Wiring circuit board

Abstract

The invention provides a wired circuit board. A suspension board (1) with a circuit is provided with: a first pattern (141) having a first terminal (141A) electrically connected to one end of a piezoelectric element (Pz1); a second pattern (142) having a second terminal (1421A) electrically connected to the other end of the piezoelectric element (Pz1); and a third pattern (143) connected in parallel to a series circuit comprising the first pattern (141), the second pattern (142), and the piezoelectric element (Pz1) in a state where the piezoelectric element (Pz1) is mounted on the suspension board (1) with the circuit. The length of the wiring (143A) of the third pattern (143) is longer than the length of the wiring (1423A) of the second pattern (142).

Description

Technical Field

[0001] The present invention relates to a wiring circuit substrate. Background Art

[0002] Conventionally, as an example of a wired circuit board, a suspension board with circuit on which a slider and a piezoelectric element can be mounted is known (for example, refer to Patent Document 1).

[0003] The suspension substrate with circuit includes a first element connection terminal connected to one end of the piezoelectric element and a second element connection terminal connected to the other end of the piezoelectric element. The first element connection terminal is grounded to a metal supporting layer of the suspension substrate with circuit. The second element connection terminal is connected to an external connection terminal via a power supply wiring.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-117674 Summary of the invention

[0007] Problem that the invention aims to solve

[0008] In the suspension board with circuit described in Patent Document 1, the piezoelectric element may be electrically polarized.

[0009] If a voltage is applied to the piezoelectric element while the piezoelectric element is electrically polarized, the expansion and contraction of the piezoelectric element may become excessively large or excessively small.

[0010] An object of the present invention is to provide a printed circuit board capable of more accurately controlling the expansion and contraction of a piezoelectric element.

[0011] Solutions for solving problems

[0012] The present invention [1] is a wiring circuit substrate, which is a wiring circuit substrate capable of mounting a piezoelectric element, wherein the wiring circuit substrate comprises: a first pattern having a first terminal electrically connected to one end of the piezoelectric element; a second pattern having a second terminal electrically connected to the other end of the piezoelectric element and a wiring connected to the second terminal, the second pattern being configured in a manner separate from the first pattern; and a third pattern having a wiring, the wiring being connected in parallel with a series circuit consisting of the first pattern, the second pattern and the piezoelectric element when the piezoelectric element is mounted on the wiring circuit substrate, the length of the wiring of the third pattern being longer than the length of the wiring of the second pattern.

[0013] According to such a configuration, in a state where the piezoelectric element is mounted on the printed circuit board, a parallel circuit is formed in which the third pattern is connected in parallel with the series circuit constituted by the first pattern, the piezoelectric element, and the second pattern.

[0014] Therefore, when the piezoelectric element is polarized, the charges in the piezoelectric element that are shifted due to the polarization can be released to the third pattern without applying a voltage to the piezoelectric element, thereby eliminating the polarization of the piezoelectric element.

[0015] In addition, the length of the wiring of the third pattern is longer than the length of the wiring of the second pattern.

[0016] Therefore, when a voltage is applied to the piezoelectric element, the wiring of the third pattern functions as a resistor, and the voltage can be accurately applied to the piezoelectric element.

[0017] As a result, the expansion and contraction of the piezoelectric element can be controlled more accurately.

[0018] The present invention [2] is the wired circuit board of the above-mentioned [1], wherein the length of the wiring of the third pattern is at least twice the length of the wiring of the second pattern.

[0019] According to such a configuration, the resistance value of the wiring of the third pattern can be increased relative to the resistance value of the wiring of the second pattern.

[0020] The present invention [3] is the wired circuit board of [1] or [2] above, wherein the thickness of the wires in the third pattern is thinner than the thickness of the wires in the second pattern.

[0021] According to such a configuration, the resistance value of the wiring of the third pattern can be increased relative to the resistance value of the wiring of the second pattern.

[0022] The present invention [4] is based on any one of the wiring circuit substrates [1] to [3] above, wherein the first pattern and the second pattern are made of copper, and the third pattern is made of a conductor or semiconductor containing at least one metal selected from the group consisting of chromium, nickel, titanium, tin, molybdenum, and palladium.

[0023] According to such a configuration, the resistance value of the wiring of the third pattern can be increased relative to the resistance value of the wiring of the second pattern.

[0024] The present invention [5] is based on any one of the wiring circuit substrates [1] to [4] above, and the wiring circuit substrate also has: a metal supporting layer; and a first insulating layer, which is arranged on the metal supporting layer and has through holes, and the first pattern and the third pattern are electrically connected to the metal supporting layer via the through holes of the first insulating layer.

[0025] According to such a structure, the first pattern and the third pattern are grounded to the metal supporting layer.

[0026] Therefore, even when there is little space for providing the third pattern, the above-mentioned parallel circuit can be formed using the metal supporting layer.

[0027] The present invention [6] is based on any one of the wiring circuit substrates [1] to [5] above, wherein the wiring circuit substrate further comprises: a metal supporting layer; and a first insulating layer, which is arranged on the metal supporting layer, and the second pattern and the third pattern are arranged on the first insulating layer.

[0028] The present invention [7] is based on any one of the wiring circuit substrates [1] to [5] above, and the wiring circuit substrate also has: a metal supporting layer; a first insulating layer, which is arranged on the metal supporting layer; and a second insulating layer, which is arranged on the first insulating layer, the third pattern is arranged on the first insulating layer and covered by the second insulating layer, and the second pattern is arranged on the second insulating layer.

[0029] The present invention [8] is based on any one of the wiring circuit substrates [1] to [5] above, and the wiring circuit substrate also has: a metal supporting layer; a first insulating layer, which is arranged on the metal supporting layer; and a second insulating layer, which is arranged on the first insulating layer, the second pattern is arranged on the first insulating layer and covered by the second insulating layer, and the third pattern is arranged on the second insulating layer.

[0030] Effects of the Invention

[0031] The wired circuit board of the present invention can more accurately control the expansion and contraction of the piezoelectric element. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a plan view showing a suspension board with circuit as one embodiment of the wired circuit board of the present invention.

[0033] Figure 2A yes Figure 1 AA cross-sectional view of the suspension board with circuit shown. Figure 2B yes Figure 1 A BB cross-sectional view of the suspension board with circuit shown. Figure 2C yes Figure 1 CC cross-sectional view of the suspension substrate with circuit shown.

[0034] Figure 3 Is Figure 1 A circuit diagram of a parallel circuit consisting of the first pattern, the piezoelectric element, the second pattern, and the third pattern shown.

[0035] Figure 4A to Figure 4D The present invention is a process diagram showing a manufacturing process of a suspension board with circuit. Figure 4A shows a first step of forming a first insulating layer on a metal supporting layer, Figure 4B represents a second step of forming a third pattern on the first insulating layer, Figure 4C represents a third step of forming a second insulating layer on the first insulating layer, Figure 4D A fourth step of forming the first pattern and the second pattern on the second insulating layer is shown.

[0036] Figure 5 It is a top view of a suspension board with circuit showing a modified example (2).

[0037] Figure 6 yes Figure 5 DD cross-sectional view of the suspension board with circuit shown.

[0038] Figure 7 Is Figure 5 A circuit diagram of a parallel circuit consisting of the first pattern, the piezoelectric element, the second pattern, and the third pattern shown.

[0039] Fig. 8A and Figure 8B This is a cross-sectional view of a suspension board with circuit according to a modification (3). Fig. 8A It is equivalent to Figure 1 The cross-sectional view of line AA, Figure 8B It is equivalent to Figure 1 Cross-sectional view of line BB.

[0040] Fig.9A and Fig. 9B This is a cross-sectional view of a suspension substrate with circuit according to a modification (4). Fig.9A It is equivalent to Figure 1 The cross-sectional view of line AA, Fig. 9B It is equivalent to Figure 1 Cross-sectional view of line BB.

[0041] Description of Reference Numerals

[0042] 1. A suspension substrate with a circuit (an example of a wiring circuit substrate); 11. A metal supporting layer; 12. A first insulating layer; 12A. A through hole; 13. A second insulating layer; 141. A first pattern; 141A. A first terminal; 142. A second pattern; 1421A. A second terminal; 1423A. Wiring; Pz1. A piezoelectric element. DETAILED DESCRIPTION

[0043] 1. Wiring circuit board

[0044] Reference Figure 1 to Figure 3, a suspension board with circuit 1 as an example of a wired circuit board will be described.

[0045] The suspension board with circuit 1 is a component constituting a head gimbal assembly of a hard disk drive.

[0046] like Figure 1 As shown, the suspension board with circuit 1 can carry a slider S and two piezoelectric elements Pz1 and Pz2. The slider S has a magnetic head. The magnetic head can read data from a recording surface of a hard disk and write data to the recording surface of the hard disk.

[0047] Specifically, the suspension board with circuit 1 includes a mounting portion 2 , a wiring portion 3 , and a neck portion 4 .

[0048] The slider S is mounted on the mounting portion 2. The mounting portion 2 is located at one end of the suspension board with circuit 1. The mounting portion 2 extends in the first direction and the second direction. The first direction is parallel to the metal supporting layer 11 (see Figure 2A ) is orthogonal to the thickness direction of the mounting portion 2. The metal supporting layer 11 will be described later. The second direction is orthogonal to the first direction and the thickness direction. The shape of the mounting portion 2 is not limited. The mounting portion 2 has, for example, a substantially rectangular flat plate shape. A first terminal 141A is disposed at one end of the mounting portion 2 in the first direction. A first terminal 141B is disposed at the other end of the mounting portion 2 in the first direction. The first terminal 141A and the first terminal 141B will be described later.

[0049] The wiring portion 3 is arranged on the other side in the second direction of the mounting portion 2. The wiring portion 3 is arranged apart from the mounting portion 2. The wiring portion 3 extends in the second direction. The wiring portion 3 has a belt shape.

[0050] The neck 4 is arranged between the mounting portion 2 and the wiring portion 3 in the second direction. The neck 4 is arranged between the first terminal 141A and the first terminal 141B in the first direction. The dimension of the neck 4 in the first direction is smaller than the dimension of the mounting portion 2 in the first direction and the dimension of the wiring portion 3 in the first direction. The neck 4 extends in the second direction. One end of the neck 4 in the second direction is connected to the mounting portion 2. The other end of the neck 4 in the second direction is connected to the wiring portion 3.

[0051] like Figure 2A As shown, the suspension board with circuit 1 includes a metal supporting layer 11, a first insulating layer 12, a second insulating layer 13, and a circuit pattern 14 (see Figure 1 ), and a third insulating layer 15.

[0052] (1) Metal support layer

[0053] The metal supporting layer 11 supports the first insulating layer 12, the second insulating layer 13, the circuit pattern 14, and the third insulating layer 15. The metal supporting layer 11 is disposed on the mounting portion 2, the wiring portion 3, and the neck portion 4. The metal supporting layer 11 of the mounting portion 2 is connected to the metal supporting layer 11 of the wiring portion 3 via the metal supporting layer 11 of the neck portion 4. Examples of the material of the metal supporting layer 11 include stainless steel and copper alloys.

[0054] (2) First insulation layer

[0055] The first insulating layer 12 is formed on a portion where at least the third pattern 143 is formed. The third pattern 143 will be described later. The first insulating layer 12 is arranged on the metal supporting layer 11 in the thickness direction of the metal supporting layer 11. The first insulating layer 12 is arranged between the metal supporting layer 11 and the third pattern 143. The first insulating layer 12 insulates the third pattern 143 from the metal supporting layer 11. The first insulating layer 12 is made of resin. Examples of the resin include polyimide, maleimide, epoxy resin, polybenzoxazole, and polyester. The first insulating layer 12 is preferably made of polyimide. The first insulating layer 12 has two through holes 12A and 12B (see Figure 1 ).

[0056] (3) Second insulation layer

[0057] The second insulating layer 13 is formed on the surface where the first pattern 141 (see Figure 2B ), the second pattern 142 and the fourth pattern 144. The first pattern 141, the second pattern 142 and the fourth pattern 144 are described later. In the portion where the first insulating layer 12 is formed, the second insulating layer 13 is arranged on the first insulating layer 12 in the thickness direction. The second insulating layer 13 covers the third pattern 143. In the portion where the first insulating layer 12 is not formed, the second insulating layer 13 is arranged on the metal supporting layer 11 in the thickness direction. The second insulating layer 13 insulates the first pattern 141, the second pattern 142 and the fourth pattern from the metal supporting layer 11 and the third pattern 143. The second insulating layer 13 is made of resin. As the resin, for example, the above-mentioned resins can be cited. The second insulating layer 13 is preferably made of the same resin as the first insulating layer 12. The second insulating layer 13 has four through holes 13A, 13B, 13C, 13D (see Figure 1 ).

[0058] (4) Circuit pattern

[0059] like Figure 1 As shown, the circuit pattern 14 includes a first pattern 141 , a second pattern 142 , a third pattern 143 , and a fourth pattern 144 . In other words, the suspension board with circuit 1 includes the first pattern 141 , the second pattern 142 , the third pattern 143 , and the fourth pattern 144 .

[0060] (4-1) Pattern 1

[0061] The first pattern 141 is grounded to the metal supporting layer 11 (see Figure 2B ). Specifically, the first pattern 141 includes two first terminals 141A and 141B. In the present embodiment, the first pattern 141 is composed of the first terminals 141A and 141B.

[0062] The first terminal 141A is arranged at one end portion in the first direction of the mounting portion 2. The first terminal 141A is arranged apart from the neck portion 4 in the first direction. The first terminal 141A is arranged on the side opposite to the first terminal 141B with respect to the neck portion 4 in the first direction. When the piezoelectric element Pz1 is mounted on the suspension board with circuit 1, the first terminal 141A is electrically connected to one end portion of the piezoelectric element Pz1. The first terminal 141A has a square shape.

[0063] The first terminal 141B is arranged at the other end portion in the first direction of the mounting portion 2. The first terminal 141B is arranged apart from the neck portion 4 in the first direction. The first terminal 141B is arranged on the side opposite to the first terminal 141A with respect to the neck portion 4 in the first direction. When the piezoelectric element Pz2 is mounted on the suspension board with circuit 1, the first terminal 141B is electrically connected to one end portion of the piezoelectric element Pz2. The first terminal 141B has a square shape.

[0064] like Figure 2B As shown, the first terminals 141A and 141B are arranged on the second insulating layer 13 in the thickness direction. In other words, the first pattern 141 is arranged on the second insulating layer 13 in the thickness direction. The first terminal 141A is connected to the metal supporting layer 11 via the through hole 13A of the second insulating layer 13. The first terminal 141B is connected to the metal supporting layer 11 via the through hole 13B of the second insulating layer 13. In other words, the first pattern 141 is electrically connected to the metal supporting layer 11. In other words, the first pattern 141 is grounded to the metal supporting layer 11.

[0065] The first pattern 141 is made of a first conductor. The first conductor has a first resistivity. Examples of the first conductor include copper, silver, gold, iron, aluminum, and alloys thereof. The first pattern 141 is preferably made of copper.

[0066] The entire first pattern 141 may be made of the first conductor. Alternatively, the first pattern 141 may include a conductor layer made of the first conductor, a first protective layer, and a second protective layer.

[0067] The first protective layer is arranged between the conductor layer and the first insulating layer 12. The first protective layer protects the conductor layer. The first protective layer is made of a metal different from the first conductor. As various materials for the first protective layer, for example, chromium, nickel, titanium, and alloys thereof can be cited. As the material for the first protective layer, chromium is preferably cited.

[0068] The second protective layer covers the surface of the conductor layer. The second protective layer protects the conductor layer together with the first protective layer. The first pattern 141 may also have a plurality of second protective layers. The second protective layer is made of a metal different from the first conductor. As various materials for the second protective layer, for example, chromium, nickel, titanium, gold, tin, and alloys thereof may be cited. As materials for the second protective layer, nickel and gold are preferably cited. More specifically, the first terminals 141A, 141B may also have at least one of a nickel plating layer and a gold plating layer as the second protective layer.

[0069] The first resistivity is, for example, less than 1.0×10 -7 Ω·m, preferably 5.0×10 -8 Ω·m or less. The first resistivity is, for example, 1.5×10 -8 Ω·m or more.

[0070] The resistance value of each of the first terminals 141A and 141B is, for example, less than 1.0×10 5 Ω, preferably 1.0×10 2 The resistance value of each of the first terminals 141A and 141B is, for example, 1.0Ω or more.

[0071] (4-2) The second pattern

[0072] like Figure 1 As shown, the second pattern 142 is a wiring pattern for supplying power to the piezoelectric elements Pz1 and Pz2 when the piezoelectric elements Pz1 and Pz2 are mounted on the suspension substrate with circuit 1. In detail, the second pattern 142 has two second terminals 1421A and 1421B, two external connection terminals 1422A and 1422B, and two wirings 1423A and 1423B. In this embodiment, the second pattern 142 is composed of the two second terminals 1421A and 1421B, the two external connection terminals 1422A and 1422B, and the two wirings 1423A and 1423B.

[0073] The second terminal 1421A is arranged at one end portion of the wiring portion 3 in the first direction. The second terminal 1421A is arranged separately from the first terminal 141A in the second direction. The second terminal 1421A is arranged separately from the neck portion 4 in the first direction. The second terminal 1421A is arranged on the side opposite to the second terminal 1421B with respect to the neck portion 4 in the first direction. When the piezoelectric element Pz1 is mounted on the suspension substrate with circuit 1, the second terminal 1421A is electrically connected to the other end portion of the piezoelectric element Pz1. The second terminal 1421A has a square shape.

[0074] The second terminal 1421B is arranged at the other end portion in the first direction of the wiring portion 3. The second terminal 1421B is arranged separately from the first terminal 141B in the second direction. The second terminal 1421B is arranged separately from the neck portion 4 in the first direction. The second terminal 1421B is arranged on the side opposite to the second terminal 1421A with respect to the neck portion 4 in the first direction. In a state where the piezoelectric element Pz2 is mounted on the suspension substrate with circuit 1, the second terminal 1421B is electrically connected to the other end portion of the piezoelectric element Pz2. The second terminal 1421B has a square shape.

[0075] The external connection terminals 1422A and 1422B are arranged at the other end of the suspension substrate with circuit 1. The external connection terminal 1422A is arranged separately from the second terminal 1421A. The external connection terminal 1422B is arranged separately from the second terminal 1421B. The external connection terminals 1422A and 1422B are electrically connected to, for example, a control substrate of a hard disk drive. The external connection terminals 1422A and 1422B each have a square shape.

[0076] The wiring 1423A electrically connects the second terminal 1421A to the external connection terminal 1422A. One end of the wiring 1423A is connected to the second terminal 1421A. The other end of the wiring 1423A is connected to the external connection terminal 1422A. When the piezoelectric element Pz1 is mounted on the suspension substrate with circuit 1, power from an external power source is supplied to the piezoelectric element Pz1 via the external connection terminal 1422A and the wiring 1423A.

[0077] The wiring 1423B electrically connects the second terminal 1421B to the external connection terminal 1422B. One end of the wiring 1423B is connected to the second terminal 1421B. The other end of the wiring 1423B is connected to the external connection terminal 1422B. When the piezoelectric element Pz2 is mounted on the suspension substrate with circuit 1, power from an external power source is supplied to the piezoelectric element Pz2 via the external connection terminal 1422B and the wiring 1423B.

[0078] like Figure 2A and Figure 2CAs shown, the second pattern 142 is arranged on the second insulating layer 13 in the thickness direction. The second pattern 142 is not connected to the metal support layer 11. The second pattern 142 is made of the first conductor. The second pattern 142 is made of the same material as the first pattern 141. The second pattern 142 is preferably made of copper. The second pattern 142, like the first pattern 141, can be made entirely of the first conductor, or can have a conductor layer made of the first conductor, a first protective layer, and a second protective layer. In detail, the wirings 1423A and 1423B can also have a nickel plating layer as the second protective layer. The second terminals 1421A and 1421B and the external connection terminals 1422A and 1422B can also have at least one of a nickel plating layer and a gold plating layer as the second protective layer.

[0079] The thickness T1 of the wirings 1423A and 1423B (see Figure 2C ) is, for example, 1 μm to 10 μm, preferably 3 μm to 7 μm.

[0080] The length of the wirings 1423A and 1423B is, for example, 1 mm to 500 mm, or preferably 10 mm to 100 mm.

[0081] The resistance value of each of the wirings 1423A and 1423B is, for example, less than 1.0×10 5 Ω, preferably 1.0×10 2 The resistance value of each of the wirings 1423A and 1423B is, for example, 1.0Ω or more.

[0082] (4-3) The third pattern

[0083] like Figure 1 As shown, the third pattern 143 and the second pattern 142 and the metal support layer 11 (see Figure 2A )Electrical connection.

[0084] Specifically, the third pattern 143 includes two wirings 143A and 143B. In the present embodiment, the third pattern 143 includes two wirings 143A and 143B.

[0085] One end of the wiring 143A is connected to the metal supporting layer 11 via the through hole 12A of the first insulating layer 12 (see Figure 2A That is, the wiring 143A is grounded to the metal supporting layer 11. The other end of the wiring 143A is connected to the wiring 1423A via the through hole 13C of the second insulating layer 13 (see Figure 2C ).

[0086] Therefore, if Figure 3As shown, when the piezoelectric element Pz1 is mounted on the suspension board with circuit 1, a parallel circuit is formed in which the wiring 143A is connected in parallel with the series circuit composed of the external connection terminal 1422A, the wiring 1423A, the second terminal 1421A, the piezoelectric element Pz1, and the first terminal 141A. That is, when the piezoelectric element Pz1 is mounted on the suspension board with circuit 1, the third pattern 143 is connected in parallel with the series circuit composed of the first pattern 141, the second pattern 142, and the piezoelectric element Pz1.

[0087] In addition, if Figure 1 As shown, one end of the wiring 143B is connected to the metal supporting layer 11 via the through hole 12B of the first insulating layer 12 (see Figure 2A ). That is, the wiring 143B is grounded to the metal supporting layer 11. The other end of the wiring 143B is connected to the wiring 1423B via the through hole 13D of the second insulating layer 13 (see Figure 2C ).

[0088] Thus, when the piezoelectric element Pz2 is mounted on the suspension substrate with circuit 1, a parallel circuit is formed in which the wiring 143B is connected in parallel with the series circuit composed of the external connection terminal 1422B, the wiring 1423B, the second terminal 1421B, the piezoelectric element Pz2 and the first terminal 141B.

[0089] like Figure 2C As shown in FIG. 1 , the third pattern 143 is arranged on the first insulating layer 12 in the thickness direction. The third pattern 143 is covered by the second insulating layer 13 .

[0090] The third pattern 143 is made of, for example, a second conductor or semiconductor. The second conductor or semiconductor contains at least one metal selected from the group consisting of copper, silver, gold, iron, aluminum, chromium, nickel, titanium, tin, molybdenum, and palladium.

[0091] Specifically, examples of the second conductor include chromium, nickel, titanium, tin, molybdenum, palladium, alloys thereof, and oxides thereof.

[0092] Examples of the semiconductor include oxide semiconductors containing at least one metal selected from the group consisting of copper, silver, gold, iron, aluminum, chromium, nickel, titanium, tin, molybdenum, and palladium.

[0093] The third pattern 143 is preferably made of the second conductor, more preferably chromium. The third pattern 143 may also be made of the above-mentioned first conductor.

[0094] The second conductor has a second resistivity. The second resistivity is higher than the first resistivity. The second resistivity is, for example, 1.0×10 -8 Ω·m or more, preferably 1.0×10 -7Ω·m or more. The second resistivity is, for example, 1.5×10 -7 Ω·m or less.

[0095] The thickness T2 of the wirings 143A and 143B is thinner than the thickness T1 of the wirings 1423A and 1423B of the second pattern 142. The thickness T2 of the wirings 143A and 143B is, for example, 100 nm or less, preferably 70 nm or less. The thickness T2 of the wirings 143A and 143B is, for example, 10 nm or more. The thickness T2 of the wirings 143A and 143B may also be 10 nm to 100 nm, or 10 nm to 70 nm.

[0096] The length of the wiring 143A is longer than the length of the wiring 1423A. The length of the wiring 143B is longer than the length of the wiring 1423B. Figure 1 As shown, at least a portion of each of the wirings 143A and 143B meanders. Therefore, the length of the wiring 143A is longer than the length of the wiring 1423A, and the length of the wiring 143B is longer than the length of the wiring 1423B.

[0097] The length of the wiring 143A is, for example, twice or more, preferably five times or more, and more preferably ten times or more, the length of the wiring 1423A. The length of the wiring 143A is, for example, 30 times or less, the length of the wiring 1423A.

[0098] Similarly, the length of the wiring 143B is, for example, twice or more, preferably 5 times or more, and more preferably 10 times or more, the length of the wiring 1423B. The length of the wiring 143B is, for example, 30 times or less, the length of the wiring 1423B.

[0099] The length of the wiring 143B may be different from the length of the wiring 143A.

[0100] Specifically, the length of the wirings 143A and 143B is, for example, 0.2 m or more, preferably 0.8 m or more. The length of the wirings 143A and 143B is, for example, 1.0 m or less.

[0101] The resistance value of the wiring 143A is higher than the resistance value of the wiring 1423A. The resistance value of the wiring 143B is higher than the resistance value of the wiring 1423B. The resistance value of each of the wirings 143A and 143B is, for example, 1.0×10 5 Ω~1.0×10 9 Ω, preferably 1.0×10 5 Ω~1.0×10 6 Ω.

[0102] (4-4) Pattern 4

[0103] like Figure 1As shown, the fourth pattern 144 is a wiring pattern electrically connected to the magnetic head in a state where the slider S is mounted on the suspension board with circuit 1 .

[0104] The fourth pattern 144 has a plurality of head connection terminals 1441A, 1441B, 1441C, 1441D, a plurality of external connection terminals 1442A, 1442B, 1442C, 1442D, and a plurality of wirings 1443A, 1443B, 1443C, 1443D. In the present embodiment, the fourth pattern 144 is composed of the head connection terminals 1441A, 1441B, 1441C, 1441D, the external connection terminals 1442A, 1442B, 1442C, 1442D, and the wirings 1443A, 1443B, 1443C, 1443D.

[0105] The magnetic head connection terminals 1441A, 1441B, 1441C, and 1441D are arranged on the mounting portion 2. When the slider S is mounted on the mounting portion 2, the magnetic head connection terminals 1441A, 1441B, 1441C, and 1441D are electrically connected to the magnetic head. The magnetic head connection terminals 1441A, 1441B, 1441C, and 1441D are arranged in the first direction. The magnetic head connection terminals 1441A, 1441B, 1441C, and 1441D each have a square shape.

[0106] The external connection terminals 1442A, 1442B, 1442C, and 1442D are arranged at the other end of the suspension substrate 1 with circuit in the second direction. The external connection terminals 1442A, 1442B, 1442C, and 1442D are electrically connected to, for example, a control substrate of a hard disk drive. The external connection terminals 1442A, 1442B, 1442C, and 1442D are arranged in the first direction. In addition, the direction in which the external connection terminals 1442A, 1442B, 1442C, and 1442D are arranged may be different from the direction in which the magnetic head connection terminals 1441A, 1441B, 1441C, and 1441D are arranged. The external connection terminals 1442A, 1442B, 1442C, and 1442D each have a square shape.

[0107] The wiring 1443A electrically connects the head connection terminal 1441A and the external connection terminal 1442A. One end of the wiring 1443A is connected to the head connection terminal 1441A. The other end of the wiring 1443A is connected to the external connection terminal 1442A.

[0108] The wiring 1443B electrically connects the head connection terminal 1441B and the external connection terminal 1442B. One end of the wiring 1443B is connected to the head connection terminal 1441B, and the other end of the wiring 1443B is connected to the terminal 1442B.

[0109] The wiring 1443C electrically connects the head connection terminal 1441C and the external connection terminal 1442C. One end of the wiring 1443C is connected to the head connection terminal 1441C. The other end of the wiring 1443C is connected to the external connection terminal 1442C.

[0110] The wiring 1443D electrically connects the head connection terminal 1441D and the external connection terminal 1442D. One end of the wiring 1443D is connected to the head connection terminal 1441D, and the other end of the wiring 1443D is connected to the external connection terminal 1442D.

[0111] like Figure 2A to Figure 2C As shown, the fourth pattern 144 is arranged on the second insulating layer 13 in the thickness direction. The fourth pattern 144 is not connected to the metal supporting layer 11. The fourth pattern 144 is made of the first conductor. The fourth pattern 144 is made of the same material as the first pattern 141 and the second pattern 142.

[0112] (5) Third insulation layer

[0113] like Figure 1 As shown, the third insulating layer 15 covers the wirings 1423A, 1423B, 1443A, 1443B, 1443C, and 1443D. The third insulating layer 15 does not cover the first terminals 141A, 141B, the second terminals 1421A, 1421B, the head connection terminals 1441A, 1441B, 1441C, and 1441D, and the external connection terminals 1422A, 1422B, 1442A, 1442B, 1442C, and 1442D.

[0114] like Figure 2A to Figure 2C As shown, the third insulating layer 15 is arranged on the second insulating layer 13 in the thickness direction. The third insulating layer 15 is made of resin. As the resin, for example, the above-mentioned resins can be cited. The third insulating layer 15 is preferably made of the same resin as the first insulating layer 12.

[0115] 2. Method for manufacturing a wiring circuit substrate

[0116] Next, refer to Figure 4A to Figure 4D and Figure 2A , a method for manufacturing a wiring circuit substrate is described.

[0117] The method for manufacturing a wiring circuit board includes a first step (refer to Figure 4A )、Step 2 (refer to Figure 4B )、Step 3 (refer to Figure 4C )、Step 4 (refer to Figure 4D ), and the fifth step (refer to Figure 2A ).

[0118] (1) Step 1

[0119] like Figure 4A As shown, in the first step, the first insulating layer 12 is formed on the metal supporting layer 11 .

[0120] Specifically, a photosensitive resin solution (varnish) is applied onto the metal supporting layer 11 and dried to form a coating film of the photosensitive resin.

[0121] Next, the coating film of the photosensitive resin is exposed and developed, thereby forming the first insulating layer 12 .

[0122] (2) Second step

[0123] Then, if Figure 4B As shown, in the second step, following the first step, the third pattern 143 is formed on the first insulating layer 12 .

[0124] Specifically, in order to form the third pattern 143 , first, a thin layer made of the second conductor or semiconductor is formed on the surfaces of the metal supporting layer 11 and the first insulating layer 12 by, for example, sputtering.

[0125] Next, a resist layer is laminated on the thin layer, and the resist layer is exposed while shielding the portion where the third pattern 143 is not to be formed.

[0126] Next, the exposed resist layer is developed, so that the resist layer of the light-shielding portion is removed, and the resist layer of the portion where the third pattern 143 is to be formed remains.

[0127] Next, the thin layer exposed by removing the resist layer is removed by etching.

[0128] After the etching is completed, the resist layer is stripped off.

[0129] Through the above steps, the third pattern 143 is formed on the first insulating layer 12 .

[0130] (3) Step 3

[0131] Then, if Figure 4C As shown, in the third step, following the second step, the second insulating layer 13 is formed on the metal supporting layer 11 and the first insulating layer 12. The second insulating layer 13 is formed by the same method as the first insulating layer 12 described above.

[0132] (4) Step 4

[0133] Then, if Figure 4D As shown, in the fourth step, following the third step, a first pattern 141 is formed on the second insulating layer 13 (see Figure 2B ), the second pattern 142, and the fourth pattern 144.

[0134] Specifically, first, a seed layer is formed on the surface of the second insulating layer 13. The seed layer is formed by, for example, sputtering. Examples of the material of the seed layer include chromium, copper, nickel, titanium, and alloys thereof.

[0135] Next, a plating resist is attached to the second insulating layer 13 on which the seed layer is formed, and the plating resist is exposed to light while shielding portions where the first pattern 141 , the second pattern 142 , and the fourth pattern 144 are to be formed.

[0136] Next, the exposed resist is developed. Thus, the resist in the light-shielding portion is removed, and the seed layer is exposed in the portion where the first pattern 141, the second pattern 142, and the fourth pattern 144 are formed. In addition, the resist in the exposed portion, i.e., the portion where the first pattern 141, the second pattern 142, and the fourth pattern 144 are not formed, remains.

[0137] Next, the first pattern 141, the second pattern 142, and the fourth pattern 144 are formed on the exposed seed layer by electroplating. After the electroplating is completed, the plating resist is peeled off.

[0138] Next, the seed layer exposed by stripping the plating resist is removed by wet etching.

[0139] (5) Step 5

[0140] Then, if Figure 2A As shown, in the fifth step, following the fourth step, the third insulating layer 15 is formed on the second insulating layer 13. The third insulating layer 15 is formed by the same method as the first insulating layer 12 described above.

[0141] Thereafter, the metal supporting layer 11 is processed into a predetermined shape by etching the metal supporting layer 11 .

[0142] According to the above, the suspension board with circuit 1 can be obtained.

[0143] 3. Effect

[0144] (1) According to the suspension substrate with circuit 1, Figure 1 As shown, the wiring 143A and the wiring 1423A and the metal support layer 11 (see Figure 2A )connect.

[0145] Thus, when the piezoelectric element Pz1 is mounted on the suspension board with circuit 1, Figure 3As shown, a parallel circuit is formed in which the third pattern 143 (wiring 143A) is connected in parallel with the series circuit composed of the second pattern 142 (external connection terminal 1422A, wiring 1423A and second terminal 1421A), the piezoelectric element Pz1, and the first pattern 141 (first terminal 141A).

[0146] Therefore, when the piezoelectric element Pz1 is polarized, the charges in the piezoelectric element Pz1 that are offset by the polarization can be released to the wiring 143A without applying a voltage to the piezoelectric element Pz1 , thereby eliminating the polarization of the piezoelectric element Pz1 .

[0147] In addition, the length of the wiring 143A of the third pattern 143 is longer than the length of the wiring 1423A of the second pattern 142 .

[0148] Therefore, when a voltage is applied to the piezoelectric element Pz1 , the wiring 143A of the third pattern 143 functions as a resistor, and the voltage can be accurately applied to the piezoelectric element Pz1 .

[0149] As a result, the expansion and contraction of the piezoelectric element Pz1 can be controlled more accurately.

[0150] (2) According to the suspension substrate 1 with circuit, Figure 1 As shown, the length of the wiring 143A of the third pattern 143 is more than twice the length of the wiring 1423A of the second pattern 142 .

[0151] Therefore, the resistance value of the wiring 143A of the third pattern 143 can be increased relative to the resistance value of the wiring 1423A of the second pattern 142 .

[0152] (3) According to the suspension substrate 1 with circuit, Figure 2A to Figure 2C As shown, the thickness T2 of the wiring 143A of the third pattern 143 is thinner than the thickness T1 of the wiring 1423A of the second pattern 142 .

[0153] Therefore, the resistance value of the wiring 143A of the third pattern 143 can be increased relative to the resistance value of the wiring 1423A of the second pattern 142 .

[0154] (4) According to the suspension substrate with circuit 1, the first pattern 141 and the second pattern 142 are made of copper, and the third pattern is made of a conductor (second conductor) or a semiconductor containing at least one metal selected from the group consisting of chromium, nickel, titanium, tin, molybdenum, and palladium.

[0155] Therefore, the resistance value of the wiring 143A of the third pattern 143 can be increased relative to the resistance value of the wiring 1423A of the second pattern 142 .

[0156] (5) According to the suspension substrate 1 with circuit, Figure 2A and Figure 2B As shown, the first pattern 141 and the third pattern 143 are grounded to the metal supporting layer 11 .

[0157] Therefore, even when there is little space for providing the third pattern 143 , the above-mentioned parallel circuit can be formed using the metal supporting layer 11 .

[0158] 4. Modifications

[0159] In the modification example, the same reference numerals are given to the same components as those of the above-described embodiment, and the description thereof will be omitted.

[0160] (1) It is also possible not to connect the first terminals 141A and 141B (see Figure 2A to Figure 2C ) and the metal supporting layer 11. The first terminals 141A and 141B may also be arranged on the metal supporting layer 11.

[0161] (2) Figure 5 As shown, one end of the wiring 143A may be connected to the first terminal 141A. One end of the wiring 143B may be connected to the first terminal 141B.

[0162] In detail, Figure 6 As shown, one end of the wiring 143A is arranged between a part of the first terminal 141A and the metal supporting layer 11. The first terminal 141A is connected to one end of the wiring 143A via a through hole 13A in the second insulating layer 13.

[0163] In addition, the first terminal 141A is grounded to the metal supporting layer 11. For example, the suspension board with circuit 1 may include a ground wiring 20A connecting the first terminal 141A and the metal supporting layer 11 (see Figure 5 ) The first terminal 141A may be grounded to the metal supporting layer 11 via a through hole (not shown).

[0164] In addition, the first insulating layer 12 is disposed between one end of the wiring 143A and the metal supporting layer 11. The wiring 143A may be grounded to the metal supporting layer 11 via a through hole (not shown) of the first insulating layer 12.

[0165] In this modification, Figure 7 As shown, when the piezoelectric element Pz1 is mounted on the suspension substrate with circuit 1, a parallel circuit is formed in which the wiring 143A is connected in parallel with the series circuit composed of the external connection terminal 1422A, the wiring 1423A, the second terminal 1421A, the piezoelectric element Pz1 and the first terminal 141A.

[0166] Therefore, also in this modification, the same effects as those of the above-described embodiment can be obtained.

[0167] (3) Fig. 8A and Figure 8B As shown, the second pattern 142 and the third pattern 143 may also be arranged on the first insulating layer 12. In this case, Figure 8B As shown, a portion of the wiring 1423A of the second pattern 142 is arranged on the other end of the wiring 143A of the third pattern 143. In addition, a portion of the wiring 1423B of the second pattern 142 is arranged on the other end of the wiring 143B of the third pattern 143. The wirings 1423A, 1423B, 143A, and 143B are covered by the second insulating layer 13.

[0168] In this modification, the fourth pattern 144 may also be arranged on the first insulating layer 12 and covered by the second insulating layer 13 .

[0169] In this modification as well, the same effects as those of the above-described embodiment can be obtained.

[0170] (4) Fig.9A and Fig. 9B As shown, the second pattern 142 may be arranged on the first insulating layer 12 and covered by the second insulating layer 13 .

[0171] In this case, the third pattern 143 is arranged on the second insulating layer 13. The other end of the wiring 143A of the third pattern 143 is connected to the wiring 1423A of the second pattern 142 via the through hole 13C of the second insulating layer 13. The other end of the wiring 143B of the third pattern 143 is connected to the wiring 1423B of the second pattern 142 via the through hole 13D of the second insulating layer 13.

[0172] In this modification, the fourth pattern 144 may also be arranged on the first insulating layer 12 and covered by the second insulating layer 13 .

[0173] In this modification as well, the same effects as those of the above-described embodiment can be obtained.

[0174] In addition, the above invention is provided as an exemplary embodiment of the present invention, which is only an example and is not to be construed as limiting. Modifications of the present invention that are obvious to a person skilled in the art are included in the above claims.

[0175] Industrial Applicability

[0176] The wired circuit board of the present invention can be used as, for example, a suspension board with circuit.

Claims

1. A wiring circuit substrate, which is a wiring circuit substrate capable of mounting a piezoelectric element, wherein: The wiring circuit substrate comprises: a first pattern having a first terminal electrically connected to one end of the piezoelectric element; a second pattern having a second terminal electrically connected to the other end of the piezoelectric element and a wiring connected to the second terminal, the second pattern being arranged to be separated from the first pattern; as well as a third pattern having wiring which is connected in parallel with a series circuit consisting of the first pattern, the second pattern, and the piezoelectric element when the piezoelectric element is mounted on the wiring circuit substrate; The length of the wiring in the third pattern is longer than the length of the wiring in the second pattern.

2. The wiring circuit substrate according to claim 1, wherein The length of the wiring in the third pattern is at least twice the length of the wiring in the second pattern.

3. The wired circuit substrate according to claim 1, wherein: The thickness of the wiring in the third pattern is thinner than the thickness of the wiring in the second pattern.

4. The wired circuit substrate according to claim 1, wherein: The first pattern and the second pattern are made of copper, The third pattern is made of a conductor or semiconductor containing at least one metal selected from the group consisting of chromium, nickel, titanium, tin, molybdenum, and palladium.

5. The wired circuit board according to any one of claims 1 to 4, wherein The wiring circuit substrate further comprises: a metal support layer; and a first insulating layer, which is disposed on the metal supporting layer and has a through hole, The first pattern and the third pattern are electrically connected to the metal supporting layer via the through-holes of the first insulating layer.

6. The wired circuit board according to any one of claims 1 to 4, wherein The wiring circuit substrate further comprises: a metal support layer; and a first insulating layer disposed on the metal supporting layer, The second pattern and the third pattern are arranged on the first insulating layer.

7. The wired circuit board according to any one of claims 1 to 4, wherein The wiring circuit substrate further comprises: Metal support layer; a first insulating layer disposed on the metal supporting layer; and a second insulating layer disposed on the first insulating layer, The third pattern is arranged on the first insulating layer and covered by the second insulating layer, and the second pattern is arranged on the second insulating layer.

8. The wired circuit board according to any one of claims 1 to 4, wherein The wiring circuit substrate further comprises: Metal support layer; a first insulating layer disposed on the metal supporting layer; and a second insulating layer disposed on the first insulating layer, The second pattern is arranged on the first insulating layer and covered by the second insulating layer, and the third pattern is arranged on the second insulating layer.

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