JPH10209162A - Electronic part for solder bump connection and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To miniaturized a part and to eliminate the need for wiring patterns by sticking lower and upper substrate to each other so that a ground electrode is located in the hole of the upper substrate, and forming a solder bump that has a narrower width than the diameter of the hole and a height higher than the thickness of the upper surface at the ground electrode and then projecting it from the hole. SOLUTION: An upper substrate 5 is stuck on a lower substrate 1 so that a ground electrode e1 formed at the lower substrate 1 is located at the center of a hole 5b by the upper substrate 5. A solder cream is printed to the hole 5b and is filled. Then, by heating and melting the solder cream, solder is coagulated in spherical body due to its surface tension, and a solder bump b1 is formed on the ground electrode 1e. The solder bump b1 and a narrower width than the diameter of the hole 5b at the ground electrode e1, and a height higher than the thickness of the upper substrate 5. Therefore, the formed solder bump b1 projects from the hole 5b, thus a solder bump connection electronic part can be connected a packaging substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic component connected by a solder bump, and more particularly to an electronic component connected to a solder bump having a lower substrate and an upper substrate for protecting or sealing a functional portion formed on the lower substrate. And its manufacturing method.

[0002]

2. Description of the Related Art A conventional solder bump connection electronic component and a method of manufacturing the same will be described with reference to FIG. FIG. 1 shows a sectional form of an acceleration sensor 20 as a conventional solder bump connection electronic component. 21 is a lower substrate,
A vibrating body 22 is formed on the lower substrate 21 so as to freely vibrate. Reference numeral 23 denotes an upper substrate, which has a concave portion 23a and
b, and is bonded to the lower substrate 21 so that the recess 2
The vibrating body 22 is covered with a cover 3a. Reference numeral 24 denotes an extraction electrode of the vibrator 22, which is formed on the lower substrate 21 exposed in the hole 23b. Reference numeral 25 denotes a base electrode for forming a solder bump formed on the upper substrate 23.
5 and the extraction electrode 24 are connected to the wiring pattern 2 passing through the hole 23b.
6. Then, the base electrode 25 has
Solder bumps 27 are formed. This solder bump 27
Is to use a solder mask with a metal mask
The printed solder cream is heated and melted, the solvent is evaporated, and the solder is aggregated into a spherical shape by surface tension.

The capacitance between the movable comb electrode (not shown) formed on the vibrating body 22 and the fixed comb electrode formed on the lower substrate 21 changes in accordance with the acceleration. The acceleration is detected by taking out from the bumps 27 and 27 and converting the voltage.

[0004]

However, the conventional solder bump connection electronic component has the draw-out electrode 24 from the functional portion.
Is formed on the lower substrate 21, a base electrode 25 for solder bump connection is formed on the upper substrate 23, and a wiring pattern 26 for connecting between the extraction electrode 24 and the base electrode 25 is required. Therefore, in the conventional solder bump connection electronic component, the hole 23b for leading the extraction electrode 24 to the outside, the wiring pattern 2
6 and a base electrode 25 are required separately, and the shape is large.

In addition, the conventional method for manufacturing a solder bump connection electronic component requires a metal mask for printing a solder cream for forming a solder bump, and requires a step of forming a wiring pattern 26.

Accordingly, the present invention provides a solder bump connection electronic component which can be downsized by forming a base electrode for solder bump connection on a lower substrate and forming a solder bump on the lower substrate. And a method of manufacturing a solder bump connection electronic component that does not require a wiring pattern by also serving as an extraction electrode as a base electrode, and uses a hole formed in an upper substrate instead of a metal mask. .

[0007]

According to a first aspect of the present invention, there is provided a solder bump connection electronic component, wherein the lower substrate and the lower substrate are connected to each other so that a base electrode formed on the lower substrate is positioned in a hole formed in the upper substrate. The solder bump having a width smaller than the diameter of the hole, and the solder bump having a height greater than the thickness of the upper substrate is formed on the base electrode, and the base electrode protrudes from the hole. It is.

In the invention of the solder bump connection electronic component, the solder bump formed on the base electrode of the lower substrate is formed so as to protrude from the hole of the upper substrate, and performs the function of connection to the mounting substrate. Since the base electrode on which the solder bumps are formed also serves as an extraction electrode from the functional unit, there is no need to separately form the extraction electrode and the base electrode, and it is also necessary to provide a wiring pattern for connecting these. It is possible to reduce the size.

According to a second aspect of the present invention, there is provided a method of manufacturing a solder bump connection electronic component, comprising: forming a base electrode for solder bump connection on a lower substrate; and forming the base electrode in a hole formed in the upper substrate. Bonding the upper substrate to the lower substrate so as to be positioned, filling the solder cream into the holes, heating and melting the solder cream to aggregate the solder, and forming the solder on the base electrode. Forming a bump and projecting from the hole.

According to the invention of the method for manufacturing a solder bump connection electronic component, a solder cream for forming a solder bump is filled in a hole formed in an upper substrate, the solder cream is heated and melted, and the solder is deposited on a base electrode. Due to the surface tension, the solder bumps are aggregated into a sphere having a height greater than the thickness of the upper substrate to form solder bumps projecting from the holes. The solder bump is formed by appropriately setting the diameter of the base electrode, the size of the hole, and the amount of the solder cream. Then, the solder bump connection electronic component of the present invention is connected to the mounting board by the solder bump.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing an electronic component connected to a solder bump according to an embodiment of the present invention. In FIG. 1, reference numeral 10 denotes an acceleration sensor as a solder bump connection electronic component in a sectional form. Reference numeral 1 denotes an SOI (Sicon On Insul) having a three-layer structure of a single crystal silicon layer 1a, a silicon oxide layer 1b, and a single crystal silicon layer 1c.
ator) A lower substrate composed of a substrate. By processing the single-crystal silicon layer 1c by using a semiconductor fine processing technique such as a photolithography technique or an etching technique, a functional portion indicated by a point set portion in FIG. 2 is formed. That is, on the single-crystal silicon layer 1c, a photoresist mask corresponding to the shape of the functional portion indicated by the point set portion and the shape of the peripheral portion of the single-crystal silicon layer 1c is formed, and sulfur hexafluoride (SF) is formed.
₆ ) Anisotropic etching is performed on the single crystal silicon layer 1c by RIE (reactive ion etching) using a gas until the silicon oxide layer 1b is visible. Next, the lower substrate 1
Is immersed in an etching solution of buffa hydrofluoric acid (BHF),
The silicon oxide layer 1b under and exposed to the vibrator 2, the support beam 2a, and the movable comb electrode 2b is removed. The lower substrate 1 shown in FIG. 1 shows a form in a cross section taken along line XX of FIG.

In FIG. 2, reference numeral 2 denotes a rectangular plate-shaped vibrator, and a support beam 2a extends from four corners thereof in a direction perpendicular to the longitudinal direction. The vibrating body 2 is supported by these four support beams 2a so as to be displaceable in the direction of the arrow. On the surface of the fixed electrode 3, a base electrode e1 for solder bump connection is formed.

A movable comb electrode 2b is formed on both sides of the center of the vibrating body 2. A fixed comb electrode 4a forming a capacitor is formed opposite the movable comb electrode 2b. The fixed comb electrode 4a is coupled to the fixed electrode 4. On the surface of the fixed electrode 4, a base electrode e1 for solder bump connection is formed.

As described above, the vibrating body 2, the supporting beam 2a, and the movable comb-teeth electrode 2b are formed so that the lower silicon oxide layer 1b is removed by etching so as to float from the single crystal silicon layer 1a and vibrate. ing.

The functional part of the acceleration sensor 10 is constructed as described above. When the direction of the arrow of the vibrating body 2 (for example, the upper part in FIG. 2) is mounted in the traveling direction of the moving body,
The acceleration of the moving object can be detected. That is, when acceleration occurs, the vibrating body 2 cannot follow the acceleration due to its inertia, and the movable comb electrode 2b and the fixed comb electrode 4a come close to each other and the capacitance formed therebetween increases. . The acceleration is obtained by converting the amount of change in the capacitance into a voltage.

In FIG. 3, reference numeral 5k denotes a thick upper substrate made of a Pyrex glass substrate, a concave portion 5a for covering a vibrating portion such as the vibrating body 2 on the back side, and a plurality of through holes 5b for forming solder bumps. And It should be noted that the upper substrate 5k is polished in a later step and is processed to have a small thickness to become a thin upper substrate 5. The upper substrate 5 shown in FIG. 1 shows a form in a cross section taken along line YY of FIG.

On the lower substrate 1 shown in FIG. 2, a thick upper substrate 5k shown in FIG. 3 is provided as shown in FIG. 4, that is, a base electrode e1 formed on the lower substrate 1 is provided on the lower substrate 1k. It is bonded by anodic bonding or the like so as to be located at the center of the hole 5b. Next, the surface of the upper substrate 5k is thinly polished and processed into a thin upper substrate 5.

Next, solder cream is printed in the holes 5b, and the holes 5b are filled with the solder cream. Thereafter, the solder cream is heated and melted to agglomerate the solder into a spherical shape due to its surface tension, and as shown in FIG.
The solder bump b1 protruding from the (upper substrate 5) is formed on the base electrode e1. This solder bump b1 is poor in wettability of the solder between the upper substrate 5 and the fixed electrode 4 (3) in which the hole 5b is formed, and is good as the base electrode e1.
1 to form a sphere.

Next, the formation of the solder bump b1 will be described in detail. 6, FIG. 1 and FIG. 2, a base electrode e1 for forming a solder bump is formed on a fixed electrode 4 (3) formed by a single crystal silicon layer 1c of a lower substrate 1.
Is formed by a lift-off method. This base electrode e1 is
From the side in contact with the fixed electrode 4 (3), a chromium (Cr) having a thickness of 50 nm,
00 nm platinum (Pt) and 200 nm gold (A
u) composed of three metal films. As shown in FIG. 3, a hole 5b having a diameter of 500 μm is formed in a thick upper substrate 5k made of a Pyrex glass substrate having a thickness of 300 μm by sandblasting or the like. As shown in FIGS. 7 and 4, a base electrode e1 is provided at the center of the hole 5b.
Is bonded to the lower substrate 1 and the upper substrate 5k by anodic bonding.

As shown in FIG. 8, the surface of a thick upper substrate 5k having a thickness of 300 μm is mechanically polished to a thickness of 80 μm.
Thin upper substrate 5. During this polishing, the holes 5b may be filled with wax or the like for temporary protection in order to prevent the base electrode e1 from being soiled. Further, at the time of this mechanical polishing, there is no concern that the polishing flow of the polishing enters the concave portion 5a shown in FIG. It is the lower substrate 1 (1c, 3, 4)
This is because the upper substrate 5k and the upper substrate 5k are integrally joined by anodic bonding.

As shown in FIG. 9, a solder cream is printed on the upper substrate 5, and the holes 5b are filled with the solder cream 6.

As shown in FIG. 10, the solder cream 6 is heated and melted in a reflow oven or the like, the solvent is evaporated, and the solder is aggregated into a sphere by the surface tension, so that the solder bump b1 is formed on the base electrode e1. Form. The shape of the solder bump b1 is such that the diameter of the base electrode e1 is 200 μm, the thickness of the upper substrate 5 is 80 μm, and the diameter of the hole 5b is 500 μm.
On the other hand, it has a spherical shape with a height of about 200 μm and a width of about 300 μm. Therefore, the formed solder bump b1
Protrudes from the hole 5b by about 120 μm, whereby the solder bump connection electronic component can be connected to a mounting board (not shown). The shape such as the height and width of the solder bump b1 is determined by the size of the base electrode e1, the size and height of the hole 5b, the amount of solder cream to be used, the composition of the solder, the printing conditions, and the like.

[0023]

According to the first aspect of the present invention, there is provided an electronic component connected to a solder bump, wherein a lower electrode serving as an extraction electrode is formed on a lower substrate, and a solder bump projecting from a hole of the upper substrate is formed on the lower electrode. Therefore, there is no need to form a lead electrode on the lower substrate and form a base electrode for forming a solder bump on the upper substrate, as in the conventional case. Since there is no need to provide a small size, miniaturization can be realized.

According to a second aspect of the invention, there is provided a method of manufacturing a solder bump connection electronic component, wherein a solder cream for forming a solder bump is filled in a hole formed in an upper substrate, and the solder cream is heated and melted. Solder is aggregated in a spherical shape on the base electrode by the surface tension to form a solder bump protruding from the hole. Therefore, in the present invention, the upper substrate having holes functions as a metal mask for solder cream printing, and the metal mask conventionally required becomes unnecessary. Further, in the present invention, the underlying electrode for forming the solder bump also functions as an extraction electrode.
There is no need to separately form the extraction electrode and the base electrode, and therefore, a wiring pattern for connecting them is unnecessary.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an acceleration sensor as one embodiment of a solder bump connection electronic component of the present invention.

FIG. 2 is a plan view of a lower substrate of the embodiment shown in FIG. 1;

FIG. 3 is a plan view of the upper substrate of the present embodiment shown in FIG. 1 before polishing.

FIG. 4 is a plan view in which the upper substrate before polishing shown in FIG. 3 is bonded to the lower substrate shown in FIG. 2 by anodic bonding;

FIG. 5 shows ZZ after polishing the upper substrate in FIG.
Line sectional view

FIG. 6 is a view showing a mode of forming a solder bump, and is a process diagram of forming a base electrode on a fixed electrode.

FIG. 7 is also a process diagram in which a thick upper substrate having holes formed thereon is bonded to a lower substrate by anodic bonding.

FIG. 8 is also a process diagram of forming a thin upper substrate by polishing its surface to be thin.

FIG. 9 is also a process diagram of filling a solder cream into a hole of the upper substrate.

FIG. 10 is a process chart of forming a solder bump by heating and melting a solder cream and agglomerating the solder into a sphere by the surface tension of the solder cream.

FIG. 11 is a sectional view of an acceleration sensor as a conventional solder bump connection electronic component.

[Explanation of symbols]

 Reference Signs List 1 lower substrate 1a single-crystal silicon layer 1b silicon oxide layer 1c single-crystal silicon layer 2 vibrator 2a support beam 2b movable comb electrode 3, 4 fixed electrode 4a fixed comb electrode 5 upper substrate 5a recess 5b hole 6 solder cream e1 base Electrode b1 Solder bump

Claims (2)

[Claims] The lower substrate and the upper substrate are bonded to each other such that a lower electrode for solder bump connection formed on the lower substrate is positioned in a hole formed in the upper substrate. Has a width smaller than the diameter of the hole, and
The solder bump connection electronic component, wherein the solder bump having a height greater than the thickness of the upper substrate is formed and protrudes from the hole. 2. A step of forming a base electrode for solder bump connection on the lower substrate, and a step of bonding the upper substrate to the lower substrate such that the base electrode is located in a hole formed in the upper substrate. Filling the holes with solder cream; heating and melting the solder cream to agglomerate the solder, forming solder bumps on the base electrode and projecting the solder bumps out of the holes; Manufacturing method for connecting electronic components.