JP5672764B2 - Wiring circuit laminate, suspension substrate using the same, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a laminate for a wiring circuit, and more particularly to a laminate for a wiring circuit that can prevent occurrence of short circuit and rust.

  Conventionally, a wiring circuit laminate has been used to form wiring on a suspension substrate or the like. The laminate for a wiring circuit is also referred to as a three-layer material, and is generally a metal support layer, an insulating layer, and a copper foil layer that are laminated in this order. When manufacturing a suspension substrate or the like, usually, the wiring on the suspension substrate or the like is formed by patterning the copper foil layer in the wiring circuit laminate.

  Various techniques have been proposed for improving the workability, the peeling strength of the formed wiring, the rust prevention property, and the like with respect to such a laminate for a wiring circuit. For example, a wiring circuit laminate capable of realizing the formation of a fine wiring pattern by improving the etching characteristics of the copper foil layer in the wiring circuit laminate and enhancing the adhesion between the copper foil layer and the insulating layer. It has been proposed (Patent Document 1). Moreover, the laminated body for wiring circuits which can prevent that the copper foil layer rusts by forming a coating layer in the surface of the copper foil layer in the laminated body for wired circuits is proposed (patent documents 2 and 3). Furthermore, a technique for preventing deformation at the time of processing the wiring circuit laminate by using a metal having high rigidity for the metal support layer in the wiring circuit laminate has been proposed (Patent Documents 4 and 5).

JP 2009-291988 A JP 58-007077 A JP-A-6-054829 JP 2006-209853 A JP 2008-310946 A

  However, in the conventional technology as described above, when plating or the like is performed to prevent rust of the copper foil layer in the laminated body for the wiring circuit, when the copper foil layer is patterned with high definition to form a wiring There was a problem that a short circuit would occur.

  The present invention has been made in view of the above problems, and prevents rust of the copper foil layer and prevents short circuit from occurring when the copper foil layer is patterned with high definition to form a wiring. A main object of the present invention is to provide a laminate for a wiring circuit that can be used.

In order to solve the above-mentioned problems, in the present invention, a laminated layer for a wiring circuit having a metal support layer, an insulating layer formed on the metal support layer, and a copper foil layer formed on the insulating layer. The copper foil layer has a conductor layer composed of plated copper, and a rust preventive layer formed on the conductor layer and containing Zn and Cr. In the copper foil layer, The larger of the Zn content and the Cr content in the region where the depth from the upper surface of the rust prevention layer is ₂ nm to 8 nm (SiO ₂ conversion) is 1.7 at% to 19.8 at%. A laminated body for a wiring circuit characterized by the above.

  According to the present invention, the copper foil layer can be prevented from rusting, and the etching characteristics of the copper foil layer can be improved, so that a short circuit occurs when the copper foil layer is patterned with high definition to form a wiring. This can be prevented.

In the said invention, the said rust prevention layer contains Ni, and content of Ni in the area | region whose depth from the upper surface of the said rust prevention layer is ₂ nm-8 nm (SiO2 conversion) is 10 at% in the said copper foil layer. The following is preferable. In the copper foil layer, Cu can be prevented from diffusing from the conductor layer to the rust preventive layer, thereby maintaining the effect of preventing the rust of the copper foil layer and improved etching characteristics of the copper foil layer It is because it can maintain.

Further, in the present invention, there is provided a suspension substrate having a metal support layer, an insulating layer formed on the metal support layer, and a wiring layer formed on the insulating layer, wherein the wiring layer includes: A conductive layer made of plated copper, and a rust preventive layer formed on the conductor layer and containing Zn and Cr. In the wiring layer, the depth from the upper surface of the rust preventive layer is A suspension substrate is provided in which the larger of the Zn content and the Cr content in a region of ₂ nm to 8 nm (in terms of SiO ₂ ) is 1.7 at% to 19.8 at%.

  According to the present invention, it is possible to prevent rust of the wiring layer and to prevent occurrence of a short circuit in the wiring layer patterned with high definition.

In the said invention, the said rust prevention layer contains Ni, and the content of Ni in the area | region whose depth from the upper surface of the said rust prevention layer is ₂ nm-8 nm (SiO2 conversion) in the said wiring layer is 10 at% or less It is preferable that In the wiring layer, Cu can be prevented from diffusing from the conductor layer to the rust preventive layer, thereby maintaining the effect of preventing the rust of the copper foil layer, and improved etching characteristics of the copper foil layer. This is because it can be maintained.

  Moreover, in this invention, it has the preparatory process which prepares the said laminated body for wiring circuits, and the pattern formation process which forms a wiring pattern by etching the copper foil layer of the said laminated body for wired circuits. A method for manufacturing a suspension substrate is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the board | substrate for suspensions which can prevent rust and can prevent that a short circuit generate | occur | produces can be manufactured.

  The present invention also provides a suspension including the suspension substrate.

  According to the present invention, it is possible to prevent rust of the wiring layer in the suspension and to prevent occurrence of a short circuit in the wiring layer in the suspension patterned with high definition.

  The present invention also provides an element-equipped suspension comprising the suspension and an element mounted in an element mounting region of the suspension.

  ADVANTAGE OF THE INVENTION According to this invention, the rust of the wiring layer in a suspension with an element can be prevented, and it can prevent that a short circuit generate | occur | produces in the wiring layer in the suspension with an element patterned in high definition.

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

  ADVANTAGE OF THE INVENTION According to this invention, the rust of the wiring layer in a hard disk drive can be prevented, and it can prevent that a short circuit generate | occur | produces in the wiring layer in the hard disk drive patterned in high definition.

  In this invention, there exists an effect that a rust of a copper foil layer can be prevented and it can prevent that a short circuit generate | occur | produces when a copper foil layer is patterned with high definition and used as wiring.

It is a schematic plan view which shows an example of the laminated body for wiring circuits of this invention. It is a schematic plan view which shows an example for description of the manufacturing method of the laminated body for wiring circuits of this invention. It is a schematic plan view which shows an example of the board | substrate for suspensions of this invention. It is a schematic sectional drawing which shows an example of the board | substrate for suspensions 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 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 plan view which shows an example of the hard disk drive of this invention. 5 is a graph showing measurement results of short-circuit occurrence frequency in suspension substrates obtained in Example 1 and Comparative Example 1. FIG. 6 is a graph showing the distribution of the content of atoms in a suspension substrate obtained in Example 1 in which the frequency of short-circuit occurrence did not increase. 6 is a graph showing the distribution of short-circuit occurrence frequency in suspension substrates obtained in Example 1 and Comparative Example 4.

  Hereinafter, the laminated body for wiring circuits of the present invention, the suspension substrate using the same, and the manufacturing method thereof will be described in detail.

A. Wiring circuit laminate First, the wiring circuit laminate of the present invention will be described. The laminate for a printed circuit according to the present invention is a laminate for a printed circuit having a metal support layer, an insulating layer formed on the metal support layer, and a copper foil layer formed on the insulating layer. The copper foil layer has a conductor layer made of plated copper, and a rust prevention layer formed on the conductor layer and containing Zn and Cr. In the copper foil layer, the rust prevention The larger one of the Zn content and the Cr content in a region having a depth from the upper surface of the layer of ₂ nm to 8 nm (in terms of SiO ₂ ) is 1.7 at% to 19.8 at%. To do. Here, the depth in terms of SiO _{2 is} the depth converted from the upper surface of the anticorrosive layer when the copper foil layer is made of SiO ₂ (hereinafter referred to as the present specification). The same).

According to this invention, the copper foil layer in the laminated body for wiring circuits has a rust prevention layer, In the said copper foil layer, the depth from the upper surface of the said rust prevention layer is ₂ nm-8 nm (SiO2 conversion) area | region. Since the content of Zn and the content of Cr are adjusted as described above, rust of the copper foil layer can be prevented, and the etching characteristics of the copper foil layer can be improved. It is possible to prevent a short circuit from occurring when the copper foil layer is patterned with high definition to form a wiring.

FIG. 1 is a schematic plan view showing an example of a laminated body for a wiring circuit according to the present invention. A wiring circuit laminate 10 shown in FIG. 1 includes a metal support layer 11, an insulating layer 12 formed on the metal support layer 11, and a copper foil layer 13 formed on the insulating layer 12. And the copper foil layer 13 has the conductor layer 14 comprised from the plated copper, and the rust prevention layer 15 formed on the conductor layer 14 and containing Zn and Cr. Further, in the copper foil layer 13, the larger of the Zn content and the Cr content in the region where the depth from the top surface 15 c of the rust prevention layer is ₂ nm to 8 nm (SiO ₂ conversion) is 1.7 at%. ˜19.8 at%. Note that “at%” means atomic% and represents the ratio of the number of each of these atoms to the total number of atoms in the region.
Hereinafter, the laminated body for wiring circuits of this invention is demonstrated in detail.

1. Copper foil layer The copper foil layer in this invention has the conductor layer comprised from the plated copper, and the rust prevention layer formed on a conductor layer and containing Zn and Cr. And in the copper foil layer in this invention, the larger one of Zn content and Cr content in the area | region whose depth from the upper surface of a rust prevention layer is ₂ nm-8 nm (SiO2 conversion) is 1.7 at. % To 19.8 at%.
Hereinafter, the copper foil layer in the present invention will be described in detail.

(1) Conductor layer The conductor layer in this invention is a layer formed on an insulating layer and comprised from copper (Cu). Moreover, it is preferable that the thickness of a conductor layer exists in the range of 5 micrometers-20 micrometers, especially in the range of 9 micrometers-12 micrometers. This is because if the thickness of the conductor layer is too small, the resistance increases, which is disadvantageous in terms of electrical characteristics, and if the thickness of the conductor layer is too large, the wiring processing accuracy cannot be ensured.

(2) Rust prevention layer The rust prevention layer in the present invention is a layer formed on the conductor layer and is not particularly limited. For example, after forming a Ni plating layer on the conductor layer, Zn and Cr are added. It is a layer formed by plating. And when the antirust layer is formed on the conductor layer, in the copper foil layer, the Zn content and the Cr content in the region having a depth from the top surface of the antirust layer of ₂ nm to 8 nm (in terms of SiO ₂ ) The larger of the amounts is 1.7 at% to 19.8 at%. This can be confirmed by, for example, X-ray photoelectron spectroscopy (XPS / ESCA).

In the present invention, as described above, the larger of the Zn content and the Cr content in the region where the depth from the upper surface of the rust prevention layer is ₂ nm to 8 nm (in terms of SiO ₂ ) is 1.7 at. % Or more is used. By setting it as such a range, the rust of a copper foil layer can be prevented. This is because Zn and Cr contained in the rust preventive layer are more easily oxidized than Cu constituting the conductor layer, so that the depth of the rust preventive layer from the top surface is ₂ nm to 8 nm (in terms of SiO ₂ ). This is because, when the larger of the amount and the Cr content is within the above range, the conductor layer is prevented from being oxidized by the oxide film previously formed on the rust prevention layer.

In the present invention, as described above, the larger one of the Zn content and the Cr content in the region having a depth from the top surface of the anticorrosive layer of ₂ nm to 8 nm (in terms of SiO ₂ ) is 19. A rust preventive layer of 8 at% or less is used, and among them, 16.0 at% or less is preferable. By setting it as such a range, the etching characteristics of the copper foil layer are effectively improved, and even when a high-definition wiring pattern is formed, the occurrence of a short circuit can be effectively prevented. .

  The advantage of the present invention is that the high-definition wiring formed from the wiring circuit laminate of the present invention has a high-definition that can cause a short circuit in the conventional wiring circuit laminate. Is preferable in that it can be effectively exhibited. Specifically, it is preferable that L / S (line and space) is in the range of 12 μm to 30 μm, especially in the range of 12 μm to 20 μm, particularly in the range of 12 μm to 15 μm. When a wiring having such L / S (line and space) is formed from a conventional laminate for a wiring circuit having poor etching characteristics, a short circuit is likely to occur. For this reason, it is because it can prevent effectively that a short circuit generate | occur | produces, when forming the wiring which has such L / S (line and space) from the laminated body for wiring circuits of this invention.

In the laminated body for a wiring circuit of the present invention, the rust prevention layer further contains Ni, and the Ni content in the region having a depth from the top surface of the rust prevention layer of ₂ nm to 8 nm (SiO ₂ conversion) is 10 at% or less. It is preferable that In the copper foil layer, Cu can be prevented from diffusing from the conductor layer to the rust prevention layer. In the copper foil layer, the inclusion of Zn in the region having a depth from the top surface of the rust prevention layer of ₂ nm to 8 nm (SiO ₂ conversion) The larger of the amount and the Cr content can be maintained in the range of 1.7 at% to 19.8 at%. Thereby, the effect which prevents the rust of a copper foil layer can be maintained, and the etching characteristic for which the copper foil layer was improved can be maintained. Furthermore, when the Ni content in the region where the depth from the top surface of the rust prevention layer is ₂ nm to 8 nm (in terms of SiO ₂ ) is 10 at% or less, the depth from the top surface of the rust prevention layer is 0 nm to 2. More preferably, the number of NiO ₂ molecules in the region of ₂ nm (in terms of SiO ₂ ) is larger than the number of Ni atoms existing as a simple substance in the region. This is because Cu can be effectively prevented from diffusing from the conductor layer to the antirust layer in the copper foil layer.

  The reason why Cu can be prevented from diffusing from the conductor layer to the rust-proof layer in this way is presumed to be because nickel has a slower diffusion rate than chromium.

In the present invention, the Ni content in the region having a depth from the top surface of the anticorrosive layer of ₂ nm to 8 nm (in terms of SiO ₂ ) is preferably 10 at% or less as described above. % To 10 at%, particularly 0.1 to 5 at% is preferable. When the Ni content in the region having a depth from the top surface of the rust-preventing layer of 2 nm to 8 nm (in terms of SiO2) is larger than the above range, the etching characteristics of the copper foil layer may be deteriorated. This is because if the Ni content is less than the above range, Cu may not be sufficiently prevented from diffusing from the conductor layer to the rust prevention layer.

In the present invention, the number of NiO ₂ molecules in a region having a depth from the top surface of the rust-preventing layer of 0 nm to 2.2 nm (in terms of SiO ₂ ) is larger than the number of Ni atoms present as a simple substance in the region. preferable. Specifically, the ratio of the number of Ni atoms to the number of molecules of NiO ₂ is preferably 8/10 or less, and particularly preferably 2/10 or less. This is because when the number of NiO ₂ molecules and the number of Ni atoms satisfy such conditions, it is possible to sufficiently prevent Cu from diffusing from the conductor layer to the rust prevention layer.

In addition, in copper foil layer, the depth from the upper surface of a rust prevention layer in the area | region whose depth from the upper surface of a rust prevention layer is ₂ nm-8 nm (SiO2 conversion), and the depth from the upper surface of a rust prevention layer ( It can be confirmed, for example, by X-ray photoelectron spectroscopy (XPS / ESCA) that the abundance ratio of NiO ₂ in the region (in terms of SiO ₂ ) is larger than Ni existing as a simple substance in the region.

Furthermore, in the copper foil layer, when the Ni content in the region having a depth from the top surface of the rust-preventing layer of ₂ nm to 8 nm (in terms of SiO ₂ ) is within the above range, the Cu content in the region is 23 at% or less. It can be. Thereby, the rust of a copper foil layer can be prevented. In addition, it can confirm by X-ray photoelectron spectroscopy (XPS / ESCA) that content of Cu in the said area | region is 23 at% or less, for example.

2. Metal Support Layer The material constituting the metal support layer in the present invention preferably has desired conductivity and spring property, and examples thereof include SUS (stainless steel). Moreover, although the thickness of a metal support layer changes with materials, for example, it exists in the range of 10 micrometers-20 micrometers, for example.

3. Insulating layer The insulating layer in this invention is a layer formed on a metal support layer. The material constituting the insulating layer is not particularly limited as long as it has a desired insulating property, and examples thereof include polyimide resin (PI). The insulating layer may be a photosensitive material or a non-photosensitive material. The insulating layer has a thickness in the range of 5 μm to 10 μm, for example.

4). Next, the manufacturing method of the laminated body for wiring circuits of this invention is demonstrated. The manufacturing method of the laminated body for wiring circuits of this invention will not be specifically limited if it is a method which can obtain the laminated body for wiring circuits mentioned above. Hereinafter, as an example of the method for manufacturing a multilayer body for a wiring circuit of the present invention, a method for manufacturing the multilayer body for a wiring circuit will be described with reference to FIG.

  First, the metal support layer 21 is formed using stainless steel as a material. Next, polyimide (PI) is applied on the metal support layer 21. Next, the coated polyimide (PI) is dried, heat-treated, inactive heat-treated, and further plasma-treated to form the insulating layer 22. And after forming the alloy layer 23 comprised from Ni, Cr, and Sn by sputtering, the conductor layer 24 is formed on the alloy layer 23 by plating Cu.

Next, the Ni plating layer 25 which will comprise the lower side of a rust prevention layer is formed on the conductor layer 24 by plating Ni. At this time, by optimizing the current value, as described above, the Ni content in the region where the SiO ₂ equivalent depth from the top surface 26c of the Zn / Cr plating layer is ₂ nm to 8 nm is adjusted. Next, the Zn / Cr plating layer 26 is formed on the Ni plating layer 25 by plating Zn and Cr. At this time, by optimizing the current value, the SiO ₂ equivalent depth from the upper surface 26c of the Zn / Cr plated layer is ₂ nm to 8 nm as described in the section “A. Wiring circuit laminate”. The Zn content and the Cr content in the region are adjusted.

  Next, the copper foil layer described above is formed from the conductor layer 24, the Ni plating layer 25, and the Zn / Cr plating layer 26 by annealing and slit / sheet cutting. The laminated body for wiring circuits of this invention is manufactured by the above.

  In addition, the method of manufacturing the laminated body for wiring circuits whose rust prevention layer does not contain Ni forms the Zn / Cr plating layer 26 on the conductor layer 24 without forming the Ni plating layer 25 on the conductor layer 24. Except for the above, it is the same method as the method for manufacturing the laminate for a wiring circuit.

B. Next, the suspension substrate of the present invention will be described. The suspension substrate according to the present invention includes a metal support layer, an insulating layer formed on the metal support layer, and a wiring layer formed on the insulating layer, and the wiring layer includes: A conductor layer made of plated copper; and a rust prevention layer formed on the conductor layer and containing Zn and Cr. In the wiring layer, the depth from the top surface of the rust prevention layer is 2 nm. The larger one of the Zn content and the Cr content in the region of ˜8 nm (in terms of SiO ₂ ) is 1.7 at% to 19.8 at%.

According to the present invention, the wiring layer in the suspension substrate has a rust prevention layer, and in the wiring layer, the inclusion of Zn in the region having a depth from the top surface of the rust prevention layer of ₂ nm to 8 nm (SiO ₂ conversion). Since the amount and the Cr content are adjusted as described above, rusting of the wiring layer can be prevented and a wiring layer without a short circuit can be obtained.

  FIG. 3 is a schematic plan view showing an example of the suspension substrate of the present invention. For convenience, the description of the insulating layer and the cover layer is omitted. The suspension substrate 30 shown in FIG. 3 is formed on the head portion side, an element mounting region 31 for mounting elements, and an external circuit substrate connection region 32 formed on the tail portion side for connection to an external circuit substrate. And wiring 33 (33a-33d) for electrically connecting the element mounting region 31 and the external circuit board connection region 32. The wirings 33a and 33b and the wirings 33c and 33d form a wiring pair, one for recording and the other for reproduction.

FIG. 4 is a cross-sectional view taken along the line AA in FIG. 3, and is a schematic cross-sectional view showing an example of the suspension substrate of the present invention. The suspension substrate 40 shown in FIG. 4 has a metal support layer 41, an insulating layer 42 formed on the metal support layer 41, and a wiring layer 43 formed on the insulating layer 42. The wiring layer 43 includes a conductor layer 44 made of plated copper, and a rust prevention layer 45 formed on the conductor layer 44 and containing Zn and Cr. Furthermore, in the wiring layer 43, the larger of the Zn content and the Cr content in the region where the depth from the upper surface 45c of the anticorrosive layer is ₂ nm to 8 nm (in terms of SiO ₂ ) is 1.7 at% to 19.8 at%.

  The wiring layer used in the present invention has a conductor layer made of plated copper and a rust prevention layer formed on the conductor layer and containing Zn and Cr. Since these conductor layers and rust preventive layers are the same as those described in the item “A. Laminate for wiring circuit”, description thereof will be omitted. The wiring constituted by the wiring layer used in the present invention is not particularly limited, but is preferably high-definition, specifically, the high-definition wiring described in the item “A. Laminate for wiring circuit”. It is preferable that

  Since the metal support layer and the insulating layer used in the present invention are the same as those described in the item “A. Laminate for wiring circuit”, description thereof will be omitted. Furthermore, the manufacturing method of the suspension substrate of the present invention is not particularly limited, but “C. Suspension substrate manufacturing method” described later can be used.

C. Next, a method for manufacturing a suspension substrate according to the present invention will be described. The suspension board manufacturing method of the present invention includes a preparation step of preparing the wiring circuit laminate described in the section “A. Wiring circuit laminate”, and etching the copper foil layer in the wiring circuit laminate. And a pattern forming step for forming a wiring pattern.

  According to the present invention, the wiring pattern on the suspension board is formed by etching the copper foil layer in the wiring circuit laminate described in the section “A. Wiring circuit laminate”. While preventing, it can prevent that a short circuit generate | occur | produces in a wiring pattern.

  FIG. 5 is a schematic cross-sectional view showing an example of a method for manufacturing a suspension substrate according to the present invention. Hereinafter, as an example of the manufacturing method of the suspension substrate of the present invention, the manufacturing method of the suspension substrate of the present invention shown in FIG. 5 will be described.

  First, the wiring circuit laminate 50 is prepared (FIG. 5A). The wiring circuit laminate 50 to be prepared is the same as that described in the item “A. Wiring circuit laminate”.

  Next, the copper foil layer 53 in the wiring circuit laminate 50 is processed by chemical etching to form a wiring pattern 54 (FIG. 5B). The wiring pattern 54 in the present invention is not particularly limited, but is preferably high-definition, and specifically, is a high-definition wiring pattern described in the item “A. Wiring circuit laminate”. preferable.

  The method of chemical etching in the present invention is particularly limited as long as the etching characteristics of the copper foil layer 53 in the wiring circuit laminate 50 can be improved and the effect of preventing a short circuit from occurring in the wiring pattern 54 can be obtained. Is not to be done. As a chemical solution used in such a chemical etching method, ferric chloride solution or the like is preferable. This is because the etching characteristics of the copper foil layer 53 can be effectively improved and the occurrence of a short circuit in the wiring pattern 54 can be effectively prevented.

  In such a chemical etching method, the chemical etching time is preferably within a range of 30 sec to 150 sec, and more preferably within a range of 30 sec to 100 sec. This is because the etching characteristics of the copper foil layer 53 can be effectively improved and the occurrence of a short circuit in the wiring pattern 54 can be effectively prevented. In such a chemical etching method, the temperature at which chemical etching is performed is preferably within a range of 30 ° C to 60 ° C, and more preferably within a range of 40 ° C to 50 ° C. This is because the etching characteristics of the copper foil layer 53 can be effectively improved and the occurrence of a short circuit in the wiring pattern 54 can be effectively prevented.

  If the copper foil layer 53 is processed and the wiring pattern 54 is formed by performing chemical etching by the method as described above, it is possible to prevent a short circuit from occurring in the wiring pattern 54.

  Next, a cover layer 55 is formed on the wiring pattern 54 using a liquid insulating material (FIG. 5C). Next, the insulating layer 52 is patterned (FIG. 5D). Next, the metal support layer 51 is patterned (FIG. 5E). As described above, the suspension substrate of the present invention can be manufactured.

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

  According to the present invention, a suspension having excellent connection stability can be obtained by using the suspension substrate described above.

  FIG. 6 is a schematic plan view showing an example of the suspension of the present invention. A suspension 60 shown in FIG. 6 has the above-described suspension substrate 30 and a load beam 62 provided on the surface of the suspension substrate 30 opposite to the surface on which the element mounting region 61 is formed. is there.

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

E. Next, the suspension with an element of the present invention will be described. A suspension with an element of the present invention includes the above-described suspension and an element mounted in an element mounting region of the suspension.

  According to the present invention, by using the above-described suspension, a suspension with an element having excellent connection stability can be obtained.

  FIG. 7 is a schematic plan view showing an example of the suspension with an element of the present invention. A suspension 70 with an element shown in FIG. 7 includes the suspension 60 described above and an element 71 mounted in an element mounting region 61 of the suspension 60.

  The suspension with an element of the present invention has at least a suspension and an element. The suspension is the same as the content described in “C. Suspension”, and therefore, the description thereof is omitted here.

F. Next, the hard disk drive of the present invention will be described. The hard disk drive of the present invention is characterized by including the above-described suspension with an element.

  According to the present invention, a hard disk drive with higher functionality can be obtained by using the above-described suspension with an element.

  FIG. 8 is a schematic plan view showing an example of the hard disk drive of the present invention. A hard disk drive 80 shown in FIG. 8 includes the above-described suspension 70 with an element, a disk 81 on which data is written and read by the suspension 70 with an element, a spindle motor 82 that rotates the disk 81, and the elements of the suspension 70 with an element. Arm 83 and voice coil motor 84 for moving the above, and a case 85 for sealing the above members.

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

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

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

[Example 1]
First, the wiring circuit laminate 10 shown in FIG. 1 was prepared. In the prepared wiring circuit laminate 10, the metal support layer 11 is SUS304 having a thickness of 18 μm, the insulating layer 12 is polyimide (PI) having a thickness of 10 μm, and the conductor layer 14 is plated copper having a thickness of 12 μm. . The rust prevention layer 15 is a layer formed by forming a Ni plating layer on the conductor layer 14 and then plating Zn and Cr.

In the present example, including the laminated body 10 for wiring circuit as shown in Table 1 below, in the copper foil layer 13, the depth from the top surface of the anticorrosive layer 15 is ₂ nm to 8 nm (SiO ₂ conversion). A plurality of wiring circuit laminates 10 in which the larger of the Zn content and the Cr content in the region was 1.7 at% to 19.8 at% were prepared. Further, the Ni content (at%) shown in Table 1 indicates the Ni content (at%) in a region where the depth from the upper surface of the rust prevention layer 15 is ₂ nm to 8 nm (SiO ₂ conversion).

  Note that the content, number, and number of molecules of the atoms described above were analyzed by X-ray photoelectron spectroscopy (XPS / ESCA). In the analysis, the X-ray condition was Al mono 200 μmΦ × 30 w (15 kW), the photoelectron uptake angle was 45 ° C., and the charge neutralization was Ion / Electron 20 μm.

  By processing each of the wiring circuit laminates 10 as shown in Table 1, a plurality of suspension substrates having a wiring pattern with L / S of 20/20 μm were obtained. At this time, the copper foil layer 13 in the laminated body for wiring circuit 10 was processed by performing chemical etching for 30 seconds using a ferric chloride solution as a chemical solution to form a wiring pattern.

[Comparative Example 1]
In this comparative example, the depth from the upper surface of the anticorrosive layer 15 is ₂ nm to 8 nm (in terms of SiO ₂ ) in the copper foil layer 13 including the laminate 10 for wiring circuit as shown in Table 2 below. A plurality of suspension substrates were prepared in the same manner as in Example 1 except that a plurality of wiring circuit laminates 10 in which the larger of the Zn content and Cr content in the region was larger than 19.8 at% were prepared. Obtained.

[Example 2]
In this comparative example, after preparing the wiring circuit laminate 10 as shown in Table 3 below, the wiring circuit laminate 10 was allowed to stand in an air atmosphere for 24 hours. Thereafter, a plurality of suspension substrates were obtained in the same manner as in Example 1.

[Comparative Example 2]
In this comparative example, after preparing the wiring circuit laminate 10 as shown in Table 4 below, the wiring circuit laminate 10 was allowed to stand in an air atmosphere for 24 hours. Thereafter, a plurality of suspension substrates were obtained in the same manner as in Example 1.

[Example 3]
In this example, a laminate 10 for a wiring circuit as shown in Table 5 below was prepared. The wiring circuit laminate 10 prepared in this example is manufactured by forming the Ni plating layer 25 on the conductor layer 24 as in the manufacturing method shown in FIG. And after preparing these laminated bodies 10 for wiring circuits, these laminated bodies 10 for wired circuits were left to stand for 24 hours in air | atmosphere. Thereafter, a plurality of suspension substrates were obtained by the same method as in Example 1.

[Comparative Example 3]
In this comparative example, a laminate 10 for a wiring circuit as shown in Table 6 below was prepared. The wiring circuit laminate 10 prepared in this comparative example is manufactured without forming the Ni plating layer 25 on the conductor layer 24 as in the manufacturing method shown in FIG. And after preparing these laminated bodies 10 for wiring circuits, these laminated bodies 10 for wired circuits were left to stand for 24 hours in air | atmosphere. Thereafter, a plurality of suspension substrates were obtained by the same method as in Example 1.

[Comparative Example 4]
In this comparative example, a plurality of suspension substrates were obtained in the same manner as in Example 1 except that a wiring circuit laminate 10 as shown in Table 7 below was prepared.

[Evaluation 1]
For the suspension substrates obtained in Example 1 and Comparative Example 1, the frequency of occurrence of a short circuit between wirings was measured. Specifically, the occurrence of a short circuit between wirings was inspected using an electric inspection machine by a four-terminal method under the conditions of a current value of 100 mA, a voltage value of 40 mV, and the number of tests of six. Then, by such a method, a plurality of suspension substrates obtained in Example 1 and Comparative Example 1 are inspected for occurrence of a short circuit, and each suspension substrate obtained in Example 1 and Comparative Example 1 is checked. The frequency of occurrence of short circuit was measured.

  FIG. 9 is a graph showing a measurement result of the frequency of occurrence of a short circuit in the suspension substrate obtained in Example 1 and Comparative Example 1. In the graph shown in FIG. 9, the horizontal axis indicates the larger content of the Zn content and the Cr content, and the vertical axis indicates the short-circuit occurrence frequency. From this graph, it can be seen that the frequency of short-circuiting increases rapidly when the larger content is 19.8% or more with the value of 19.8% of the larger content as the inflection point. It was. Further, it was confirmed that short-circuiting hardly occurred when the larger content was 16.0% or less.

FIG. 10 is a graph showing the distribution of the content of atoms in the suspension substrate obtained in Example 1 in which the frequency of short-circuit occurrence did not increase. In the graph shown in FIG. 10, the depth in terms of SiO ₂ from the top surface 15c of the anticorrosive layer is shown for the copper foil layer 13 in the laminated body 10 for the wiring circuit that constitutes the suspension substrate in which the occurrence frequency of the short circuit did not increase. Shows the distribution of Cu, Cr, Ni, and Zn in the region of 2 nm to 8 nm. From this graph, in the copper foil layer 13 in the wiring circuit laminate 10 constituting the suspension substrate obtained in Example 1 in which the frequency of short-circuit occurrence did not increase, the Cu content in the region was 23%. It was confirmed to be at or below.

[Evaluation 2]
With respect to the suspension substrates obtained in Example 2 and Comparative Example 2, the occurrence of rust in the wiring pattern was evaluated under the condition of being left for 24 hours in an air atmosphere. Table 8 shows that the larger of the Zn content and the Cr content in the region where the SiO ₂ conversion depth from the top surface 15c of the rust preventive layer is ₂ nm to 8 nm, and whether or not the wiring pattern is discolored It is the table | surface which showed the relationship of the evaluation result of (the presence or absence of generation | occurrence | production of rust).

  Table 8 shows that, in the suspension substrate, when the larger content of Zn and Cr is 1.65 at% or less, rust is generated in the wiring pattern. . And when the said content was 1.70 at% or more, it turned out that rust does not generate | occur | produce in a wiring pattern.

[Evaluation 3]
About the suspension substrate obtained in Example 3 and Comparative Example 3, the occurrence of rust in the wiring pattern was evaluated under the condition of being left for 24 hours in an air atmosphere. Table 9 shows the relationship between the Ni content in the region where the SiO ₂ conversion depth from the top surface 15c of the anticorrosive layer is ₂ nm to 8 nm and the evaluation result of the presence or absence of discoloration (whether rust is generated) in the wiring pattern. It is the table shown.

  From Table 9, in the wiring circuit laminate 10 obtained in Example 3, the discoloration (generation of rust) was not confirmed unlike the wiring circuit laminate 10 obtained in Comparative Example 3. This is because, in the wiring circuit laminate 10 obtained in Example 3, the diffusion of Cu from the conductor layer 14 to the defense layer 15 is prevented by containing Ni in the rust prevention layer 15. Estimated.

[Evaluation 4]
With respect to the suspension substrates obtained in Example 1 and Comparative Example 4, the frequency of occurrence of a short circuit between wirings was measured. Specifically, the occurrence of a short circuit between wirings was inspected using an electric inspection machine by a four-terminal method under the conditions of a current value of 100 mA, a voltage value of 40 mV, and the number of tests of six. Then, by such a method, a plurality of suspension substrates obtained in Example 1 and Comparative Example 4 are inspected for occurrence of a short circuit, and each suspension substrate obtained in Example 1 and Comparative Example 4 is checked. The frequency of occurrence of short circuit was measured.

FIG. 11 is a graph showing the distribution of short-circuit occurrence frequency in the suspension substrates obtained in Example 1 and Comparative Example 4. From the graph shown in FIG. 11, in the suspension substrate obtained in Example 1, almost no short circuit occurred, whereas in the suspension substrate obtained in Comparative Example 4, short circuit occurred frequently. It was confirmed that it occurred. This is because, in the wiring circuit laminate 10 in which the Ni content is greater than 10 at% in the region where the depth from the upper surface 15 c of the rust prevention layer is ₂ nm to 8 nm (SiO ₂ conversion), the etching characteristics deteriorate. In the suspension substrate obtained from the wiring circuit laminate 10, it is shown that short-circuits frequently occur.

  DESCRIPTION OF SYMBOLS 10 ... Laminated body for wiring circuits, 11 ... Metal support layer, 12 ... Insulating layer, 13 ... Copper foil layer, 14 ... Conductor layer, 15 ... Rust prevention layer, 15c ... Top surface of a rust prevention layer, 21 ... (in manufacturing process) ) Metal support layer, 22... (In manufacturing process) Insulating layer, 23... (Manufacturing process) Alloy layer, 24... (Manufacturing process) Conductor layer, 26... (Manufacturing process) Zn / Cr plated layer, 26 c. Upper surface of Zn / Cr plated layer (of manufacturing process), 30 ... suspension substrate, 31 ... element mounting region, 32 ... external circuit board connection region, 33 ... wiring, 40 ... suspension substrate, 41 ... metal support layer, 42 Insulating layer, 43 ... Wiring layer, 44 ... Conductor layer, 45 ... Anticorrosive layer, 45c ... Upper surface of antirust layer, 50 ... Laminate for wiring circuit, 51 ... Metal support layer, 52 ... Insulating layer, 53 ... Copper Foil layer 54 ... Wiring pattern 55 ... Cover layer 60 ... Suspension , 61 ... element mounting region, 62 ... load beam 70 ... suspension with element, 71 ... device, 80 ... hard disk drive, 81 ... disc, 82 ... spindle motor, 83 ... arm, 84 ... voice coil motor, 85 ... Case

Claims (8)

A laminate for a wiring circuit having a metal support layer, an insulating layer formed on the metal support layer, and a copper foil layer formed on the insulating layer,
The copper foil layer has a conductor layer made of plated copper, and a rust prevention layer formed on the conductor layer and containing Zn and Cr,
In the copper foil layer, the larger one of the Zn content and the Cr content in a region having a depth from the top surface of the anticorrosive layer of ₂ nm to 8 nm (in terms of SiO ₂ ) is 1.7 at% to 10. .9 at%, a laminate for a printed circuit. The rust preventive layer contains Ni;
_2. The wiring according to claim 1, wherein the copper foil layer has a Ni content of 10 at% or less in a region having a depth of ₂ nm to 8 nm (in terms of SiO ₂ ) from the top surface of the rust prevention layer. Laminate for circuit. A suspension substrate having a metal support layer, an insulating layer formed on the metal support layer, and a wiring layer formed on the insulating layer,
The wiring layer has a conductor layer made of plated copper, and a rust prevention layer formed on the conductor layer and containing Zn and Cr,
In the wiring layer, the larger one of the Zn content and the Cr content in a region having a depth from the top surface of the rust prevention layer of ₂ nm to 8 nm (SiO ₂ conversion) is 1.7 at% to 10. A suspension substrate, characterized by 9 at%. The rust preventive layer contains Ni;
4. The suspension according to claim 3, wherein the wiring layer has a Ni content of 10 at% or less in a region having a depth of ₂ nm to 8 nm (in terms of SiO ₂ ) from the upper surface of the rust prevention layer. substrate. A preparation step for preparing the multilayer body for a wiring circuit according to claim 1 or 2,
A pattern forming step of forming a wiring pattern by etching the copper foil layer in the laminate for a wiring circuit;
A method for manufacturing a suspension substrate, comprising:   A suspension comprising the suspension substrate according to claim 3.   A suspension with an element, comprising: the suspension according to claim 6; and an element mounted in an element mounting region of the suspension.   A hard disk drive comprising the suspension with an element according to claim 7.

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