the notch | incision part in this invention. It is a schematic plan view which shows an example of the board | substrate for suspensions of this invention. It is AA sectional drawing of FIG. It is explanatory drawing explaining the notch | incision part in this invention. It is explanatory drawing explaining the cover layer in this invention. It is explanatory drawing explaining the cover layer in this invention. It is explanatory drawing explaining the notch | incision part in this invention. It is explanatory drawing which shows an example of the manufacturing method of the board | substrate for suspensions of this invention. It is explanatory drawing which shows the other example of the manufacturing method of the board | substrate for suspensions of this invention. It is a schematic plan view which shows an example of the suspension of this invention. It is a schematic plan view which shows an example of the suspension with a head of this invention. It is a schematic plan view which shows an example of the hard disk drive of this invention.

  Hereinafter, the suspension substrate, suspension, suspension with head, hard disk drive and suspension substrate manufacturing method of the present invention will be described in detail.

A. First, the suspension substrate of the present invention will be described. The suspension substrate of the present invention covers at least one of the gimbal part, the external connection board connection part, the wiring part connecting the gimbal part and the external connection board connection part, and the wiring layer constituting the wiring part. A suspension substrate having a cover layer, wherein, in the wiring portion, the cover layer has one or more cut portions.

  FIG. 1 is a schematic plan view showing an example of the suspension substrate of the present invention. For convenience, the cover layer is not shown in FIG. A suspension substrate 20 shown in FIG. 1 includes a gimbal portion 11 formed at one tip portion, an external connection substrate connection portion 12 formed at the other tip portion and connected to an external connection substrate, and a gimbal portion. 11 and the external connection substrate connection part 12 and a cover layer (not shown) covering at least one of the wiring layers constituting the wiring part 13. Further, the wiring section 13 in FIG. 1 has a write wiring composed of one wiring pair and a lead wiring composed of the other wiring pair. Examples of the external connection board include a relay board and a main flexible board.

  FIG. 2 is a cross-sectional view taken along the line AA in FIG. The suspension substrate 20 shown in FIG. 2 includes a metal substrate 1, a first insulating layer 2a formed on the metal substrate 1, a first wiring layer 3a and a second wiring formed on the first insulating layer 2a. It has the layer 3b and the cover layer 4 which covers the 1st wiring layer 3a and the 2nd wiring layer 3b. In the suspension substrate in FIG. 2, the first wiring layer 3 a and the second wiring layer 3 b constituting the wiring part are covered with the cover layer 4. In the present invention, in the wiring portion 13 shown in FIG. 1, the cover layer 4 has one or two or more cut portions.

  Further, the suspension substrate 20 in FIG. 1 is located between the gimbal portion 11 and the external connection substrate connecting portion 12 and has a bending portion 14 for performing bending processing. The “bending portion” in the present invention is a portion that is bent to connect the suspension substrate to the external connection substrate, and is a portion that is bent at an angle of, for example, about 90 ° with respect to the suspension substrate plane. It is.

  Further, the wiring portion 13 in FIG. 1 has a longitudinal wiring region 13X in which a wiring layer exists along the longitudinal direction X of the suspension substrate 20 between the bending portion 14 and the gimbal portion 11. In the present invention, in the longitudinal wiring region 13X, the cover layer 4 preferably has one or more cut portions. Further, as shown in FIG. 1, the end of the longitudinal wiring region 13 </ b> X on the side of the bent portion 14 is, for example, a portion where all of the wiring layers constituting the wiring portion 13 are along the longitudinal direction X of the suspension substrate 20. It is preferable that On the other hand, the end portion of the gimbal portion 11 in the longitudinal wiring region 13X is preferably a portion immediately before the gimbal portion 11 as shown in FIG.

  The longitudinal wiring region 13X in the present invention is usually a region that does not include the bent portion 14. Here, for the purpose of improving the bendability of the bent portion 14, it is conceivable to form a cut portion in the cover layer of the bent portion 14. However, it can be said that the cut portion in the cover layer of the bent portion 14 and the cut portion in the present invention have completely different functions. That is, the cut portion in the present invention preferably has a function of suppressing the warp in the longitudinal direction of the suspension substrate, which is most susceptible to the expansion and contraction of the cover layer, whereas the cover of the bent portion 14 is covered. Such a function cannot be exhibited in the cut portion in the layer.

  FIG. 3 is a schematic plan view showing an example of the longitudinal wiring region in the present invention. In FIG. 3, the longitudinal wiring region is schematically shown for convenience, and the same applies to FIGS. 4, 6, 8 to 13, and 16 to 21 described later. In the present invention, in the longitudinal wiring region 13X where the wiring layers (the first wiring layer 3a and the second wiring layer 3b) exist along the longitudinal direction X of the suspension substrate, the cover layer 4 makes one or more cut portions 15 or It is preferable to have two or more.

Thus, according to the present invention, since the cover layer has a cut portion, a suspension substrate with suppressed warpage can be obtained. In the present invention, the cut portion can absorb a part of the expansion / contraction change of the cover layer. Thereby, the absolute value of the variation | change_quantity of the whole cover layer by expansion and contraction can be lowered | hung. As a result, stress can be reduced and warpage of the suspension substrate can be suppressed. Furthermore, in the present invention, it is preferable to provide a cut portion in the cover layer in the longitudinal wiring region where the influence of the warp is most likely to appear, whereby the warp of the suspension substrate can be effectively suppressed.
Hereinafter, the suspension substrate of the present invention will be described in more detail.

1. Cover Layer First, the cover layer in the present invention will be described. The cover layer in this invention is a layer which covers at least one of the wiring layers which comprise a wiring part. Examples of the material for the cover layer include polyimide (PI). The material of the cover layer may be a photosensitive material or a non-photosensitive material. Furthermore, the thickness of the cover layer is preferably in the range of 3 μm to 30 μm, for example.

  In addition, the cover layer in the present invention usually has one or more cut portions in the wiring portion, and preferably has the cut portions in the longitudinal wiring region. The length of the longitudinal wiring region in the present invention is, for example, 4 mm or more, and preferably 6 mm or more. On the other hand, the length of the longitudinal wiring region is, for example, 40 mm or less, and preferably 35 mm or less.

  In the present invention, the cut portion may be a through cut portion penetrating from one end portion of the cover layer to the other end portion in the width direction of the cover layer, or from one end portion of the cover layer. A non-penetrating cut portion that does not penetrate through to the other end may be used, but the former is preferable. This is because warpage of the suspension substrate can be effectively suppressed.

  An example of the penetration notch is shown in FIG. In FIG. 4, in the width direction y of the cover layer 4, a through-cut 15x penetrating from one end of the cover layer 4 to the other end is formed. 5 is a schematic sectional view of FIG. 4, FIG. 5 (a) is an AA sectional view of FIG. 4, and FIG. 5 (b) is a BB sectional view of FIG. As shown in FIG. 5A, the cover layer 4 is formed so as to cover the first wiring layer 3a and the second wiring layer 3b in the cross section in which the through cut portion is not formed. On the other hand, as shown in FIG. 5B, the first wiring layer 3a and the second wiring layer 3b are exposed in the cross section in which the through-cut 15x is formed. In addition, it is preferable to form the wiring plating layer mentioned later in the exposed 1st wiring layer 3a and 2nd wiring layer 3b. Moreover, you may form the thin layer mentioned later instead of exposing the 1st wiring layer 3a and the 2nd wiring layer 3b.

  The notch of the penetration notch is not particularly limited as long as it penetrates from one end of the cover layer to the other end in the width direction of the cover layer. The plan view shape of the through-cut portion may be linear or curved. In addition, the penetration notch 15x shown by FIG. 4 is a linear notch.

  As shown in FIG. 6, when the angle formed by the cut direction s of the through cut portion 15x and the length direction t of the cover layer is α, α is in the range of 30 ° to 90 °, for example. It is preferable that it is in the range of 45 ° to 90 °. In particular, in the present invention, α is preferably 90 °. Further, the number of through-cut portions formed in the wiring portion is not particularly limited, but is preferably in the range of 1 to 10, for example, and preferably in the range of 2 to 5. Is more preferable. Among them, in the present invention, it is preferable that the above number of through-cut portions be formed in the longitudinal wiring region.

  The width of the cut portion in the present invention is not particularly limited, but when the cover layer expands, the width is such that the end of one cover layer does not contact the end of the other cover layer. Preferably there is. This is because warpage of the suspension substrate can be effectively suppressed. Here, an example of a method for determining the width of the cut portion will be described with reference to FIG. As shown in FIG. 7A, the initial length of the cover layer 4 in the longitudinal wiring region 13x is L (mm). When the cover layer is divided into n, n-1 cut portions 15 are formed. Further, as shown in FIG. 7B, when the width of each cut portion 15 is xL (x is the ratio of the width of the cut portion to the initial length L, and 0 <x <1 is satisfied), it is divided. The length of the cover layer 4 is {L− (n−1) × L} / n. Further, in consideration of expansion due to moisture absorption, when the hygroscopic expansion coefficient is h (1 /% RH) and the humidity change amount is y (%), the length of the cover layer 4 divided by expansion is Therefore, [{L− (n−1) × L} / n] * (hy) is increased. Therefore, as shown in FIG. 7C, the length of the divided cover layer 4 is [{L− (n−1) × L} / n] * 1/2 (hy) at one end. Will increase. Therefore, when [{L- (n-1) xL} / n] * 1/2 (hy) <1 / 2xL is satisfied, that is, when x> 1 / {n / hy + (n-1)} is satisfied. It can prevent that the edge parts of the notch part 15 contact.

For example, when the initial length L = 30 (mm), the hygroscopic expansion coefficient h = 30 × 10 ⁻⁶ (1 /% RH), the humidity change rate y = 100 (%), and the division number n = 3, each notch The width xL of 15 is 29.94 μm, and if the value is larger than this value, it is possible to prevent the ends of the cut portion 15 from contacting each other. In the above example, the expansion due to moisture absorption was considered. However, when the expansion due to heat absorption is considered, the linear thermal expansion coefficient α (1 / ° C.) is used instead of the hygroscopic expansion coefficient h (1 /% RH), A temperature change amount T (° C.) may be used instead of the humidity change amount y (%).

  Further, as described above, the width of the cut portion varies depending on the material of the cover layer and the number of divisions. It is preferable to be within. If the width of the cut portion is too small, the end portions of the cover layer at the cut portion may contact each other, and the warping of the suspension substrate may not be sufficiently suppressed. If the width of the cut portion is too large, the wiring layer is deteriorated. It is because it becomes easy to occur.

  In the present invention, the cut portion may have at least one of a first cut portion and a second cut portion described later. In this case, the first cut portion and the second cut portion are preferably arranged so as not to overlap each other in the width direction of the cover layer (see FIG. 11 described later).

  Moreover, in this invention, it is preferable to have an exposed part which a wiring layer exposes in a notch part, and the wiring plating layer is formed in the said exposed part. This is because the warp of the suspension substrate can be effectively suppressed by providing the deep cut portion. Further, by providing a wiring plating layer on the exposed wiring layer, deterioration of the wiring layer can be suppressed. As an example of the longitudinal wiring region having the wiring plating layer, for example, as shown in FIGS. 8A and 8B, the exposed portions of the first wiring layer 3a and the second wiring layer 3b exposed at the notch 15 are formed. A longitudinal wiring region 13X in which the wiring plating layer 5 is formed can be exemplified. FIG. 8B is a cross-sectional view taken along the line AA in FIG. The wiring plating layer is not particularly limited as long as it can protect the wiring layer, and examples thereof include a nickel plating layer and a gold plating layer. The wiring plating layer may be composed of a plurality of metal plating layers. The thickness of the wiring plating layer is, for example, in the range of 0.1 μm to 5.0 μm.

  Moreover, in this invention, it is preferable that the thin layer whose thickness is smaller than a cover layer is formed in the cut | notch part. This is because the warp of the suspension substrate can be effectively suppressed without providing the wiring plating portion. As an example of the longitudinal wiring region having a thin layer, for example, as shown in FIGS. 9A and 9B, the thin layer 4a is formed on the upper surfaces of the first wiring layer 3a and the second wiring layer 3b of the cut portion 15. The longitudinal wiring region 13X in which is formed can be mentioned. FIG. 9B is a cross-sectional view taken along the line AA in FIG. The thin layer 4 a is preferably made of the same material as the cover layer 4. The thin layer 4a can be formed, for example, by etching the cover layer 4. When the thickness of the cover layer is 100%, the thickness of the thin layer is preferably in the range of 10% to 80%, for example, and more preferably in the range of 30% to 60%. The thickness of the thin layer formed on the wiring layer is preferably in the range of 0.4 μm to 3.2 μm, for example, and more preferably in the range of 1.2 μm to 2.4 μm. If the thickness of the thin layer is too small, the wiring layer may be exposed due to pinholes and the like, which may cause deterioration of the wiring layer. If the thickness of the thin layer is too large, warping of the suspension substrate is sufficiently suppressed. It may not be possible.

2. Next, the configuration of the suspension substrate of the present invention will be described. The suspension substrate of the present invention is not particularly limited as long as it has the cover layer and the cut portion described above. Hereinafter, specific examples of the suspension substrate of the present invention will be described separately for the first embodiment and the second embodiment.

(1) First Embodiment In the first embodiment of the suspension substrate, the wiring portion has a first wiring layer and a second wiring layer, and the suspension substrate is disposed on the metal substrate and the metal substrate. A first insulating layer formed; the first wiring layer and the second wiring layer formed on the first insulating layer; and the cover layer covering the first wiring layer and the second wiring layer. It is what you have.

  FIG. 2 described above shows an example of the first embodiment of the suspension substrate of the present invention. In the case of the first embodiment, as shown in FIG. 2, the cover layer 4 covering the first wiring layer 3 a and the second wiring layer 3 b has the above-described cut portion. In the first embodiment, the wiring composed of the first wiring layer and the second wiring layer is usually a write wiring or a read wiring. In the present invention, the cover layer having the cut portion may be formed on one of the write wiring and the lead wiring, and the cover layer having the cut portion is formed on both the write wiring and the lead wiring. May be.

  In the first embodiment, the cut portion may have other cut portions other than the through cut portion and the non-penetrated cut portion described above. As an example of the other cut portion, an inter-wire cut portion formed between the first wiring layer and the second wiring layer can be cited. Furthermore, in this case, it is preferable that the penetration notch and the inter-wiring notch are connected to each other. This is because warpage of the suspension substrate can be effectively suppressed. Specifically, as shown in FIG. 10A, a cover layer 4 having a through cut 15x and an inter-wire cut 15y formed between the first wiring layer 3a and the second wiring layer 3b. Can be mentioned. FIG. 10B is a cross-sectional view taken along the line AA in FIG. 10A, and includes a notch portion 15y between the first wiring layer 3a and the second wiring layer 3b.

  Further, in the first embodiment, for example, as shown in FIG. 11, the cut portion is formed on the one end side of the cover layer 4 in the width direction y of the cover layer 4, A second cut portion formed on the other end side of the cover layer 4, and the first cut portion 15 a and the second cut portion 15 b are arranged so as not to overlap each other in the width direction y of the cover layer 4. It is preferable that By arranging in this way, it is possible to prevent the first wiring layer 3a and the second wiring layer 3b from being short-circuited by foreign substances while suppressing the warpage of the suspension substrate.

The first cut portion 15a is preferably a non-through cut portion. Further, the length of the first cut portion 15a (length in the width direction of the cover layer) is not particularly limited, but when the width of the cover layer is 100%, it may be 20% or more. Preferably, it is 30% or more, more preferably 50% or more. The plan view shape of the first cut portion 15a is not particularly limited, and may be linear or curved. The second cut portion 15b is the same as the first cut portion 15a. As shown in FIG. 11 that, when the distance of the first slit portion 15a and the second slit portion 15b adjacent to the _{L 1,} the length of _{L 1} is, it is, for example 200μm or more preferably, 500 [mu] m or more Is more preferable. This is because a short circuit between the first wiring layer 3a and the second wiring layer 3b can be effectively prevented.

  In the first embodiment, for example, as shown in FIG. 12 (a), the cut portion includes the first wiring layer 3a and the second wiring layer 3b in addition to the first cut portion 15a and the second cut portion 15b. It is preferable that the inter-wiring cut portion 15y formed between the first cut portion 15a, the second cut portion 15b, and the inter-wire cut portion 15y are connected to each other. This is because warpage of the suspension substrate can be effectively suppressed. 12B is a cross-sectional view taken along the line AA in FIG. 12A, and FIG. 12C is a cross-sectional view taken along the line BB in FIG.

  As a modification of the notch shown in FIG. 12, as shown in FIG. 13, only the adjacent first notch 15a and second notch 15b are connected by an inter-wire notch 15y. it can. The notch in this case can also be handled as an example of the above-described penetration notch.

  In the first embodiment, in addition to the first wiring layer and the second wiring layer described above, one or more lower wiring layers may be provided between the first insulating layer and the cover layer. . An example of the lower wiring layer is a ground wiring. Further, when two or more lower wiring layers are provided, these wirings can be used as a write wiring or a read wiring. In this case, both the write wiring and the read wiring are included in one cover layer.

  In addition, it is preferable that the wiring plating layer or thin layer mentioned above is formed also about the 1st notch part, the 2nd notch part, and the notch part between wiring.

  Next, members used for the suspension substrate will be briefly described (see FIG. 2). Examples of the material of the metal substrate 1 include stainless steel. The thickness of the metal substrate 1 is, for example, preferably in the range of 10 μm to 30 μm, and more preferably in the range of 15 μm to 25 μm.

  Examples of the material of the first insulating layer 2a include polyimide (PI). The material of the first insulating layer 2a may be a photosensitive material or a non-photosensitive material. The thickness of the first insulating layer 2a is, for example, preferably in the range of 5 μm to 30 μm, and more preferably in the range of 10 μm to 20 μm.

  Examples of the first wiring layer 3a and the second wiring layer 3b include copper (Cu). The thicknesses of the first wiring layer 3a and the second wiring layer 3b are each preferably in the range of, for example, 4 μm to 18 μm, and more preferably in the range of 5 μm to 12 μm.

(2) Second Embodiment In a second embodiment of the suspension substrate, the wiring portion has a first wiring layer and a second wiring layer, and the suspension substrate is disposed on the metal substrate and the metal substrate. Formed on the first insulating layer, the first wiring layer formed on the first insulating layer, the second insulating layer covering the first wiring layer, the second insulating layer, The second wiring layer overlapped with the first wiring layer in the thickness direction, and the cover layer covering the second wiring layer.

  FIG. 14 is a schematic plan view showing an example of the second embodiment of the suspension substrate of the present invention. 15 is a cross-sectional view taken along line AA in FIG. The suspension substrate 20 shown in FIG. 14 includes a metal substrate 1, a first insulating layer 2a formed on the metal substrate 1, a first wiring layer 3a formed on the first insulating layer 2a, A second insulating layer 2b covering the wiring layer 3a, a second wiring layer 3b formed on the second insulating layer 2b and overlapping the first wiring layer 3a in the thickness direction, and a cover layer covering the second wiring layer 3b 4.

  In the second embodiment, since the first wiring layer 3a and the second wiring layer 3b are laminated via the second insulating layer 2b, there is an advantage that the impedance can be reduced, but the presence of the second insulating layer is present. Therefore, warpage is likely to occur. Providing a notch for such a suspension substrate has the advantage that warpage can be suppressed while lowering impedance.

  About the notch part in a 2nd embodiment, it is the same as that of the content described in "1. cover layer" mentioned above. For example, as shown in FIGS. 16A and 16B, the cover layer 4 is preferably formed with a through cut 15x. Further, as shown in FIGS. 16C and 16D, it is preferable that the wiring plating layer 5 is formed on the exposed portion of the second wiring layer 3 b exposed at the cut portion 15. Further, as shown in FIGS. 16E and 16F, a thin layer 4 a may be formed on the upper surface of the second wiring layer 3 b of the cut portion 15. FIGS. 16B, 16D, and 16F are cross-sectional views taken along lines AA of FIGS. 16A, 16C, and 16E, respectively.

  In the second embodiment, one or more lower wiring layers may be provided between the first insulating layer and the second insulating layer. An example of the lower wiring layer is a ground wiring. Further, when two or more lower wiring layers are provided, these wirings can be used as a write wiring or a read wiring. Specifically, as shown in FIGS. 17A to 17C, in addition to the first wiring layer 3a and the second wiring layer 3b, there are two gaps between the first insulating layer 2a and the second insulating layer 2b. The lower wiring layer 3x can be formed. 17B is a cross-sectional view taken along the line AA in FIG. 17A, and FIG. 17C is a cross-sectional view taken along the line BB in FIG. 17A. In addition, since the lower wiring layer 3x is formed between the first insulating layer 2a and the second insulating layer 2b, it is usually not necessary to provide the cover layer 4 on the lower wiring layer 3x. The cover layer 4 may be provided on the lower wiring layer 3x in consideration of symmetry with the layer 3a and the second wiring layer 3b side. By providing the cover layer 4 on the lower wiring layer 3x, the occurrence of distortion can be suppressed.

  In the second embodiment, each of the first wiring layer and the second wiring layer may have two or more. In this case, the plurality of second wiring layers formed on the second insulating layer is usually covered with a cover layer. Specifically, as shown in FIGS. 18A and 18B, a plurality of first wiring layers 3a and second wiring layers 3b may be formed. In this case, the plurality of second wiring layers 3 b are covered with the cover layer 4. 18B is a cross-sectional view taken along the line AA in FIG. 18A, and FIG. 18C is a cross-sectional view taken along the line BB in FIG. 18A. Further, it is preferable that one of the wirings composed of the first wiring layer 3a and the second wiring layer 3b is a write wiring and the other is a lead wiring.

  Further, when two or more first wiring layers and two or more second wiring layers are formed, the same cut portion as that of the first embodiment described above may be formed in two or more second wiring layers. For example, as shown in FIGS. 19A and 19B, there is a cut portion in which a through cut portion 15x and an inter-wire cut portion 15y formed between two second wiring layers 3b are connected to each other. It may be formed. Moreover, as shown in FIG.19 (c), (d), the 1st notch part 15a and the 2nd notch part 15b may be formed as a notch part. Further, as shown in FIGS. 19E and 19F, a cut portion in which the first cut portion 15a, the second cut portion 15b, and the inter-wire cut portion 15y are connected to each other may be formed. FIGS. 19B, 19D, and 19F are cross-sectional views taken along line AA in FIGS. 19A, 19C, and 19E, respectively.

  Moreover, it is preferable that the wiring plating layer or thin layer mentioned above is formed also about the 1st notch part, the 2nd notch part, and the notch part between wiring.

3. Next, a method for manufacturing a suspension substrate according to the present invention will be described. The manufacturing method of the suspension substrate of the present invention is not particularly limited as long as it is a method capable of obtaining the above-described suspension substrate.

  FIG. 20 is an explanatory view showing an example of a method for manufacturing a suspension substrate according to the present invention. 20 (b), (d), (f), (h), (j), (l) are respectively shown in FIGS. 20 (a), (c), (e), (g), (i). It is AA sectional drawing of (k). In the method for manufacturing a suspension substrate shown in FIG. 20, first, a metal substrate 1 (for example, stainless steel) is prepared (FIGS. 20A and 20B). Next, the first insulating layer 2a is formed on the surface of the metal substrate 1 by applying and processing polyimide (FIGS. 20C and 20D). Next, a diffusion prevention layer (for example, a Cr thin film layer) and a seed layer (for example, a Cu thin film layer) are formed on the surface of the first insulating layer 2a by sputtering. Thereafter, a predetermined resist pattern is formed on the surface on which the seed layer is formed, and the first wiring layer 3a and the second wiring layer 3b are formed by an electrolytic plating method (FIGS. 20E and 20F).

  Thereafter, the unnecessary resist pattern, diffusion preventing layer and seed layer are removed, and the cover layer 4 is formed by applying and processing polyimide on the substrate surface on which the first wiring layer 3a and the second wiring layer 3b are formed. Are formed (FIGS. 20G and 20H). Next, a resist pattern having an exposed portion is formed on the surface of the cover layer 4 at a position where the cut portion is formed, and the exposed cover layer 4 is removed by wet etching to form the cut portion 15 (FIG. 20 ( i), (j)). Here, the formation method of the cut | notch part 15 in this invention is not specifically limited. As described above, a method of removing the cover layer exposed from the resist may be used. However, for example, when the material of the cover layer 4 is a photocurable material, the cover layer at the position where the cut portion 15 is formed is cured. By not doing so, a cut portion can be formed. The thin layer described above can be formed by appropriately changing the wet etching conditions or adjusting the amount of light to be irradiated. Finally, Ni plating and Au plating are performed on the surfaces of the first wiring layer 3a and the second wiring layer 3b exposed at the cut portion 15, thereby forming the wiring plating layer 5 to obtain the suspension substrate of the present invention. (FIG. 20 (k), (l)).

  FIG. 21 is an explanatory view showing another example of a method for manufacturing a suspension substrate according to the present invention. 21 (b), (d), (f), (h), (j), (l) are respectively shown in FIGS. 21 (a), (c), (e), (g), (i). It is AA sectional drawing of (k). In the method for manufacturing the suspension substrate shown in FIG. 21, first, a member having the metal substrate 1, the first insulating layer 2a, and the first wiring layer 3a is formed in the same manner as in FIGS. (FIGS. 21A and 21B). Next, a second insulating layer 2b is formed by applying and processing polyimide on the surfaces of the first insulating layer 2a and the first wiring layer 3a (FIGS. 21C and 21D). Next, a diffusion prevention layer (for example, a Cr thin film layer) and a seed layer (for example, a Cu thin film layer) are formed on the surface of the second insulating layer 2b by sputtering. Thereafter, a predetermined resist pattern is formed on the surface on which the seed layer is formed, and the second wiring layer 3b is formed by an electrolytic plating method (FIGS. 21E and 21F).

  Thereafter, unnecessary resist patterns, diffusion preventing layers and seed layers are removed, and a cover layer 4 is formed by applying and processing polyimide on the surface of the substrate on which the second wiring layer 3b is formed (FIG. 21). (G), (h)). Next, a resist pattern having an exposed portion is formed on the cover layer 4 at a position where the cut portion is to be formed, and the exposed cover layer 4 is removed by wet etching to form the cut portion 15 (FIG. 21 (i)). ), (J)). Finally, Ni plating and Au plating are performed on the surface of the second wiring layer 3b exposed at the cut portion 15, thereby forming the wiring plating layer 5 to obtain the suspension substrate of the present invention (FIG. 21 (k)). (L)).

  20 and 21, the suspension substrate is formed from the metal substrate. For example, the metal substrate, the insulating layer for forming the first insulating layer, and the first wiring layer are formed. The suspension substrate may be formed using a laminated material (three-layer material) made of a conductor layer.

B. Suspension Next, the suspension of the present invention will be described. The suspension of the present invention includes the above-described suspension substrate.

  FIG. 22 is a schematic plan view showing an example of the suspension of the present invention. A suspension 40 shown in FIG. 22 has the suspension substrate 20 described above and a load beam 30 provided on the surface of the suspension substrate 20 on the opposite side to the surface on which the gimbal portion 11 is formed. .

  According to the present invention, a suspension with less warpage can be obtained by using the above-described suspension substrate.

  The suspension of the present invention has at least a suspension substrate, and usually further has a load beam. The suspension substrate is the same as the content described in “A. Suspension substrate”, and therefore, the description thereof is omitted here. The load beam can be the same as the load beam used for a general suspension.

C. Next, the suspension with a head according to the present invention will be described. The suspension with a head of the present invention includes the above-described suspension and a magnetic head slider mounted on the suspension.

  FIG. 23 is a schematic plan view showing an example of a suspension with a head according to the present invention. A suspension 50 with a head shown in FIG. 23 includes the above-described suspension 40 and a magnetic head slider 41 mounted on the gimbal portion 11 of the suspension 40.

  According to the present invention, by using the suspension described above, a suspension with a head with less warpage can be obtained.

  The suspension with a head of the present invention has at least a suspension and a magnetic head slider. The suspension is the same as that described in “B. Suspension” above, and is not described here. Further, the magnetic head slider can be the same as the magnetic head slider used in a general suspension with a head.

D. Next, the hard disk drive of the present invention will be described. The hard disk drive of the present invention includes the above-described suspension with a head.

  FIG. 24 is a schematic plan view showing an example of the hard disk drive of the present invention. A hard disk drive 60 shown in FIG. 24 is connected to the suspension 50 with a head described above, a disk 61 on which the head suspension 50 writes and reads data, a spindle motor 62 that rotates the disk 61, and the suspension 50 with a head. The arm 63, the voice coil motor 64 that moves the magnetic head slider of the suspension 50 with head, and the case 65 that seals the above members are included.

  According to the present invention, a high-performance hard disk drive can be obtained by using the suspension with a head described above.

  The hard disk drive of the present invention has at least a suspension with a head, and usually further includes a disk, a spindle motor, an arm, and a voice coil motor. The suspension with a head is the same as the contents described in the above “C. Suspension with a head”, and therefore description thereof is omitted here. As other members, the same members as those used in a general hard disk drive can be used.

E. Next, a method for manufacturing a suspension substrate according to the present invention will be described. A method for manufacturing a suspension substrate according to the present invention is a method for manufacturing a suspension substrate as described above, and includes a preparation step of preparing a processing member having the wiring portion, and a wiring constituting the wiring portion of the processing member. A cover layer forming step for forming at least one cover layer; and a cut portion forming step for forming the cut portion with respect to the cover layer.

  According to the present invention, it is possible to obtain a suspension substrate in which warpage is suppressed by providing a cut portion in the cover layer.

  The preparation step in the present invention is a step of preparing the processing member. The processing member is a member having at least a wiring portion, and is usually a member before the cover layer is formed. Examples of such a processing member include the members shown in FIGS. 20 (e) and 20 (f) and FIGS. 21 (e) and 21 (f). In addition, the manufacturing method of the processing member will not be specifically limited if it is a method which can obtain the desired processing member.

  Further, the cover layer forming step in the present invention is a step of forming a cover layer that covers at least one of the wires constituting the wiring portion of the processing member. The method for applying the material for the cover layer is not particularly limited, and a general application method can be used.

  Moreover, the notch formation in this invention is a process of forming the said notch with respect to the said cover layer. The method for forming the cut portion is the same as that described in the above-mentioned “A. Suspension substrate”, so description thereof is omitted here. Moreover, in this invention, you may have the wiring plating process of plating to the wiring layer exposed by a notch part. Moreover, when forming a notch part, you may form the thin layer mentioned above.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present invention has substantially the same configuration and exhibits the same function and effect regardless of the case. It is included in the technical scope of the invention.

  DESCRIPTION OF SYMBOLS 1 ... Metal substrate, 2a ... 1st insulating layer, 2b ... 2nd insulating layer, 3a ... 1st wiring layer, 3b ... 2nd wiring layer, 3x ... Lower wiring layer, 4 ... Cover layer, 4a ... Thin-walled layer, 5 DESCRIPTION OF SYMBOLS ... Wiring plating layer, 11 ... Gimbal part, 12 ... External connection board connection part, 13 ... Wiring part, 13X ... Longitudinal wiring area, 14 ... Bending process part, 15 ... Notch part, 15x ... Through notch part, 15y ... Wiring Intermittent part, 15a ... first notch part, 15b ... second notch part, 20 ... suspension substrate, 30 ... load beam, 40 ... suspension, 41 ... magnetic head slider, 50 ... suspension with head, 60 ... hard disk drive, 61 ... Disc, 62 ... Spindle motor, 63 ... Arm, 64 ... Voice coil motor, 65 ... Case

Claims (16)

Suspension board having a gimbal part, an external connection board connection part, a wiring part for connecting the gimbal part and the external connection board connection part, and a cover layer covering at least one of the wiring layers constituting the wiring part Because
In the wiring part, the cover layer may have a cut portion one or more,
The suspension substrate has a bent portion positioned between the gimbal portion and the external connection substrate connection portion,
The wiring portion has a longitudinal wiring region in which the wiring layer is present along the longitudinal direction of the suspension substrate between the bent portion and the gimbal portion,
The longitudinal in the direction wiring region, said cover layer, suspension substrate, characterized by chromatic said slit portion. 2. The suspension substrate according to claim 1, wherein the cut portion is a through cut portion penetrating from one end portion of the cover layer to the other end portion in the width direction of the cover layer. The suspension substrate according to claim 2 , wherein an angle formed by a cut direction of the through cut portion and a length direction of the cover layer is within a range of 30 ° to 90 °. The said notch part has an exposed part which the said wiring layer exposes, and the wiring plating layer is formed in the said exposed part, The claim in any one of Claim 1 to 3 characterized by the above-mentioned. Suspension board. The suspension substrate according to any one of claims 1 to 3 , wherein a thin layer having a thickness smaller than that of the cover layer is formed in the cut portion. Suspension board having a gimbal part, an external connection board connection part, a wiring part for connecting the gimbal part and the external connection board connection part, and a cover layer covering at least one of the wiring layers constituting the wiring part Because
  In the wiring portion, the cover layer has one or more cut portions,
A suspension substrate, wherein a thin layer having a thickness smaller than that of the cover layer is formed in the cut portion. The suspension substrate according to claim 6, wherein the cut portion is a through cut portion that penetrates from one end portion of the cover layer to the other end portion in the width direction of the cover layer. The wiring portion has a first wiring layer and a second wiring layer,
  The suspension substrate includes a metal substrate, a first insulating layer formed on the metal substrate, the first wiring layer and the second wiring layer formed on the first insulating layer, and the first The suspension substrate according to any one of claims 1 to 7, further comprising a wiring layer and the cover layer covering the second wiring layer. Suspension board having a gimbal part, an external connection board connection part, a wiring part for connecting the gimbal part and the external connection board connection part, and a cover layer covering at least one of the wiring layers constituting the wiring part Because
  In the wiring portion, the cover layer has one or more cut portions,
  The wiring portion has a first wiring layer and a second wiring layer,
The suspension substrate includes a metal substrate, a first insulating layer formed on the metal substrate, the first wiring layer and the second wiring layer formed on the first insulating layer, and the first A suspension board comprising: a wiring layer; and the cover layer covering the second wiring layer. The suspension substrate according to claim 9, wherein the cut portion is a through cut portion penetrating from one end portion of the cover layer to the other end portion in the width direction of the cover layer. The cut portion includes the through cut portion, and an inter-wire cut portion formed between the first wiring layer and the second wiring layer,
  The suspension substrate according to any one of claims 8 to 10, wherein the through-cut portion and the inter-wire cut portion are connected to each other. The cut portion includes a first cut portion formed on one end side of the cover layer and a second cut portion formed on the other end side of the cover layer in the width direction of the cover layer. Have
  The said 1st notch part and said 2nd notch part are arrange | positioned so that it may not mutually overlap in the width direction of the said cover layer, The claim in any one of Claims 8-10 characterized by the above-mentioned. Suspension board. The notch has the first notch, the second notch, and the inter-wire notch formed between the first wiring layer and the second wiring layer,
  The suspension substrate according to claim 12, wherein the first cut portion, the second cut portion, and the inter-wire cut portion are connected to each other.   A suspension comprising the suspension substrate according to any one of claims 1 to 13.   15. A suspension with a head, comprising: the suspension according to claim 14; and a magnetic head slider mounted on the suspension.   A hard disk drive comprising the suspension with a head according to claim 15.

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