Method for manufacturing wiring board

Abstract

The invention provides a method for manufacturing a wiring board, which can simply and reliably peel off a carrier. The method for manufacturing the wiring board comprises the following steps of: preparing a laminated sheet which is provided with a stripping layer and a wiring layer in sequence on a carrier; a step or a gap is formed between the wiring layer and the carrier to serve as a stripping starting point part; inserting a rigid plate having a long portion into the peeling starting point portion from the long portion, the long portion being longer than the width of the laminated sheet; and developing peeling of the wiring layer from the carrier by moving the rigid plate from the peeling starting point along the peeling layer, the bending elastic modulus of the wiring layer at 25 DEG C measured in accordance with JIS K6911-1995 being 0.3 GPa or more and 300 GPa or less.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a wiring substrate. Background Art

[0002] In recent years, in order to increase the mounting density of printed circuit boards and miniaturize them, the multilayering of printed circuit boards has become widespread. Such multilayer printed circuit boards are used in many portable electronic devices for the purpose of weight reduction and miniaturization. In addition, the thickness of the interlayer insulating layer of the multilayer printed circuit board is required to be further reduced, and the wiring board is required to be further lightweight.

[0003] As a technology that meets such requirements, a method for manufacturing a multilayer printed circuit board using a coreless build-up method is adopted. The coreless build-up method refers to a method of multilayering by alternately stacking (Buildup: buildup) insulating layers and wiring layers without using a so-called core substrate. In the coreless build-up method, in order to easily peel off the support body and the multilayer printed circuit board, a scheme of using a metal foil with a carrier is proposed. For example, Patent Document 1 (Japanese Patent Publication No. 2005-101137) discloses a method for manufacturing a package substrate for mounting semiconductor elements, which includes the following steps: an insulating resin layer is attached to the carrier surface of a copper foil with a carrier to form a support body, a first wiring conductor is formed on the ultra-thin copper layer side of the copper foil with a carrier through processes such as photoresist processing, pattern copper plating, and resist removal, and then a build-up wiring layer is formed, and the support substrate with a carrier is peeled off to remove the ultra-thin copper layer.

[0004] In addition, in order to miniaturize the embedded circuit as shown in Patent Document 1, it is ideal to set the thickness of the metal layer to a metal foil with a carrier of less than 1 μm. Therefore, in order to reduce the thickness of the metal layer, a scheme of forming the metal layer by a vapor phase method such as sputtering is proposed. For example, Patent Document 2 (International Publication No. 2017 / 150283) discloses a copper foil with a carrier having a peeling layer, an anti-reflection layer, and an extremely thin copper layer (e.g., a film thickness of 300 nm) formed on a carrier such as a glass sheet by sputtering. In addition, Patent Document 3 (International Publication No. 2017 / 150284) discloses a copper foil with a carrier having an intermediate layer (e.g., a close-fitting metal layer and a peeling auxiliary layer), a peeling layer, and an extremely thin copper layer (e.g., a film thickness of 300 nm) formed on a carrier such as a glass sheet by sputtering. Patent documents 2 and 3 also provide the following suggestion: by providing an intermediate layer composed of a specified metal to give the carrier excellent stability in mechanical peel strength, or by making the anti-reflection layer an ideal dark color, the visibility in image inspection (such as automatic image inspection (AOI)) can be improved.

[0005] In particular, with the further miniaturization and power saving of electronic devices, the demand for high integration and thinning of semiconductor chips and printed circuit boards is increasing. As a new generation of packaging technology to meet this demand, FO-WLP (Fan-Out Wafer Level Packaging) and PLP (Panel Level Packaging) are being studied in recent years. In addition, in FO-WLP and PLP, the use of coreless lamination is also being studied. As one of such methods, there is a method called RDL-First (Redistribution Layer-First) method, that is, after forming a wiring layer on the surface of a coreless support body and laminating the wiring layer as needed, the chip is installed and sealed, and then the support body is peeled off. For example, patent document 4 (Japanese Patent Gazette No. 2015-35551) discloses a method for manufacturing a semiconductor device, which includes the following steps: forming a metal peeling layer on the main surface of a support body made of a glass or silicon wafer; forming an insulating resin layer thereon; forming a redistribution layer (Redistribution Layer) including a build-up layer thereon; mounting and sealing a semiconductor integrated circuit thereon; exposure of the peeling layer due to removal of the support body; exposure of a secondary mounting pad due to removal of the peeling layer; and formation of solder bumps on the surface of the secondary mounting pad; and secondary mounting.

[0006] In addition, when peeling a carrier from a carrier with a wiring layer made using a coreless lamination method, the wiring layer bends greatly and causes disconnection and peeling, resulting in a possible reduction in the connection reliability of the wiring layer. Therefore, a method for removing the carrier to address this problem is proposed. For example, Patent Document 5 (International Publication No. 2017 / 075151) discloses a method for processing a first substrate bonded to a second substrate, wherein a wire is moved along an interface to propagate a peeling front and the first substrate is peeled from the second substrate. In the method disclosed in Patent Document 5, a thin and soft wire is used to reduce the bending of the first substrate during peeling. If the bending of the first substrate during peeling is reduced, relatively less bending stress is applied to the first substrate during the peeling process. In addition, by utilizing the softness of the wire, the wire can be matched with the peeling front, and the stress that may increase due to the interaction with the shape change that may occur due to damage to the glass can be released.

[0007] In addition, Patent Document 6 (Japanese Patent Publication No. 2015-145306) discloses that, in a method for manufacturing an electronic device, a peeling process has the following steps: inserting a knife from the end surface of a laminated body to the interface between a first substrate and a second substrate by a predetermined amount, and forming a peeling start portion at the interface; starting from the peeling start portion, the interface is peeled off in sequence along the peeling direction from one end side of the laminated body toward the other end side. Patent Document 6 also discloses that, in the peeling start portion forming step, inclusions such as liquid are supplied to the knife, and the knife to which the inclusions are attached is inserted into the interface. According to this method, even if the knife is pulled out from the interface between the first substrate and the second substrate, the peeling start portion can be reliably formed using the liquid that has penetrated into the interface.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2005-101137

[0011] Patent Document 2: International Publication No. 2017 / 150283

[0012] Patent Document 3: International Publication No. 2017 / 150284

[0013] Patent Document 4: Japanese Patent Application Publication No. 2015-35551

[0014] Patent Document 5: International Publication No. 2017 / 075151

[0015] Patent Document 6: Japanese Patent Application Publication No. 2015-145306 Summary of the invention

[0016] However, in the method disclosed in Patent Document 5, when the gap formed by stripping is developed, the strength of the wire used is sometimes insufficient and breaks, and the stripping process is interrupted. In addition, when the bending elastic modulus of the substrate (for example, a wiring layer containing resin) is high, there is a problem that the substrate is damaged or cracked during the stripping process. On the other hand, in the method disclosed in Patent Document 6, since a knife with a chemical solution attached thereto is used to develop the stripping, the chemical solution sometimes adheres to the metal constituting the substrate and reacts, which hinders the metal etching performed in the subsequent process. Thus, from the perspective of simple and reliable carrier stripping, the conventional methods have room for improvement.

[0017] The inventors of the present invention have now reached the following understanding: for a laminated sheet that sequentially includes a carrier, a peeling layer, and a wiring layer having a specified bending elastic modulus, a peeling starting point is formed between the wiring layer and the carrier, and after a specified rigid board is inserted into the peeling starting point, the rigid board is moved along the peeling layer, thereby enabling the carrier to be easily and reliably peeled off to manufacture a wiring substrate.

[0018] Therefore, an object of the present invention is to provide a method for manufacturing a wiring substrate capable of easily and reliably peeling off a carrier.

[0019] According to the present invention, the following technical solutions are provided.

[0020] [Technical solution 1]

[0021] A method for manufacturing a wiring substrate, wherein the manufacturing method of the wiring substrate includes the following steps: preparing a laminated sheet having a peeling layer and a wiring layer in sequence on a carrier; forming a step or a gap between the wiring layer and the carrier as a peeling starting point; inserting a rigid plate having a long strip portion from the long strip portion into the peeling starting point, wherein the long strip portion is longer than the width of the laminated sheet; and advancing the peeling of the wiring layer from the carrier by moving the rigid plate from the peeling starting point along the peeling layer, wherein the bending elastic modulus of the wiring layer at 25°C measured based on JIS K6911-1995 is greater than 0.3 GPa and less than 300 GPa.

[0022] [Technical Solution 2]

[0023] The method for manufacturing a wiring board according to claim 1, wherein the bending strength of the wiring layer at 25°C measured in accordance with JIS K6911-1995 is 5 MPa or more and 1000 MPa or less.

[0024] [Technical Solution 3]

[0025] The method for manufacturing a wiring substrate according to claim 1 or 2, wherein the Rockwell hardness of the rigid plate at 25° C. measured based on JIS Z2245:2016 is R135 or less.

[0026] [Technical Solution 4]

[0027] The method for manufacturing a wiring board according to any one of claims 1 to 3, wherein the rigid plate has a breaking strength of 0.50 kgf or more at 25°C as measured in accordance with JIS K7161-1:2014.

[0028] [Technical Solution 5]

[0029] The method for manufacturing a wiring substrate according to any one of claims 1 to 4, wherein a peel strength when the wiring layer is peeled off from the carrier is 0.10 gf / cm or more and 50 gf / cm or less.

[0030] [Technical Solution 6]

[0031] The method for manufacturing a wiring substrate according to any one of technical solutions 1 to 5, wherein the peeling starting point is formed at an end of the wiring layer and / or an end of the carrier.

[0032] [Technical Solution 7]

[0033] The method for manufacturing a wiring board according to any one of claims 1 to 6, wherein an insertion angle of the rigid plate with respect to the main surface of the carrier is not less than 0° and not more than 90°.

[0034] [Technical Solution 8]

[0035] A method for manufacturing a wiring substrate according to any one of technical solutions 1 to 7, wherein the front end angle of the long strip side is greater than 0° and less than 90° or the front end of the long strip side has a curvature of greater than 0.1 mm and less than 10 mm when the rigid plate is cross-sectioned.

[0036] [Technical Solution 9]

[0037] A method for manufacturing a wiring substrate according to any one of technical solutions 1 to 8, wherein the total angle of the insertion angle of the rigid plate relative to the main surface of the carrier and the front end angle of the long strip side when the rigid plate is cross-sectioned is greater than 0° and less than 120°.

[0038] [Technical Solution 10]

[0039] The method for manufacturing a wiring substrate according to any one of claims 1 to 9, wherein the width of the rigid plate is not less than 1.0 mm and not more than 300 mm.

[0040] [Technical Solution 11]

[0041] The method for manufacturing a wiring substrate according to any one of claims 1 to 10, wherein the rigid plate has a thickness of 0.040 mm to 10 mm.

[0042] [Technical Solution 12]

[0043] The method for manufacturing a wiring substrate according to any one of claims 1 to 11, wherein the rigid plate is made of resin.

[0044] [Technical Solution 13]

[0045] The method for manufacturing a wiring substrate according to any one of technical solutions 1 to 12, wherein the step of forming the peeling starting point and / or the step of advancing the peeling are performed without causing liquid to adhere to the step or gap.

[0046] [Technical Solution 14]

[0047] The method for manufacturing a wiring substrate according to any one of claims 1 to 13, wherein the wiring layer includes at least one selected from the group consisting of a metal layer, a semiconductor element, and a resin-containing layer.

[0048] [Technical Solution 15]

[0049] The method for manufacturing a wiring substrate according to any one of claims 1 to 14, wherein the thickness of the wiring layer is not less than 0.1 μm and not more than 5.0 mm.

[0050] [Technical Solution 16]

[0051] The method for manufacturing a wiring substrate according to any one of claims 1 to 15, wherein the wiring layer includes a metal layer and a resin-containing layer.

[0052] [Technical Solution 17]

[0053] The method for manufacturing a wiring substrate according to any one of claims 1 to 15, wherein the wiring layer includes a resin-containing layer, and the resin-containing layer contains a filler.

[0054] [Technical Solution 18]

[0055] The method for manufacturing a wiring board according to any one of claims 14 to 17, wherein the filler content of the resin-containing layer is 95% by weight or less. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic cross-sectional view showing an example of a laminated sheet used in the present invention.

[0057] Figure 2A This is a process flow chart showing an example of a method for manufacturing a wiring board of the present invention using a schematic plan view, and corresponds to the previous steps (step (i) and step (ii)).

[0058] Figure 2B A schematic cross-sectional view is used to represent Figure 2A The process flow chart of the corresponding process.

[0059] Figure 3A This is a process flow chart showing an example of a method for manufacturing a wiring substrate of the present invention using a schematic top view, which is equivalent to the following Figure 2AThe subsequent steps (step (iii) and step (v)) of the steps shown.

[0060] Figure 3B A schematic cross-sectional view is used to represent Figure 3A The process flow chart of the corresponding process.

[0061] Figure 4 Schematic cross-sectional view for explaining the angle θ of the front end of the rigid plate.

[0062] Figure 5 This is a schematic cross-sectional view showing an example of a conventional carrier peeling method using a wire rod.

[0063] Figure 6 These are photographs of the intermediate layer (copper layer) and the metal layer (titanium layer) of the laminated sheet produced in Example 1 after the carrier has been peeled off.

[0064] Figure 7 These are photographs of the intermediate layer (copper layer) and the metal layer (titanium layer) of the laminated sheet produced in Example 2 (comparison) after the carrier has been peeled off. DETAILED DESCRIPTION

[0065] Method for manufacturing wiring substrate

[0066] The present invention relates to a method for manufacturing a wiring substrate, which comprises the following steps: (1) preparing a laminated sheet, (2) forming a peeling starting point, (3) inserting a rigid board, (4) moving the rigid board, and (5) peeling off a carrier as desired.

[0067] An example of a laminate sheet used in the present invention is shown in Figure 1 , and an example of a method for manufacturing a wiring substrate of the present invention is shown in Figure 2A to Figure 3B Hereinafter, each step (1) to (5) will be described with reference to the drawings.

[0068] (1) Preparation of laminated sheets

[0069] like Figure 1 , Figure 2A (i) and Figure 2B As shown in (i), a build-up sheet 10 is prepared which includes a release layer 16 and a wiring layer 26 in this order on a carrier 12. The release layer 16 is provided on the carrier 12 and is a layer that facilitates the separation of the carrier 12 and the wiring layer 26. The wiring layer 26 is a layer provided on the release layer 16 and includes a wiring conductor.

[0070] The build-up sheet 10 may further include an intermediate layer 14 between the carrier 12 and the release layer 16. The intermediate layer 14, the release layer 16, and the wiring layer 26 may each be a single layer consisting of one layer, or may be a multilayer consisting of two or more layers.

[0071] For example, the laminated sheet 10 can be prepared as follows. First, a metal foil with a carrier having an intermediate layer 14, a peeling layer 16 and a metal layer 18 on a carrier 12 is prepared. Next, a first wiring layer is formed on the surface of the metal layer 18. Thereafter, a redistribution layer 20 is constructed based on the first wiring layer. The formation of the first wiring layer and the construction of the redistribution layer 20 can be carried out by a known method, for example, the coreless lamination method described above can be preferably used. In addition, a semiconductor element 22 can be installed on the first wiring layer (or on the redistribution layer 20 constructed based on the first wiring layer) as needed (see Figure 1 ). The semiconductor element 22 is electrically connected to the redistribution layer 20 by bonding the electrodes of the semiconductor element 22 to the wiring of the redistribution layer 20. Preferably, the semiconductor element 22 is covered with the resin-containing layer 24 after being mounted on the redistribution layer 20. In this specification, the "wiring layer" is defined as including not only the redistribution layer 20 (also called the wiring layer in a narrow sense), but also the metal layer 18, the semiconductor element 22 and the resin-containing layer 24, and may also be referred to as a "device layer". In addition, in this specification, the carrier 12, the intermediate layer 14 (if present), the peeling layer 16 and the metal layer 18 are sometimes collectively referred to as "metal foil with a carrier". The preferred embodiment of the metal foil with a carrier is described later.

[0072] As described above, the wiring layer 26 may include at least one selected from the group consisting of the metal layer 18, the semiconductor element 22, and the resin-containing layer 24. The wiring layer 26 preferably includes at least the resin-containing layer 24, and more preferably includes the metal layer 18 and the resin-containing layer 24.

[0073] The bending modulus of the wiring layer 26 is 0.3 GPa or more and 300 GPa or less, preferably 0.7 GPa or more and 200 GPa or less, more preferably 1.0 GPa or more and 100 GPa or less, further preferably 1.5 GPa or more and 70 GPa or less, and particularly preferably 2.0 GPa or more and 28 GPa or less. In addition, the bending strength of the wiring layer 26 is preferably 5 MPa or more and 1000 MPa or less, more preferably 8 MPa or more and 700 MPa or less, further preferably 15 MPa or more and 500 MPa or less, particularly preferably 25 MPa or more and 350 MPa or less, and most preferably 70 MPa or more and 200 MPa or less. The bending modulus and bending strength in this specification are values ​​measured at 25°C based on JIS K6911-1995. Even if the wiring layer 26 has a large bending modulus and / or bending strength, in other words, is a hard and brittle device, the method of the present invention can effectively suppress damage or destruction of the wiring layer 26 while peeling off the carrier 12. In addition, when the wiring layer 26 has a resin-containing layer 24, at least the bending modulus and / or bending strength of the resin-containing layer 24 is within the above range.

[0074] The thickness of the wiring layer 26 is preferably 0.1 μm or more and 5.0 mm or less, more preferably 0.1 μm or more and 3.0 mm or less, further preferably 0.4 μm or more and 2.0 mm or less, and particularly preferably 0.8 μm or more and 1.0 mm or less. In addition, when the wiring layer 26 includes a resin-containing layer 24, the thickness of the resin-containing layer 24 is preferably 2.0 mm or less, more preferably 5 μm or more and 1.0 mm or less, further preferably 8 μm or more and 500 μm or less, and particularly preferably 15 μm or more and 350 μm or less. Even in the case where the wiring layer 26 is thin, according to the method of the present invention, the carrier 12 can be peeled off while effectively suppressing damage or destruction of the wiring layer 26 (especially the resin-containing layer 24).

[0075] The resin-containing layer 24 is a layer containing resin, typically a layer (molding layer) for sealing and protecting semiconductor elements (chips). Preferred examples of the resin constituting the resin-containing layer 24 include epoxy resins and resins containing epoxy resins. From the viewpoint of improving the bending modulus and / or bending strength, the resin-containing layer 24 preferably contains fillers. Preferred examples of fillers include silica and titanium dioxide. The content of fillers in the resin-containing layer 24 is preferably 0% by weight or more and 95% by weight or less, more preferably 50% by weight or more and 93% by weight or less, and further preferably 82% by weight or more and 91% by weight or less. The average particle size D50 of the filler is preferably 1.0 μm or more and 70 μm or less, more preferably 10 μm or more and 25 μm or less. In addition, in this specification, the average particle size D50 refers to the particle size with a cumulative volume of 50% from the small particle size side in the particle size distribution obtained by the laser diffraction scattering method.

[0076] (2) Formation of the peeling starting point

[0077] A step or gap is formed between the wiring layer 26 and the carrier 12 to serve as a peeling starting point S ( Figure 2B (ii) Refer to). By inserting and moving the rigid plate described later starting from the peeling starting point S, the carrier 12 can be peeled off smoothly. Figure 2B In (i) and (ii), the cross section of the resin-containing layer 24 is formed into a trapezoidal shape, but it may be formed into a rectangular or oblong shape.

[0078] From the viewpoint of facilitating the insertion of the rigid board, the peeling starting point S is preferably formed at the end of the wiring layer 26 and / or the end of the carrier 12. Furthermore, when the build-up sheet 10 is polygonal (e.g., rectangular), the peeling starting point S is more preferably formed at the corner portion of the wiring layer 26 and / or the corner portion of the carrier 12.

[0079] The method for forming the peeling starting point S is not particularly limited, and any method may be used. For example, by inserting a thin sheet between the wiring layer 26 and the carrier 12 (near the peeling layer 16), applying force to the end of the build-up sheet 10 in the direction of separating the wiring layer 26 from the carrier 12, and partially peeling the area including the end of the peeling layer 16, the peeling starting point S can be formed.

[0080] On the other hand, Figure 1 As shown, when the end of the peeling layer 16 is covered by the metal layer 18, it becomes difficult to form the peeling starting point S. In this case, it is preferable to Figure 2AAs shown in (ii), the edge of the peeling layer 16 is exposed by cutting around the laminated sheet 10. Specifically, it is preferred to cut the laminated sheet 10 from the surface on the side opposite to the side where the carrier 12 is located so as to penetrate the metal layer 18, the peeling layer 16, and the intermediate layer 14 (if present) when the laminated sheet 10 is cross-sectioned. By removing the portion of the metal layer 18 that covers the edge of the peeling layer 16, the end surface of the peeling layer 16 can be exposed.

[0081] The stripping starting point S can be formed without causing liquid (e.g., liquid such as lubricant) to adhere to the step or gap. In this way, the following inconveniences can be prevented: liquid adheres to the metal portion of the wiring layer 26 and the etching rate of the adhered portion changes. That is, the occurrence of insufficiently etched portions, the need for a longer time to perform a predetermined etching, or the occurrence of uneven etching due to the presence of such areas can be suppressed.

[0082] (3) Insertion of rigid plate

[0083] The rigid plate 28 having the elongated portion is inserted from the elongated portion into the formed peeling starting point S (see Figure 3A (iii) and Figure 3B (iii)). The rigid board 28 is a board having the desired rigidity, and may be in the form of a film or a sheet. Here, at least the long strip portion of the rigid board 28 is longer than the width of the laminated sheet 10. Thus, the movement of the rigid board 28 described later can be performed while holding the long strip portion of the rigid board 28 near both ends. As a result, it is easy to apply uniform force to the wiring layer 26 without bending the rigid board 28, and the carrier 12 can be efficiently peeled off. In the case where the laminated sheet 10 is rectangular in shape, the long strip portion of the rigid board 28 only needs to be longer than the length of the short side of the laminated sheet 10, and may include the long side or the short side. On the other hand, in the case where the laminated sheet 10 is in the form of a circular plate, the length of the long strip portion of the rigid board 28 is preferably larger than the diameter of the laminated sheet 10. In any case, the length of the long strip portion of the rigid board 28 can be appropriately changed according to the size of the laminated sheet 10.

[0084] The insertion angle of the rigid board 28 relative to the main surface of the carrier 12 is preferably greater than 0° and less than 90°, more preferably greater than 0° and less than 65°, further preferably greater than 3° and less than 30°, and particularly preferably greater than 5° and less than 15°. Thus, when the rigid board 28 is inserted and moved toward the buildup sheet 10, it is easy to apply force to the wiring layer 26 at a desired peeling angle, and it is easy to cause the wiring layer 26 to peel off from the carrier 12. The insertion angle is defined as the angle between the front end of the rigid board 28 and the surface of the carrier 12 at the location where the front end (or an imaginary line passing through the front end) of the rigid board 28 is in contact with the surface of the carrier 12 (the surface of the intermediate layer 14 if present) when the buildup sheet 10 is cut.

[0085] The rigid plate 28 is Figure 4 When viewed in section as shown, the front end angle θ of the long strip side (the side in contact with the wiring layer 26) is preferably greater than 0° and less than 90°, more preferably greater than 0° and less than 45°, and further preferably greater than 5° and less than 45°. In addition, the total angle of the insertion angle of the above-mentioned rigid board 28 and the front end angle of the above-mentioned rigid board 28 is preferably greater than 0° and less than 120°, more preferably greater than 0° and less than 90°, and most preferably greater than 5° and less than 45°. Alternatively, the front end of the long strip side (the side in contact with the wiring layer 26) of the rigid board 28 can have a curvature of greater than 0.1 mm and less than 10 mm, more preferably a curvature of greater than 0.2 mm and less than 10 mm, and further preferably a curvature of greater than 0.5 mm and less than 5.0 mm. As a result, it is easier to cause the wiring layer 26 to peel off from the carrier 12, and the damage to the wiring layer 26 can be more effectively suppressed when the rigid board 28 contacts the wiring layer 26.

[0086] The Rockwell hardness of the rigid board 28 at 25°C measured based on JIS Z2245:2016 is preferably R135 or less, more preferably R132 or less, further preferably R130 or less, and particularly preferably R128 or less. The lower limit of the Rockwell hardness is not particularly limited, but is typically R50 or more. By using such a soft material, it is difficult to damage the wiring layer 26 when the rigid board 28 is inserted into the build-up sheet 10 and moved, and damage to the wiring layer 26 caused by contact with the rigid board 28 when the peeling of the wiring layer 26 from the carrier 12 progresses can be more effectively suppressed.

[0087] The breaking strength of the rigid board 28 at 25°C measured based on JIS K7161-1:2014 is preferably 0.50 kgf or more, more preferably 0.80 kgf or more, further preferably 2.0 kgf or more, and particularly preferably 4.0 kgf or more. The upper limit of the breaking strength is not particularly limited, but is typically 10 kgf or less. By using a material having such strength, when the rigid board 28 is inserted into the build-up sheet 10 and moved to cause the wiring layer 26 to peel off from the carrier 12, the breaking of the rigid board 28 can be suppressed, effectively preventing the interruption of the process.

[0088] The peel strength when peeling the wiring layer 26 from the carrier 12 is preferably 0.10 gf / cm or more and 50 gf / cm or less, more preferably 1.0 gf / cm or more and 30 gf / cm or less, further preferably 1.5 gf / cm or more and 10 gf / cm or less, and particularly preferably 2.0 gf / cm or more and 5.0 gf / cm or less. By using a material having such a peel strength, when the rigid board 28 is inserted into the build-up sheet 10 and moved to cause the peeling of the wiring layer 26 from the carrier 12 to progress, the peeling of the wiring layer 26 from the carrier 12 can be easily progressed, and the damage to the wiring layer 26 caused by the contact with the rigid board 28 can be more effectively suppressed, and the rigid board 28 can be prevented from breaking, thereby effectively preventing the interruption of the process.

[0089] The bending elastic modulus of the rigid board 28 is preferably 0.1 GPa or more and 20 GPa or less, more preferably 0.3 GPa or more and 10 GPa or less, further preferably 0.5 GPa or more and 7.0 GPa or less, and particularly preferably 1.0 GPa or more and 5.0 GPa or less. By using a material having such a bending elastic modulus to form the rigid board 28, when the rigid board 28 is inserted into the build-up sheet 10 and moves so that the wiring layer 26 is peeled off from the carrier 12, damage such as destruction and breakage of the wiring layer 26 can be more effectively suppressed, and a reduction in yield and interruption of the process can be effectively prevented.

[0090] The width (short side length) of the rigid board 28 is preferably 1.0 mm or more and 300 mm or less, more preferably 2.0 mm or more and 100 mm or less, further preferably 3.0 mm or more and 50 mm or less, and particularly preferably 4.0 mm or more and 30 mm or less. Thus, even a thin rigid board 28 can improve strength and easily apply force to the wiring layer 26, and as a result, the carrier 12 can be peeled off more efficiently. In addition, the width of the rigid board 28 can be the same as the length of the long strip (that is, a square-shaped rigid board 28).

[0091] The thickness of the rigid board 28 is preferably 0.040 mm to 10 mm, more preferably 0.060 mm to 8.0 mm, further preferably 0.080 mm to 5.0 mm, and particularly preferably 0.20 mm to 3.0 mm. With such a thin rigid board 28, it is easy to peel the wiring layer 26 from the carrier 12 at an ideal peeling angle, and cracking and damage caused by bending of the wiring layer 26 can be more effectively suppressed.

[0092] From the perspective of being able to easily impart the desired rigidity, Rockwell hardness, breaking strength, etc., the rigid plate 28 is preferably made of resin. Examples of such resins include polyethylene terephthalate (PET), ultra-high molecular weight polyethylene, hard polyethylene (HPE), polypropylene (PP), polystyrene (PS), methacrylic acid (MA), acrylonitrile-butadiene-styrene (ABS), polyamide (nylon 6, 6N), monomer cast nylon (MC), polyacetal (POM), polycarbonate (PC), polytetrafluoroethylene (PTFE), hard vinyl chloride (PVC), polyphenylene ether (PPO) and polyurethane (PUR). The rigid plate 28 is particularly preferably made of at least one selected from the group consisting of polyethylene terephthalate (PET), ultra-high molecular weight polyethylene (UHMW), hard polyethylene (HPE), polypropylene (PP) and polystyrene (PS), and more preferably made of polyethylene terephthalate (PET). The elastic modulus of the resin constituting the rigid plate 28 is preferably 4×10 3 kgf / cm 2 Above and 70×10 3 kgf / cm 2 Below, more preferably 10×10 3 kgf / cm 2 Above and 40×10 3 kgf / cm 2 Below, more preferably 25×10 3 kgf / cm 2 Above and 35×10 3 kgf / cm 2 As a result, when the rigid board 28 is inserted into the build-up sheet 10 and moved, force is easily applied to the wiring layer 26, and the wiring layer 26 is easily peeled off from the carrier 12, and damage to the wiring layer 26 caused by contact with the rigid board 28 can be more effectively suppressed. In addition, the elastic modulus of the present invention is a value measured based on JIS K6911-1995.

[0093] It is preferred that the rigid plate 28 be inserted into the peeling starting point S without allowing liquid (e.g., a lubricant or other liquid) to adhere to the rigid plate 28. This can prevent the liquid from adhering to the metal portion of the wiring layer 26 and reacting, thereby avoiding obstruction of metal etching that will be performed in a subsequent process.

[0094] (4) Movement of the rigid plate

[0095] The rigid plate 28 is moved from the peeling starting point S along the peeling layer 16 (see Figure 3A (iv) and Figure 3B (iv)). Thus, the peeling of the wiring layer 26 from the carrier 12 progresses. That is, by moving the rigid plate 28 inserted into the peeling starting point S in a direction substantially parallel to the main surface of the carrier 12, a force (peeling force) in a direction of separation from the carrier 12 is applied to the wiring layer 26. Thus, the step or gap between the wiring layer 26 and the carrier 12 gradually expands, and as a result, the peeling of the carrier 12 is promoted. In this way, for the laminated sheet 10 having the carrier 12, the peeling layer 16 and the wiring layer 26 having a specified bending elastic modulus in sequence, a peeling starting point S is formed between the wiring layer 26 and the carrier 12, a specified rigid plate 28 is inserted into the peeling starting point S, and then the rigid plate 28 is moved along the peeling layer 16, so that the carrier 12 can be easily and reliably peeled off to manufacture a wiring substrate.

[0096] In this regard, from the perspective of simple and reliable carrier peeling, the conventional wiring substrate manufacturing methods disclosed in Patent Document 5 (International Publication No. 2017 / 075151) and Patent Document 6 (Japanese Patent Publication No. 2015-145306) are not sufficient. Figure 5 An example of a conventional carrier peeling method using a wire is shown in FIG. Figure 5 In the conventional example shown, in a laminated sheet 110 having a carrier 112 and a wiring layer 126, a wire W is inserted between the carrier 112 and the wiring layer 126 to allow the peeling of the two to progress. In this regard, the shorter the distance between the peeling position (fulcrum) and the position (force point) of the wire W, the greater the force applied to the wiring layer 126, and the easier it is to allow the peeling to progress. However, since the wire W is easily bent in the direction of the peeling progress, there is a risk that a force greater than the force required for peeling is applied to the surface of the wiring layer 126, thereby damaging or destroying the wiring layer 126. In addition, in the case where the strength of the wire W is insufficient and breaks, the peeling process is interrupted. On the other hand, even in the case where the wire W' with a thicker cross-sectional diameter is changed to improve the strength of the wire, it is possible that the wiring layer 126 is cracked due to the large bending of the wiring layer 126. This problem becomes apparent in particular when the wiring layer 126 has a thin resin-containing layer (e.g., a resin-containing layer containing fillers) with a large bending elastic modulus.

[0097] On the other hand, in the conventional carrier stripping method using a knife or the like, there is a possibility that the carrier or the metal layer that may be included in the wiring layer may be damaged by the knife when the stripping progresses, resulting in the production of something that cannot be used as a wiring substrate, and the yield rate is reduced. In addition, when a knife or the like with a chemical solution attached thereto is used, the metal constituting the wiring layer reacts with the attached chemical solution, which may hinder the metal etching performed in the subsequent process.

[0098] In contrast, in the present invention, since the stripping progresses using the rigid plate 28 having a long strip portion, a large force can be applied to the wiring layer 26 without causing the rigid plate 28 itself to break. In addition, even when the rigid plate 28 is thin, the strength can be increased by increasing the width of the rigid plate 28, so the carrier 12 can be stripped while suppressing the bending of the wiring layer 26. Furthermore, in the present invention, even without using a liquid such as a lubricant, the carrier 12 can be stripped without damaging the wiring layer 26, so in the etching process as a post-process, there is no need to remove the lubricant or the like. Therefore, it is preferable to carry out the process of progressing the stripping without causing the liquid to adhere to the steps or gaps formed in the laminated sheet 10.

[0099] The movement of the rigid plate 28 can be performed manually or automatically by a machine or the like. In any case, it is preferred to move the rigid plate 28 while holding the long strip of the rigid plate 28 near both ends (by hand or machine or the like). This makes it easy to apply a uniform force to the wiring layer 26 without bending the rigid plate 28, and the carrier 12 can be peeled off more efficiently. In addition, it is preferred to move the rigid plate 28 while fixing the surface of the carrier side of the laminated sheet 10.

[0100] (5) Peeling off the carrier (optional step)

[0101] If desired, the process of peeling the carrier 12 from the laminated sheet 10 may be further included (see Figure 3A (v) and Figure 3B (v)). For example, by continuing to move the rigid plate 28 until the end of the build-up sheet 10 on the side opposite to the peeling starting point S, the wiring layer 26 and the carrier 12 can be completely separated. Alternatively, after the peeling of the wiring layer 26 from the carrier 12 progresses to a certain extent due to the movement of the rigid plate 28, a force is applied to the build-up sheet 10 in the direction of separating the carrier 12 and the wiring layer 26, thereby peeling the wiring layer 26 from the carrier 12.

[0102] When the wiring layer 26 includes the metal layer 18, the metal layer 18 exposed after the carrier 12 is peeled off may be removed by etching. In this way, the wiring (embedded wiring) formed on the surface of the metal layer 18 is exposed, so it is more suitable to further form a circuit thereon by a photolithography process. The etching of the metal layer 18 can be performed based on a well-known method and is not particularly limited.

[0103] Metal foil with carrier

[0104] As reference Figure 1 As described above, in the method of the present invention, the metal foil with a carrier to be used as desired includes the carrier 12 , the intermediate layer 14 provided as desired, the release layer 16 , and the metal layer 18 in this order.

[0105] The carrier 12 can be composed of any one of glass, ceramic, silicon, resin and metal, but is preferably a substrate or glass substrate containing silicon. As a substrate containing silicon, any substrate can be used as long as Si is contained as an element, and SiO2 substrates, SiN substrates, Si single crystal substrates, Si polycrystalline substrates, etc. can be applied. More preferably, it is a glass carrier, a single crystal silicon substrate or a polycrystalline silicon substrate. According to a preferred embodiment of the present invention, the carrier 12 is a disk-shaped having a diameter of more than 100 mm, and more preferably a disk-shaped having a diameter of more than 200 mm and less than 450 mm. According to other preferred embodiments of the present invention, the carrier 12 is a rectangular shape with a short side of more than 100 mm, and more preferably a short side of more than 150 mm and less than 650 mm. The rectangular carrier 12 can be a roller-shaped carrier whose long side is sufficiently longer than the short side, but preferably the long side is more than 200 mm and less than 650 mm.

[0106] The form of the carrier 12 can be any one of a sheet, a film, and a plate. In addition, the carrier 12 can also be a carrier obtained by stacking these sheets, films, plates, etc. For example, the carrier 12 can be a glass plate, a ceramic plate, a silicon wafer, a metal plate, etc., which can function as a rigid support body, or it can be a metal foil, a resin film, etc., which do not have rigidity. Preferred examples of metals constituting the carrier 12 include copper, titanium, nickel, stainless steel, aluminum, etc. Preferred examples of ceramics include alumina, zirconium oxide, silicon nitride, aluminum nitride, and various other fine ceramics. Preferred examples of resins include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyamide, polyimide, nylon, liquid crystal polymer, polyether ether ketone (PEEK (registered trademark)), polyamide-imide, polyether sulfone, polyphenylene sulfide, polytetrafluoroethylene (PTFE), ethylene-tetrafluoroethylene (ETFE), etc. From the viewpoint of preventing the warping of the coreless support body caused by heating when the semiconductor element is mounted, a material with a coefficient of thermal expansion (CTE) of less than 25ppm / K (typically 1.0ppm / K or more and 23ppm / K or less) is more preferred. Examples of such materials include various resins as described above (especially low thermal expansion resins such as polyimide and liquid crystal polymer), glass, silicon, and ceramics. In addition, from the viewpoint of ensuring the handling and flatness during chip mounting, the Vickers hardness of the carrier 12 is preferably 100HV or more, more preferably 150HV or more and 2500HV or less. As a material that satisfies these characteristics, the carrier 12 is preferably composed of glass, silicon or ceramics, more preferably composed of glass or ceramics, and particularly preferably composed of glass. As a carrier 12 composed of glass, for example, a glass plate can be cited. When glass is used as the carrier 12, it has the advantages of being extremely smooth on the surface of the metal layer 18 due to its light weight, low coefficient of thermal expansion, high insulation, rigidity, and flat surface. In addition, when the carrier 12 is glass, it has the following advantages: it has surface flatness (coplanarity) that is conducive to the formation of fine circuits; it has chemical resistance in the decontamination process in the wiring manufacturing process and various plating processes. As preferred examples of glass constituting the carrier 12, quartz glass, borosilicate glass, alkali-free glass, soda-lime glass, aluminosilicate glass, and combinations thereof are mentioned, and alkali-free glass, soda-lime glass, and combinations thereof are more preferred, and alkali-free glass is particularly preferred. Alkali-free glass is glass that contains alkaline earth metal oxides such as silicon dioxide, aluminum oxide, boron oxide, and calcium oxide or barium oxide as main components and further contains boric acid, and does not substantially contain alkali metals. The thermal expansion coefficient of this alkali-free glass in a wide temperature range of 0°C to 350°C is in the range of 3 ppm / K or more and 5 ppm / K or less, which is low and stable, and therefore has the advantage of being able to minimize the warping of the glass in a process accompanied by heating.The thickness of the carrier 12 is preferably 100 μm or more and 2000 μm or less, more preferably 300 μm or more and 1800 μm or less, and further preferably 400 μm or more and 1100 μm or less. When the carrier 12 has a thickness within this range, it is possible to ensure appropriate strength that does not hinder handling, and to achieve thinning of wiring and reduce warping generated when mounting electronic components.

[0107] The intermediate layer 14 set as desired can be a single-layer structure or a structure of two or more layers. When the intermediate layer 14 is composed of two or more layers, the intermediate layer 14 includes a first intermediate layer arranged directly above the carrier 12 and a second intermediate layer arranged adjacent to the peeling layer 16. From the perspective of ensuring the adhesion with the carrier 12, the first intermediate layer is preferably a layer composed of at least one metal selected from the group consisting of Ti, Cr, Al and Ni. The first intermediate layer can be a pure metal or an alloy. The thickness of the first intermediate layer is preferably 5 nm or more and 500 nm or less, more preferably 10 nm or more and 300 nm or less, further preferably 18 nm or more and 200 nm or less, and particularly preferably 20 nm or more and 100 nm or less. From the perspective of controlling the peel strength with the peeling layer 16 to the desired value, the second intermediate layer is preferably a layer composed of Cu. The thickness of the second intermediate layer is preferably 5 nm or more and 500 nm or less, more preferably 10 nm or more and 400 nm or less, further preferably 15 nm or more and 300 nm or less, and particularly preferably 20 nm or more and 200 nm or less. There may also be other interlayers between the first intermediate layer and the second intermediate layer. Examples of the constituent materials of the interlayers include alloys of at least one metal selected from the group consisting of Ti, Cr, Mo, Mn, W and Ni and Cu. On the other hand, when the intermediate layer 14 is a single-layer structure, the first intermediate layer described above may be directly used as the intermediate layer, or the first intermediate layer and the second intermediate layer may be replaced by a single intermediate alloy layer. The intermediate alloy layer is preferably composed of the following copper alloy: the content of at least one metal selected from the group consisting of Ti, Cr, Mo, Mn, W, Al and Ni is 1.0 at% or more, and the Cu content is 30 at% or more. The thickness of the intermediate alloy layer is preferably 5 nm or more and 500 nm or less, more preferably 10 nm or more and 400 nm or less, further preferably 15 nm or more and 300 nm or less, and particularly preferably 20 nm or more and 200 nm or less. In addition, the thickness of each layer is set to a value measured by analyzing the layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) of a transmission electron microscope. The metal constituting the intermediate layer 14 may also contain unavoidable impurities caused by raw material components, film forming steps, etc. In addition, when the intermediate layer 14 is exposed to the atmosphere after film formation, the presence of oxygen mixed therein is allowed. The intermediate layer 14 can be manufactured by any method, but from the perspective of being able to have uniform film thickness distribution, a layer formed by a magnetron sputtering method using a metal target is particularly preferred.

[0108] The peeling layer 16 is a layer that can realize the peeling of the carrier 12 and the peeling of the intermediate layer 14 when the intermediate layer 14 is present, or makes the peeling easier. In addition to being able to be peeled by physically applying force, the peeling layer 16 can also be peeled by a method of peeling using a laser (laser peeling, LLO). In the case where the peeling layer 16 is composed of a material that can be peeled by laser peeling, the peeling layer 16 can be composed of a resin whose interface bonding strength is reduced due to the irradiation of laser light after curing, or it can also be a layer of silicon, silicon carbide, metal oxide, etc. that is modified by laser light irradiation. In addition, the peeling layer 16 can be any of an organic peeling layer and an inorganic peeling layer. Examples of organic components used in the organic peeling layer include nitrogen-containing organic compounds, sulfur-containing organic compounds, carboxylic acids, etc. Examples of nitrogen-containing organic compounds include triazole compounds, imidazole compounds, etc. On the other hand, as examples of inorganic components used in the inorganic peeling layer, metal oxides or metal nitrides or carbon containing at least one of Cu, Ti, Al, Nb, Zr, Cr, W, Ta, Co, Ag, Ni, In, Sn, Zn, Ga, and Mo can be cited. Among these, from the perspective of ease of peeling, layer formation, etc., the peeling layer 16 is preferably a layer mainly containing carbon, more preferably a layer mainly formed by carbon or hydrocarbons, and further preferably a layer formed by amorphous carbon as a hard carbon film. At this time, the peeling layer 16 (i.e., the carbon-containing layer) preferably has a carbon concentration of 60 atomic % or more as measured by XPS, more preferably 70 atomic % or more, more preferably 80 atomic % or more, and particularly preferably 85 atomic % or more. The upper limit of the carbon concentration is not particularly limited, and can be 100 atomic %, but 98 atomic % or less is more realistic. The peeling layer 16 may contain unavoidable impurities (e.g., oxygen, carbon, hydrogen, etc. derived from the surrounding environment such as the atmosphere). In addition, the release layer 16 may contain metal atoms of a type other than the metal contained in the release layer 16 due to the film forming method of the metal layer 18 or the like which is subsequently laminated. When a carbon-containing layer is used as the release layer 16, the mutual diffusion and reactivity between the release layer 16 and the carrier are small, and even if subjected to press processing at a temperature greater than 300°C, the mutual diffusion of metal elements between the metal layer and the bonding interface caused by high temperature heating can be prevented, and the carrier can be kept in a state where it is easy to remove. From the perspectives of suppressing excessive impurities in the release layer 16 and continuous productivity of other layers, the release layer 16 is preferably a layer formed by a gas phase method such as sputtering. When a carbon-containing layer is used as the release layer 16, the thickness is preferably greater than 1 nm and less than 20 nm, and more preferably greater than 1 nm and less than 10 nm. The thickness is set to a value measured by analyzing a layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) using a transmission electron microscope.

[0109] The peeling layer 16 may be a layer containing either or both of a metal oxide layer and a carbon-containing layer, or may be a layer containing both of a metal oxide and carbon. In particular, when the metal foil with a carrier includes an intermediate layer 14, the carbon-containing layer contributes to the stable peeling of the carrier 12, and the diffusion of the metal elements from the intermediate layer 14 and the metal layer 18 caused by heating can be more effectively suppressed by the metal oxide layer, resulting in stable peeling properties even after heating at a high temperature of, for example, 350°C or more. The metal oxide layer is preferably a layer containing an oxide of a metal composed of Cu, Ti, Al, Nb, Zr, Cr, W, Ta, Co, Ag, Ni, In, Sn, Zn, Ga, Mo and a combination thereof. From the perspective of being able to easily control the film thickness by adjusting the film forming time, it is particularly preferred that the metal oxide layer is a layer formed by a reactive sputtering method using a metal target and sputtering in an oxidizing atmosphere. The thickness of the metal oxide layer is preferably 0.1 nm or more and 100 nm or less. The upper limit of the thickness of the metal oxide layer is more preferably 60 nm or less, further preferably 30 nm or less, and particularly preferably 10 nm or less. The thickness is set to a value measured by analyzing the layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) of a transmission electron microscope. At this time, the order in which the metal oxide layer and the carbon layer are stacked as the peeling layer 16 is not particularly limited. In addition, the peeling layer 16 may also exist in a mixed phase (i.e., a layer containing both metal oxide and carbon) in which the boundary between the metal oxide layer and the carbon-containing layer cannot be clearly determined.

[0110] Similarly, from the viewpoint of maintaining stable peeling properties even after heat treatment at high temperatures, the peeling layer 16 can also be a metal-containing layer whose surface adjacent to the metal layer 18 is a fluorinated surface and / or a nitrided surface. The region in which the sum of the fluorine content and the nitrogen content in the metal-containing layer is 1.0 atomic % or more (hereinafter referred to as the "(F+N) region") preferably exists with a thickness of 10 nm or more, and the (F+N) region preferably exists on the metal layer 18 side of the metal-containing layer. The thickness (SiO2 conversion) of the (F+N) region is set to a value determined by performing depth-direction elemental analysis of the metal foil with a carrier using XPS. The fluorinated surface or the nitrided surface can be preferably formed by reactive ion etching (RIE: Reactive ion etching) or reactive sputtering. On the other hand, the metal element contained in the metal-containing layer preferably has a negative standard electrode potential. Preferred examples of metal elements contained in the metal-containing layer include Cu, Ag, Sn, Zn, Ti, Al, Nb, Zr, W, Ta, Mo and combinations thereof (e.g., alloys, intermetallic compounds). The content of metal elements in the metal-containing layer is preferably greater than 50 atomic % and less than 100 atomic %. The metal-containing layer may be a single layer consisting of one layer, or a multilayer consisting of two or more layers. The overall thickness of the metal-containing layer is preferably greater than 10 nm and less than 1000 nm, more preferably greater than 30 nm and less than 500 nm, further preferably greater than 50 nm and less than 400 nm, and particularly preferably greater than 100 nm and less than 300 nm. The thickness of the metal-containing layer itself is set to a value measured by analyzing a layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) using a transmission electron microscope.

[0111] Alternatively, the peeling layer 16 may also be a layer containing metal nitride oxides instead of the carbon layer, etc. The surface of the layer containing metal nitride oxides on the side opposite to the side where the carrier 12 is located (i.e., the metal layer 18 side) preferably contains at least one metal nitride oxide selected from the group consisting of TaON, NiON, TiON, NiWON and MoON. In addition, from the perspective of ensuring the adhesion between the carrier 12 and the metal layer 18, the surface of the layer containing metal nitride oxides on the side of the carrier 12 preferably contains at least one selected from the group consisting of Cu, Ti, Ta, Cr, Ni, Al, Mo, Zn, W, TiN and TaN. In this way, the number of foreign particles on the surface of the metal layer 18 can be suppressed to improve the circuit formation, and even after long-term heating under high temperature conditions, stable peeling strength can be maintained. The thickness of the layer containing metal nitride oxides is preferably 5 nm or more and 500 nm or less, more preferably 10 nm or more and 400 nm or less, further preferably 20 nm or more and 200 nm or less, and particularly preferably 30 nm or more and 100 nm or less. This thickness is a value measured by analyzing a layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) using a transmission electron microscope.

[0112] The metal layer 18 is a layer composed of metal. The metal layer 18 can be a single-layer structure or a structure of two or more layers. When the metal layer 18 is composed of two or more layers, the metal layer 18 can be a structure in which the first metal layer to the mth metal layer (m is an integer greater than 2) are stacked in sequence on the surface side of the release layer 16 opposite to the carrier 12. The overall thickness of the metal layer 18 is preferably greater than 1 nm and less than 2000 nm, preferably greater than 100 nm and less than 1500 nm, more preferably greater than 200 nm and less than 1000 nm, further preferably greater than 300 nm and less than 800 nm, and particularly preferably greater than 350 nm and less than 500 nm. The thickness of the metal layer 18 is set to a value measured by analyzing the layer cross section using an energy dispersive X-ray spectrometer (TEM-EDX) of a transmission electron microscope. Below, an example in which the metal layer 18 is composed of two layers, the first metal layer and the second metal layer, is described.

[0113] The first metal layer is preferably a layer that imparts desired functions such as an etching stop function and an anti-reflection function to the metal foil with a carrier. Preferred examples of metals constituting the first metal layer include Ti, Al, Nb, Zr, Cr, W, Ta, Co, Ag, Ni, Mo and combinations thereof, more preferably Ti, Zr, Al, Cr, W, Ni, Mo and combinations thereof, further preferably Ti, Al, Cr, Ni, Mo and combinations thereof, and particularly preferably Ti, Mo and combinations thereof. These elements have the property of being difficult to dissolve in a flash etching solution (e.g., a copper flash etching solution), and as a result, can exhibit excellent chemical resistance to the flash etching solution. Therefore, compared with the second metal layer described later, the first metal layer is a layer that is difficult to be etched by the flash etching solution, and therefore can function as an etching stop layer that can delay etching. In addition, the above-mentioned metal constituting the first metal layer also has the function of preventing reflection of light, so the first metal layer can also function as an anti-reflection layer for improving the visibility in image inspection (e.g., automatic image inspection (AOI)). The first metal layer can be a pure metal or an alloy. The metal constituting the first metal layer can also include inevitable impurities caused by raw material components, film forming steps, etc. In addition, the upper limit of the content of the above-mentioned metal is not particularly limited, and can also be 100 atomic %. The first metal layer is preferably a layer formed by a physical vapor deposition (PVD) method, and more preferably a layer formed by sputtering. The thickness of the first metal layer is preferably more than 1nm and less than 500nm, more preferably more than 10nm and less than 400nm, further preferably more than 30nm and less than 300nm, and particularly preferably more than 50nm and less than 200nm.

[0114] Preferred examples of the metal constituting the second metal layer include transition elements of the 4th subgroup, the 5th subgroup, the 6th subgroup, the 8th subgroup (the 9th group), the 8th subgroup (the 10th group) and the 1st subgroup (the 11th group), Al, and combinations thereof (e.g., alloys and intermetallic compounds), more preferably transition elements of the 4th subgroup and the 1st subgroup (the 11th group), Al, Nb, Co, Ni, Mo, and combinations thereof, further preferably transition elements of the 1st subgroup (the 11th group), Ti, Al, Mo, and combinations thereof, particularly preferably Cu, Ti, Mo, and combinations thereof, and most preferably Cu. The second metal layer can be manufactured by any method, for example, it can be a metal foil formed by a wet film forming method such as chemical metal plating and electrolytic metal plating, a physical vapor deposition (PVD) method such as sputtering and vacuum evaporation, a chemical vapor film forming method, or a combination thereof. From the viewpoint of being easy to cope with the fine pitch caused by the ultra-thinning, the second metal layer is particularly preferably a metal layer formed by a physical vapor deposition (PVD) method such as sputtering and vacuum evaporation, and the most preferred is a metal layer manufactured by sputtering. In addition, the second metal layer is preferably a metal layer that has not been roughened, but as long as it does not cause obstacles to the formation of the wiring pattern, the second metal layer can also be a layer that has been subjected to a secondary roughening treatment by a preliminary roughening treatment, a soft etching treatment, a cleaning treatment, and an oxidation-reduction treatment. From the viewpoint of coping with fine pitch, the thickness of the second metal layer is preferably 10 nm or more and 1000 nm or less, more preferably 20 nm or more and 900 nm or less, further preferably 30 nm or more and 700 nm or less, further more preferably 50 nm or more and 600 nm or less, particularly preferably 70 nm or more and 500 nm or less, and most preferably 100 nm or more and 400 nm or less. From the viewpoint of the in-plane uniformity of the film thickness, the productivity in the sheet and roller form, the metal layer with a thickness within the above range is preferably manufactured by sputtering.

[0115] When the metal layer 18 is a single-layer structure, it is preferred to directly use the second metal layer as the metal layer 18. On the other hand, when the metal layer 18 is an n-layer structure (n is an integer greater than or equal to 3), it is preferred to set the metal layer 18 from the first metal layer to the (n-1)th metal layer to the structure of the first metal layer, and it is preferred to set the outermost layer of the metal layer 18, that is, the nth metal layer, to the structure of the second metal layer.

[0116] Preferably, the metal layer 18, the intermediate layer 14 provided as desired, and the release layer 16 provided as desired (i.e., at least the metal layer 18, for example, the metal layer 18 and the intermediate layer 14) are extended to the end face of the carrier 12, thereby covering the end face. That is, preferably, not only the surface of the carrier 12 is covered, but also the end face of the carrier 12 is at least covered by the metal layer 18. By also covering the end face, it is possible to prevent the infiltration of the chemical solution into the carrier 12 during the manufacturing process of the wiring substrate, and to firmly prevent the fragmentation caused by the peeling of the side end portion of the metal foil or the laminated sheet 10 with the carrier when handling it, that is, the defect of the coating film (i.e., the metal layer 18) on the release layer 16. The coverage area of ​​the end face of the carrier 12 is preferably an area of ​​0.1 mm or more from the surface of the carrier 12 in the thickness direction (i.e., the direction perpendicular to the carrier surface), more preferably an area of ​​0.2 mm or more, and even more preferably the entire area of ​​the end face of the carrier 12.

[0117] Example

[0118] The present invention will be further described in detail by the following examples.

[0119] Example 1

[0120] According to the method of the present invention, the laminated sheet is prepared and the carrier is peeled off as follows.

[0121] (1) Preparation of laminated sheets

[0122] A glass substrate (material: soda lime glass) having a size of 98 mm × 68 mm and a thickness of 1.1 mm was prepared as the carrier 12. A titanium layer (thickness 50 nm) and a copper layer (thickness 200 nm) as the intermediate layer 14 of the two-layer structure, an amorphous carbon layer (thickness 6 nm) as the release layer 16, and a titanium layer (thickness 100 nm) and a copper layer (thickness 300 nm) as the metal layer 18 of the two-layer structure were sequentially formed on the carrier 12 by sputtering to obtain a metal foil with a carrier. At this time, the metal layer 18 was formed to extend to the end surface of the carrier 12 to cover the end of the release layer 16.

[0123] A redistribution layer 20 having a size of 98 mm × 68 mm and a thickness of 20 μm is formed on the metal layer 18 of the metal foil with a carrier. Specifically, first, a photosensitive dry film is attached to the surface of the metal layer 18 side of the metal foil with a carrier, and exposure and development are performed to form a photoresist layer of a predetermined pattern. Next, the exposed surface of the metal layer 18 (i.e., the portion not covered by the photoresist layer) is subjected to pattern electroplating of copper, and the photoresist layer is peeled off after the copper electroplating layer is formed. In this way, the metal layer 18 and the copper electroplating layer are retained in the form of a wiring pattern, while on the other hand, the metal layer 18 in the portion where these wiring patterns are not formed is exposed. Thereafter, the unwanted portion of the exposed metal layer 18 is removed by using an etching solution to form a wiring layer. In addition, an insulating resin material (photosensitive insulating material, AR-5100 manufactured by Showa Denko Materials Co., Ltd.) is laminated on the wiring layer side of the metal foil with a carrier, and a heat curing treatment is performed at 230°C for 60 minutes to form an insulating layer. In this way, a redistribution layer 20 including a wiring layer and an insulating layer is formed.

[0124] On the redistribution layer 20, an epoxy resin containing SiO2 filler (bending strength and bending elastic modulus are shown in Table 1) is applied to form a resin-containing layer 24 having a size of 90 mm×60 mm and a thickness of 0.2 mm. The epoxy resin is obtained by mixing liquid bisphenol F type epoxy resin and phenol biphenyl aralkyl resin (curing agent) at a molar ratio of epoxy group / phenolic hydroxyl group=1.0, and mixing 86 parts by weight of SiO2 filler into 14 parts by weight of the obtained resin mixture. In this way, a laminated sheet 10 having a carrier 12, an intermediate layer 14, a peeling layer 16, a metal layer 18 as a wiring layer 26, a redistribution layer 20, and a resin-containing layer 24 in this order is produced. The peel strength when the laminated sheet 10 is separated into the carrier 12 and the wiring layer 26 by the peeling layer 16 is 6.5 gf / cm.

[0125] (2) Formation of the peeling starting point

[0126] The surface of the laminated sheet 10 on the carrier 12 side is fixed to the workbench using a commercially available double-sided tape. Next, the blade of a cutting tool (material: tungsten) is inserted from the surface of the metal layer 18 of the laminated sheet 10 in a direction approximately perpendicular to the main surface of the carrier 12, thereby forming an incision. When the laminated sheet 10 is viewed from above, the incision is formed into a rectangular pattern (a linear pattern with four sides) in a manner surrounding the resin-containing layer 24. In addition, when the laminated sheet 10 is viewed in section, the incision has a depth that penetrates the metal layer 18, the peeling layer 16, and the intermediate layer 14 but does not penetrate the carrier 12. The laminated sheet 10 is cut in this way to remove the portion of the metal layer 18 that covers the end of the peeling layer 16. Then, a cutting tool is inserted near the exposed peeling layer 16 at one end (corner portion) of the laminated sheet 10 to form a gap as the peeling starting point S.

[0127] (3) Insertion of rigid plate

[0128] For the peeling starting point S formed on the laminated sheet 10, a long PET film (flexural modulus: 3.1 GPa, flexural strength: 130 MPa, Rockwell hardness: R125, breaking strength: 6.3 kgf, elastic modulus: 30.7 × 10 3 kgf / cm 2 ) is used as a rigid plate 28 and is inserted from the long strip portion of the PET film. At this time, the insertion angle of the rigid plate 28 is 0° (parallel to the main surface of the carrier 12).

[0129] (4) Movement of the rigid plate

[0130] While holding the long strip of the rigid board 28 near both ends by hand, the rigid board 28 is moved from the peeling starting point S along the peeling layer 16. The rigid board 28 is moved until it reaches the end of the laminated sheet 10 on the opposite side of the peeling starting point S, thereby completely separating the wiring layer 26 and the carrier 12. In addition, no liquid such as a lubricant is used in the steps of forming the peeling starting point and inserting and moving the rigid board.

[0131] Example 2 (Comparison)

[0132] The preparation of the laminated sheet and the peeling of the carrier are carried out in the same manner as in Example 1, except that a wire having a cross-sectional diameter of about 0.23 mm (manufactured by Japan Button Trading Co., Ltd., Super Nylon Textile, No.: A10-13, material: nylon, flexural modulus: 11 GPa, Rockwell hardness: R120, breaking strength: 0.41 kgf) is used instead of the PET film as the rigid plate 28 for insertion and movement toward the peeling starting point.

[0133] Example 3~Example 12

[0134] In the preparation of the laminated sheet, the preparation of the laminated sheet and the peeling of the carrier are carried out in the same manner as in Example 1, except that the thickness of the resin-containing layer 24 and / or the properties of the epoxy resin constituting the resin-containing layer 24 (filler content, bending strength and bending modulus) are changed as shown in Table 1.

[0135] evaluate

[0136] The laminated sheet after the carrier was peeled off was subjected to the various evaluations shown below.

[0137] (a) Confirmation of cracks and damage

[0138] It was visually checked whether the wiring layer 26 was cracked after peeling off the carrier 12. As a result, in Examples 1 to 12, no cracks were confirmed in the wiring layer 26. In addition, it was visually observed whether the peeled surface of the laminated sheet 10, that is, the copper layer side surface of the intermediate layer 14 and the titanium layer side surface of the metal layer 18 were damaged. As a result, in Examples 1 and 3 to 12, no damage was confirmed on the peeled surface of the laminated sheet 10. On the other hand, in Example 2 (comparison), damage was confirmed on the copper layer side surface of the intermediate layer 14 and the titanium layer side surface of the metal layer 18. For reference, photographs of the copper layer of the intermediate layer 14 and the titanium layer of the metal layer 18 after peeling off in Examples 1 and 2 are shown in the figure below, respectively. Figure 6 and Figure 7 .

[0139] (b) Discoloration after etching

[0140] The titanium layer side surface of the metal layer 18 (the peeling surface of the wiring layer 26) was subjected to metal etching for 150 seconds using a titanium etching solution (Meltex Corporation, Melstrip TI-3991). Afterwards, the surface of the wiring layer 26 on the metal-etched side was visually observed to check whether there was any discoloration (a spot pattern due to the depth of the color). As a result, in Examples 1 to 12, no discoloration was observed in the wiring layer 26.

[0141]

Table 1

[0142]

Claims

1. A method for manufacturing a wiring substrate, wherein: The manufacturing method of the wiring substrate comprises the following steps: preparing a build-up sheet having a peeling layer and a wiring layer in sequence on a carrier; forming a step or a gap between the wiring layer and the carrier as a peeling starting point; Inserting a rigid plate having a long strip portion from the long strip portion into the peeling starting point, wherein the long strip portion is longer than the width of the laminated sheet; as well as The wiring layer is peeled off from the carrier by moving the rigid board from the peeling starting point along the peeling layer. The wiring layer has a bending elastic modulus of 0.3 GPa or more and 300 GPa or less at 25° C. measured in accordance with JIS K6911-1995.

2. The method for manufacturing a wiring substrate according to claim 1, wherein: The wiring layer has a bending strength of 5 MPa or more and 1000 MPa or less at 25° C. measured based on JIS K6911-1995.

3. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate has a Rockwell hardness of R135 or less at 25° C. measured in accordance with JIS Z2245:2016.

4. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate has a breaking strength of 0.50 kgf or more at 25° C. as measured in accordance with JIS K7161-1:2014.

5. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The peel strength when the wiring layer is peeled off from the carrier is 0.10 gf / cm or more and 50 gf / cm or less.

6. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The peeling starting point is formed at an end of the wiring layer and / or an end of the carrier.

7. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate is inserted at an angle of not less than 0° and not more than 90° with respect to the main surface of the carrier.

8. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: When the rigid plate is cross-sectionally viewed, the angle of the front end of the long portion is greater than or equal to 0° and less than or equal to 90°, or the front end of the long portion has a curvature of greater than or equal to 0.1 mm and less than or equal to 10 mm.

9. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The total angle of an insertion angle of the rigid plate with respect to the main surface of the carrier and a front end angle of the rigid plate on the long portion side when the rigid plate is viewed in section is greater than or equal to 0° and less than or equal to 120°.

10. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate has a width of 1.0 mm or more and 300 mm or less.

11. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate has a thickness of 0.040 mm or more and 10 mm or less.

12. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The rigid plate is made of resin.

13. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The step of forming the peeling starting point and / or the step of advancing the peeling are performed without causing the liquid to adhere to the step or the gap.

14. The method for manufacturing a wiring substrate according to claim 1 or 2, wherein: The wiring layer includes at least one selected from the group consisting of a metal layer, a semiconductor element, and a resin-containing layer.

15. The method for manufacturing a wiring substrate according to claim 14, wherein: The wiring layer has a thickness of 0.1 μm or more and 5.0 mm or less.

16. The method for manufacturing a wiring substrate according to claim 14, wherein: The wiring layer includes a metal layer and a resin-containing layer.

17. The method for manufacturing a wiring substrate according to claim 14, wherein: The wiring layer includes a resin-containing layer, and the resin-containing layer contains a filler.

18. The method for manufacturing a wiring substrate according to claim 17, wherein: The resin-containing layer has a filler content of 95% by weight or less.

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