JP2012015209A - Through-wiring board and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a through-wiring board having a through-via capable of preventing the formation of void.SOLUTION: The present invention provides a through-wiring board with a through-via which comprises: a substrate provided with a through-hole; a conductor which is arranged in the through-hole and electrically connects an upper face and a lower face of the substrate; and resin filled in a gap between the conductor and the through-hole. The invention also provides a manufacturing method of such a through-wiring board. The substrate may be a glass substrate. The resin may be a polyimide. The resin may also be a polymer. Further, the resin may be photo-curable resin which reacts to light and changes into a solid.

Description

  The present invention relates to a through wiring substrate and a manufacturing method.

Conventionally, through vias filled with a conductive metal are formed on a substrate, and wirings formed on both surfaces of the substrate are electrically connected. Here, when the coefficient of thermal expansion differs between the substrate and the conductive metal, a conductive brazing material is filled between the conductive metal and the substrate to prevent the substrate from being damaged and between the substrate and the conductive metal. It was prevented that a gap was formed on the surface (for example, see Patent Document 1).
Patent Document 1 JP 2006-60119 A

  Such a through via filled with a brazing material has different coefficients of thermal expansion among the brazing material, the substrate, and the conductive metal. Therefore, depending on the heating temperature and the heating time of the high-temperature heat treatment in the manufacturing process or the heat treatment in the processing process, A cavity called a void is formed between the metal and the conductive metal. When a device is sealed using a substrate on which a void has occurred, outside air has entered from the void, deteriorating the function of the device.

  In order to solve the above-mentioned problem, in the first aspect of the present invention, there is provided a through wiring substrate provided with through vias, a substrate in which through holes are formed, and a top surface of the substrate provided in the through holes. Provided is a through wiring board including a conductor that electrically connects the lower surface and a lower surface, and a resin filled in a gap between the conductor and the through hole.

  It should be noted that the above summary of the invention does not enumerate all the necessary features of the present invention. In addition, a sub-combination of these feature groups can also be an invention.

2 shows a configuration example of a through wiring board 100 according to the present embodiment. The manufacturing flow of the penetration wiring board 100 concerning this embodiment is shown. The manufacturing method of the penetration wiring board 100 concerning this embodiment is shown. The modification of the manufacturing method of the penetration wiring board 100 concerning this embodiment is shown.

  Hereinafter, the present invention will be described through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of features described in the embodiments are essential for the solving means of the invention.

  FIG. 1 shows a configuration example of a through wiring substrate 100 according to the present embodiment. FIG. 1A is a top view of the through wiring substrate 100. FIG. 1B is a cross-sectional view of the through wiring substrate 100 taken along line AA ′ in FIG. The through wiring substrate 100 is provided with a through via without generating a void between the substrate and the conductive metal. The through wiring substrate 100 includes a substrate 110, a conductor 130, and a resin 140.

  The substrate 110 may be a glass substrate, a semiconductor substrate such as silicon, or various substrates such as a ceramic substrate. The substrate 110 has a through hole 120 formed therein.

  The conductor 130 is provided in the through hole 120 and electrically connects the upper surface and the lower surface of the substrate 110. The conductor 130 may be tungsten, molybdenum, stainless steel, Kovar (an alloy of iron, nickel, cobalt), iron nickel, or the like. The conductor 130 may be made of a material having a thermal expansion coefficient close to that of the substrate 110. For example, when the substrate 110 is borosilicate glass having a thermal expansion coefficient of about 3.3 [ppm / K], the conductor 130 is made of Kovar having a thermal expansion coefficient of about 5.3 [ppm / K]. The conductor 130 may have a columnar shape, and may instead have a cylindrical shape.

  The resin 140 is filled in the gap between the conductor 130 and the through hole 120. The resin 140 may be a polyimide that is imidized by a heat treatment after applying and drying a polyamic acid solution to become an insulating solid. Alternatively, the resin 140 may be a polymer with low degassing property that is solidified by heat treatment or moisture evaporation. Alternatively, the resin 140 may be a photo-curing resin that changes to a solid in response to light.

  FIG. 2 shows a manufacturing flow of the through wiring board 100 according to the present embodiment. FIG. 3 shows a method for manufacturing the through wiring substrate 100 according to the present embodiment.

  First, the through hole 120 is formed in the substrate 110 (S200). Next, the support base 210 is attached to the substrate 110 having the through holes 120 (S210). The substrate 110 and the support base 210 may be bonded together by heating at about 100 ° C. Here, the substrate 110 and the support base 210 may be bonded together by the bonding material 220. FIG. 3A shows a state in which the support base 210 is bonded to the substrate 110 on which the through hole 120 is formed by the bonding material 220.

  The bonding material 220 may be an adhesive resin or the like, and may instead be a double-sided pressure-sensitive adhesive sheet that can be easily peeled off due to a decrease in adhesive strength by heating at about 100 ° C. Instead of this, a resist obtained by applying a resist on the substrate 110 and solidifying it may be used as the support base 210. Accordingly, the support base 210 can be bonded to the substrate 110 without using the bonding material 220.

  Next, the conductor 130 is inserted into the through hole 120 (S220). FIG. 3B shows a state where the conductor 130 is inserted into the through hole 120. Here, the conductors 130 may be inserted into the through holes 120 by placing a plurality of conductors 130 on the upper surface of the substrate 110 and applying vibration. Alternatively, the conductor 130 may be moved by tweezers or the like and inserted into the through hole 120.

  Next, the resin 140 is applied to the surface opposite to the surface on which the support base 210 of the substrate 110 is pasted, and the resin 140 is filled in the gap between the conductor 130 and the through hole 120 (S230). In the present embodiment, an example in which polyimide is used as the resin 140 will be described.

  FIG. 3C shows a state in which the resin 140 is applied and the gap between the conductor 130 and the through hole 120 is filled with the resin 140. Here, the resin 140 may be applied to the upper surface of the substrate 110, and the substrate 110 may be rotated by a spin coater or the like to uniformly form the resin 140 on the substrate 110. Alternatively, the resin 140 may be sprayed onto the substrate 110 with a spray coater to form a film.

  Next, pre-baking is performed to volatilize the solvent contained in the polyamic acid solution to form and fix the polyimide film (S240). The prebaking temperature may be about 100 ° C. Next, the bonding material 220 is melted with a stripping solution, and the substrate 110 and the support base 210 are separated. Here, the stripping solution may be a solvent such as acetone that melts the bonding material 220 without melting the polyimide film. Next, the resin 140 is cured (S250). Here, the resin 140 may be cured by a plurality of heat treatments. Here, instead of melting the bonding material 220 with the stripping solution, the substrate 110 and the support base 210 may be separated by melting in the process of forming a polyimide film by at least one heat treatment. Thereby, the man-hour for separating the support base 210 can be omitted.

  Here, the temperature of the heat treatment for melting the bonding material 220 may be different from the temperature of the heat treatment for curing the resin 140. As an example, the bonding material 220 is melted at the pre-baking stage, and the substrate 110 and the support base 210 are separated. By using the bonding material 220 that melts at a temperature lower than the temperature at which the resin 140 is cured, the bonding material 220 can be separated while pre-baking.

  FIG. 3D shows the substrate 110 in which the support base 210 is separated after pre-baking or by pre-baking. The substrate 110 may be further heat-treated at a temperature of about 200 to 350 ° C. in an oven or the like. Instead, the substrate 110 may be heat-treated at a temperature of about 200 to 350 ° C. by a hot plate or the like. As a result, imidization of the polyimide film is promoted, and the resin 140 is cured.

  Here, when the resin 140 is a photo-curing resin that changes to a solid in response to light, the resin 140 may be cured by irradiating the substrate 110 with light. As a result, heat treatment for curing polyimide or polymer can be omitted, and formation of voids resulting from the heat treatment can be suppressed.

  When the resin 140 is cured by irradiating light, the bonding material 220 may be separated by heat treatment. In this case, by using the bonding material 220 that melts at a temperature lower than the temperature at which the resin 140 is cured, the through wiring substrate 100 can be manufactured by a heat treatment at about 100 ° C., for example.

  Instead of this, after the resin 140 is cured, the bonding material 220 may be melted with a peeling solution to separate the substrate 110 and the support base 210. The stripping solution may be a solvent such as acetone, which can reduce the number of heat treatments. Further, when the support base is formed of a resist or when the bonding material 220 that does not melt by heating is used, the resist may be separated from the substrate 110 by a developer or a stripping solution after the resin 140 is cured. As a result, the number of heat treatments can be reduced. In particular, heat treatment can be eliminated by combining with the case where the resin 140 is a photo-curing resin.

  Next, the resin 140 cured on the surface of the substrate 110 is removed (S260). FIG. 3E shows the substrate 110 from which polyimide is removed. As an example, the polyimide cured on the surface of the substrate 110 is removed by polishing. Here, the conductor 130 may be exposed by polishing to the surface of the substrate 110.

  Alternatively, the resin 140 may be removed by etching. It can be removed with high precision by dry etching or wet etching. In addition, by using a mask in the course of etching, the resin cured on the surface of the substrate 110 can be removed while leaving the shape of the mask.

  According to the manufacturing method of the present embodiment described above, the polyimide filled and cured in the gap between the through hole 120 of the substrate 110 and the conductor 130 remains, and the conductor 130 penetrates while being exposed on the surface of the substrate 110. It can be supported and bonded in the hole 120.

  Accordingly, the through via can be provided in the substrate 110 by using a heat treatment at a temperature at which the resin 140 is cured without using the brazing material. Since a brazing material having a thermal expansion coefficient larger than that of the substrate 110 and the conductor 130, that is, about 20 ppm / ° C., for example, is not used, and a heat treatment exceeding 600 ° C. for filling the brazing material is not used. Formation of voids due to breakage of the substrate 110 or peeling or chipping of the brazing material can be suppressed.

  Moreover, since the polyimide resin of this example has little degassing, the through wiring substrate 100 can be used as a substrate for sealing the device. In addition, since the polyimide resin is also excellent in heat resistance, when the through wiring substrate 100 is used as a substrate for sealing a device, anodic bonding in which heat treatment is performed while applying an electric field can be used. Moreover, since the polyimide resin is excellent in filling property, the through wiring substrate 100 can be easily formed.

  The resin 140 may be filled at least twice, and the resin 140 that is filled first may have a higher viscosity than the resin 140 that is filled later. In this manner, by filling the resin 140 with a changed viscosity in several batches, bubbles or the like can be prevented from being generated in the gap between the conductor 130 and the through hole 120.

  FIG. 4 shows a modification of the method for manufacturing the through wiring substrate 100 according to the present embodiment. Here, since the process from the pre-baking of the resin 140 to the separation of the support base 210 is the same as the content up to FIG. 3D described with reference to FIG. 3, the state of FIG. a). Also, the description of the contents that are substantially the same as the description of FIG. 3 is omitted.

  In FIG. 4A, the resin 140 may be a photosensitive resin. In this case, in FIG. 4B, the resin 420 is irradiated with light 420 through the mask 410. When the portion of the resin 140 exposed to the developer is removed, the portion of the resin 140 that is masked and not exposed remains (FIG. 4C). Next, the substrate 110 is heat-treated to cure the resin 140 that has not been removed.

  The through wiring substrate 100 thus formed is shown in FIGS. 4C and 4D. FIG. 4C is a cross-sectional view taken along the line AA ′ of FIG. On the surface of the through wiring substrate 100, the resin 140 remains in a form of covering the resin 140 filled in the gap between the through hole 120 and the conductor 130 while exposing the conductor 130 in a circular shape. Thereby, since the boundary between the through hole 120 and the resin 140 and the boundary between the resin 140 and the conductor 130 are covered, voids are not generated at the respective boundaries, and the airtightness can be improved. Further, when the resin 140 has photosensitivity, it can be protected by the lid-shaped resin 140 so that light does not reach the resin 140 filled in the gap between the through hole 120 and the conductor 130.

  Further, the resin 140 is also applied to the back surface side of the through wiring substrate 100, exposed through substantially the same mask 410, and removed with a developer, so that the gap between the through hole 120 and the conductor 130 is filled. The resin 140 may be formed so as to cover the resin 140. By forming the lid-like resin 140 on both surfaces of the through wiring substrate 100, the airtightness can be further improved. Further, since the lid-shaped resin 140 is formed, even when the through wiring substrate 100 is anodically bonded when used as a substrate for sealing a device, formation of voids or deterioration of hermeticity due to heat treatment can be prevented. it can.

  In the above modification of the present embodiment, the resin 140 has been described as a photosensitive resin. Alternatively, if the resin 140 does not have photosensitivity, the resin 140 is removed by dry etching using a reactive gas, a reactive ion, or an ion beam instead of the light 420 through the mask 410. Good. In this case, the resin 140 may be removed by dry etching after the resin 140 is cured. Instead of this, the resin 140 may be removed by wet etching with an etchant. In either case of dry etching or wet etching, the mask 410 may be formed on the surface of the substrate 110 with a resist or the like.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above-described embodiment. It is apparent from the scope of the claims that the embodiments added with such changes or improvements can be included in the technical scope of the present invention.

  The order of execution of each process such as operations, procedures, steps, and stages in the apparatus, system, program, and method shown in the claims, the description, and the drawings is particularly “before” or “prior to”. It should be noted that the output can be realized in any order unless the output of the previous process is used in the subsequent process. Regarding the operation flow in the claims, the description, and the drawings, even if it is described using “first”, “next”, etc. for convenience, it means that it is essential to carry out in this order. It is not a thing.

100 through wiring substrate, 110 substrate, 120 through hole, 130 conductor, 140 resin, 210 support base, 220 bonding material, 410 mask, 420 light

Claims (19)

A through wiring board provided with through vias,
A substrate having a through hole formed thereon;
A conductor provided in the previous through-hole and electrically connecting the upper surface and the lower surface of the substrate;
A resin filled in a gap between the conductor and the through hole;
A through wiring board comprising:   The through wiring substrate according to claim 1, wherein the substrate is a glass substrate.   The through wiring board according to claim 1, wherein the resin is polyimide.   The through wiring board according to claim 1, wherein the resin is a polymer.   The through wiring board according to claim 1, wherein the resin is a photo-curing resin that changes to a solid in response to light. A manufacturing method for manufacturing a through wiring substrate provided with a through via,
Forming a through hole in the substrate;
An insertion step of attaching a support base to the previous substrate in which the through-hole is opened, and inserting a conductor into the through-hole,
A filling step of applying a resin to a surface opposite to the surface of the substrate on which the support base is bonded, and filling the resin into a gap between the conductor and the through hole;
A curing step for curing the resin;
Removing to remove the resin on the surface of the substrate;
The manufacturing method which manufactures a penetration wiring board provided with.   The manufacturing method according to claim 6, wherein the substrate is a glass substrate.   The manufacturing method according to claim 6 or 7, wherein the resin is polyimide.   The manufacturing method according to claim 6 or 7, wherein the resin is a polymer.   The method according to any one of claims 6 to 9, wherein in the filling step, the resin is filled at least twice, and the resin to be filled first has higher viscosity than the resin to be filled later. The resin is a photo-curing resin that changes to a solid in response to light,
The manufacturing method according to claim 6, wherein in the curing step, the resin is cured by irradiating the substrate with light.   The manufacturing method according to claim 6, wherein in the curing step, the resin is cured by heat treatment. In the filling step, the substrate and the support base are bonded together by a bonding material,
In the curing step, the resin is cured by a plurality of heat treatments,
The manufacturing method according to claim 6, wherein the bonding material is melted by at least one heat treatment in the curing stage to separate the substrate and the support base.   The manufacturing method according to claim 12, wherein the temperature of the heat treatment for melting the bonding material is different from the temperature of the heat treatment for curing the resin. In the filling step, the substrate and the support base are bonded together by a bonding material,
The manufacturing method according to any one of claims 6 to 11, wherein in the curing step, the bonding material is melted with a peeling solution to separate the substrate and the support base. In the insertion step, the support base is a resist solidified by applying a resist on the substrate,
The manufacturing method according to claim 6, wherein in the curing step, the resist is separated from the substrate by a developer or a stripping solution.   The manufacturing method according to claim 6, wherein in the removing step, the resin cured on the surface of the substrate in the curing step is removed by polishing.   The manufacturing method according to claim 6, wherein in the removing step, the resin cured on the surface of the substrate in the curing step is removed by etching. The resin has photosensitivity,
In the removing step, the resin applied to the surface of the substrate is irradiated with light through a mask to remove an exposed portion of the resin with a developer,
The manufacturing method according to claim 6, wherein in the curing step, the resin that has not been removed in the removing step is cured.

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