Method for forming wiring of semiconductor device

Abstract

The present invention provides a method for forming a conductive portion of a pattern on a substrate, which suppresses deformation of a wiring pattern formed on the substrate, enables complete transfer, and enables improvement of productivity. A method for forming a conductive portion of a pattern on a substrate, wherein a conductive paste containing an activated light ray curable resin (4) containing an activated light ray curable resin having an average particle diameter set to 0.1 to 20 μm is filled in a recess (3) of a printing plate (2), the printing plate (2) is overlapped with a substrate (1), and an activated light ray is irradiated from the printing plate (2) side, at least a contact interface portion of the conductive paste containing an activated light ray curable resin (4) with the recess (3) is cured, and then the printing plate (2) is separated from the substrate (1), the conductive paste containing an activated light ray curable resin (4) is transferred to the substrate (1), and a conductive portion (5) of a prescribed pattern is formed on the substrate (1).

Description

TECHNICAL FIELD

[0001] The present application relates to a method for forming a conductive portion of a pattern on a substrate. BACKGROUND

[0002] Due to the miniaturization of wiring rules of semiconductor chips, the size of the chips is being reduced. On the other hand, the present state of the substrate (semiconductor package substrate) on which the chips are mounted is that there is a limit to the miniaturization of bump pitch, so it becomes difficult to miniaturize the substrate area at the same rate as the chip size.

[0003] Based on such a background, the present applicant has developed a technology for making the substrate wiring narrow pitch using gray-scale lithography and imprint technology, and proposed a manufacturing method of a substrate having a conductive portion disclosed in Japanese Patent Application Publication No. 2016-58664 (hereinafter referred to as the prior art example).

[0004] In the prior art example, a conductive paste is filled in a recess of a printing plate provided with the recess formed in the same pattern as a wiring pattern formed on a substrate, the printing plate in which the conductive paste is filled in the recess is overlapped with the substrate and pressure-bonded, whereby the conductive paste filled in the recess of the printing plate is transferred to the substrate, and a wiring of a prescribed pattern is formed on the substrate.

[0005] PRIOR ART DOCUMENT

[0006] PATENT DOCUMENT

[0007] Patent Document 1: Japanese Patent Application Publication No. 2016-58664 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] Incidentally, in the above-described prior art example, a thermosetting resin-containing conductive paste containing a thermosetting resin in a conductive paste is used, and when the conductive paste filled in the recess of the printing plate is transferred to the substrate, the resin of the portion of the conductive paste in contact with the printing plate is cured by a heating treatment, and the releasability of the conductive paste from the printing plate is improved.

[0010] However, in the prior art example, although the releasability is improved by using the thermosetting resin-containing conductive paste, on the other hand, thermal expansion or thermal contraction occurs by the heating treatment, and the possibility of incomplete transfer caused thereby due to the deformation of the pattern or stress occurring between the printing plate and the conductive paste due to the deformation of the pattern increases, and in the heating treatment, a heating state needs to be maintained for a certain period of time, so there is a possibility that the problem of a reduction in productivity due to a longer processing time occurs.

[0011] The present application has been achieved in view of such a situation, and aims to provide a method for forming a conductive portion of a pattern on a substrate, which can achieve complete transfer of a conductive paste, can perform a curing process in a short time, can achieve improvement in productivity, and is excellent in practicality, while suppressing pattern deformation at the time of curing the conductive paste when transferring a prescribed wiring pattern on a substrate.

[0012] Means for solving the problem

[0013] The gist of the present application will be described with reference to the drawings.

[0014] A method for forming a conductive portion of a pattern on a substrate, characterized by comprising: a step of filling a concave portion 3 of a prescribed pattern formed in a printing plate 2 with a conductive paste 4 containing an activated light-curing resin, which is made of an activated light-curing resin, having an average particle diameter of a conductive material set to 0.1 to 20 μm; a step of overlapping the printing plate 2 filled with the conductive paste 4 containing the activated light-curing resin with a substrate 1; a step of curing the conductive paste 4 containing the activated light-curing resin filled in the concave portion 3 of the printing plate 2 by irradiating the activated light to the conductive paste 4 containing the activated light-curing resin; and a step of transferring the conductive paste 4 containing the activated light-curing resin to the substrate 1 by separating the printing plate 2 from the substrate 1, to form a conductive portion 5 of a prescribed pattern on the substrate 1.

[0015] Further, the method for forming a conductive portion of a pattern on a substrate according to Technical Solution 1, characterized in that the activated light is irradiated from the bottom side of the concave portion 3 of the printing plate 2 at the time of curing the conductive paste 4 containing the activated light-curing resin.

[0016] Further, the method for forming a conductive portion of a pattern on a substrate according to Technical Solution 1, characterized in that the volume content of the activated light-curing resin in the conductive paste 4 containing the activated light-curing resin is 70% or less.

[0017] Further, the method for forming a conductive portion of a pattern on a substrate according to Technical Solution 2, characterized in that the volume content of the activated light-curing resin in the conductive paste 4 containing the activated light-curing resin is 70% or less.

[0018] Further, the method for forming a conductive portion in a pattern on a substrate according to any one of the aspects 1 to 4, wherein the intermediate layer 6 that deforms due to pressure is provided on the substrate 1, the printing plate 2 in which the conductive paste 4 containing the active light curing resin is filled is overlapped on the intermediate layer 6, and the conductive paste 4 containing the active light curing resin is transferred on the substrate 1 via the intermediate layer 6.

[0019] Further, the method for forming a conductive portion in a pattern on a substrate according to the aspect 5, wherein the intermediate layer 6 is formed of an active light curing resin or a thermal curing resin.

[0020] Further, the method for forming a conductive portion in a pattern on a substrate according to any one of the aspects 1 to 4, wherein the active light curing resin is an ultraviolet curing resin that is cured by ultraviolet irradiation.

[0021] Further, the method for forming a conductive portion in a pattern on a substrate according to the aspect 5, wherein the active light curing resin is an ultraviolet curing resin that is cured by ultraviolet irradiation.

[0022] Further, the method for forming a conductive portion in a pattern on a substrate according to the aspect 6, wherein the active light curing resin is an ultraviolet curing resin that is cured by ultraviolet irradiation.

[0023] Effects of the Invention

[0024] The present application is as described above, and thus, when a prescribed wiring pattern is transferred and formed on a substrate, the pattern deformation when the conductive paste is cured is suppressed, complete transfer of the conductive paste can be achieved, further, the active light curing resin is cured in a short time (instantaneously) if the necessary active light is effectively irradiated, and thus the time taken for the curing process can be shortened, productivity can be improved, and furthermore, the present application uses a conductive paste containing an active light curing resin in which the average particle diameter of the conductive material is set to 0.1 to 20 μm, and thus the shape of the wiring pattern transferred and formed on the substrate becomes a smooth shape (a smooth shape with few irregularities), and thus the local electric field concentration between the wirings is moderated, the long-term reliability of the wirings is improved, and a novel, epoch-making method for forming a conductive portion in a pattern on a substrate is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 is a process flow diagram of the present embodiment.

[0026] Figure 2is a schematic cross-sectional view showing a semiconductor device at an intermediate stage of manufacture in this embodiment.

[0027] Figure 3 is a schematic cross-sectional view showing a semiconductor device at an intermediate stage of manufacture in another example (without an intermediate layer) of this embodiment. DETAILED DESCRIPTION

[0028] The operation and effects of the present application will be shown based on the drawings and a preferred embodiment of the present application will be explained simply.

[0029] The conductive paste 4 containing the activated light-curable resin is filled in the recess 3 formed in the printing plate 2, the printing plate 2 filled with the conductive paste 4 containing the activated light-curable resin is overlapped with the substrate 1 (the substrate 1 can also be overlapped with the printing plate 2), and at least the contact interface portion of the conductive paste 4 containing the activated light-curable resin filled in the recess 3 is cured by irradiation of the activated light from the side of the printing plate 2, for example, and then the printing plate 2 is separated from the substrate 1.

[0030] Thus, the conductive paste 4 containing the activated light-curable resin filled in the recess 3 of the printing plate 2 is transferred to the substrate 1, and a conductive portion 5 of a prescribed pattern is formed on the substrate 1. Note that the printing plate 2 can also be overlapped with the substrate 1 after at least the contact interface portion of the conductive paste 4 containing the activated light-curable resin filled in the recess 3 is cured by irradiation of the activated light.

[0031] As described above, the present application uses the conductive paste 4 containing the activated light-curable resin as the conductive paste for forming the conductive portion 5, and the conductive paste 4 containing the activated light-curable resin is cured by irradiation of the activated light, and thus the releasability of the conductive paste 4 containing the activated light-curable resin with respect to the printing plate 2 is improved, and the occurrence of adverse conditions such as pattern deformation and incomplete transfer due to heat curing is prevented, and further, the time taken for the curing process is shortened (instantaneous curing) compared to the case of heat curing, and the productivity is also improved.

[0032] Further, the present application forms the conductive portion 5 using the conductive paste 4 containing the activated light-curable resin in which the conductive material having an average particle diameter of 0.1 μm to 20 μm is contained in the conductive paste containing the activated light-curable resin, and thus the shape of the conductive portion 5 formed on the substrate 1 becomes a smooth shape (a flat shape with less irregularities), and thus the local electric field concentration between the wirings is alleviated, and the long-term reliability of the wirings is improved.

[0033] Thus, the present application is a formation method of a conductive portion of a pattern formed on a substrate, which has not been available in the past and is epoch-making.

[0034] EMBODIMENT

[0035] A specific embodiment of the present application will be described based on the drawings.

[0036] This embodiment is a method for manufacturing a semiconductor device (a method for forming a wiring of a semiconductor device).

[0037] Specifically, it is a method for forming a conductive portion 5 (wiring) of a prescribed pattern on a substrate 1 using an imprint method, and has a step of filling a recessed portion 3 of a prescribed pattern formed in a printing plate 2 with an activated light ray curable resin-containing conductive paste 4 made of an activated light ray curable resin-containing conductive paste in which the average particle diameter of a conductive material is set to 0.1 to 20 μm (conductive paste filling treatment step); a step of overlapping the printing plate 2 filled with the activated light ray curable resin-containing conductive paste 4 with the substrate 1 (printing plate overlapping treatment step); a step of irradiating the activated light ray curable resin-containing conductive paste 4 filled in the recessed portion 3 of the printing plate 2 with an activated light ray to cure the activated light ray curable resin-containing conductive paste 4 (conductive paste curing treatment step); and a step of separating the printing plate 2 from the substrate 1 to transfer the activated light ray curable resin-containing conductive paste 4 to the substrate 1 to form the conductive portion 5 of a prescribed pattern on the substrate 1 (conductive paste transfer treatment step).

[0038] First, components and the like used in this embodiment will be described.

[0039] The substrate 1 is provided with an intermediate layer 6 on a conductive portion formation surface on which the conductive portion 5 is formed. The intermediate layer 6 is used to uniformly contact the activated light ray curable resin-containing conductive paste 4 with the conductive portion formation surface of the substrate 1, and is formed of a material having adhesion and deforming by pressure, specifically, an activated light ray curable resin or a heat curable resin, and is provided at least at a position at which the conductive portion 5 is formed.

[0040] In addition, the printing plate 2 is formed with the recessed portion 3 of a pattern identical to the conductive portion 5 of a prescribed pattern transferred to the substrate 1.

[0041] Specifically, the printing plate 2 of this embodiment is a replication mold formed by dropping a resin material such as COC (cyclo olefin polymer), PET (polyethylene terephthalate), LCP (liquid crystal polymer), PMMA (polymethyl methacrylate), PDMS (polydimethylsiloxane), PI (polyimide), and the like on a master mold prepared in advance, and pressing and curing it on a support substrate.

[0042] In addition, the recessed portion 3 is formed in a shape having different depths so as to be able to simultaneously transfer the conductive portion 5 as a wiring and the conductive portion 5 as a bump.

[0043] Specifically, the recess 3 is formed in a shape in which the aspect ratio of the conductive portion 5 formed on the substrate 1 is 0.5 or more, and specifically, in a shape in which the aspect ratio of the conductive portion 5 as a bump is 2 to 3.

[0044] Further, the recess 3 is formed in a shape in which the conductive portion 5 becomes a conical shape (a right conical shape). By forming the recess 3 in such a conical shape, the conductive paste 4 containing the ultraviolet-curable resin easily releases from a mold, and the transfer is smoothly performed, and the yield is improved.

[0045] Further, the conductive paste 4 containing the activated light-curable resin of the conductive portion 5 is an ultraviolet-curable resin-containing conductive paste 4 in which the conductive paste contains an ultraviolet-curable resin that is cured by ultraviolet irradiation. Note that, as the conductive paste of the conductive member, for example, a silver (Ag) paste / nano paste, a copper (Cu) paste / nano paste, a gold (Au) paste / nano paste, a platinum (Pt) paste / nano paste, a palladium (Pd) paste / nano paste, a ruthenium (Ru) paste / nano paste, a carbon (C) paste / nano paste, or the like can be used.

[0046] The volume content of the activated light-curable resin (ultraviolet-curable resin) in the ultraviolet-curable resin-containing conductive paste 4 is set to 70% or less, and specifically, 20% to 40%. That is, the volume ratio of the conductive paste to the ultraviolet-curable resin in the ultraviolet-curable resin-containing conductive paste 4 used in the present embodiment is set to 6:4 to 8:2.

[0047] Further, the average particle diameter of the conductive material contained in the conductive paste of the ultraviolet-curable resin-containing conductive paste 4 is set to 0.1 μm to 20 μm. Note that, the average particle diameter of the conductive material is preferably 1 / 5 to 1 / 10 of the minimum line width of the conductive portion 5 (wiring) formed on the substrate 1. That is, for example, in the case of forming a pattern of the conductive portion 5 in which the minimum L / S (line width & pitch) = 5 μm / 5 μm, the ultraviolet-curable resin-containing conductive paste 4 in which the ultraviolet-curable resin is contained in the conductive paste in which the average particle diameter of the conductive material is set to 0.5 μm to 1.0 μm can be used.

[0048] Next, a specific manufacturing method of the present embodiment will be described.

[0049] Figure 1 is a process flow diagram of the present embodiment. Further, Figure 2 is a schematic cross-sectional view illustrating a semiconductor device at an intermediate stage of manufacturing in the present embodiment.

[0050] As Figure 1As shown, in the present embodiment, first, in the conductive paste filling process, the conductive paste 4 containing the ultraviolet-curable resin is selectively filled in the recess 3 of the printing plate 2. The filling method can use an appropriate method, and in the present embodiment, as shown in FIG. 2, a doctor blade is used as the filling unit. Figure 2 As shown, a doctor blade is used as the filling unit.

[0051] Next, in the printing plate overlapping process, the printing plate 2 filled with the conductive paste 4 containing the ultraviolet-curable resin is overlapped with the substrate 1.

[0052] Specifically, after the printing plate 2 is overlapped with the substrate 1, pressure is applied to press the printing plate 2 and the substrate 1. Thereby, the printing plate 2 presses the intermediate layer 6 on the substrate 1, the intermediate layer 6 is deformed, and the surface (the surface exposed from the opening of the recess 3) of the conductive paste 4 containing the ultraviolet-curable resin filled in the recess 3 of the printing plate 2 is uniformly and tightly attached (bonded) to the surface of the substrate 1 via the intermediate layer 6.

[0053] Next, in the conductive paste curing process, the printing plate 2 overlapped with the substrate 1 is irradiated with ultraviolet rays from the side of the printing plate 2, i.e., from the bottom side of the recess 3 of the printing plate 2, to cure the contact interface portion of the conductive paste 4 containing the ultraviolet-curable resin filled in the recess 3 of the printing plate 2. Thereby, the releasability of the conductive paste 4 containing the ultraviolet-curable resin with respect to the printing plate 2 is improved.

[0054] The ultraviolet-curable resin is cured instantaneously by ultraviolet irradiation, so the processing time is greatly shortened compared with heat treatment. Also, in the present embodiment, only the conductive paste 4 containing the ultraviolet-curable resin near the contact interface with the recess 3 is cured, so the ultraviolet irradiation time can be set to a very short time.

[0055] Finally, in the conductive paste transfer process, the printing plate 2 is separated from the substrate 1 to transfer the conductive paste 4 containing the ultraviolet-curable resin to the substrate 1, and a conductive portion 5 of a prescribed pattern is formed on the substrate 1.

[0056] Note that the conductive paste curing process can also be performed before the printing plate overlapping process. That is, after the conductive paste 4 containing the ultraviolet-curable resin is filled in the recess 3 of the printing plate 2, the conductive paste 4 containing the ultraviolet-curable resin in the recess 3 can be cured by ultraviolet irradiation first, and then the printing plate 2 can be overlapped with the substrate 1.

[0057] In addition, in the present embodiment, the case where the intermediate layer 6 is provided is described, but as shown in FIG. 3, the conductive paste 4 containing the ultraviolet-curable resin can be filled in the recess 3 of the printing plate 2 without the intermediate layer 6. Figure 3In the case where a conductive portion such as a wiring, a bump, or the like is formed on a substrate on which an intermediate layer 6 is omitted or on a substrate on which a wiring (wiring layer) has been formed although not illustrated, the formation method of the conductive portion formed on a substrate of the present application can also be employed.

[0058] The present embodiment is as described above, and thus when the conductive portion 5 of a prescribed pattern is transferred and formed on the substrate 1, the pattern deformation at the time of curing the conductive paste 4 containing the ultraviolet-curable resin is suppressed, complete transfer of the conductive paste 4 containing the ultraviolet-curable resin can be achieved, and the curing process can be performed in a short time, productivity is improved, and a formation method of a conductive portion formed on a substrate that is excellent in practicality is achieved.

[0059] That is, in the case where a conductive paste containing a thermally-curable resin that is cured by heat treatment is used, based on the difference in the thermal expansion rate of the printing plate having a recess portion and the conductive paste, the pattern after curing deforms depending on the curing temperature, or the occurrence of a defective condition in which stress is generated between the printing plate and the conductive paste due to the deformation of the pattern and complete transfer is difficult is highly likely. In contrast, in the present embodiment, as the conductive paste for forming the conductive portion 5, the conductive paste 4 containing an ultraviolet-curable resin is used, and the conductive paste 4 containing the ultraviolet-curable resin is cured by irradiation of ultraviolet rays, and thus compared to the case where a conductive paste containing a thermally-curable resin is used and cured by heat treatment, the pattern deformation is reduced, the generation of stress is also suppressed, complete transfer of 100% is possible, the curing time is further greatly shortened, and productivity is improved.

[0060] In addition, in the present embodiment, the conductive paste 4 containing an ultraviolet-curable resin in which the average particle diameter of the conductive material contained in the conductive paste is set to 0.1 μm to 20 μm is used, and thus the shape of the conductive portion 5 (wiring and bump) formed on the substrate 1 becomes a smooth shape (a smooth shape with few irregularities), and thus the local electric field concentration between the conductive portions 5 is alleviated, the long-term reliability of the conductive portion 5 is improved, and further, in the present embodiment, only the conductive paste 4 containing an ultraviolet-curable resin in the vicinity of the contact interface of the recess portion 3 of the printing plate 2 is cured, and thus the particle diameter of the conductive material can also be freely designed.

[0061] In addition, in the present embodiment, since the conductive paste 4 containing an ultraviolet-curable resin in which the volume ratio of the conductive paste to the ultraviolet-curable resin is set to 6:4 to 8:2 is used, the final resistance value of the conductive portion 5 (wiring) formed by the conductive paste 4 containing an ultraviolet-curable resin can be reduced.

[0062] In addition, in the present embodiment, the intermediate layer 6 that deforms due to pressure is provided on the substrate 1, and the conductive paste 4 containing the ultraviolet-curable resin is transferred on the substrate 1 via the intermediate layer 6, and thus, when the printing plate 2 is overlapped with the substrate 1 and pressure is applied, the intermediate layer 6 deforms, and the printing plate 2 is uniformly attached to the transfer surface of the substrate 1, and thus, the conductive paste 4 containing the ultraviolet-curable resin can be completely transferred more reliably.

[0063] In addition, in the present embodiment, since the shape of the recess 3 of the printing plate 2 is formed in a conical shape (a right conical shape), the conductive portion 5 is formed in a right conical shape, and the release property of the conductive paste 4 containing the ultraviolet-curable resin from the recess 3 of the printing plate 2 at the time of transfer is improved, and the separation is smoothly performed, and the yield in the conductive paste transfer processing step is improved.

[0064] Thus, the present embodiment exerts the epoch-making role effect as described above, and can form a high-aspect-ratio wiring and a bump favorably and easily, and further becomes an epoch-making forming method of a conductive portion that forms a pattern on a substrate that has not existed in the past.

[0065] Note that the present application is not limited to the present embodiment, and the specific configuration of each component can be appropriately designed.

Claims

1. A method for forming wiring in a semiconductor device, comprising forming wiring on a substrate by imprinting using a replica die obtained from a master mold, characterized in that, Having: a conductive paste filling process of filling a conductive paste containing a UV-curable resin in a recessed portion formed in a prescribed pattern in the replication mold, wherein the conductive paste containing a UV-curable resin contains a conductive paste and a UV-curable resin in a volume ratio of 6:4 to 8:2, and the average particle diameter of the conductive material of the conductive paste is set to 0.1 to 20 μm and is 1 / 5 to 1 / 10 of the minimum line width of the wire to be transferred to the substrate; a replication mold overlapping process of overlapping the replication mold filled with the conductive paste containing a UV-curable resin with the substrate; a conductive paste curing process of curing the conductive paste containing a UV-curable resin by irradiating the conductive paste containing a UV-curable resin with ultraviolet rays in a state where the replication mold is overlapped with the substrate; and a conductive paste transfer process of transferring the conductive paste containing a UV-curable resin to the substrate by detaching the replication mold from the substrate, and forming a wire in a prescribed pattern; wherein the substrate is provided with an intermediate layer deformed by pressure on a conductive portion formation surface of a conductive portion, and the intermediate layer is formed of an activated light-curable resin or a heat-curable resin, the replication mold overlapping process is a process of overlapping the replication mold filled with the conductive paste containing a UV-curable resin on the intermediate layer of the substrate, and pressure-bonding the replication mold to the intermediate layer by pressure, the conductive paste curing process is a process of curing only the contact interface portion of the conductive paste containing a UV-curable resin with the recessed portion by irradiating the ultraviolet rays from the bottom side of the recessed portion of the replication mold.

2. The wiring forming method of a semiconductor device according to claim 1, wherein The recessed portion is formed as a tapered recessed portion in which the wire becomes a positive taper.

3. The wiring forming method of a semiconductor device according to claim 1, wherein The recessed portion is formed in a shape in which the aspect ratio of the wire to be transferred to the substrate is 2 to 3.

4. The wiring forming method of a semiconductor device according to claim 2, wherein The recessed portion is formed in a shape in which the aspect ratio of the wire to be transferred to the substrate is 2 to 3.

5. The wiring forming method of a semiconductor device according to any one of claims 1 to 4, wherein The replication mold is composed of any one of a cyclic olefin polymer, polyethylene terephthalate, a liquid crystal polymer, polymethyl methacrylate, polydimethylsiloxane, and polyimide.

6. The wiring forming method of a semiconductor device according to any one of claims 1 to 4, wherein The conductive paste is any one of a silver paste, a silver nano-paste, a copper paste, a copper nano-paste, a gold paste, a gold nano-paste, a platinum paste, a platinum nano-paste, a palladium paste, a palladium nano-paste, a ruthenium paste, a ruthenium nano-paste, a carbon paste, and a carbon nano-paste.

7. The wiring forming method of a semiconductor device according to claim 5, wherein The conductive paste is any one of a silver paste, a silver nano-paste, a copper paste, a copper nano-paste, a gold paste, a gold nano-paste, a platinum paste, a platinum nano-paste, a palladium paste, a palladium nano-paste, a ruthenium paste, a ruthenium nano-paste, a carbon paste, and a carbon nano-paste.

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