Method for manufacturing a substrate

Abstract

To provide a method for manufacturing a substrate having a recess and processing the inside of the recess, in which adhesion of secondary materials generated by substrate processing, such as debris and dross, to the substrate is suppressed.SOLUTION: A method for manufacturing a substrate has the following processes: a protective film formation process in which a protective film 4a' cross-linked to a recess 2 is formed on the surface of a substrate 1 having the recess 2; a protective film hanging process in which the protective film 4a cross-linked to the recess 2 is made to hang down toward the bottom surface 2a of the recess 2; a substrate processing process in which the surface of the recess 2 is processed; and a protective film stripping process in which the protective film 4a is peeled off.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a substrate for processing a surface of a substrate having a recess.

Background Art

[0002] In a light-emitting device, there has been proposed a device in which a plurality of light-emitting elements are mounted on a flat substrate surface, or a device in which a light-emitting element is mounted in a recess of a substrate having a recess formed on one surface, and the recess opening is sealed with a lid. In such a substrate on which a light-emitting element is mounted, a configuration may be adopted in which the light-emitting element mounted on one surface of the substrate and the wiring pattern formed on the other surface of the substrate are electrically connected by an electrode via.

[0003] The via used for the electrical connection between the light-emitting element and the wiring pattern formed on the other surface of the substrate has, for example, a structure in which a through hole connecting the front and back surfaces of the substrate is formed in the substrate, and a conductor layer is formed by filling the through hole with metal. When forming a through hole in a substrate, a processing method is known in which a laser beam is irradiated onto an object to be processed such as a substrate to form a through hole, a groove, or the like. This processing method by laser beam irradiation has a problem that debris (scattered matter) generated by the scattering of the material surface of the object to be processed and molten solidified matter (dross) of the melted material substance are generated, and it is inevitable that they adhere to the processing site and the periphery of the processing site. The adhesion of debris and dross to the object to be processed not only impairs the appearance, but also, when forming a film such as a wiring pattern around the processing site, debris and dross intervene as foreign substances between the object to be processed and the film covering it, which becomes a factor in reducing the adhesion between the object to be processed and the film.

[0004] Regarding such a point, in Patent Document 1, in order to prevent the adhesion of debris to the object to be processed, a method has been proposed in which a resin protection tape is formed on the surface of the substrate as the object to be processed, and after processing by laser beam irradiation, the resin protection tape to which debris has adhered is peeled off to remove the debris from the substrate.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-80968 [Summary of the Invention] [Problems to be Solved by the Invention]

[0006] However, in the processing method described in the above-mentioned Patent Document 1, when forming a through hole in the concave portion of a substrate having a concave portion, it is not easy to form a resin protection tape on the surface and side surfaces of the concave portion located around the through hole. Particularly, in a very small lighting device or the like, it is substantially impossible to form a resin protection tape in the concave portion.

[0007] The present invention has been made in view of the above problems, and in a substrate having a concave portion and processing the inside of the concave portion, it is an object to provide a method for manufacturing a substrate that suppresses the adhesion of by-products generated by substrate processing such as debris and dross to the substrate. [Means for Solving the Problems]

[0008] A method for manufacturing a substrate, comprising: a protective film forming step of forming a protective film crosslinked to the concave portion on the surface of the substrate having the concave portion; a protective film hanging step of hanging the protective film crosslinked to the concave portion toward the bottom surface of the concave portion; a substrate processing step of processing the surface of the concave portion; and a protective film peeling step of peeling the protective film. The protective film may be configured to cover at least a part of the bottom surface and side surface of the concave portion through a gap by hanging down. Further, the protective film hanging step may be a step of hanging the protective film by irradiating a laser beam on the surface of the concave portion, and the substrate processing step may be a step of processing the surface of the concave portion by the laser beam that has passed through the protective film. Furthermore, the substrate processing step may be a step of forming a through hole in the bottom surface of the concave portion. Also, the protective film may be a resin protection tape.

Advantages of the Invention

[0009] According to the method for manufacturing a substrate of the present invention, adhesion of by-products generated by processing such as debris and dross to the substrate having recesses can be suppressed, and a high-quality substrate can be manufactured.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In this embodiment, a wiring substrate having vias on a substrate having recesses will be taken as an example, and the method for manufacturing a substrate of the present invention will be described. In the drawings, in order to make each configuration easy to understand, the actual shape, the actual structure, the scale, the number, etc. in each structure may be made different.

[0012] FIG. 2 is a cross-sectional view of a wiring substrate manufactured by the method for manufacturing a substrate of the present invention. The wiring substrate 10 includes a substrate 1 having a recess 2 formed on one surface thereof, and wiring patterns 3 and circuit patterns 9 formed on the other surface of the substrate 1 and the bottom surface 2a of the recess 2. The substrate 1 includes a through hole 6 penetrating from the bottom surface 2a of the recess 2 to the other surface, and a via 20 formed by filling the through hole 6 with a metal paste 8. The via 20 is electrically connected to the wiring pattern 3 and the circuit pattern 9. An electronic device such as a light-emitting element (not shown) is mounted on the thus configured wiring substrate 10. Specifically, an electronic component such as a light-emitting element is housed in the recess 2 of the substrate 1 and is mounted on the wiring substrate 10 by being electrically connected to the circuit pattern 9. Here, the wiring pattern 3 is used to mount the wiring substrate 10 to an external device and to establish an electrical connection between the electronic components mounted on the wiring substrate 10 and the external device.

[0013] Next, a method for manufacturing the wiring board 10 will be described. FIG. 1 is a schematic diagram showing the method for manufacturing the substrate of the present invention. The wiring board 10 is manufactured by the following method.

[0014] [Protective film forming step: FIG. 1(a)] First, a substrate 1 having a recess 2 is prepared. The substrate 1 in this embodiment is a silicon substrate with a diameter of 4 inches and a thickness of 0.3 mm. The recess 2 formed on one surface of the substrate 1 includes a bottom surface 2a and a side surface 2b, has a square opening of approximately 0.4 mm, and has a substantially rectangular cross-section with a depth of approximately 0.1 mm, which is the distance from the surface of the substrate 1 where the recess 2 is not formed to the bottom surface 2a. A protective film 4a is formed on the entire surface of the surface of the substrate 1 where the recess 2 is formed (one surface). At this time, the protective film 4a is formed in contact with the surface of one surface of the substrate 1 excluding the recess 2, and is formed in a state where the opening of the recess 2 is bridged. Here, the portion of the protective film 4a that bridges the recess 2 is referred to as the protective film 4a'. Also, a protective film 4b is formed on the entire surface of the other surface of the substrate 1. In this embodiment, a resin protective tape with a thickness of approximately 0.15 mm, which is composed of a tape base material and an adhesive layer provided on one surface thereof, is used as the protective films 4a and 4b, and the protective films 4a and 4b are formed on the substrate 1 by adhering the adhesive layer to the substrate 1.

[0015] [Protective film hanging step and substrate processing step: FIGS. 1(b) and 1(c)] Next, a laser beam 5 is irradiated toward the bottom surface 2a of the recess 2 of the substrate 1 at a position corresponding to the through hole 6 of the wiring board 10, more specifically, above the protective film 4a, that is, above the protective film 4a' that bridges the recess 2. The laser beam 5 to be irradiated at this time has an energy intensity capable of processing the protective film 4a' and melting the portion from the bottom surface 2a of the recess 2 to the other surface of the substrate 1. The laser beam 5 is appropriately selected according to the material, thickness, etc. of the substrate 1, and for example, a CO2 laser or a YAG laser can be used.

[0016] In this protective film hanging process and substrate processing process, first, a through hole 4a1 is formed in the protective film 4a' by irradiating with a laser beam 5. Also, when the through hole 4a1 is formed in the protective film 4a', the peripheral portion of the irradiation region of the laser beam 5 (the peripheral portion of the through hole 4a1) is softened by the thermal energy generated by the irradiation of the laser beam 5 and hangs down toward the bottom surface 2a of the recess 2 (protective film hanging process). By hanging down the protective film 4a' in this way, at least a part of the bottom surface 2a and the side surface 2b of the recess 2 is covered with a gap with the hanging-down protective film 4a'. In other words, at least a part of the bottom surface 2a and the side surface 2b is shielded by the hanging-down protective film 4a' and is not exposed to the outside. In this embodiment, when the protective film 4a' hangs down, its end portion, specifically, the edge portion of the through hole 4a1 contacts the bottom surface 2a, and the bottom surface 2a and the side surface 2b are in a state of being almost completely not exposed to the outside by the hanging-down protective film 4a'. By hanging down the protective film 4a', which is a part of the protective film 4a, to the bottom surface 2a of the recess 2 as in this embodiment, it is possible to easily form a film covering the bottom surface 2a and the side surface 2b without directly forming a film covering the difficult bottom surface 2a and side surface 2b of the recess 2.

[0017] Subsequently, in this process, a through hole 4a1 is formed in the protective film 4a', and the laser beam 5 that has passed through the protective film 4a' is irradiated onto the bottom surface 2a of the recess 2 to form a through hole 6 that penetrates from the bottom surface 2a through the other surface of the substrate 1 and the protective film 4b (substrate processing process). When the substrate 1 is irradiated with the laser beam 5, debris and dross (hereinafter referred to as debris, etc. 7) are generated from the substrate 1. The generated debris, etc. 7 scatters around the through hole 6, but since the bottom surface 2a and the side surface 2b of the recess 2, which are around the through hole 6 on one surface of the substrate 1, are covered by the hanging-down protective film 4a', most of the debris, etc. 7 will adhere to the hanging-down protective film 4a'. Also, since the periphery of the through hole 6 on the other surface of the substrate 1 is covered by the protective film 4b, the debris, etc. 7 adheres onto the protective film 4b.

[0018] In this embodiment, as described above, the protective film 4a' is in a state where its end contacts the bottom surface 2a by hanging down. Whether the protective film 4a' contacts the bottom surface 2a by hanging down is determined by the size and depth of the opening of the recess 2, the diameter of the irradiation area of the laser beam 5 (the diameter of the through-hole 4a1), the light intensity of the laser beam 5, and the material of the protective film 4a'. However, by adopting a configuration in which the protective film 4a' contacts the bottom surface 2a of the recess 2 when it hangs down, most of the bottom surface 2a and the side surface 2b can be covered, and the adhesion of debris 7 or the like to the bottom surface 2a and the side surface 2b can be reliably prevented. Note that the protective film 4a' may be configured not to contact the bottom surface 2a when it hangs down. When the protective film 4a' is configured not to contact the bottom surface 2a, the range covering the bottom surface 2a and the side surface 2b becomes smaller compared to the case where it contacts, and it is conceivable that a part of the bottom surface 2a and the side surface 2b is exposed to the outside. However, even in this case, the adhesion of debris 7 or the like to the substrate 1 can be greatly suppressed compared to the state where the protective film 4a' does not cover the bottom surface 2a and the side surface 2b at all.

[0019] Also, in this embodiment, the protective film hanging step of hanging down a part of the protective film 4a and the substrate processing step of forming the through-hole 6 in the substrate 1 are performed by a single irradiation with the laser beam 5. By adopting such a process, the manufacturing process can be shortened, and the positioning of the hanging position of the protective film 4a' in the protective film hanging step and the processing position in the substrate processing step can be completed at once, enabling highly accurate processing.

[0020] [Protective film peeling step: Fig. 1(d)] Next, the protective films 4a and 4b are peeled from the substrate 1. Since the protective film 4a is integral with the protective film 4a' that hung down in the previous step, when the protective film 4a is peeled from the substrate 1, debris 7 or the like attached to the protective film 4a' does not remain on the substrate 1. Also, debris 7 or the like attached to the protective film 4b does not remain on the substrate 1 by peeling the protective film 4b. The peeling of the protective films 4a and 4b is performed, for example, by irradiating the protective films 4a and 4b with ultraviolet rays to cure the adhesive layer and reduce the adhesive force, and then peeling them from the substrate 1. By thus reducing the adhesive force of the adhesive layer of the protective films 4a and 4b, the protective films 4a and 4b can be easily peeled from the substrate 1.

[0021] [Via and Wiring Pattern Formation Step: FIG. 1(e)] Next, the through-hole 6 of the substrate 1 is filled with the metal paste 8, and the substrate 1 is fired to form vias 20 in the substrate 1. Next, a wiring pattern 3 and a circuit pattern 9 are formed on the surface of the recess 2 of the substrate 1 using a known photolithography technique. Through the above steps, a wiring board 10 is obtained.

[0022] As described above, the method for manufacturing a substrate according to the present invention has been described based on the embodiments. However, the scope of the present invention is not limited to the above-described embodiments and can be arbitrarily changed within the scope of the technical idea of the present invention. For example, in this embodiment, the wiring board 10 having the through-hole 6 is used as an example to describe the embodiments of the present invention. However, the method for manufacturing a substrate according to the present invention is not limited to this example and can be applied to various articles for processing a substrate (base material). Further, in the embodiments, an example in which the substrate is processed by irradiating the laser beam 5 has been described. However, for example, instead of irradiating the laser beam 5, it can also be applied to machining such as cutting that generates by-products by machining. Further, the base material of the substrate 1 is silicon, but it is not limited to silicon and may be composed of other materials such as aluminum nitride. Further, the substrate 1 is not limited to a circular substrate and may be a rectangular substrate. Further, the protective films 4a and 4b are not limited to resin-made protective tapes, and any material that can be cross-linked in the recess 2 and can hang down toward the bottom surface 2a of the recess 2 may be used.

[0023] Furthermore, the protective film hanging step and the substrate processing step may be performed in separate steps. In this embodiment, a through-hole 4a1 is formed in the protective film 4a by irradiating the laser beam 5, and the protective film 4a' is hung down. Further, the substrate 1 is processed by the laser beam 5 that has passed through the protective film 4a. However, for example, the protective film 4a' may be hung down by pressing it with a pin or the like, and then the substrate 1 may be processed.

[0024] Furthermore, in this embodiment, the protective film hanging step is performed after the protective film forming step. However, for example, a protective film 4a having a portion that hangs down (bends toward the recess 2) in advance at a position corresponding to the recess 2 may be prepared, and the protective film 4a may be formed on the substrate 1.

Explanation of Reference Numerals

[0025] 1 Substrate 2 Recess 2a Bottom Surface 2b Side Surface 3 Wiring Pattern 4a Protective Film 4a´ Protective Film 4a1 Through-Hole 4b Protective Film 5 Laser Beam 6 Through-Hole 7 Debris, etc. 9 Circuit Pattern 10 Wiring Substrate 20 Via

Claims

1. A method for manufacturing a substrate, comprising: a protective film forming step of forming a protective film crosslinked to the concave portion on the surface of the substrate having the concave portion; a protective film hanging step of hanging the protective film crosslinked to the concave portion toward the bottom surface of the concave portion; a substrate processing step of processing the surface of the concave portion; a protective film peeling step of peeling the protective film. The method for manufacturing a substrate is characterized by comprising these steps.

2. The method for manufacturing a substrate according to claim 1, wherein the protective film covers at least a part of the bottom surface and the side surface of the concave portion through a gap by hanging down.

3. The protective film hanging step is a step of hanging the protective film by irradiating a laser beam on the protective film crosslinked to the concave portion, and the substrate processing step is a step of processing the surface of the concave portion by the laser beam that has passed through the protective film. The method for manufacturing a substrate according to claim 1 or 2 is characterized by this.

4. The method for manufacturing a substrate according to any one of claims 1 to 3, wherein the substrate processing step is a step of forming a through hole in the bottom surface of the concave portion.

5. The method for manufacturing a substrate according to any one of claims 1 to 4, wherein the protective film is a resin protection tape.

Images