JP2013033570A - Substrate for suspension, suspension, suspension with element, hard disk drive, and method for manufacturing substrate for suspension - Google Patents

Abstract

PROBLEM TO BE SOLVED: To mainly provide a substrate for a suspension for suppressing the occurrence of a short circuit of metal bump parts adjacent to each other.SOLUTION: The substrate for a suspension of the invention has a metal support substrate, an insulation layer formed on the metal support substrate, and a wiring layer formed on the insulation layer. In the substrate for a suspension, the wiring layer has a terminal part for performing connection to an external circuit board, and includes a metal bump part having a first side and a second side in a longitudinal direction in a planar view on the terminal part, and at least one of the first side and the second side has a non-projecting shape in which a center part does not project more than both end parts in a planar view.

Description

  The present invention relates to a suspension substrate that prevents occurrence of a short circuit between adjacent metal bump portions.

  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.

  A suspension substrate (flexure) used in an HDD is usually formed at one end portion, and is formed at an element mounting region for mounting an element such as a magnetic head slider, and at the other end portion, and is connected to an external circuit board. An external circuit board connection region for performing the above and a wiring layer for connecting the element mounting region and the external circuit board connection region.

  In addition, it is known that a metal bump portion for electrically connecting to an external circuit board is provided at the terminal portion of the wiring layer. Furthermore, some devices are known in order to prevent a short circuit between adjacent metal bump portions. For example, Patent Document 1 discloses a printed circuit board including an inter-terminal insulating layer having a groove for preventing the flow of conductive particles between adjacent terminal portions.

  Patent Document 2 discloses a printed circuit board in which a recessed portion for receiving molten metal is formed integrally with a conductor pattern in a terminal portion. Note that Patent Document 3 discloses providing a notch in a terminal portion as a solder joint observation window.

JP 2007-115321 A JP 2006-86219 A JP 2008-300594 A

  The number of terminal portions is increasing as the function of the suspension substrate increases. Further, with the downsizing of the suspension substrate, there is a spatial restriction on the location of the terminal portion. For this reason, the pitch between adjacent terminal portions tends to be narrowed, and the possibility that a short circuit will occur between adjacent metal bump portions is increased.

  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 that prevents occurrence of a short circuit between adjacent metal bump portions.

  In order to solve the above problems, the present invention is a suspension substrate having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer formed on the insulating layer. The wiring layer has a terminal portion for connection to an external circuit board, and includes a metal bump portion having a first side and a second side in the longitudinal direction in plan view on the terminal portion. At least one of the one side and the second side has a non-protruding shape in which a central portion does not protrude from both end portions in a plan view.

  According to the present invention, since the metal bump portion has a non-projecting shape, it is possible to provide a suspension substrate in which occurrence of a short circuit between adjacent metal bump portions is prevented.

  In the above invention, the terminal portion has a third side and a fourth side in the longitudinal direction in plan view, and at least one of the third side and the fourth side has both ends at the center in plan view. Preferably, the metal bump portion has a non-projecting shape that does not protrude from the portion, and the non-projecting shape of the metal bump portion follows the non-projecting shape of the terminal portion. This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the shape of the terminal portion.

  The present invention also provides a suspension comprising the above-described suspension substrate and a load beam provided on the surface of the suspension substrate on the metal support substrate side.

  According to the present invention, by using the above-described suspension substrate, it is possible to provide a suspension that prevents the occurrence of a short circuit between adjacent metal bump portions.

  The present invention also provides an element-equipped suspension comprising the above-described suspension and an element mounted on the suspension.

  According to the present invention, by using the above-described suspension, it is possible to provide a suspension with an element that prevents occurrence of a short circuit between adjacent metal bump portions.

  Further, in the present invention, there is provided a method for manufacturing a suspension substrate comprising a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer formed on the insulating layer, A precursor member forming step of forming a precursor member of a suspension substrate for forming a wiring layer having a terminal portion for connection to the circuit board; and a first member in the longitudinal direction in plan view on the terminal portion of the precursor member. A metal bump part forming step for forming a metal bump part having a side and a second side, and at least one of the first side and the second side protrudes from the both ends in a plan view. There is provided a method of manufacturing a suspension substrate, wherein the metal bump portion is formed so as to have a non-projecting shape.

  According to the present invention, since the metal bump portion having a non-projecting shape is formed, it is possible to obtain a suspension substrate that prevents occurrence of a short circuit between adjacent metal bump portions.

  In the above invention, the terminal portion has a third side and a fourth side in the longitudinal direction in plan view, and at least one of the third side and the fourth side has both ends at the center in plan view. It is preferable to form the non-projecting shape of the metal bump portion so as to have a non-projecting shape that does not protrude from the portion and follow the non-projecting shape of the terminal portion. This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the shape of the terminal portion.

  The suspension substrate of the present invention has an effect of preventing the occurrence of a short circuit between adjacent metal bump portions.

It is a schematic diagram showing an example of a general suspension substrate. It is an enlarged view of the external circuit board connection area | region in Fig.1 (a). It is a schematic diagram which shows an example of the conventional metal bump part. It is a schematic diagram which shows an example of the metal bump part in this invention. It is a schematic plan view explaining the metal bump part in this invention. It is a schematic plan view explaining the metal bump part in this invention. It is a schematic plan view explaining the metal bump part in this invention. It is a schematic plan view explaining the metal bump part in this invention. It is a schematic plan view explaining the terminal part in this invention. It is a schematic plan view explaining the terminal part in 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 an element of this invention. It is a schematic sectional drawing which shows an example of the manufacturing method of the board | substrate for suspensions of this invention. It is a schematic sectional drawing which shows an example of the formation method of the precursor member by a subtractive method. It is a schematic sectional drawing which shows an example of the formation method of the precursor member by an additive method. It is a schematic plan view which shows the terminal part in an Example.

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

A. Suspension substrate The suspension substrate of the present invention is a suspension substrate having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer formed on the insulating layer, The wiring layer has a terminal portion for connection to an external circuit board, and includes a metal bump portion having a first side and a second side in the longitudinal direction in plan view on the terminal portion, and the first side In addition, at least one of the second sides has a non-projecting shape in which the central portion does not protrude from both end portions in plan view.

  FIG. 1 is a schematic view showing an example of a general suspension substrate. FIG. 1A is a schematic plan view of a suspension substrate, and FIG. 1B is a cross-sectional view taken along line AA in FIG. In FIG. 1A, illustration of the insulating layer and the cover layer is omitted for convenience. A suspension substrate 100 shown in FIG. 1A includes an element mounting region 101 formed at one tip portion, an external circuit board connection region 102 formed at the other tip portion, an element mounting region 101 and an external portion. And a plurality of wiring layers 103a to 103d for electrically connecting the circuit board connection region 102. The wiring layer 103a and the wiring layer 103b are a pair of wiring layers. Similarly, the wiring layer 103c and the wiring layer 103d are also a pair of wiring layers. One of these two wiring layers is a wiring layer for writing (for recording and writing), and the other is a wiring layer for reading (for reproduction and reading). On the other hand, as shown in FIG. 1B, the suspension substrate 100 includes a metal support substrate 1, an insulating layer 2 formed on the metal support substrate 1, and a wiring layer 3 formed on the insulating layer 2. And a cover layer 4 formed on the wiring layer 3.

  FIG. 2 is an enlarged view of the external circuit board connection region in FIG. As shown in FIG. 2A, the wiring layer 3 has a terminal portion 3a for connection to an external circuit board. Further, as shown in FIG. 2B, a metal bump portion 5 is formed on the terminal portion 3a.

FIG. 3A is a schematic plan view showing an example of a conventional metal bump portion, and FIG. 3B is a cross-sectional view taken along line AA of FIG. It should be noted that the height of the metal bump portion is not limited to the drawing and is actually higher than the illustrated height. As shown in FIG. 3 (a), each of the metal bump 5, a plan view, and a longitudinal first side in the direction L S ₁ and the second side S _2. The first side S ₁ and the second side S ₂ are affected by the surface tension and have a protruding shape in which the central portion protrudes from both ends in plan view. Therefore, as shown in FIG. 3B, there is a problem in that the distance X between the adjacent metal bump portions 5 becomes short in the center portion, and a short circuit is likely to occur. In addition, the higher the height of the metal bump portion, the more easily affected by the surface tension, and the central portion tends to protrude more.

FIG. 4A is a schematic plan view showing an example of the metal bump portion in the present invention, and FIG. 4B is a cross-sectional view taken along line AA in FIG. It should be noted that the height of the metal bump portion is not limited to the drawing and is actually higher than the illustrated height. As shown in FIG. 4 (a), each of the metal bump 5, a plan view, and a longitudinal first side in the direction L S ₁ and the second side S _2. Further, the first side S ₁ and the second side S ₂ have a non-projecting shape in which the central portion does not protrude from both ends in plan view. Therefore, as shown in FIG. 4B, there is an advantage that the distance X between the adjacent metal bump portions 5 can be maintained long in the central portion, and short-circuiting hardly occurs.

  Thus, according to the present invention, since the metal bump portion has a non-projecting shape, it is possible to provide a suspension substrate in which occurrence of a short circuit between adjacent metal bump portions is prevented. Further, the suspension substrate of the present invention has an advantage that it is possible to prevent occurrence of a short circuit even when the terminal pitch is narrowed to such an extent that the influence of surface tension cannot be ignored. In addition, according to the present invention, since the suspension substrate has the metal bump portion (precoated), there is an advantage that the connection reliability with the external circuit substrate is high.

  Here, Patent Document 1 discloses a printed circuit board including an inter-terminal insulating layer having a predetermined groove between adjacent terminal portions. However, the provision of the inter-terminal insulating layer itself hinders the downsizing of the suspension substrate. Further, in Patent Document 1, when the conductive particles trapped in the groove are solder, when the heat treatment for forming the metal bump portion is performed, the trapped conductive particles are melt-connected to each other, thereby causing a short circuit. There is also the possibility of triggering.

  Patent Document 2 discloses a printed circuit board in which a recessed portion for receiving molten metal is formed integrally with a conductor pattern in a terminal portion. Patent Document 2 has a problem that it is difficult to reduce the size of the terminal portion, although it may have a certain effect in preventing the occurrence of a solder bridge when melting the solder ball. Furthermore, when forming a metal bump part by melting a paste containing solder fine particles having a particle diameter smaller than that of the solder ball, it is difficult to prevent the occurrence of solder bridges.

Patent Document 3 discloses providing a notch in a terminal portion as a solder joint observation window. On the other hand, the terminal part in this invention may have a notch so that it may mention later. However, the notch in Patent Document 3 is merely an observation window for determining whether or not the solder joint is appropriate. Further, among the notches illustrated in Patent Document 3, for example, as shown in FIGS. 14 to 16, there is a notch formed in the center portion of the terminal portion, but its size is small, and the center portion due to surface tension is small. It is difficult to form a non-projecting shape by suppressing the bulge. In Patent Document 3, as shown in FIG. 11, solder bumps are formed on the FPC board (external circuit board) side, and in the terminal portion of the suspension board as in the present invention, adjacent metal bumps are formed. It does not prevent the occurrence of short circuit.
Hereinafter, the suspension substrate of the present invention will be described separately for the suspension substrate member and the suspension substrate configuration.

1. First, members of the suspension substrate of the present invention will be described. The suspension substrate of the present invention has at least a metal support substrate, an insulating layer, a wiring layer, and a metal bump portion.

  The metal support substrate in the present invention functions as a support for the suspension substrate. The material of the metal support substrate is preferably a metal having a spring property, and specific examples include stainless steel. Moreover, although the thickness of a metal support substrate changes with kinds of the material, it is preferable to exist in the range of 5 micrometers-40 micrometers, for example, and it is more preferable that it is in the range of 10 micrometers-20 micrometers.

  The insulating layer in the present invention is formed on a metal support substrate. The material of the insulating layer is not particularly limited as long as it has insulating properties, and examples thereof include a resin. Examples of the resin include polyimide resin, polybenzoxazole resin, polybenzimidazole resin, acrylic resin, polyether nitrile resin, polyether sulfone resin, polyethylene terephthalate resin, polyethylene naphthalate resin, and polyvinyl chloride resin. Of these, polyimide resin is preferred. It is because it is excellent in insulation, heat resistance and chemical resistance. In addition, the material of the insulating layer may be a photosensitive material or a non-photosensitive material. The thickness of the insulating layer is, for example, preferably in the range of 5 μm to 30 μm, more preferably in the range of 5 μm to 18 μm, and still more preferably in the range of 5 μm to 12 μm.

  The wiring layer in the present invention is formed on the insulating layer. The material of the wiring layer is not particularly limited as long as it has conductivity, and examples thereof include metals such as copper (Cu) and nickel (Ni), and copper is preferable. Moreover, the material of the wiring layer may be rolled copper or electrolytic copper. The thickness of the wiring layer is preferably in the range of 5 μm to 18 μm, for example, and more preferably in the range of 9 μm to 12 μm.

  The wiring layer in the present invention usually has a write wiring layer and a read wiring layer connected to an element (for example, a magnetic head slider). In addition, the above wiring layers are, as necessary, heat assist wiring layers, noise shield wiring layers, crosstalk prevention wiring layers, power supply wiring layers, ground wiring layers, flight height control wiring layers, and sensors. A wiring layer or the like may be provided.

  Moreover, it is preferable that the protective plating part is formed in the one part surface of a wiring layer. This is because by providing the protective plating portion, the deterioration (corrosion and the like) of the wiring layer can be prevented. In particular, in the present invention, it is preferable that a protective plating portion is formed in a terminal portion that is connected to an element or an external circuit board. Although the kind of protective plating part is not specifically limited, For example, Au plating, Ni plating, Ag plating, Cu plating etc. can be mentioned. Especially, in this invention, it is preferable that Ni plating and Au plating are formed from the surface side of the wiring layer. The thickness of the protective plating portion is, for example, in the range of 0.1 μm to 4 μm.

  The metal bump part in this invention is formed on the terminal part of a wiring layer. The material of the metal bump portion is not particularly limited, but an alloy can be mentioned, and among them, solder is preferable. In general, solder can be roughly classified into lead-containing solder and lead-free solder. The lead-containing solder is usually solder containing lead (Pb) and tin (Sn) as main components. The lead-free solder is usually solder that does not contain lead (Pb) and contains tin (Sn) as a main component. Among these, in the present invention, it is preferable to use lead-free solder. This is because the load on the environment can be reduced. Specific examples of lead-free solder include Sn—Sb, Sn—Cu, Sn—Cu—Ni, Sn—Ag, Sn—Ag—Cu, Sn—Ag—Cu—Bi, Sn -Zn-based, Sn-Ag-In-Bi-based, Sn-Zn-based, Sn-Bi-based, Sn-In-based, Sn-Sb-based solder, and the like. Specific examples of the lead-containing solder include Sn—Pb, Sn—Ag—Pb, Sn—Pb—Bi, Sn—Sb—Pb, Sn—Ag—Sb—Pb, and the like. be able to.

  The cover layer in the present invention is formed on the wiring layer. By providing the cover layer, deterioration (corrosion etc.) of the wiring layer can be prevented. Examples of the material for the cover layer include those described above as the material for the insulating layer, and among them, a polyimide resin is preferable. The material of the cover layer may be a photosensitive material or a non-photosensitive material. The thickness of the cover layer is preferably in the range of 2 μm to 30 μm, for example, and more preferably in the range of 2 μm to 10 μm.

2. Next, the configuration of the suspension substrate of the present invention will be described. The suspension substrate of the present invention includes a metal bump portion having a first side and a second side in the longitudinal direction in plan view on a terminal portion, and at least one of the first side and the second side is a plane. From the viewpoint of visual characteristics, the central portion has a non-projecting shape that does not protrude from both end portions.

In the present invention, the “both end portions” of the first side or the second side refer to regions including both ends in the longitudinal direction, and specifically, as shown in FIG. 5, the metal bump portion 5 along the longitudinal direction. refers to a region R ₂ from both ends to the position where the 30% of the total length, respectively. On the other hand, the “central portion” of the first side or the second side refers to a region R ₁ inside the region R ₂ . Further, “the central portion does not protrude from both ends in plan view” means that the central portion does not protrude outward with respect to a straight line connecting both ends in plan view. Specifically, as shown in FIG. 6 (a), assume that P ₁ in one end portion, a straight line connecting the P ₂ at the other end. At this time, P ₁ and P ₂ are set so as to be tangent to both ends. If the central portion does not protrude outward in plan view with respect to this straight line, the shape of the metal bump portion can be said to be a non-protruding shape. 6A, the straight line connecting both ends is parallel to the longitudinal direction of the metal bump portion 5. However, as shown in FIG. 6B, the straight line connecting both ends is the longitudinal length of the metal bump portion 5. It does not have to be parallel to the direction. Moreover, as shown in FIG.6 (c), the straight line which connects both ends, and the 1st edge | side or 2nd edge | side of the metal bump part 5 may correspond. In particular, in the present invention, as shown in FIGS. 6 (a) and 6 (b), it is preferable to have a shape in which the central portion is recessed inward with respect to a straight line connecting both ends in plan view. This is because the shape control of the metal bump portion is easy.

FIG. 7 is a schematic plan view for explaining a metal bump portion in the present invention. As shown in FIG. 7, the metal bump portions 5 in the present invention are usually arranged so that the metal bump portions 5 face each other in the longitudinal direction. Here, the length in the longitudinal direction of the metal bump portion 5 is L ₁ , the length in the short direction of the metal bump portion 5 is L ₂ , the shortest distance in the short direction of the adjacent metal bump portions 5 is L ₃ , and adjacent. the longest distance to L ₄ in the widthwise direction of the metal bump 5 fit.

L ₁ is preferably in the range of 400 μm to 800 μm, for example, and more preferably in the range of 500 μm to 700 μm. In the L ₁ is too small, there is a possibility that the contact area between the terminal portions of the external circuit board becomes insufficient, when L ₁ is too large, since size reduction of the metal bumps may become difficult is there. L ₂ is preferably in the range of 100 μm to 400 μm, for example, and more preferably in the range of 200 μm to 300 μm. If L ₂ is too small, it is likely to be affected by surface tension, and it may be difficult to obtain a non-projecting shape. If L ₂ is too large, it may be difficult to reduce the size of the metal bump portion. Because there is. L ₃ is preferably in the range of 100 μm to 400 μm, for example, and more preferably in the range of 200 μm to 300 μm. When L ₃ is too small, there is a possibility that short circuit between the metal bump portion adjacent occurs when L ₃ is too large, because a narrow pitch between the terminal portions adjacent may become difficult It is. Although not shown, the height of the metal bump portion formed on the surface of the terminal portion is preferably 120 μm or more, more preferably in the range of 140 μm to 240 μm, and in the range of 170 μm to 210 μm. More preferably. In addition, since the short of an adjacent metal bump part becomes easy to generate | occur | produce as the height of a metal bump part becomes high, the effect of a non-protruding shape is exhibited more.

In the present invention, it is only necessary that at least one of the first side and the second side located in the longitudinal direction of the metal bump portion has a non-projecting shape. Therefore, as shown in FIG. 4 (a), both the first side S ₁ and the second side S ₂ is may have a non-protruding shape, as shown in FIG. 8 (a), first only one of the sides S ₁ and the second side S ₂ may have a non-protruding shape. Incidentally, as shown in FIG. 8 (b), a central portion only one of the first side S ₁ and the second side S ₂ even have a non-protruding shape, which protrudes under the influence of surface tension, Since the center part which is dented in the non-projecting shape is opposed, it is possible to prevent occurrence of a short circuit between adjacent metal bump parts.

  Further, in the present invention, the terminal portion has a third side and a fourth side in the longitudinal direction in plan view, and at least one of the third side and the fourth side has both ends at the center portion in plan view. It is preferable that the metal bump portion has a non-protruding shape that does not protrude further, and that the non-protruding shape of the metal bump portion follows the non-protruding shape of the terminal portion. This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the shape of the terminal portion.

In the present invention, the “both ends” of the third side or the fourth side refers to a region including both ends in the longitudinal direction, and specifically, as shown in FIG. The region R ₄ from the both ends of the part 3a to a position that is 30% of the total length. On the other hand, the “central portion” of the third surface or the fourth surface refers to a region R ₃ inside the region R ₄ . Further, “the central portion does not protrude from both ends in plan view” means that the central portion does not protrude outward with respect to a straight line connecting both ends in plan view. Since this definition is the same as in the case of the metal bump portion described above, description thereof is omitted here. In addition, “the non-projecting shape of the metal bump portion is formed so as to follow the non-projecting shape of the terminal portion” means that the planar view shape of the metal bump portion is relative to the planar view shape of the terminal portion. Say that it is almost similar.

  9A to 9D, each has a shape in which the central portion is recessed inward with respect to a straight line connecting both end portions. When the portion formed by the central portion being recessed inward is a cutout portion, the cutout portion is rectangular in FIG. 9A, the cutout portion is trapezoidal in FIG. 9B, and FIG. Then, the notch is a triangle. Moreover, in FIG. 9 (a)-(c), although comprised from the notch part, as shown in FIG.9 (d), the notch part may have a curve in this invention.

  In the present invention, a pattern composed of a lyophilic portion and a lyophobic portion is formed on the surface of the terminal portion, and the non-projecting shape of the metal bump portion is formed so as to follow the pattern. Is preferred. This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the difference in wettability. In each of FIGS. 10A to 10D, a pattern including the lyophilic portion 6a and the lyophobic portion 6b is formed. In addition, the shape of the lyophilic portion 6a in FIGS. 10A to 10D is the same as the shape of the terminal portion 3a in FIGS. 9A to 9D. The pattern is preferably formed by plating. This is because deterioration (corrosion or the like) of the terminal portion can be prevented while forming a desired pattern.

B. Suspension Next, the suspension of the present invention will be described. The suspension according to the present invention includes the suspension substrate described above and a load beam provided on the surface of the suspension substrate on the metal support substrate side.

  FIG. 11 is a schematic plan view showing an example of the suspension of the present invention. A suspension 400 shown in FIG. 11 includes the above-described suspension substrate 100 and a load beam 300 provided on the surface of the suspension substrate 100 on the metal support substrate side.

  According to the present invention, by using the above-described suspension substrate, it is possible to provide a suspension that prevents the occurrence of a short circuit between adjacent metal bump portions.

  The suspension of the present invention has at least a suspension substrate and a load beam. The suspension substrate in the present invention is the same as the content described in the above “A. Suspension substrate”, and therefore description thereof is omitted here. On the other hand, the load beam in the present invention is provided on the surface of the suspension substrate on the metal support substrate side. Although the material of the load beam is not particularly limited, for example, a metal can be used, and stainless steel is preferable.

C. Next, the suspension with an element of the present invention will be described. The suspension with an element of the present invention includes the above-described suspension and an element mounted on the suspension.

  FIG. 12 is a schematic plan view showing an example of the suspension with an element of the present invention. A suspension 500 with an element shown in FIG. 12 includes the above-described suspension 400 and an element 210 mounted on the suspension 400.

  According to the present invention, by using the above-described suspension, it is possible to provide a suspension with an element that prevents occurrence of a short circuit between adjacent metal bump portions.

  The suspension with an element of the present invention includes at least a suspension and an element. The suspension according to the present invention is the same as the content described in “B. Suspension” above, and thus the description thereof is omitted here. Examples of the element in the present invention include a magnetic head slider, an actuator, and a semiconductor. The actuator may have a magnetic head or may not have a magnetic head. Further, the element in the present invention is preferably an element (recording / reproducing element) that performs recording / reproducing with respect to a disk, such as a magnetic head slider.

D. 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 having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer formed on the insulating layer. A precursor member forming step of forming a precursor member of a suspension substrate for forming a wiring layer having a terminal portion for connection to an external circuit board; and a plan view of the precursor member on the terminal portion of the precursor member. A metal bump part forming step of forming a metal bump part having a first side and a second side in the direction, and at least one of the first side and the second side is opposite in the center in plan view The metal bump portion is formed so as to have a non-projecting shape that does not protrude from the portion.

  FIG. 13 is a schematic cross-sectional view showing an example of a method for manufacturing a suspension substrate according to the present invention. FIG. 13 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. 3A, similar to FIG. In FIG. 13, a precursor member for a suspension substrate is prepared, and a metal bump portion forming layer 5a is formed on the terminal portion 3a (FIG. 13A). Next, the metal bump part forming layer 5a is melted and solidified to form the metal bump part 5 having a non-projecting shape (FIG. 13B).

According to the present invention, since the metal bump portion having a non-projecting shape is formed, it is possible to obtain a suspension substrate that prevents occurrence of a short circuit between adjacent metal bump portions.
Hereinafter, the manufacturing method of the suspension substrate according to the present invention will be described step by step.

1. Precursor member forming step The precursor member forming step in the present invention is a step of forming a precursor member of a suspension substrate for forming a wiring layer having a terminal portion for connection to an external circuit board.

  In addition, a precursor member means the whole member before forming a metal bump part. Therefore, the precursor member is not particularly limited as long as it includes a wiring layer having a terminal portion. In addition, the precursor member is preferably a suspension substrate before forming the metal bump portion. The suspension substrate before forming the metal bump portion can be obtained by, for example, a subtractive method or an additive method.

(1) Subtractive method As a specific example of the method of forming the precursor member by the subtractive method, a metal support member, an insulating member formed on the metal support member, and a conductor member formed on the insulating member; A laminated member preparing step of preparing a laminated member having a wiring layer; a wiring layer forming step of forming a wiring layer having a terminal portion for etching the conductive member of the laminated member and connecting to an external circuit substrate; and the insulating member And forming a metal support substrate by etching the metal support member and forming a metal support substrate.

  FIG. 14 is a schematic cross-sectional view showing an example of a method for forming a precursor member by a subtractive method. 14 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. 1A, similarly to FIG. In FIG. 14, first, a laminated member in which the metal supporting member 1X, the insulating member 2X, and the conductor member 3X are laminated in this order is prepared (FIG. 14A). Next, the conductive member 3X is patterned by wet etching to form the wiring layer 3 (FIG. 14B). At this time, wet etching may be performed on the metal support member 1X to form a jig hole. Next, the cover layer 4 is formed so as to cover the wiring layer 3 (FIG. 14C). Next, the insulating member 2X is patterned by wet etching to form the insulating layer 2 (FIG. 14D). Next, although not shown, a protective plating portion is formed on the terminal portion of the wiring layer. Finally, the outer shape of the metal support member 1X is processed to form the metal support substrate 1 (FIG. 14 (e)). Thereby, a suspension substrate (precursor member) before forming the metal bump portion is obtained.

(I) Laminated member preparation step The laminated member preparation step is a step of preparing a laminated member having a metal supporting member, an insulating member formed on the metal supporting member, and a conductor member formed on the insulating member. It is.

  In the subtractive method, a metal supporting board is obtained by etching the metal supporting member of the laminated member, an insulating layer is obtained by etching the insulating member of the laminated member, and the conductive member of the laminated body is etched. A wiring layer is obtained. The laminated member may be a commercially available three-layer material, or may be obtained by sequentially forming an insulating member and a conductor member on a metal support member.

(Ii) Wiring layer forming step The wiring layer forming step is a step of etching the conductor member of the laminated member to form a wiring layer having a terminal portion for connection to an external circuit board.

  Examples of the method for forming the wiring layer include a method in which a resist pattern is formed on a conductive member of a laminated member using a dry film resist (DFR) or the like, and the conductive member exposed from the resist pattern is wet-etched. Can do. The type of etching solution used for wet etching is preferably selected as appropriate according to the type of conductor member. For example, when the material of the conductor member is Cu, an iron chloride-based etching solution or the like can be used.

  Moreover, you may etch a metal supporting member simultaneously with the etching of a conductor member. Examples of the etching of the metal support member include etching for forming openings and jig holes. Further, if necessary, at least a part of the processing performed in the metal support substrate forming step described later may be performed simultaneously with the etching of the conductor member.

(Iii) Cover layer forming step The cover layer forming step is a step of forming a cover layer on the wiring layer.

  The method for forming the cover layer is not particularly limited, and is preferably selected as appropriate according to the material of the cover layer. For example, when the material of the cover layer is a photosensitive material, a patterned cover layer can be obtained by exposing and developing the cover layer formed on the entire surface. In addition, when the cover layer material is a non-photosensitive material, a predetermined resist pattern is formed on the entire surface of the cover layer, and a portion exposed from the resist pattern is removed by wet etching. The cover layer can be obtained.

(Iv) Insulating layer forming step The insulating layer forming step is a step of etching the insulating member to form an insulating layer.

  Examples of the method for forming the insulating layer include a method of forming a resist pattern on the insulating member using a dry film resist (DFR) or the like, and wet etching the insulating member exposed from the resist pattern. . The type of etchant used for wet etching is preferably selected as appropriate according to the type of insulating member. For example, when the material of the insulating member is a polyimide resin, an alkaline etchant or the like can be used.

(V) Protection plating part formation process A protection plating part formation process is a process of forming a protection plating part on the surface of the above-mentioned terminal part. Examples of the method for forming the protective plating portion include an electrolytic plating method and an electroless plating method, and the electrolytic plating method is preferable.

(Vi) Metal Support Substrate Formation Step The metal support substrate formation step is a step of etching the metal support member to form a metal support substrate. In this step, the outer shape of the metal support substrate is usually processed.

  Although the method for etching the metal support member is not particularly limited, specific examples include wet etching. The type of etchant used for wet etching is preferably selected as appropriate according to the type of metal support member. For example, when the material of the metal support member is stainless steel, an iron chloride-based etchant or the like can be used. .

(2) Additive method As a specific example of the forming method of the precursor member by the additive method, a metal support member preparation step of preparing a metal support member, an insulating layer formation step of forming an insulating layer on the metal support member, A wiring layer forming step of forming a wiring layer having a terminal portion for connection to an external circuit board on the insulating layer, a cover layer forming step of forming a cover layer on the wiring layer, and the metal support member And a metal support substrate forming step of forming a metal support substrate by etching.

  FIG. 15 is a schematic cross-sectional view showing an example of a method for forming a precursor member by an additive method. 15 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. 1A, as in FIG. In FIG. 15, first, a metal support member 1X is prepared (FIG. 15 (a)). Next, the patterned insulating layer 2 is formed on the surface of the metal support member 1X (FIG. 15B). Next, the wiring layer 3 is formed on the surface on the insulating layer 2 side (FIG. 15C). Next, the cover layer 4 is formed so as to cover the wiring layer 3 (FIG. 15D). Next, although not shown, a protective plating portion is formed on the terminal portion of the wiring layer. Finally, the outer shape of the metal support member 1X is processed to form the metal support substrate 1 (FIG. 15E). Thereby, a suspension substrate (precursor member) before forming the metal bump portion is obtained.

(I) Metal support member preparation process A metal support member preparation process is a process of preparing a metal support member. For example, a commercially available metal support member can be used as the metal support member.

(Ii) Insulating layer forming step The insulating layer forming step is a step of forming an insulating layer on the metal support member.

  The method for forming the insulating layer is not particularly limited, and it is preferable to select appropriately according to the material of the insulating layer. For example, when the material of the insulating layer is a photosensitive material, a patterned insulating layer can be obtained by exposing and developing the insulating layer formed on the entire surface. In addition, when the material of the insulating layer is a non-photosensitive material, a predetermined resist pattern is formed on the surface of the insulating layer formed on the entire surface, and a portion exposed from the resist pattern is removed by wet etching to form a pattern. Insulating layer can be obtained.

(Iii) Wiring layer forming step The wiring layer forming step is a step of forming a wiring layer having a terminal portion for connection to an external circuit board on the insulating layer. Examples of the method for forming the wiring layer include an electrolytic plating method. When the electrolytic plating method is used, it is preferable to form a seed layer on the surface of the insulating layer by sputtering or the like before forming the wiring layer.

(Iv) Other steps Since the other steps are the same as those in the subtractive method, description thereof is omitted here.

2. Metal bump part formation process Next, the metal bump part formation process in this invention is demonstrated. The metal bump portion forming step in the present invention is a step of forming a metal bump portion having a first side and a second side in the longitudinal direction in plan view on the terminal portion of the precursor member.

  In the present invention, the metal bump portion is formed so that at least one of the first side and the second side has a non-projecting shape in which the central portion does not protrude from both end portions in plan view. The non-protruding shape of the metal bump portion is the same as the content described in the above “A. Suspension substrate”, and the description is omitted here.

  The method for forming the metal bump portion is not particularly limited as long as it can obtain a desired metal bump portion. For example, as shown in FIG. 13, the metal plate portion is formed on the terminal portion 3a. A method of forming the metal bump portion 5 by forming the forming layer 5a and melting and solidifying the metal plate portion forming layer 5a can be exemplified. Examples of the material for the metal bump portion forming layer include a metal-containing paste. The metal-containing paste contains at least a metal (for example, solder), and may further contain an additive such as a flux. In addition, the method for forming the metal bump portion forming layer is not particularly limited, and examples thereof include a general printing method such as screen printing.

  Further, in the present invention, the terminal portion has a third side and a fourth side in the longitudinal direction in plan view, and at least one of the third side and the fourth side has both ends at the center portion in plan view. It is preferable to form the non-projecting shape of the metal bump portion so as to have a non-projecting shape that does not protrude more and to follow the non-projecting shape of the terminal portion. This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the shape of the terminal portion. In the present invention, it is preferable that a pattern composed of a lyophilic part and a lyophobic part is formed on the surface of the terminal part, and the non-projecting shape of the metal bump part is formed so as to follow the pattern. . This is because a desired non-projecting shape can be imparted to the metal bump portion by utilizing the difference in wettability. Since these matters are the same as those described in “A. Suspension substrate”, 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.

[Condition 1]
A metal bump part (solder bump part) was formed on the terminal part having the notch and the terminal part not having the notch, and the solder bridge occurrence rate was determined. As shown in FIG. 16A, the terminal portion having the notch has a length L ₁ in the longitudinal direction = 0.500 mm, a length in the short direction 0.150 mm, a pitch L ₃ = 0.370 mm, The length from the end to the notch was L ₄ = L ₁ × 20% mm, and the notch depth L _{5 was} 0.02 mm. On the other hand, as shown in FIG. 16B, the terminal portion having no notch has a length L ₁ in the longitudinal direction = 0.500 mm, a length in the short direction 0.150 mm, and a pitch L ₃ = 0.370 mm. did.

The solder height was calculated by the following formula.
Solder height = Solder paste printing volume / terminal area x correction value <terminal without notch>
In the above terminal area, various solder mask openings were provided, and the presence or absence of the bridge was confirmed by a test. In addition, the solder paste printing volume at which no solder bridge was generated was obtained.
<Terminal with notch>
From the solder paste printing volume obtained above and the notched terminal area, the solder height at which no bridge is generated was estimated.

[Conditions 2-6]
The occurrence of solder bridges was confirmed in the same manner as in Condition 1 except that the dimensions and pitch of the terminal portions were changed to the contents shown in Table 1.

  Under Condition 1, even when the solder height was 200 μm, a metal bump portion having a non-projecting shape was obtained, and no solder bridge was generated. Under conditions 2 and 3, when the solder height was 200 μm, a metal bump portion having a non-projecting shape was not obtained, and it was confirmed that a solder bridge was generated. Under conditions 4 and 5, when the solder height was 190 μm, a metal bump portion having a non-projecting shape was not obtained, and it was confirmed that a solder bridge was generated. Under Condition 6, when the solder height was 170 μm, a metal bump portion having a non-projecting shape was not obtained, and it was confirmed that a solder bridge was generated.

  DESCRIPTION OF SYMBOLS 1 ... Metal support board | substrate, 2 ... Insulating layer, 3 ... Wiring layer, 3a ... Terminal part, 4 ... Cover layer, 5 ... Metal bump part, 6a ... Lipophilic part, 6b ... Lipophilic part, 100 ... Suspension board, 101 ... Element mounting area, 102 ... External circuit board connection area, 103 ... Wiring layer

Claims (6)

A suspension substrate having a metal support substrate, an insulating layer formed on the metal support substrate, and a wiring layer formed on the insulating layer,
The wiring layer has a terminal portion for connection with an external circuit board,
On the terminal portion, in plan view, provided with a metal bump portion having a first side and a second side in the longitudinal direction,
A suspension substrate, wherein at least one of the first side and the second side has a non-projecting shape in which a central portion does not project from both ends in plan view. The terminal portion has a third side and a fourth side in the longitudinal direction in plan view,
At least one of the third surface and the fourth surface has a non-protruding shape in which the central portion does not protrude from both end portions in plan view,
The suspension board according to claim 1, wherein the non-projecting shape of the metal bump portion is formed so as to follow the non-projecting shape of the terminal portion.   A suspension board comprising: the suspension substrate according to claim 1; and a load beam provided on a surface of the suspension substrate on the metal support substrate side.   A suspension with an element, comprising: the suspension according to claim 3; and an element mounted on the suspension. A method for manufacturing a suspension substrate, comprising: a metal support substrate; an insulating layer formed on the metal support substrate; and a wiring layer formed on the insulating layer.
A precursor member forming step of forming a precursor member of a suspension substrate for forming a wiring layer having a terminal portion for connection to an external circuit board;
On the terminal portion of the precursor member, a metal bump portion forming step of forming a metal bump portion having a first side and a second side in the longitudinal direction in plan view,
The suspension substrate, wherein the metal bump portion is formed such that at least one of the first side and the second side has a non-projecting shape in which a central portion does not protrude from both end portions in plan view. Manufacturing method. The terminal portion has a third side and a fourth side in the longitudinal direction in plan view,
At least one of the third side and the fourth side has a non-projecting shape in which the central part does not project from both ends in plan view,
The suspension board manufacturing method according to claim 5, wherein the non-projecting shape of the metal bump portion is formed so as to follow the non-projecting shape of the terminal portion.

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