JP2011023063A - Suspension substrate, and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a suspension substrate having external connection terminals excellent in mechanical strength. <P>SOLUTION: The suspension substrate has a metal substrate, an insulation layer formed on the metal substrate, a striped conductor pattern formed on the insulation layer, a cover layer formed on the conductor pattern, a front surface opening formed on the cover layer to expose the conductor pattern, a back surface opening formed on the metal substrate and the insulation layer to expose the conductor pattern, and external connection terminals formed by exposing both surfaces of the conductor pattern through the front and back surface openings and plating the exposed surfaces of the conductor pattern. The length of the surface side opening is larger than the back side opening in the direction along the conductor pattern stripe, and the cover layer and the insulation layer make a level difference on the cross section in the direction along the pattern stripe. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a suspension substrate used for a hard disk drive (HDD) or the like, and more particularly to a suspension substrate having an external connection terminal portion excellent in mechanical strength.

  In recent years, due to the spread of the Internet and the like, there has been a demand for an increase in the amount of information processing of personal computers and an increase in information processing speed, and along with this, the capacity of hard disk drives (HDD) incorporated in personal computers has increased. Increasing information transmission speed is required. In addition, a component called a magnetic head suspension that supports the magnetic head used in the HDD also has a signal line such as a copper wiring directly formed on a stainless steel spring from a conventional type in which a signal line such as a gold wire is connected. The so-called wireless suspension is now integrated into a wiring integrated type (flexure).

  A suspension substrate used for such a suspension usually has a connection terminal portion (external connection terminal portion) with an external circuit. Specifically, the external connection terminal portion is formed on the metal substrate 1, the insulating layer 2 formed on the metal substrate 1, and the insulating layer 2, as shown in FIG. Stripe-shaped conductor pattern 3, cover layer 4 formed on conductor pattern 3, surface-side opening 5 formed in cover layer 4 exposing conductor pattern 3, and formed on metal substrate 1 and insulating layer 2 And the back surface side opening 6 exposing the conductor pattern 3, and the both surfaces of the conductor pattern 3 are exposed by the front surface side opening 5 and the back surface side opening 6. Usually, plating layers (not shown) are formed on both surfaces of the conductor pattern 3 exposed by the front surface side opening 5 and the back surface side opening 6. Moreover, FIG.8 (b) is the schematic plan view which looked at Fig.8 (a) from the surface side opening part 5 side.

  The external connection terminal portion where the conductor pattern is exposed in the air has a problem that the mechanical strength is weakened, and various ideas have been made for this problem. For example, in Patent Document 1, a printed circuit board including a conductor pattern having a wide portion extending in a width direction substantially orthogonal to the direction in which the conductor pattern extends at an intersection where the edge of the opening and the conductor pattern intersect. (For example, FIG. 2 of Patent Document 1), and a wiring circuit in which the first insulating layer and / or the second insulating layer (cover layer) has a protrusion at the intersection where the edge of the opening and the conductor pattern intersect A substrate (for example, FIG. 5 of Patent Document 1) is disclosed.

  However, when the conductor pattern having the wide portion is formed, the connection strength is improved, but there is a problem that it is difficult to narrow the conductor pattern. On the other hand, in the case of forming the above-described protrusion, there is a problem that it is difficult to accurately provide the protrusion on the insulating layer (for example, polyimide).

Japanese Patent No. 3692314

  The present invention has been made in view of the above circumstances, and a main object of the present invention is to provide a suspension substrate having an external connection terminal portion excellent in mechanical strength.

  In order to solve the above problems, in the present invention, a metal substrate, an insulating layer formed on the metal substrate, a striped conductor pattern formed on the insulating layer, and formed on the conductor pattern A cover layer formed on the cover layer and exposing the conductor pattern; a back surface opening formed on the metal substrate and the insulating layer to expose the conductor pattern; and A suspension substrate comprising external connection terminal portions in which both surfaces of the conductor pattern are exposed by the front surface side opening and the back surface side opening, and plating layers are formed on both surfaces of the exposed conductor pattern, The length of the opening on the front surface side in the direction along the stripe of the conductor pattern is larger than the length of the opening on the back surface side in the direction along the stripe of the conductor pattern. Ku, and the cover layer and the insulating layer is, in cross-section in the direction along the stripe of the conductive pattern to provide a substrate for suspension, characterized in that it constitutes a step shape.

  According to the present invention, the length of the front surface side opening is made larger than the length of the back surface side opening, the end surface of the cover layer facing the front surface side opening, and the end surface of the insulating layer facing the back surface side opening Are arranged at different positions in the thickness direction of the conductor pattern so that the end face of the cover layer and the end face of the insulating layer, which will be the breaking point, do not overlap, and the cover layer and the insulating layer are oriented along the stripe of the conductor pattern. By forming a stepped shape in the cross section at, a suspension substrate having an external connection terminal portion excellent in mechanical strength can be obtained by dispersing the stress applied to the conductor pattern. In the present invention, since the length of the plating layer formed in the front side opening is larger than the length of the plating layer formed in the back side opening, the mechanical strength of the conductor pattern is improved. be able to.

In the invention, the difference between the length of the opening on the front surface side in the direction along the stripe of the conductor pattern and the length of the opening on the back surface side in the direction along the stripe of the conductor pattern is A, In the side opening, when the lengths of the portions where the both ends of the exposed conductor pattern in the direction along the stripe of the conductor pattern are in contact with the insulating layer are respectively A ₁ and A ₂ , A = A ₁ + A ₂ and it is preferable that both A ₁ and A ₂ have a length equal to or greater than the thickness of the conductor pattern. Each of the part opposite ends of the conductor pattern is in contact with the insulating layer lengths A ₁ and A _2, either by the above thickness of the length of the conductor pattern while maintaining the mechanical strength of the conductive pattern This is because the pitch of the conductor pattern can be reduced.

In the above invention, the length of the _{A 1} and _{A 2} are preferably each a length within the range of 5Myuemu～180myuemu. Each of the part opposite ends of the conductor pattern is in contact with the insulating layer lengths A ₁ and A _2, by a length within the above range, while maintaining the mechanical strength of the conductive pattern, the conductive pattern narrow This is because the pitch can be increased.

In the above invention, the length of the opening formed by the metal substrate in the direction along the stripe of the conductor pattern is formed in the opening on the back surface side, and the insulating layer is formed in the direction along the stripe of the conductor pattern. The difference between the length of the opening formed by the metal substrate and the length of the opening formed by the insulating layer is B, and is directed toward the back surface side opening. When the lengths of the protruding portions of the insulating layer protruding in parallel with the end surface of the metal substrate from the end surface are B ₁ and B ₂ , respectively, B = B ₁ + B ₂ , and the above B ₁ and B ₂ However, it is preferable that the length is equal to or greater than the thickness of the insulating layer. In addition to the length of the opening on the front surface side being larger than the length of the opening on the back surface side, the length of the metal substrate opening and the insulating layer opening in the opening on the back surface side is different. This is because a suspension substrate having an external connection terminal portion having excellent mechanical strength can be obtained by dispersing the stress applied to the side opening and shifting the boundary where breakage or deformation occurs. Further, the lengths B ₁ and B ₂ of the protruding portions of the insulating layer protruding in parallel with the end face of the metal substrate are set such that the lengths B ₁ and B ₂ are equal to or longer than the thickness of the insulating layer. By doing so, it is possible to reduce the pitch of the conductor pattern while maintaining the mechanical strength of the conductor pattern.

In the above invention, the length of the _{B 1} and _{B 2} are preferably each a length within the range of 2Myuemu～200myuemu. By making each length B ₁ and B ₂ of the protruding portion of the insulating layer protruding parallel to the end face of the metal substrate within the above range, while maintaining the mechanical strength of the conductor pattern, This is because the pitch of the conductor pattern can be reduced.

  Further, in the present invention, a laminate preparation process for preparing a laminate in which a metal substrate, an insulating layer, and a conductor layer are laminated in this order, etching the metal substrate and the insulating layer of the laminate, and opening the back side opening A back side opening forming process to be formed, a conductor pattern forming process for etching a conductor layer of the laminate and forming a striped conductor pattern, and covering the conductor pattern and the insulating layer with a cover layer forming material; By performing exposure and development, the length of the surface side opening in the direction along the stripe of the conductor pattern is larger than the length of the back side opening in the direction along the stripe of the conductor pattern. A plating layer is formed on both surfaces of the cover layer forming process for forming a cover layer having a portion and the conductor pattern exposed at the front surface side opening and the back surface side opening. To provide a method for manufacturing a suspension substrate characterized by having a Rumekki layer forming process, the external connection terminal portion forming step with.

  According to the present invention, by designing the length of the opening on the front surface side to be larger than the length of the opening on the back surface side, it is possible to disperse the stress applied to the conductor pattern and to provide an external connection with excellent mechanical strength. A suspension substrate having a terminal portion can be obtained.

  In the above invention, in the back side opening forming process, the length of the opening formed by etching the metal substrate is larger than the length of the opening formed by etching the insulating layer, and the insulating layer However, pattern etching is preferably performed so as to protrude from the end surface of the metal substrate toward the back-side opening in parallel with the end surface of the metal substrate. By devising the pattern of the metal substrate and the pattern of the insulating layer at the time of pattern etching, the length of the metal substrate opening and the insulating layer opening in the back side opening is changed, and the stress applied to the back side opening is dispersed. This is because a suspension substrate having an external connection terminal portion excellent in mechanical strength can be manufactured by shifting a boundary portion where breakage or deformation occurs.

  According to the suspension substrate of the present invention, the stress applied to the conductor pattern is dispersed, and the cover layer end surface and the insulating layer end surface, which are likely to be breaking points, are located at different positions, thereby providing an excellent external mechanical strength. There is an effect that a suspension substrate having a connection terminal portion can be obtained. Furthermore, it is possible to provide a suspension substrate having external connection terminal portions having excellent mechanical strength by forming plating layers on both surfaces of the conductor pattern exposed at the front surface side opening and the back surface side opening. There is an effect that can be done.

  According to the method for manufacturing a suspension substrate of the present invention, the length of the front surface side opening is designed to be greater than the length of the back surface side opening, and the metal substrate opening and the insulating layer opening in the back surface side opening By changing the length, the stress applied to the conductor pattern can be dispersed, and the suspension substrate having the external connection terminal portion having a narrow pitch conductor pattern and excellent mechanical strength can be manufactured.

It is explanatory drawing explaining the external connection terminal part in 1st Embodiment of the board | substrate for suspensions of this invention. It is explanatory drawing explaining the external connection terminal part in 2nd Embodiment of the board | substrate for suspensions of this invention. It is explanatory drawing explaining the external connection terminal part in the other example of 2nd Embodiment of the board | substrate for suspensions of this invention. It is explanatory drawing explaining the stress added to a conductor pattern. It is a schematic plan view which illustrates the whole image of the suspension substrate of the present invention. It is explanatory drawing which shows an example of the manufacturing method of the board | substrate for suspensions of this invention shown in FIG. In the Example of this invention, it is explanatory drawing which measures the breaking strength of a conductor pattern with a breaking strength test apparatus. It is explanatory drawing explaining the external connection terminal part of the conventional board | substrate for suspensions. It is a figure which shows Ni plating thickness and breaking strength in wiring width 75micrometer. It is a figure which shows Ni plating thickness and breaking strength in the wiring width of 100 micrometers. It is a figure which shows Ni plating thickness and breaking strength in wiring width 125micrometer. It is a figure which shows Ni plating thickness and breaking strength in wiring length 0.75mm. It is a figure which shows Ni plating thickness and breaking strength in wiring length 1.00mm. It is a figure which shows Ni plating thickness and breaking strength in wiring length 1.50mm.

  Hereinafter, the suspension substrate and the manufacturing method thereof according to 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 includes a metal substrate, an insulating layer formed on the metal substrate, a striped conductor pattern formed on the insulating layer, and a cover layer formed on the conductor pattern. A front-side opening that is formed in the cover layer and exposes the conductive pattern; a back-side opening that is formed in the metal substrate and the insulating layer and exposes the conductive pattern; and the front-side opening A suspension substrate including external connection terminal portions in which both surfaces of the conductor pattern are exposed by the opening portion and the back-side opening, and plating layers are formed on both surfaces of the exposed conductor pattern, the stripes of the conductor pattern The length of the front surface side opening in the direction along the length of the wiring pattern (that is, the length direction of the wiring pattern) is the back surface in the direction along the stripe of the conductor pattern. Greater than the length of the opening, and the cover layer and the insulating layer is, in cross-section in the direction along the stripe of the conductor pattern, is characterized in that configuring the stepped shape.

  According to the present invention, the length of the front-side opening is determined by the length of the opening of the cover layer, and the length of the back-side opening is determined by the length of the opening of the insulating layer. The length of the opening on the front surface side is made larger than the length of the opening on the back surface side, and the cover layer end surface and the insulating layer end surface, which will be the breaking point, are placed at different positions. By forming the step shape in the cross section in the direction along the stripe of the conductor pattern, it is possible to disperse the stress applied to the conductor pattern and to provide a suspension substrate having an external connection terminal portion excellent in mechanical strength. In the present invention, since the length of the plating layer formed in the front side opening is larger than the length of the plating layer formed in the back side opening, the mechanical strength of the conductor pattern is improved. be able to. Therefore, for example, sufficient mechanical strength can be maintained even when the conductor pattern is thin.

  Furthermore, according to the present invention, an external connection terminal portion having excellent mechanical strength can be formed simply by designing the length of the front surface side opening to be larger than the length of the back surface side opening. As described above, the conventional method of providing a wide portion in the conductor pattern has been difficult to reduce the pitch, but the suspension substrate of the present invention has an advantage that the pitch can be easily reduced. In addition, although the conventional method of providing a protrusion on an insulating layer or the like has been difficult to form the protrusion, the suspension substrate of the present invention has a mechanical strength of a conductor pattern without providing a protrusion. It has the advantage that can be improved. The application of the suspension substrate of the present invention can be used for a magnetic head suspension of a hard disk drive (HDD), for example.

  Next, an embodiment of a suspension substrate according to the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are used to indicate the same portions.

(First embodiment)
FIG. 1A is a schematic cross-sectional view illustrating an external connection terminal portion in the first embodiment of the suspension substrate of the present invention, and FIG. 1B is a front side opening portion of FIG. It is the schematic plan view seen from 5 side. 1A includes a metal substrate 1, an insulating layer 2 formed on the metal substrate 1, a striped conductor pattern 3 formed on the insulating layer 2, and a conductor pattern. 3, the cover layer 4 formed on the surface 3, the front surface side opening 5 formed in the cover layer 4 to expose the conductor pattern 3, and the back surface side opening formed in the metal substrate 1 and the insulating layer 2 to expose the conductor pattern 3. Furthermore, both surfaces of the conductor pattern 3 are exposed by the front surface side opening 5 and the back surface side opening 6, and the plating layer 7 is formed on both surfaces of the exposed conductor pattern 3.

  In this external connection terminal portion, the length of the front surface side opening 5 in the direction along the stripe of the conductor pattern 3 is larger than the length of the back surface side opening 6 in the direction along the stripe of the conductor pattern 3. Insulation that faces the front surface side opening 5 and extends in the direction orthogonal to the conductor pattern 3 and the end surface of the cover layer 4 that extends in the direction orthogonal to the conductor pattern 3 and the rear surface side opening 6 The end surface of the layer 2 is arranged at a different position so as not to overlap in the thickness direction perpendicular to the stripe of the conductor pattern 3, and the cover layer 4 and the insulating layer 2 are cross sections in the direction along the stripe of the conductor pattern 3. A step shape is formed. In the present embodiment, the length of the opening formed by the metal substrate 1 in the back surface side opening 6 is the same as the length of the opening formed by the insulating layer 2.

  As a planar shape of the embodiment of the present invention, as shown in FIG. 1B, the end surface of the cover layer 4 on the front surface side is made to be the end surface of the opening 6 of the insulating layer 2 on the back surface side. On the other hand, the form arrange | positioned only the predetermined distance in the direction along the stripe of the conductor pattern 3 can be illustrated. With such a shape, the step shape can be easily configured.

  As shown in FIG. 1A, in the present invention, the length of the front surface side opening 5 is larger than the length of the back surface side opening 6. Here, FIG. 4 is an explanatory view for explaining the stress applied to the conductor pattern, FIG. 4 (a) is a case of a conventional suspension substrate, and FIG. 4 (b) is a schematic case of a suspension substrate of the present invention. It is sectional drawing. As shown in FIG. 4A, the length of the front surface side opening 5 and the length of the back surface side opening 6 of the external connection terminal portion of the conventional suspension board are the same. Therefore, stress is concentrated on the end of the opening (region C in FIG. 4A), and the conductor pattern 3 is likely to break. This tendency becomes more prominent as the conductor pattern becomes thinner. For example, it is difficult to use a conductor pattern having a thin film thickness and a low mechanical strength such as an electrolytic copper foil. On the other hand, in the present invention, as shown in FIG. 4B, the length of the front surface side opening 5 and the length of the back surface side opening 6 are different, and the cover layer 4 and the insulating layer 2 are made of a conductor. A cross-section in the direction along the stripe of the pattern 3 forms a step shape. Therefore, the stress applied to the end of the opening is dispersed (region D in FIG. 4B), and the conductor pattern 3 is not easily broken.

(Second Embodiment)
FIG. 2A is a schematic cross-sectional view illustrating an external connection terminal portion in the second embodiment of the suspension substrate of the present invention, and FIG. 2B is a front side opening portion of FIG. It is the schematic plan view seen from 5 side. The external connection terminal shown in FIG. 2A includes a metal substrate 1, an insulating layer 2 formed on the metal substrate 1, a striped conductor pattern 3 formed on the insulating layer 2, and a conductor pattern. 3, the cover layer 4 formed on the surface 3, the front surface side opening 5 formed in the cover layer 4 to expose the conductor pattern 3, and the back surface side opening formed in the metal substrate 1 and the insulating layer 2 to expose the conductor pattern 3. Furthermore, both surfaces of the conductor pattern 3 are exposed by the front surface side opening 5 and the back surface side opening 6, and the plating layer 7 is formed on both surfaces of the exposed conductor pattern 3.

  In this external connection terminal portion, the length of the front surface side opening 5 in the direction along the stripe of the conductor pattern 3 is larger than the length of the back surface side opening 6 in the direction along the stripe of the conductor pattern 3. Insulation that faces the front surface side opening 5 and extends in the direction orthogonal to the conductor pattern 3 and the end surface of the cover layer 4 that extends in the direction orthogonal to the conductor pattern 3 and the back surface side opening 6 and extends in the direction orthogonal to the conductor pattern 3 The end surface of the layer 2 is arranged at a different position so as not to overlap in the thickness direction perpendicular to the stripe of the conductor pattern 3, and the cover layer 4 and the insulating layer 2 are cross sections in the direction along the stripe of the conductor pattern 3. A step shape is formed. Further, in the rear surface side opening 6, the length of the opening formed by the metal substrate 1 is designed to be larger than the length of the opening formed by the insulating layer 2. Thus, the insulating layer 2 protrudes. In the present embodiment, the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2 and is smaller than the length of the opening 5 formed by the cover layer 4. Yes.

  As shown in FIG. 2A, in the present invention, the length of the front surface side opening 5 is larger than the length of the back surface side opening 6. Therefore, there is an advantage that the stress applied to the end of the opening is dispersed and the conductor pattern 3 is hardly broken. Furthermore, in this embodiment, the stress applied to the back surface side opening 6 is different because the length of the opening of the metal substrate 1 that forms the back surface side opening 6 and the length of the opening formed by the insulating layer 2 are different. It is possible to disperse and shift the boundary where breakage or deformation occurs, and the mechanical strength of the conductor pattern 3 can be further increased.

  Furthermore, as shown in FIG. 2A, the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2, and the length of the opening formed by the cover layer 4 is longer. If the thickness is smaller than the above, since the plating layer 7 formed on the cover layer 4 side of the conductor pattern 3 covers the end of the opening formed by the metal substrate 1, the opening formed by the metal substrate 1 is formed. This has the effect of reinforcing the conductor pattern 3 against the stress generated at the end of the portion.

(Another example of the second embodiment)
FIG. 3A is a schematic cross-sectional view illustrating an external connection terminal portion in another example of the second embodiment of the suspension substrate of the present invention, and FIG. It is the schematic plan view seen from the surface side opening part 5 side. 3A includes a metal substrate 1, an insulating layer 2 formed on the metal substrate 1, a stripe-shaped conductor pattern 3 formed on the insulating layer 2, and a conductor pattern. 3, the cover layer 4 formed on the surface 3, the front surface side opening 5 formed in the cover layer 4 to expose the conductor pattern 3, and the back surface side opening formed in the metal substrate 1 and the insulating layer 2 to expose the conductor pattern 3. Furthermore, both surfaces of the conductor pattern 3 are exposed by the front surface side opening 5 and the back surface side opening 6, and the plating layer 7 is formed on both surfaces of the exposed conductor pattern 3.

  In this external connection terminal portion, the length of the front surface side opening 5 in the direction along the stripe of the conductor pattern 3 is larger than the length of the back surface side opening 6 in the direction along the stripe of the conductor pattern 3. Insulation that faces the front surface side opening 5 and extends in the direction orthogonal to the conductor pattern 3 and the end surface of the cover layer 4 that extends in the direction orthogonal to the conductor pattern 3 and the back surface side opening 6 and extends in the direction orthogonal to the conductor pattern 3 The end surface of the layer 2 is arranged at a different position so as not to overlap in the thickness direction perpendicular to the stripe of the conductor pattern 3, and the cover layer 4 and the insulating layer 2 are cross sections in the direction along the stripe of the conductor pattern 3. A step shape is formed. Further, in the rear surface side opening 6, the length of the opening formed by the metal substrate 1 is designed to be larger than the length of the opening formed by the insulating layer 2. Thus, the insulating layer 2 protrudes. In the present embodiment, the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2 and the length of the opening 5 formed by the cover layer 4. .

  As shown in FIG. 3A, in the present invention, the length of the front surface side opening 5 is larger than the length of the back surface side opening 6. Therefore, there is an advantage that the stress applied to the end of the opening is dispersed and the conductor pattern 3 is hardly broken. Furthermore, in this embodiment, the stress applied to the back surface side opening 6 is different because the length of the opening of the metal substrate 1 that forms the back surface side opening 6 and the length of the opening formed by the insulating layer 2 are different. It is possible to disperse and shift the boundary where breakage and deformation occur, and further increase the mechanical strength.

  As described in the second embodiment and the other examples of the second embodiment, in order to shift the boundary where the conductor pattern 3 is broken or deformed and increase the mechanical strength, the cover layer 4 is Either the length of the opening 5 to be formed or the length of the opening formed by the metal substrate 1 may be larger. However, in order to pattern-etch the insulating layer 2, the length of the opening formed by the insulating layer 2 must be smaller than the length of the opening formed by the metal substrate 1.

  FIG. 5 is a schematic plan view illustrating the entire image of the suspension substrate of the present invention, and the cover layer is omitted for convenience. The suspension substrate shown in FIG. 5 has a structure in which a metal substrate (not shown) and an insulating layer 2 are laminated, and a gimbal for mounting a magnetic head on one end of the suspension substrate. Part 11 is formed, an external connection terminal region 12 for connecting to an external circuit is formed at the other end, and wirings 13a to 13d for connecting the gimbal part 11 and the external connection terminal region 12 are formed. ing. In the external connection terminal region 12, the external connection terminal portion described above is formed in accordance with each of the wirings 13a to 13d.

  Hereinafter, the suspension substrate of the present invention will be described in more detail. Since the suspension substrate of the present invention is characterized by the external connection terminal portion, the description will be made mainly on the external connection terminal portion. The configuration other than the external connection terminal portion is not particularly limited, and the same configuration as a general suspension board can be employed.

1. Material of External Connection Terminal Part First, the material of the external connection terminal part in the present invention shown in the above embodiment will be described. The external connection terminal portion in the present invention usually has a metal substrate, an insulating layer, a striped conductor pattern, a cover layer, and a plating layer.

  The metal substrate used in the present invention is a support substrate for the suspension substrate, and usually has an appropriate spring property. Examples of the material for the metal substrate include stainless steel (SUS). The thickness of the metal substrate varies depending on the material of the metal substrate and is not particularly limited, but is usually in the range of 10 μm to 30 μm, and preferably in the range of 15 μm to 25 μm.

  The insulating layer used in the present invention insulates the metal substrate and the conductor pattern. The material for the insulating layer is not particularly limited as long as it has a desired insulating property, and examples thereof include a polyimide resin and a thermoplastic polyimide resin. In particular, in the present invention, the insulating layer is preferably an insulating layer made of a polyimide resin or a composite insulating layer made of a polyimide resin and a thermoplastic polyimide resin. The thickness of the insulating layer is not particularly limited as long as a desired insulating property can be exhibited. However, in order to protect the bent conductor pattern and facilitate the fine patterning of the insulating layer, it is usual. It is preferably within the range of 2 μm to 30 μm, and more preferably within the range of 5 μm to 20 μm.

  The conductor pattern used in the present invention has a striped pattern and is used for connection to an external circuit. The material for the conductor pattern is not particularly limited as long as it has desired conductivity, and examples thereof include copper. Although the thickness of the said conductor pattern is not specifically limited, It is preferable that it is thin from a viewpoint of refinement | miniaturization, Usually, it exists in the range of 5 micrometers-18 micrometers, and it is preferable that it exists in the range of 9 micrometers-15 micrometers especially. The stripe width of the conductor pattern is usually in the range of 20 μm to 600 μm, preferably in the range of 50 μm to 400 μm, and more preferably narrow from the viewpoint that a narrow pitch can be achieved.

  Examples of the method for forming the conductor pattern include plating methods such as an electrolytic plating method and an electroless plating method, and a sputtering method. In particular, in the present invention, the conductor pattern is preferably an electrolytic copper foil formed by an electrolytic plating method. In the present invention, a conventional rolled copper foil may be used as the conductor pattern.

  The cover layer used in the present invention is formed on the conductor pattern. By forming the cover layer, the warp of the suspension substrate can be controlled and the rigidity can be reduced, and the conductor pattern can be protected. it can. The material of the cover layer is not particularly limited, but for simplifying the production process, for example, a photosensitive resin can be used. Specifically, a photosensitive synthetic resin such as a photosensitive polyimide resin, a photosensitive acrylic resin, or a photosensitive epoxy resin can be preferably used as the photosensitive resin. Although it does not specifically limit as thickness of the said cover layer, Usually, it exists in the range of 3 micrometers-30 micrometers, and it is preferable to exist in the range of 3 micrometers-15 micrometers especially.

  The plating layer used in the present invention is formed on both surfaces of the conductor pattern exposed by the front surface side opening and the back surface side opening, and is also plated on the side surfaces of the exposed conductor pattern. By providing the plating layer, the mechanical strength of the conductor pattern can be improved. Therefore, for example, even when the thickness of the conductor pattern is reduced, the conductor pattern is less likely to be broken by plating. Moreover, the corrosion resistance of a conductor pattern can be improved by providing a plating layer.

  Examples of the material for the plating layer include copper (Cu), nickel (Ni), and gold (Au). The plating layer may be formed by a plurality of metal platings. Examples of the plurality of metal platings include a combination of Cu plating, Ni plating, and Au plating, and a combination of Ni plating and Au plating. Examples of the Cu plating include copper sulfate plating and copper pyrophosphate plating. Examples of the Ni plating include nickel sulfamate plating. Examples of the Au plating include neutral cyan bath and acidic gold plating. In addition, it is preferable to perform a degreasing process and a pickling process with respect to a conductor pattern as pre-processing for forming the said plating layer.

  The thickness of the plating layer is not particularly limited, but is preferably thin from the viewpoint of miniaturization of the conductor pattern, and thick from the viewpoint of improving the corrosion resistance and mechanical strength of the conductor pattern. preferable. Usually, it exists in the range of 0.1 micrometer-5 micrometers, and it is preferable to exist in the range of 0.3 micrometer-3 micrometers especially.

2. Next, the configuration of the external connection terminal portion in the present invention will be described. The external connection terminal portion in the present invention includes a metal substrate, an insulating layer formed on the metal substrate, a striped conductor pattern formed on the insulating layer, and a cover layer formed on the conductor pattern. A surface-side opening that is formed in the cover layer and exposes the conductor pattern; a back-side opening that is formed in the metal substrate and the insulating layer and exposes the conductor pattern; and further, the surface side Both surfaces of the conductor pattern are exposed by the opening and the back surface side opening, and plating layers are formed on both surfaces of the exposed conductor pattern.

  Furthermore, in the present invention, the length of the opening on the front surface side in the direction along the stripe of the conductor pattern is larger than the length of the opening on the back surface side in the direction along the stripe of the conductor pattern. The end face of the cover layer facing the side opening and the end face of the insulating layer facing the back side opening are arranged at different positions so that the cover layer and the insulating layer are the conductor One feature is that a step shape is formed by a cross section in a direction along the stripe of the pattern.

(1) Case of First Embodiment Here, the shape of the external connection terminal portion of the first embodiment of the present invention will be further described. In the present invention, as shown in FIG. 1, the length of the front surface side opening 5 in the direction along the stripe of the conductor pattern 3 and the length of the back surface side opening 6 in the direction along the stripe of the conductor pattern 3 The difference is A, and the lengths of the portions where both ends of the exposed conductor pattern in the direction along the stripe of the conductor pattern are in contact with the insulating layer in the opening on the surface side are A ₁ and A ₂ , respectively. In this case, it is preferable that A = A ₁ + A ₂ , and both A ₁ and A ₂ have a length equal to or greater than the thickness of the conductive pattern 3. Each of the part opposite ends of the conductor pattern is in contact with the insulating layer lengths A ₁ and A _2, either by the above thickness of the length of the conductor pattern while maintaining the mechanical strength of the conductive pattern This is because the pitch of the conductor pattern can be reduced. Accordingly, the cover layer and the insulating layer form a step shape in a cross section in a direction along the stripe of the conductor pattern. It is preferable that the lengths of A ₁ and A ₂ are both in the range of 5 μm to 180 μm. A ₁ and A ₂ may be the same value or different values. By taking the above form, the stress applied to the conductor pattern is dispersed, and an external connection terminal portion having excellent mechanical strength is obtained.

The length of A ₁ and A ₂ is a value outside the above range, the A ₁ and A ₂ is less than 5 [mu] m, unpreferably dispersion effect of stress on the end portion of the opening is too decreased, On the other hand, if A ₁ and A ₂ exceed 180 μm, there is a problem that the conductor pattern 3 is excessively exposed to easily cause a short circuit or the like, which is not preferable.

  In the present invention, the length of the surface side opening 5 in the direction along the stripe of the conductor pattern 3 is usually in the range of 100 μm to 1800 μm, and preferably in the range of 400 μm to 1500 μm. The length of the back surface side opening 6 in the direction along the stripe of the conductor pattern 3 is usually in the range of 50 μm to 1500 μm, and preferably in the range of 200 μm to 1300 μm. The thickness of the conductor pattern after plating (denoted as T) is usually in the range of 5 μm to 18 μm, and preferably in the range of 6 μm to 15 μm. The stripe width (denoted as W) of the conductor pattern 3 after plating is usually in the range of 20 μm to 600 μm, preferably in the range of 50 μm to 400 μm, from the viewpoint that a narrow pitch can be achieved. Is more preferably narrow.

(2) Second Embodiment Next, the shape of the external connection terminal portion of the second embodiment of the present invention will be further described. In the present invention, as shown in FIG. 2, the length of the opening formed by the metal substrate 1 in the direction along the stripe of the conductor pattern 3 in the back surface side opening 6 is the opening formed by the insulating layer 2. The difference between the length of the opening formed by the metal substrate 1 and the length of the opening formed by the insulating layer 2 is B, and toward the back-side opening 6 from the end surface of the metal substrate 1, When the length of the protruding portion of the insulating layer 2 protruding parallel to the end face of the metal substrate 1 is B ₁ and B ₂ , B = B ₁ + B ₂ , and both B ₁ and B ₂ are The length is preferably equal to or greater than the thickness of the insulating layer 2. Each of the length B ₁ and B ₂ of the protruding portion of the insulating layer that protrudes parallel to the end surface of the metal substrate, the B ₁ and B ₂ are both be at least the thickness of the length of the insulating layer This is because the pitch of the conductor pattern can be reduced while maintaining the mechanical strength of the conductor pattern. B ₁ and B ₂ may be the same value or different values.

In the present embodiment, it is preferable that the lengths of B ₁ and B ₂ are both in the range of ₂ μm to 200 μm. In this embodiment, the case where the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2 and smaller than the length of the opening 5 formed by the cover layer 4 is shown. Yes. If it is in the said range, the conductor pattern 3 which bends can be protected, a breaking stress can be disperse | distributed and the mechanical strength of the conductor pattern 3 can be maintained, and the pitch of the conductor pattern 3 can be reduced. For example, by providing the insulating layer 2 with the same width so as to protrude from the end surface of the metal substrate 1, it is not necessary to provide the protrusions on the insulating layer with high accuracy as in the prior art described in Patent Document 1. In addition, patterning of the insulating layer 2 is facilitated, the influence of the positional deviation between the insulating layer 2 and the conductor pattern 3 is reduced, and the manufacturing is facilitated.

In the present invention, as described above, the thickness of the insulating layer 2 is not particularly limited as long as a desired insulating property can be exhibited, but usually 2 μm to 30 μm is within a preferable range, and in particular, 5 μm to 20 μm. Is within a more preferable range. In the present invention, each of B ₁ and B ₂ has a preferable value within the range of 2 μm to 200 μm.

The length of B ₁ and B ₂ is a value outside the above range, the B ₁ and B ₂ is less than 2 [mu] m, since the effect of dispersing the stress applied to the end portion of the back-surface-side opening 6 is reduced preferably On the other hand, if B ₁ and B ₂ exceed 200 μm, the area occupied by the metal substrate as the support substrate decreases, and the strength as the suspension substrate decreases, which is not preferable.

(3) Another Example of the Second Embodiment Another example of the second embodiment shown in FIG. 3 is similar to the second embodiment described above, in the back surface side opening 6 in the stripe of the conductor pattern 3. The length of the opening formed by the metal substrate 1 in the direction along the length is larger than the length of the opening formed by the insulating layer 2, and the length of the opening formed by the metal substrate 1 and the opening formed by the insulating layer 2 The length of the protruding portion of the insulating layer 2 protruding in parallel with the end surface of the metal substrate 1 from the end surface of the metal substrate 1 toward the back-side opening 6 is set to B ₁ . In the case of B ₂ , it is preferable that B = B ₁ + B ₂ and that both B ₁ and B ₂ have a length equal to or greater than the thickness of the insulating layer 2. B ₁ and B ₂ may be the same value or different values.

In the present embodiment, it is preferable that the lengths of B ₁ and B ₂ are both in the range of ₂ μm to 200 μm. In the present embodiment, the case where the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2 and the length of the opening 5 formed by the cover layer 4 is shown. . Within the above range, it is possible to protect the bent conductor pattern, disperse the breaking stress and maintain the mechanical strength of the conductor pattern, and to reduce the pitch of the conductor pattern. For example, by causing the insulating layer 2 to protrude from the end face of the metal substrate 1 with the same width, it is not necessary to accurately provide a protrusion on the insulating layer as in the prior art described in Patent Document 1, Patterning of the insulating layer 2 becomes easy, and the influence of the positional deviation between the insulating layer 2 and the conductor pattern 3 is reduced, and the manufacturing is facilitated.

In the present embodiment, as described in the second embodiment, each of B ₁ and B ₂ has a preferable value within the range of 2 μm to 200 μm. If B ₁ and B ₂ are less than ₂ μm, it is not preferable because the effect of dispersing stress applied to the end of the back surface side opening 6 is reduced. On the other hand, if B ₁ and B ₂ exceed 200 μm, the metal substrate Since the function as a support substrate is deteriorated, it is not preferable.

B. Next, a method for manufacturing a suspension substrate according to the present invention will be described. The method for manufacturing a suspension substrate according to the present invention includes a laminate preparation process for preparing a laminate in which a metal substrate, an insulating layer, and a conductor layer are laminated in this order, etching the metal substrate and the insulating layer of the laminate, Back side opening forming process for forming a side opening, a conductor pattern forming process for forming a striped conductor pattern by etching the conductor layer of the laminate, and forming the cover pattern for the conductor pattern and the insulating layer By covering with a material and performing exposure development, the length of the front side opening in the direction along the stripe of the conductor pattern is longer than the length of the back side opening in the direction along the stripe of the conductive pattern. Cover layer forming process for forming a cover layer having a large front side opening, and both sides of the conductor pattern exposed at the front side opening and the back side opening And it is characterized by having a plating layer forming process for forming a plating layer, the external connection terminal portion forming step with.

  According to the present invention, by designing the length of the opening on the front surface side to be larger than the length of the opening on the back surface side, it is possible to disperse the stress applied to the conductor pattern and to provide an external connection with excellent mechanical strength. A suspension substrate having a terminal portion can be obtained.

  In the method for manufacturing a suspension substrate of the present invention, the length of the opening formed by etching the metal substrate in the back surface side opening forming process is such that the opening formed by etching the insulating layer is formed. It is preferable that pattern etching is performed so that the insulating layer is larger than the length and protrudes from the end surface of the metal substrate toward the back-side opening parallel to the end surface of the metal substrate. By devising the pattern of the metal substrate and the pattern of the insulating layer at the time of pattern etching, the length of the metal substrate opening and the insulating layer opening in the back side opening is changed, and the stress applied to the back side opening is dispersed. This is because a suspension substrate having an external connection terminal portion excellent in mechanical strength can be manufactured by shifting a boundary portion where breakage or deformation occurs.

  Next, a method for manufacturing a suspension board according to the present invention will be described with reference to the drawings, taking the suspension board of the first embodiment as an example. FIG. 6 is an explanatory view showing a method of manufacturing the suspension substrate of the present invention shown in FIG. In the method for manufacturing a suspension substrate shown in FIG. 6, first, a laminate in which the metal substrate 1, the insulating layer 2, and the conductor layer 3 ′ are laminated in this order is prepared (FIG. 6A). Next, this laminated body is degreased and pickled, and a photosensitive resist is applied to both sides of the laminated body and dried. Next, the conductor layer 3 ′ is exposed so as to obtain a desired conductor pattern, and the metal substrate 1 is exposed so as to obtain a desired back side opening, and thereafter developed. Thus, a photosensitive resist pattern 21 is formed (FIG. 6B).

  Next, the conductor layer 3 ′ is etched with an etching solution to form a striped conductor pattern 3. Further, the metal substrate 1 is etched with an etching solution. Next, the surface of the conductor pattern 3 is roughened, the conductor pattern 3 and the insulating layer 2 are covered with a photosensitive cover layer, and exposed and developed, whereby the surface-side opening 5 in the direction along the stripe of the conductor pattern 3 is obtained. A cover layer 4 having the following structure is formed (FIG. 6C).

  Next, in order to etch the insulating layer 2, the photosensitive dry film is laminated with a vacuum laminator, and exposed and developed so as to obtain a desired back side opening. Thereafter, the insulating layer 2 is etched to form openings in the insulating layer 2. Thereby, compared with the length of the surface side opening part 5 in the direction along the stripe of the conductor pattern 3, the back surface side opening part 6 and the conductor pattern 3 whose length in the direction along the stripe of the conductor pattern 3 is short are provided. A member is obtained (FIG. 6D).

  As described above, since FIG. 6 shows the case of the first embodiment of the present invention, the metal substrate in the direction along the stripe of the conductor pattern 3 in the back surface side opening 6 shown in FIG. The length of the opening formed by 1 is the same as the length of the opening formed by the insulating layer 2.

In the surface-side opening 5, the lengths of the portions where both ends of the exposed conductor pattern 3 in the direction along the stripe of the conductor pattern 3 are in contact with the insulating layer 2 are A ₁ and A ₂ , respectively. . Finally, the external connection terminal portions are formed by forming the plating layers 7 on both surfaces of the conductor pattern 3 exposed in the front surface side opening 5 and the back surface side opening 6 (FIG. 6E).

  Although not shown, in the case of the suspension substrate manufacturing method according to the second embodiment of the present invention, the opening formed by the metal substrate 1 in the direction along the stripe of the conductor pattern 3 in the back surface side opening 6. The photosensitive resist of the metal substrate 1 in the opening on the back side is such that the length of the portion is larger than the length of the opening formed by the insulating layer 2 and smaller than the length of the opening 5 formed by the cover layer 4. What is necessary is just to set the pattern and the photosensitive dry film pattern of the insulating layer 2.

  Similarly, although not shown, in the case of the suspension board manufacturing method according to another example of the second embodiment of the present invention, the back surface side opening 6 has a direction along the stripe of the conductor pattern 3. The back surface side so that the length of the opening formed by the metal substrate 1 is larger than the length of the opening formed by the insulating layer 2 and larger than the length of the front surface opening 5 formed by the cover layer 4. What is necessary is just to set the photosensitive resist pattern of the metal substrate 1 of an opening part, and the photosensitive dry film pattern of the insulating layer 2. FIG.

  Since the suspension board manufacturing method of the present invention includes an external connection terminal portion forming step, the description will be further focused on the external connection terminal portion forming step. The other steps are not particularly limited, and are the same as the steps in a general suspension board manufacturing method.

(External connection terminal part formation process)
The external connection terminal portion forming step in the present invention usually includes a laminate preparation process, a back side opening forming process, a conductor pattern forming process, a cover layer forming process, and a plating layer forming process. Hereinafter, each process will be described.

(1) Laminated body preparation process The laminated body preparation process in this invention is a process which prepares the laminated body by which the metal substrate, the insulating layer, and the conductor layer were laminated | stacked in this order. Since each member used in this process is the same as that described in “A. Suspension substrate”, description thereof is omitted here.

(2) Back-side opening forming process The back-side opening forming process in the present invention is a process for forming the back-side opening by etching the metal substrate and the insulating layer of the laminate. In the present invention, the order of the back surface side opening forming process and the conductor pattern forming process to be described later is not particularly limited, and either process may be performed first. Moreover, in this invention, you may perform a conductor pattern formation process in the middle of a back surface side opening part formation process. Specifically, the conductor layer may be etched simultaneously with the etching of the metal substrate, and then the insulating layer may be etched.

  The method for etching the metal substrate of the laminate is not particularly limited, and examples thereof include a method of forming a photosensitive resist pattern on the metal substrate and then etching with an etching solution. As a method for forming a photosensitive resist pattern, specifically, a solid photosensitive resist layer is formed by applying a photosensitive resist on a metal substrate and drying or laminating with a roll laminator. And a method of exposing and developing according to the shape of the opening on the back side. For example, when the metal substrate is stainless steel, it can be etched with an iron chloride etching solution.

  As for the method of etching the insulating layer of the laminate, a method of etching with an etchant after forming a photosensitive resist pattern can be mentioned as in the case of the metal substrate. For example, when the material of the insulating layer is a polyimide resin, the insulating layer can be etched using a polyimide-dedicated etchant. In addition, since the back side opening obtained is the same as that described in “A. Suspension substrate”, description thereof is omitted here.

(3) Conductor pattern formation process The conductor pattern formation process in this invention is a process which etches the conductor layer of a laminated body and forms a stripe-shaped conductor pattern. The method for etching the conductor layer of the multilayer body is not particularly limited, and for example, a method of etching with an etching solution after forming a photosensitive resist pattern on the conductor layer can be mentioned. For example, when the material of the conductor layer is copper, it can be etched with an iron chloride based etchant. The conductor pattern obtained is the same as that described in “A. Suspension Substrate”, and therefore the description thereof is omitted here.

(4) Cover layer forming treatment The cover layer forming treatment in the present invention is performed by covering the conductor pattern and the insulating layer with a cover layer forming material, and performing exposure and development, thereby opening the back side opening in the direction along the stripe of the conductor pattern. This is a process of forming a cover layer having a surface-side opening having a large length in the direction along the stripe of the conductor pattern as compared with the length of.

  The material for forming the cover layer is not particularly limited as long as a desired cover layer can be obtained. A photosensitive or non-photosensitive resin is used, but the process is shortened when the photosensitive resin is used. It is more preferable. For example, when the photosensitive resin is a photosensitive dry film, the cover layer is formed by laminating the photosensitive dry film on the conductor pattern and the insulating layer and performing exposure development. Further, for example, when the photosensitive resin is a photosensitive resin solution, the cover layer is formed by applying the photosensitive resin solution onto the conductor pattern and the insulating layer, drying, and performing exposure and development. Further, if necessary, the cover layer may be cured after development. In the curing process, heating is preferably performed in an atmosphere of an inert gas such as nitrogen in order to prevent oxidation of the conductor pattern. The surface-side opening obtained is the same as that described in “A. Suspension substrate”, and the description is omitted here.

(5) Plating layer formation process The plating layer formation process in this invention is a process which forms a plating layer on both surfaces of the conductor pattern exposed by the surface side opening part and a back surface side opening part. The type of plating layer, the method of forming the plating layer, and the like are the same as the contents described in the above “A. Suspension substrate”, and thus the description thereof is omitted here.

  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.

  Hereinafter, the present invention will be described more specifically with reference to examples.

[Example 1]
(Production of suspension substrate)
A laminate in which a SUS304TA (metal substrate) with a thickness of 20 μm, a polyimide layer (insulating layer) with a thickness of 10 μm, and a Cu wiring layer (conductor pattern) made of an electrolytic copper foil with a thickness of 9 μm is laminated in this order is prepared. For the suspension in which a nickel (Ni) plating layer is formed on both surfaces of the conductor pattern exposed at the front surface side opening and the back surface side opening as shown in FIG. A substrate was produced.

  As a production procedure, first, a photosensitive dry film was laminated on both surfaces of the above laminate, and both surfaces were patterned simultaneously to obtain a patterned resist. Thereafter, SUS304TA on the back surface side and the copper foil on the front surface side were etched using a ferric chloride solution, and the resist was stripped after the etching. Here, the positional accuracy of both surfaces of the SUS side and the wiring pattern layer side could be improved by simultaneously patterning the dry film.

  Next, a non-photosensitive polyimide liquid cover material is coated with a die coater, dried, and after forming a photosensitive resist pattern, the cover material is etched and the resist is peeled off, and then the cover material is cured and covered. A layer was obtained. The film thickness of the cover layer after curing was 4 μm on the wiring. By forming such a cover layer, it is possible to control warpage and reduce rigidity, and to protect the wiring pattern layer.

  Next, a 10 μm-thick polyimide layer (insulating layer) is resist-engraved, etched using an organic alkaline etchant to form a patterned insulating layer, and Cu (conductor pattern) without a plating layer is formed. A suspension substrate was obtained. Furthermore, nickel (Ni) plating layers were formed on both surfaces of Cu exposed at the front surface side opening and the back surface side opening, thereby obtaining the suspension substrate of the present invention.

In the suspension substrate described above, in the schematic cross-sectional view shown in FIG. 6E, the length of the surface side opening 5 in the direction along the stripe of the conductor pattern 3 is 0.85 mm, 1.1 mm, and 1.6 mm. The length of the back side opening 6 in the direction along the stripe of the conductor pattern 3 (hereinafter also referred to as “wiring length”) is 0.75 mm in order according to the length of the front side opening 5. Breaking strength measurement samples were prepared with three types of 00 mm and 1.50 mm, and three types of wiring width W of the conductor pattern 3 of 75 μm, 100 μm, and 125 μm. The length of A ₁ and A ₂ in the sample is 50 μm for both A ₁ and A _{2 in} both samples. Further, in the above sample, the Ni plating layer 7 has two thicknesses of 1 μm and 3 μm, and a suspension substrate having Cu (conductor pattern) on which the plating layer 7 is not formed was used as a reference. The reference suspension substrate may be referred to as “Cu only” hereinafter.

(Results of measuring the breaking strength of the suspension substrate)
Next, the breaking strength of the suspension substrate was measured using the sample. 7A and 7B are explanatory views of the intensity measurement of the sample. FIG. 7A is a schematic cross-sectional view (the top of the sample is opposite to the other drawings), and FIG. 7B is a schematic view seen from the metal substrate 1 side. It is a top view. As shown in FIG. 7, by using a breaking strength test apparatus for measuring the breaking strength of the suspension substrate, a load is applied to the conductor pattern 3 from the center of the surface-side opening portion 5 using a hook 8 in the vertical direction. The breaking strength of pattern 3 was determined, and the relative strength of each sample was compared. The results are shown in FIGS.

  9 to 14 show the breaking strength (N / mm) (vertical axis) in the case where only Cu is used, the Ni plating thickness is 1 μm, and the Ni plating thickness is 3 μm. 9 to 11 are diagrams showing Ni plating thicknesses and breaking strengths at wiring widths of 75 μm, 100 μm, and 125 μm, and show cases where the wiring lengths are 0.75 mm, 1.00 mm, and 1.50 mm. 12 to 14 are diagrams showing the Ni plating thickness and breaking strength when the wiring length is 0.75 mm, 1.00 mm, and 1.50 mm, and shows the case where the wiring width is 75 μm, 100 μm, and 125 μm.

  As shown in FIGS. 9 to 14, the breaking strength tended to increase as the Ni plating thickness increased, particularly as the wiring length was as small as 0.75 mm, as compared to the case of Cu alone. However, when the wiring length becomes as large as 1.50 mm, the effect of Ni plating is not necessarily clear.

[Comparative Example 1]
On the other hand, for comparison, as shown in FIG. 8, the front-side opening 5 and the back-side opening 6 have a cross-sectional structure of a conventional external connection terminal portion having the same length. A sample of the plated suspension substrate was prepared, and the breaking strength was measured by the above breaking strength test apparatus. The sample of this conventional suspension substrate is manufactured using the same material and manufacturing method as in the first embodiment, and the front side opening 5 and the back side opening 6 have the same length. Except for this, the configuration was the same as in Example 1.

  When the breaking strength of the sample of Comparative Example 1 was measured, none of the samples reached the breaking strength value of Example 1, and as described with reference to FIG. And the opening C between the end face of the insulating layer 2 was easily broken.

  From the above results, the suspension substrate of the present invention disperses the stress applied to the conductor pattern, and the mechanical strength of the suspension layer is changed by setting the end face of the cover layer and the end face of the insulating layer, which will be the breaking points, at different positions. It was confirmed to be excellent.

DESCRIPTION OF SYMBOLS 1 ... Metal substrate 2 ... Insulating layer 3 ... Conductor pattern 4 ... Cover layer 5 ... Front side opening 6 ... Back side opening 7 ... Plating layer 8 ... Hook

Claims (7)

A metal substrate; an insulating layer formed on the metal substrate; a striped conductor pattern formed on the insulating layer; a cover layer formed on the conductor pattern; and the cover layer formed on the cover layer A front-side opening that exposes the conductor pattern; and a back-side opening that is formed in the metal substrate and the insulating layer and exposes the conductor pattern; and further, the front-side opening and the back-side opening. Both sides of the conductor pattern are exposed, and the suspension substrate includes external connection terminal portions in which plating layers are formed on both sides of the exposed conductor pattern,
The length of the opening on the front surface side in the direction along the stripe of the conductor pattern is larger than the length of the opening on the back surface side in the direction along the stripe of the conductor pattern, and the cover layer and the insulating layer are A suspension substrate comprising a step shape in a cross section in a direction along a stripe of the conductor pattern. The difference between the length of the opening on the front surface side in the direction along the stripe of the conductor pattern and the length of the opening on the back surface side in the direction along the stripe of the conductor pattern is A,
When the lengths of the portions where both ends of the exposed conductor pattern in the direction along the stripe of the conductor pattern are in contact with the insulating layer in the surface side opening are A ₁ and A ₂ , respectively. ,
_2. The suspension substrate according to claim 1, wherein A = A ₁ + A ₂ , and both A ₁ and A ₂ are longer than the thickness of the conductor pattern. Suspension substrate of claim 2, wherein the length of A ₁ and A _2, characterized in that both the length of the range of 5Myuemu～180myuemu. In the opening on the back side, the length of the opening formed by the metal substrate in the direction along the stripe of the conductor pattern is the length of the opening formed by the insulating layer in the direction along the stripe of the conductor pattern. Bigger than
The difference between the length of the opening formed by the metal substrate and the length of the opening formed by the insulating layer is B,
When the lengths of the protruding portions of the insulating layer protruding in parallel to the end surface of the metal substrate from the end surface of the metal substrate toward the back surface side opening are B ₁ and B ₂ , respectively.
4. The claim according to claim 1, wherein B = B ₁ + B ₂ , and both B ₁ and B ₂ are longer than the thickness of the insulating layer. The suspension substrate as described in 1. The suspension substrate according to claim 4, wherein the lengths of B ₁ and B ₂ are both in the range of ₂ μm to 200 μm. A laminate preparation process for preparing a laminate in which a metal substrate, an insulating layer, and a conductor layer are laminated in this order;
Etching the metal substrate and the insulating layer of the laminate, and forming a back side opening part to form a back side opening part,
Etching the conductor layer of the laminate, a conductor pattern forming treatment to form a stripe conductor pattern;
The conductor pattern and the insulating layer are covered with a cover layer forming material and exposed and developed, so that the length of the surface side opening in the direction along the stripe of the conductor pattern is along the stripe of the conductor pattern. A cover layer forming process for forming a cover layer having a front side opening larger than the length of the back side opening in the direction;
A plating layer forming process for forming a plating layer on both surfaces of the conductor pattern exposed at the front surface side opening and the back surface side opening,
The manufacturing method of the board | substrate for suspension characterized by having the external connection terminal part formation process which has these. In the back side opening forming process,
The length of the opening formed by etching the metal substrate is larger than the length of the opening formed by etching the insulating layer, and the insulating layer is parallel to the end surface of the metal substrate. The method of manufacturing a suspension substrate according to claim 6, wherein pattern etching is performed so as to protrude from an end surface of the metal substrate toward the portion.

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