JP2009164153A - Through hole filling method for substrate for electronic component - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a through-hole filling method for a substrate for electronic components, in which a through-hole can be surely filled. <P>SOLUTION: The through-hole filling method for the substrate for electronic components includes a through-hole boring process of forming the through-hole 13 in a truncated cone shape in a wafer W as the substrate for electronic components by sand blasting or etching, and a metal film forming process of providing a metal film by electrolytic plating on a main surface of the wafer W constituting the substrate for electronic components including a peripheral surface of the through-hole 13 bored in the through-hole boring process, wherein the through-hole 13 is filled with the metal film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for filling a through hole in an electronic component substrate that fills a through hole provided in an electronic component substrate used for an electronic component.

2. Description of the Related Art Conventionally, an electronic component substrate using an insulating material has been used as a substrate body, a wiring substrate, a printed substrate, and a module substrate for electronic components mounted on various electronic devices.
These electronic component substrates may be configured to be thinner due to the miniaturization of electronic components. For example, in the electronic component substrate 210 shown in FIG. 5A, a wiring pattern 214 (see FIG. 5B) made of a metal film provided on the electronic component substrate 210 is changed from one main surface to the other. When drawing around the main surface, a structure using the through hole 230 may be employed.
The through hole 230 is provided by, for example, drilling with a drill device (see, for example, Patent Document 1) or drilling with a laser device (see, for example, Patent Document 2).
The space shape of the through hole 230 provided by the drill device or the laser device is a cylindrical shape.
In addition, when the wiring pattern 214 is provided on the electronic component substrate 10, an electrolytic plating method may be used (see, for example, Patent Document 3). In this case, when the wiring patterns 214 on both main surfaces of the electronic component substrate 10 are routed through the through hole 230, metal is also introduced into the through hole 230 so that the through hole 230 is filled with metal. Is ideal.

Japanese Patent No. 3535509 Japanese Patent No. 3441945 Japanese Patent No. 3357875

However, when the through hole 230 has a cylindrical shape, if the inside of the through hole 230 is filled with metal by an electrolytic plating method, the through hole 230 is surrounded by metal as shown in FIG. A space S may be formed.
When such a space S is formed, if the electronic component substrate 210 is used as a substrate body constituting a package of a piezoelectric vibrator, for example, the inside of the package that must be hermetically sealed is the space S. As a result, the state of communication with the outside, that is, the state in which airtightness cannot be maintained, cannot be ensured for the normal operation of the piezoelectric vibrator.
Further, when used for a wiring board, a printed board, a module board, etc., gas or the like emitted from other components is likely to be accumulated in the space S, which may cause metal corrosion or poor conduction.
In addition, when these substrates are stacked and used, expansion and contraction due to heat occur in the space, which may cause cracks in the substrate.

  Therefore, an object of the present invention is to solve the above-described problems and provide a method for filling a through hole in an electronic component substrate that can reliably fill the inside of the through hole.

  In order to solve the above-mentioned problems, the present invention is a method of filling a through hole in an electronic component substrate, wherein a through hole forming step of providing a frustoconical through hole in the electronic component substrate by sandblasting or etching, and the through hole formation And a metal film forming step of providing a metal film on the main surface of the electronic component substrate including the peripheral surface of the through hole provided by the step by electrolytic plating.

According to such a method for filling a through hole in a substrate for an electronic component, the metal film is provided first from the smaller one of the openings of the through hole having a truncated cone shape, so that the through hole is surrounded by metal. The formation of the open space can be prevented. Therefore, the through hole can be reliably filled.

  Next, the best mode for carrying out the present invention (hereinafter referred to as “embodiment”) will be described in detail with reference to the drawings as appropriate.

FIG. 1 is a conceptual diagram showing an example of a piezoelectric vibrator. FIG. 2 is a conceptual diagram showing an example of a state in which a through hole is provided in the wafer. FIG. 3 is a conceptual diagram showing an example of a state in which a metal film is provided on the wafer. FIG. 4 is a conceptual diagram of a through hole filling method for an electronic component substrate according to an embodiment of the present invention. FIG. 4A is a conceptual diagram showing a state where a wafer is masked, and FIG. It is a conceptual diagram which shows an example of the obtained state, (c) is a conceptual diagram which shows an example of the state which provided the base layer in the part to electroplate, (d) is the state by which the through-hole was filled by electrolytic plating It is a conceptual diagram which shows an example.
The case where the electronic component substrate is used for a package of a piezoelectric vibrator will be described as an example.

Here, the configuration of the piezoelectric vibrator will be described.
A piezoelectric vibrator 100 shown in FIG. 1 includes, for example, a substrate body 10 having a rectangular shape in plan view, a piezoelectric vibration element 20 made of quartz mounted on the substrate body 10, and a recess 31, and the piezoelectric vibration element 20 in the recess 31. And a lid 30 that hermetically seals and hermetically seals.

  The lid body 30 is formed in a rectangular shape in plan view, and a concave portion 31 is formed on one main surface. The concave portion 31 can be hermetically sealed by joining the substrate body 10 so that the concave portion 31 faces the substrate body 10 described later and the piezoelectric vibration element 20 is accommodated in the concave portion 31.

  The substrate body 10 is formed in a rectangular shape in plan view, and two mounting pads 11 for mounting the piezoelectric vibration element 20 are provided on one main surface side thereof. The surfaces of the mounting pads 11 are provided so as to be parallel to the other main surface side of the substrate body 10. Further, external terminals 12 that are electrically connected to the respective mounting pads 11 are provided on the other main surface side.

As shown in FIG. 2, two pairs of through holes 13 are provided in the substrate body 10 and are used when the mounting pads 11 and the external terminals 12 are electrically connected (see FIG. 1).
The through hole 13 is provided so as to be positioned in the recess 31 of the lid 30 (see FIG. 1), and is provided corresponding to a position where a wiring pattern 14 described later is provided.

  For example, as shown in FIG. 3, one external terminal (not shown) is provided at a position away from one mounting pad 11, and the other external terminal 12 (FIG. 3), one through hole 13 is provided at a position away from one mounting pad 11, and the other through hole 13 is formed as shown in FIG. 4 (d). As shown in FIG. 4, the other mounting pad 11 and the other external terminal 11 are provided so as to be positioned in an overlapping region (see FIG. 4D).

The mounting pad 11 and the external terminal 12 are electrically connected by a wiring pattern 14 (see, for example, FIG. 4D).
The wiring pattern 14 is provided up to an opening 13A of one through hole 13 that penetrates one mounting pad 11 and the substrate body 10 (see FIG. 4), and is provided inside the one through hole 13 so as to be connected thereto. (See FIG. 4), and provided on the surface of the other main surface (not shown) so as to connect the opening 13B of one through-hole 13 and one external terminal 12. Further, the wiring pattern 14 is provided in the other through hole 13 so as to connect the other mounting pad 11 and the other external terminal 12 (see FIG. 4D).

  As shown in FIG. 1, the piezoelectric vibration element 20 has excitation electrodes 22 provided on both main surfaces of a quartz plate 21, and a lead pattern 23 is formed so as to reach one end side of the quartz plate. Yes. The routing pattern 23 is electrically and mechanically connected to the mounting pad 11 of the substrate body 10 by the conductive adhesive D.

  Thus, the substrate body 10 used for the piezoelectric vibrator 100 is formed in the state of the wafer W as shown in FIG. A through hole filling method for closing the through hole 13 provided in the wafer W will be described.

The wafer W is an electronic component substrate, and for example, crystal, glass, ceramics, resin glass, or the like can be used.
First, for example, a plurality of regions to be the substrate body 10 are set in the wafer W, which is a substrate for electronic components, and a through hole forming step is performed in which the through holes 13 are provided at predetermined positions in the region to be the substrate body 10. .
In this through hole forming step, sand blasting or etching is used when forming the through hole 13 in the wafer W. The case where sandblasting is used will be described.

As shown in FIGS. 4A and 4B, the through hole 13 formed by sandblasting has a truncated cone shape in the spatial shape. Even when etching is used, the through hole 13 has a truncated cone shape.
When sandblasting is used, the portion where the mask M is not provided is shaved. This part to be cut becomes a hole and later becomes a through hole 13. As the hole becomes deeper, the diameter of the hole bottom becomes smaller. When the hole penetrates the wafer W, the opening 13A on the side penetrating the wafer W is formed narrower than the opening 13B. As a result, the through hole 13 has a so-called wedge shape, that is, a truncated cone shape.

  As shown in FIG. 4C, a metal film B serving as a base layer is formed by vapor deposition on the peripheral surface of the through-hole 13 and the portions that become the mounting pad 11, the external terminal 12, and the wiring pattern 14.

Thereafter, a metal film forming step is performed in which another metal film is formed by electrolytic plating on the metal film B formed on the wafer W including the peripheral surface of the through hole 13 provided by the through hole forming step.
By this metal film forming step, as shown in FIG. 4D, a metal film is formed on each of the portion that becomes the wiring pattern 14, the portion that becomes the mounting pad 11, and the portion that becomes the external terminal 12.

In this case, a metal film is also formed in the through hole 13, but the metal formed first from the smaller opening 13A of the through hole 13 because the space shape of the through hole 13 has a truncated cone shape. Blocked by a membrane. That is, when electrolytic plating is performed until the thickness reaches a predetermined thickness, the openings 13A and 13B become smaller with the thickness of the metal film, and the smaller opening 13A is eventually closed. Furthermore, electrolytic plating may be performed to form a metal film until the opening 13B is filled.
Thereby, the conventional space S is not formed inside the through hole 13, and the through hole 13 can be reliably filled with the metal film.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment. For example, the substrate for an electronic component has been described as the substrate body (wafer) of the piezoelectric vibrator. However, the present invention is not limited to this, and the substrate for an electronic component may be provided if the through hole 13 is provided and the metal is buried therein. You may use for a wiring board, a printed circuit board, a substrate for modules, etc. The material for the electronic component substrate may be an insulating material. The metal film may be any metal that can be electroplated. When performing electrolytic plating, the plating solution may be applied with the opening 13A facing downward. By performing electrolytic plating in this way, the opening 13A can be easily closed with a metal film.

It is a conceptual diagram which shows an example of a piezoelectric vibrator. It is a conceptual diagram which shows an example of the state which provided the through hole in the wafer. It is a conceptual diagram which shows an example of the state which provided the metal film in the wafer. It is a conceptual diagram of the through-hole filling method of the board | substrate for electronic components which concerns on embodiment of this invention, (a) is a conceptual diagram which shows the state which masked the wafer, (b) was provided with the through-hole in the wafer It is a conceptual diagram which shows an example of a state, (c) is a conceptual diagram which shows an example of the state which provided the base layer in the part to electroplat, (d) is an example of the state by which the through-hole was filled by electrolytic plating FIG. (A) is a conceptual diagram which shows the state of the conventional through hole, (b) is a conceptual diagram which shows the state which filled the conventional through hole, (c), The space was formed in the inside of the through hole It is a conceptual diagram which shows an example of a state.

Explanation of symbols

W wafer (Electronic component substrate)
10 Substrate body (substrate for electronic components)
13 Through-hole 13A, 13B Opening 11 Mounting pad (metal film)
12 External terminal (metal film)
14 Wiring pattern (metal film)
B Metal film

Claims (1)

A through hole forming step of providing a frustoconical through hole in the electronic component substrate by sandblasting or etching;
And a metal film forming step in which a metal film is provided by electrolytic plating on a main surface of the electronic component substrate including a peripheral surface of the through hole provided in the through hole forming step. How to fill holes.

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