JP2001257236A - Manufacturing method of electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the manufacturing method of an electronic device that prevents fail such as damage from being generated, does not increase the allocating space of an element, and at the same time can be joined by sufficient junction force when the plurality of elements are subjected to flip chip bonding to an electrode land that is formed on the bottom surface of the recessed part of a package. SOLUTION: A plurality of elements 10 and 20 are joined to electrode lands 4 and 5 that are formed on the bottom surface of the recessed part of a package 1 having cavity structure by the flip chip bonding method. After the first element 10 is joined to the electrode land 4 of the package 1 by a tool 30 for junction, the second element 20 is joined to the electrode land 5 of the package 1 near the first element 10 by the tool 30 for junction. The thickness of the second element 20 is thicker than that of the first element 10, thus preventing the tool 30 for joining the second element 20 from coming into contact with the first element 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electronic device in which a plurality of electrode lands are formed on the bottom surface of a concave portion of a package having a cavity structure, and a plurality of elements are joined to these electrode lands by flip chip bonding. is there.

[0002]

2. Description of the Related Art In recent years, as a method of connecting electronic component elements,
A flip chip bonding method has been used as a method capable of realizing a reduction in mounting space and an improvement in mounting workability as compared with a wire bonding method or the like. When an element is bonded to an electrode land formed on the element mounting surface by using a flip chip bonding method, a bonding tool having a tip surface having substantially the same dimensions as the element is usually used. The bonding tool has a suction hole that vacuum-adsorbs the back surface of the element. After adsorbing the element and transporting it to the position of the electrode land on the element mounting surface, the upper surface of the element is pressed to apply ultrasonic waves and heat simultaneously. Thereby, the metal bump formed on the electrode pad of the element is bonded to the electrode land.

In some cases, a plurality of electrode lands are formed on the bottom surface of a concave portion of a package having a cavity structure, and a plurality of elements are bonded to these electrode lands by a flip chip bonding method. In this case, since it is necessary to accommodate a plurality of elements in a space as small as possible, the plurality of elements are arranged close to each other.

[0004] However, if a joining tool having a tip surface substantially the same as the size of the element is used as described above, the first element can be joined without any problem. The end of the tool may come into contact with the previously joined element, causing damage or other defects. As a countermeasure, there is a method of increasing the interval between the joining positions of the elements. However, this has a problem that the arrangement space of the elements becomes large and the package becomes large.

[0005]

Therefore, as shown in FIG. 1, if the dimension of the distal end surface of the joining tool T for joining the element C2 to be joined later is made smaller than the outer dimension of the element C2, Even if the position of the joining tool T is slightly shifted in the lateral direction (shown by a two-dot chain line in FIG. 1), the element C that has been joined first
1 can be prevented from coming into contact. Note that P
Is a package, and R is an electrode land. However, in this case, since the dimension of the distal end surface of the joining tool T becomes small, ultrasonic waves and heat are not always efficiently transmitted to the metal bumps B, and there is a possibility that the joining force is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device for flip-chip bonding a plurality of devices to electrode lands formed on the bottom surface of a concave portion of a package without causing defects such as breakage and increasing a space for arranging the devices. Another object of the present invention is to provide a method of manufacturing an electronic device that can be bonded with a sufficient bonding force.

[0007]

In order to achieve the above object, according to the present invention, a plurality of electrode lands are formed on the bottom surface of a concave portion of a package having a cavity structure, and a plurality of elements are formed on these electrode lands. In a method of manufacturing an electronic device to be joined by a flip chip bonding method, a step of joining a first element to an electrode land of a package by a joining tool, and a step of joining a second element to an electrode land of a package adjacent to the first element. Bonding with a bonding tool, wherein the thickness of the second element is greater than the thickness of the first element, and the electrode land to which the second element is bonded and the electrode land to which the first element is bonded are formed. Provided is a method for manufacturing an electronic device, which is substantially at the same height. According to a second aspect of the present invention, in a method of manufacturing an electronic device, a plurality of electrode lands are formed on a bottom surface of a concave portion of a package having a cavity structure, and a plurality of elements are bonded to the electrode lands by a flip chip bonding method. A step of joining the first element to an electrode land of the package by a joining tool, and a step of joining the second element to an electrode land of the package adjacent to the first element by a joining tool; The thickness of the element is equal to or greater than the thickness of the first element, and the electrode land to which the second element is joined is located higher than the electrode land to which the first element is joined. Provided is a method for manufacturing an electronic device.

According to the first aspect of the present invention, the electrode lands to which the second element is joined and the electrode lands to which the first element is joined are substantially at the same height, but the electrode lands to which the first element is joined are more distant than the first element. 2
Since the thickness of the element is thick, the upper surface of the second element is at a position higher than the upper surface of the first element. Therefore, even if the size of the tip surface of the joining tool is the same as or larger than the size of the second element, and even if it is slightly shifted in the lateral direction, there is a risk that the tip of the tool contacts the first element. Can be avoided. In addition, since it is not necessary to reduce the size of the tip surface of the joining tool, ultrasonic waves and heat can be efficiently transmitted to the joining portion (metal bump), and a decrease in joining force can be prevented. In the case of claim 2, the thickness of the second element is equal to or greater than the thickness of the first element, and the electrode land to which the second element is bonded is the electrode land to which the first element is bonded. Since the position is higher than the land, the upper surface of the second element is higher than the upper surface of the first element. Therefore, it is possible to avoid the risk that the tip of the bonding tool for flip-chip bonding the second element contacts the first element.

According to a third aspect, the first and second elements are:
It is preferable that the surface acoustic wave element has an IDT electrode formed on the back surface opposite to the bottom surface of the concave portion of the package. In the case of a surface acoustic wave device, an IDT electrode and an electrode pad are formed on the surface thereof, a bump is formed on the electrode pad, and then the electrode surface is turned over and flip chip bonding is performed on an electrode land formed on the bottom surface of the concave portion of the package. do it. Also,
When the first and second elements are surface acoustic wave elements having different characteristics from each other, a dual filter can be configured.

[0010]

FIG. 2 shows a surface acoustic wave device as an example of an electronic device according to the present invention. The surface acoustic wave device includes a package 1 having a flat element mounting surface (recess bottom surface) 2a and two surface acoustic wave devices 10 mounted on the element mounting surface 2a of the package 1 by a flip chip bonding method. , 20 and is configured as a surface mount type dual filter. The package 1 is formed in a cavity shape by a bottom wall portion 2 and a side wall portion 3 made of ceramic or the like, and a plurality of electrode lands for input / output and ground are formed on an element mounting surface 2a of the package 1. 4 and 5 are formed. The electrode lands 4 and 5 are formed so as to extend to the outer lower surface of the package 1. A cover plate 6 made of ceramic, metal, or the like is provided on the upper surface of the side wall portion 3.
Are joined by a brazing material 7 made of high melting point solder, and the inside of the package 1 is hermetically sealed. The method of sealing the cover plate 6 is not limited to brazing, and a method such as resistance welding or resin sealing may be used.

The surface acoustic wave elements 10 and 20 have different characteristics from each other, and are bonded to electrode lands 4 and 5 formed on the element mounting surface 2a of the package 1 by a flip chip bonding method. Surface acoustic wave devices 10, 2
Reference numeral 0 denotes IDT electrodes 11 and 12 made of aluminum, an aluminum alloy, or the like on the surface of a piezoelectric substrate made of a piezoelectric material such as lithium tantalate, lithium niobate, or quartz.
1 and electrode pads 12 and 22 drawn out from the IDT electrodes 11 and 21 via extraction electrodes. The electrode pads 12 and 22 and the electrode lands 4 and 5 of the package 1 , 23 are connected. A gap 8 is provided between the surface acoustic wave elements 10 and 20 and the element mounting surface 2a in order to efficiently propagate the surface wave.
9 are provided. The surface acoustic wave devices 10, 20
However, the present invention is not limited to the case where the IDT electrode is formed on the piezoelectric substrate, but may be the case where a piezoelectric thin film such as ZnO is formed on an insulating substrate such as alumina or glass.

In this embodiment, the first surface acoustic wave element 1
The thickness t2 of the second surface acoustic wave element 20 is set to be thicker than the thickness t1 of zero. Specifically, the first element 1
0 thickness t1 = 0.25 mm, thickness t of the second element 20
2 = 0.35 mm. Therefore, the elements 10, 2
0 is mounted on the element mounting surface 2a, and a step of 0.1 mm is provided on the upper surfaces of the two elements 10 and 20.

Here, a method of manufacturing the surface acoustic wave device having the above configuration will be described with reference to FIG. First, as shown in FIG. 3A, Au or metal bumps 13 and 23 containing Au as a main component are formed on the electrode pads 12 and 22 of the first element 10 and the second element 20 by a ball bonding method. I do. Next, as shown in FIG. 3B, the first element 10
Is sucked through the vacuum suction hole 31 of the joining tool 30, and the surface wave propagation surface on which the IDT electrode 11 and the like are formed is placed so as to face the element mounting surface 2a. The metal bumps 13 on the electrode pads 12 are bonded to the electrode lands 4 by simultaneously applying ultrasonic waves and heat from the bonding tool 30. Next, FIG.
As shown in (c), the second element 20 is joined to the electrode lands 5 via the metal bumps 23 by the same flip chip bonding method. At this time, the bonding may be performed in a state where the joining tool 30 is laterally displaced from the second element 20 in the direction of the first element 10. However, the thickness t2 of the second element 20 Since it is thicker than t1, even if the tool 30 protrudes in the direction of the first element 10, it does not interfere with the first element 10. for that reason,
The distance between the elements 10 and 20 can be reduced, and the size of the package 1 can be reduced. In this case, it is not necessary to use a tool whose tip surface 30a is smaller than the second element 20 as the tool 30. Even if a tool 30 having the same shape as or larger than the second element 20 is used, Element 1 of
There is no interference with 0. Therefore, the ultrasonic waves and the heat can be efficiently transmitted to the metal bumps 23, and the bonding property is improved.
After joining the first and second elements 10 and 20, the lid plate 6, on which the brazing material 7 is previously rolled, is placed on the upper surface of the side wall 3 of the package 1.
Is placed in a reflow furnace, and all parts including the package 1 are uniformly heated so as to have a temperature higher than the melting point of the brazing material 7, thereby melting the brazing material 7. The cover plate 6 is joined. Thus, a hermetically sealed dual filter is obtained.

FIG. 4 shows another embodiment of the electronic device according to the present invention. In this embodiment, as compared with the element mounting surface 2b (electrode land 4) of the first element 10 which is flip-chip bonded first, the element mounting surface 2c of the second element 20 which is flip-chip bonded later. (Electrode lands 5). The first element 10 and the second element 20 may have the same thickness, or the second element 20
May be thicker than the first element 10. In this case, even if the joining tool 30 for flip chip bonding the second element 20 protrudes in the direction of the first element 10,
Does not interfere with the element 10. Therefore, element 1
The distance between 0 and 20 can be reduced, and the package 1
Can be reduced in size. In this embodiment, the element mounting surface 2c is set to be 0.1 mm higher than the element mounting surface 2b,
The thicknesses of the first and second elements 10 and 20 are the same.
Therefore, the upper surface of the two elements 10 and 20 is 0.1 mm
Is provided.

In the above-described embodiment, an example in which the surface acoustic wave element is flip-chip bonded in the package has been described. However, a semiconductor chip or a piezoelectric element may be used instead of the surface acoustic wave element. Further, the present invention is not limited to the case where two elements are mounted in the package, and three or more elements may be mounted. Furthermore, in FIG. 3, the first tool 1
Although the 0 element and the second element 20 are flip-chip bonded, when the elements 10 and 20 have different shapes, bonding may be performed using tools having different shapes.

[0016]

As is apparent from the above description, claim 1
According to the invention described in (1), when a plurality of elements are bonded to the electrode lands formed on the bottom surface of the concave portion of the package by the flip chip bonding method, the second element to be bonded later is first bonded to the first element. Because it was thicker than the element of
The joining tool for joining the second element can be prevented from contacting the first element, and defects such as breakage can be eliminated. Further, even if the joining tool protrudes in the direction of the first element, it does not interfere with the first element, so that the distance between the elements can be reduced, and the size of the package can be reduced. Further, since the size of the joining tool is not limited, sufficient ultrasonic waves and heat can be applied to the element, and there is an advantage that the joining force is improved. According to the second aspect of the present invention, the electrode lands to which the second element is bonded are located at positions higher than the electrode lands to which the first element is bonded. It is possible to reliably prevent the joining tool from contacting the first element. for that reason,
As in the case of the first aspect, it is possible to eliminate defects such as breakage, downsize the package, and improve the bonding force.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flip chip bonding process using a conventional bonding tool.

FIG. 2 is a cross-sectional view of an example of a surface acoustic wave device using the manufacturing method according to the present invention.

FIG. 3 is a diagram showing a manufacturing process of the surface acoustic wave device shown in FIG.

FIG. 4 is a sectional view of a second embodiment of the manufacturing method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Package 2a, 2b, 2c Element mounting surface 4,5 Electrode land 10,20 Surface acoustic wave element 11,21 IDT electrode 12,22 Electrode pad 30 Joining tool

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Shingo Iwasa 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto F-term in Murata Manufacturing Co., Ltd. (reference) 5F044 KK01 QQ00 RR01 5J097 AA28 AA29 AA34 BB11 HA04 HA09 JJ01 JJ09 KK10

Claims (4)

[Claims] 1. A method of manufacturing an electronic device, comprising: forming a plurality of electrode lands on a bottom surface of a concave portion of a package having a cavity structure; and bonding a plurality of elements to the electrode lands by a flip-chip bonding method. And a step of joining the second element to an electrode land of a package adjacent to the first element by using a joining tool, wherein the thickness of the second element is equal to the first element. Thicker than the element's thickness,
A method for manufacturing an electronic device, wherein an electrode land to which a second element is joined and an electrode land to which a first element is joined are substantially at the same height. 2. A method of manufacturing an electronic device, comprising: forming a plurality of electrode lands on a bottom surface of a concave portion of a package having a cavity structure; and bonding a plurality of elements to the electrode lands by a flip-chip bonding method. And a step of joining the second element to an electrode land of a package adjacent to the first element by using a joining tool, wherein the thickness of the second element is equal to the first element. A method for manufacturing an electronic device, wherein the electrode land to which the second element is bonded is higher than or equal to the electrode land to which the first element is bonded. 3. The electronic device according to claim 1, wherein each of the first and second elements is a surface acoustic wave element having an IDT electrode formed on a back surface facing a bottom surface of the concave portion of the package. Device manufacturing method. 4. The method according to claim 1, wherein said first and second elements are surface acoustic wave elements having different characteristics.