JPH1012621A - Structure of protruded electrode and its formation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent excessive pressure from being applied on an insulating film disposed under a protruded electrode of a semiconductor chip and a connection pad when the protruded electrode of the semiconductor chip is bonded to the connection pad, etc., on a circuit board under pressure. SOLUTION: An insulating resin layer 15 comprising polyimide and the like is formed on an upper surface of a connection pad 12 exposed through an opening 14 in an insulating film 13 at the center of the same, and a lower protruded electrode 20 is formed on the connection pad 12 including the insulating resin layer 15 and on the insulating film 13 around the connection pad 12 through a diffusion prevention layer 16 and a bonding layer 17. An upper protruded electrode 23 is formed on the lower protruded electrode 20 at a portion corresponding to the center of the insulating resin layer 15. Since a flat plane size of the upper protruded electrode 23 is small, pressure required for bonding may be small. Further, the pressure is dispersed owing to the lower protruded electrode 20 having a large flat plane size, and is moderated because the insulating resin layer 15 under the lower protruded electrode 20 is compressed and deformed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a bump electrode and a method of forming the same.

[0002]

2. Description of the Related Art For example, in a semiconductor chip mounting technique called a COG (Chip On Glass) method, a semiconductor chip is mounted on a circuit board. In this case, the protruding electrodes provided on the semiconductor chip are bonded to connection pads on the circuit board. Therefore, it is necessary to provide a protruding electrode on the semiconductor chip.

Next, a conventional method for forming such a bump electrode will be described with reference to FIGS. First, as shown in FIG. 6, a connection pad 2 is formed on a silicon substrate 1, and an insulating film (passivation film) 3 is formed on a portion of the upper surface except for the center of the connection pad 2. A part whose part is exposed through the opening 4 formed in the insulating film 3 is prepared. Next, as shown in FIG. 7, a diffusion preventing layer 5 and an adhesive layer 6 as a base metal layer are formed on the entire upper surface. Next, a plating resist layer 7 is formed on a portion of the upper surface of the adhesive layer 6 except for a portion corresponding to the connection pad 2. Therefore, in this state, the plating resist layer 7 in the portion corresponding to the connection pad 2 has the opening 8.
Are formed. Next, a protruding electrode 9 is formed on the upper surface of the adhesive layer 6 in the opening 8 of the plating resist layer 7 by performing electrolytic plating using the adhesive layer 6 as a plating current path.
Next, when the plating resist layer 7 is peeled off, it becomes as shown in FIG. Next, as shown in FIG. 9, unnecessary portions of the adhesive layer 6 and the diffusion preventing layer 5 are removed by wet etching or dry etching using the bump electrodes 9 as a mask. Thus, the formation of the protruding electrodes 9 is completed.

[0004]

By the way, in such a conventional method of forming a bump electrode, as shown in FIG. 9, the plane size of the bump electrode 9 is larger than the plane size of the opening 4 of the insulating film 3. I am trying to become. The reason is that when unnecessary portions of the adhesive layer 6 and the diffusion preventing layer 5 are removed by wet etching or dry etching using the bump electrodes 9 as a mask, the connection pads 2 are prevented from being eroded or damaged by the etchant. That's why. As a result, the planar size of the projecting electrode 9 becomes relatively large, and a relatively large pressure is required when bonding the projecting electrode 9 to a connection pad on a circuit board (not shown) with pressurization. However, the projecting electrode 9
Is the connection pad 2 exposed through the opening 4 of the insulating film 3
Since a relatively large pressure is applied to the protruding electrodes 9, a relatively large pressure is applied to a portion of the insulating film 3 around the opening 4, since the insulating film 3 is formed on and around the insulating film 3. However, insulating film (passivation film)
3 is generally made of a glassy relatively brittle material such as silicon oxide or silicon nitride. Therefore, when a relatively large pressure is applied, cracks or the like may occur, and the reliability of the semiconductor chip decreases. there were. In addition, a relatively large pressure is applied to the exposed surface of the connection pad 2 exposed through the opening 4 of the insulating film 3, which may cause cracks, disconnections, and the like, and also lowers the reliability of the semiconductor chip. There was a problem. SUMMARY OF THE INVENTION It is an object of the present invention to prevent an excessive pressure from being applied to an insulating film and a connection pad under a bump electrode when bonding the bump electrode to a connection pad or the like on a circuit board with pressurization.

[0005]

According to a first aspect of the present invention, there is provided a bump electrode structure including a resin layer formed on a predetermined portion of a connection pad formed on a substrate, and a resin layer including the resin layer. The projection electrode is formed by the projection electrode formed on the connection pad and on the insulating film located around the connection pad. 6. The method according to claim 5, wherein a resin layer is formed on a predetermined part of the connection pad formed on the substrate, and the connection pad including the resin layer and the periphery of the connection pad are formed. Are formed on the insulating film located at the position (1). According to the first or fifth aspect of the present invention, when the protruding electrode is bonded to a connection pad or the like on the circuit board with pressurization, the resin layer under the protruding electrode is compressed and deformed. The pressure applied to the insulating film and the connection pad is reduced, so that an excessive pressure is not applied to the insulating film and the connection pad below the protruding electrode.

According to a second aspect of the present invention, there is provided a structure of a bump electrode, wherein a resin layer formed on a predetermined portion of a connection pad formed on a substrate, the connection pad including the resin layer, and the connection are formed. A protruding electrode is formed by a lower protruding electrode formed on an insulating film located around a pad and an upper protruding electrode formed on a portion of the lower protruding electrode corresponding to at least a part of the resin layer. It was done. Claim 6
In the method of forming a bump electrode according to the invention described above, a resin layer is formed on a predetermined portion of a connection pad formed on a substrate, and the resin layer is located on the connection pad including the resin layer and around the connection pad. A lower projecting electrode is formed on an insulating film, and an upper projecting electrode is formed on the lower projecting electrode at a portion corresponding to at least a part of the resin layer.
According to the second or sixth aspect of the present invention, since the projecting electrode is formed by the lower projecting electrode having a large planar size and the upper projecting electrode having a small planar size, the upper projecting electrode having a small planar size is formed on the circuit board. Bonding is performed with pressure on connection pads and the like. In this case, since the planar size of the upper protruding electrode is small, the pressure required for bonding can be reduced, and this pressure is dispersed by the lower protruding electrode having a larger planar size, and the resin layer under the lower protruding electrode is compressed. Therefore, it is possible to prevent excessive pressure from being applied to the insulating film and the connection pad under the lower protruding electrode.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 to 5 show respective steps of forming a bump electrode according to an embodiment of the present invention. Therefore, the structure of the bump electrode in this embodiment will be described together with the method of forming the bump electrode, referring to these drawings in order.

First, as shown in FIG.
1, a connection pad 12 made of aluminum or the like is formed, and an insulating film (passivation film) 13 made of silicon oxide, silicon nitride, or the like is formed on a portion of the upper surface of the connection pad 12 except for a central portion. The one whose central portion is exposed through the opening 14 formed in the insulating film 13 is prepared.

Next, as shown in FIG. 2, an insulating resin layer 15 made of polyimide or the like is formed on the center of the upper surface of the connection pad 12 exposed through the opening 14 of the insulating film 13 by spin coating and photolithography. Is formed. Therefore, in this state, only the peripheral portion of the upper surface of the connection pad 12 exposed through the opening 14 of the insulating film 13, that is, the portion around the insulating resin layer 15 is exposed. Next, a diffusion preventing layer 16 made of a titanium-tungsten alloy, chromium, or the like and an adhesive layer 17 made of gold, copper, nickel, or the like are formed on the entire upper surface by a sputtering method, a vacuum evaporation method, or the like. Next, a first plating resist layer 18 is formed on a portion of the upper surface of the adhesive layer 17 except for a portion corresponding to the connection pad 12. Therefore, in this state, the first plating resist layer 1 in a portion corresponding to the connection pad 12 is formed.
An opening 19 is formed in 8. Next, the adhesive layer 17
Is used as a plating current path to form a lower projecting electrode 20 made of gold, copper, nickel or the like on the upper surface of the adhesive layer 17 in the opening 19 of the first plating resist layer 18. After that, the first plating resist layer 18 is peeled off.

Next, as shown in FIG.
The second plating resist layer 21 is formed in a portion excluding a portion corresponding to the central portion of FIG. Therefore, in this state, an opening 22 is formed in the second plating resist layer 21 at a portion corresponding to the center of the insulating resin layer 15. Next, by performing electroplating using the adhesive layer 17 as a plating current path, gold, copper, nickel, and the like are formed on the upper surface of the lower protruding electrode 20 in the opening 22 of the second plating resist layer 21.
An upper projecting electrode 23 made of solder or the like is formed. After this,
When the second plating resist layer 21 is peeled off, the result is as shown in FIG. Next, as shown in FIG.
Unnecessary portions of the adhesive layer 15 and the diffusion preventing layer 16 are removed by dry etching or wet etching using argon gas plasma using the mask as a mask. Thus,
A protruding electrode including the lower protruding electrode 20 and the upper protruding electrode 23 is formed.

As described above, since the projecting electrodes are formed by the lower projecting electrodes 20 having a large plane size and the upper projecting electrodes 23 having a small plane size, the upper projecting electrodes 23 having a small plane size are formed on a circuit board (not shown). Bonding is performed with pressure on connection pads and the like. In this case, since the planar size of the upper protruding electrode 23 is small, the pressure required for bonding can be reduced, and this pressure is dispersed by the lower protruding electrode 20 having a large planar size, and the insulating resin under the lower protruding electrode 20 is formed. The compression and deformation of the layer 15 will alleviate it.
Therefore, it is possible to prevent an excessive pressure from being applied to the insulating film 13 and the connection pad 12 under the lower protruding electrode 20. As a result, cracks do not occur in the insulating film 13 at the time of bonding, and cracks or disconnections do not occur in the connection pads 12, so that the reliability of the semiconductor chip can be improved.

Here, as an example of a preferable combination of metal materials, the diffusion preventing layer 16 is made of a titanium-tungsten alloy, the adhesive layer 17 is made of gold, the lower projecting electrode 20 is made of gold, and the upper projecting electrode 23 is made of gold. There are cases.
Next, a specific example of the dimensions of each part will be described. The thickness of the connection pad 12 is 2-3 μm and the plane size is 120
× 120 μm ^{2 to} 150 × 150 μm ² . Insulating film 1
3, the thickness of the opening 14 is 10 μm, and the thickness of the opening 14 is 10 μm.
It is 0 × 100 μm ^{2 to} 110 × 110 μm ² . The thickness of the insulating resin layer 15 is 2-3 μm, and the plane size is 80 × 80.
μm ^{2 to} 90 × 90 μm ² . The thickness of the diffusion preventing layer 16 is 0.5 to 0.6 μm, and the thickness of the adhesive layer 17 is 0.2 to 0.6 μm.
0.3 μm. The height of the lower protruding electrode 20 is 5 to 20
μm, plane size is 120 × 120 μm ^{2 to} 150 × 1
It is 50 μm ² . The thickness of the first plating resist layer 18 may be equal to or higher than the height of the lower protruding electrode 20. The height of the upper projecting electrode 23 is 20 to 50 μm, and the plane size is 50 × 50 μm ² to 70 × 70 μm ² . Second
The thickness of the plating resist layer 21 may be equal to or greater than the total height of the two projecting electrodes 20, 23. In particular,
The respective heights of the lower protruding electrode 20 and the upper protruding electrode 23 may be substantially the same, depending on the respective materials, the bonding method, and the like.
The height of 0 may be higher than the height of the upper protruding electrode 23.

In the above embodiment, the insulating resin layer 15 is formed at the center of the exposed surface of the connection pad 12. However, the present invention is not limited to this. Good. Further, although the upper protruding electrode 23 is formed corresponding to the central portion of the insulating resin layer 15, the present invention is not limited to this, as long as it is a predetermined part of the insulating resin layer 15. It may be formed correspondingly. further,
Although the upper projecting electrode 23 is formed by plating, the present invention is not limited to this. For example, the upper projecting electrode 23 may be formed by using a transfer method.

In the above embodiment, the protruding electrode is formed by the lower protruding electrode 20 having a large planar size and the upper protruding electrode 23 having a small planar size. However, the present invention is not limited to this. 20 may be formed only by the same protruding electrode 20a (not shown). In this case, referring to FIG. 5, when bonding the protruding electrode 20a to a connection pad or the like on a circuit board (not shown) with pressure,
By compressing and deforming the insulating resin layer 15 under the bump electrode 20a, the pressure applied to the insulating film 13 and the connection pad 12 under the bump electrode 20a is reduced. Therefore, the insulating film 13 and the connection pad 12 under the protruding electrode 20a
To avoid excessive pressure. As a result, cracks do not occur in the insulating film 13 at the time of bonding, and cracks or disconnections do not occur in the connection pads 12, so that the reliability of the semiconductor chip can be improved.

[0015]

As described above, claim 1 or claim 5
According to the invention described above, when bonding the projecting electrode to the connection pad or the like on the circuit board with pressure, the resin layer under the projecting electrode is compressed and deformed, thereby forming the insulating film and the connection under the projecting electrode. The pressure applied to the pad is relieved, so that excessive pressure is not applied to the insulating film and the connection pad under the protruding electrode.As a result, the insulating film is cracked during bonding, and the connection pad is cracked or disconnected. And the reliability of the semiconductor chip can be improved. According to the second or sixth aspect of the present invention, since the planar size of the upper projecting electrode is small, the pressure required for bonding can be reduced, and this pressure is dispersed by the lower projecting electrode having a large planar size. Therefore, the resin layer under the lower protruding electrode is compressed and deformed, thereby being alleviated. Therefore, it is possible to prevent an excessive pressure from being applied to the insulating film and the connection pad under the lower protruding electrode. The reliability of the semiconductor chip can be increased without cracking or cracking or disconnection of the connection pad.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a projection electrode prepared at the time of forming a projection electrode according to an embodiment of the present invention.

FIG. 2 is a sectional view of a forming step following FIG. 1;

FIG. 3 is a sectional view of a forming step following FIG. 2;

FIG. 4 is a sectional view of a forming step following FIG. 3;

FIG. 5 is a sectional view of a forming step following FIG. 4;

FIG. 6 is a cross-sectional view of what was initially prepared when a conventional bump electrode was formed.

FIG. 7 is a sectional view of a forming step following FIG. 6;

FIG. 8 is a cross-sectional view of a forming step following FIG. 7;

FIG. 9 is a sectional view of a forming step following FIG. 8;

DESCRIPTION OF SYMBOLS 11 Silicon substrate 12 Connection pad 13 Insulating film 14 Opening 15 Insulating resin layer 16 Diffusion prevention layer 17 Adhesive layer 18 First plating resist layer 19 Opening 20 Lower projection electrode 21 Second plating resist layer 22 Opening 23 Top protruding electrode

Claims (9)

[Claims] 1. A resin layer formed on a predetermined portion of a connection pad formed on a substrate, and formed on the connection pad including the resin layer and on an insulating film located around the connection pad. A structure of a protruding electrode, comprising: a protruding electrode. 2. A resin layer formed on a predetermined portion of a connection pad formed on a substrate, and formed on the connection pad including the resin layer and on an insulating film located around the connection pad. A lower protruding electrode, and an upper protruding electrode formed on a portion of the lower protruding electrode corresponding to at least a part of the resin layer. 3. The structure of claim 2, wherein an underlying metal layer is formed below the lower projecting electrode. 4. The structure of claim 2, wherein the height of the upper projecting electrode is higher than the height of the lower projecting electrode. 5. A resin layer is formed on a predetermined portion of a connection pad formed on a substrate, and a projecting electrode is formed on the connection pad including the resin layer and on an insulating film located around the connection pad. A method for forming a protruding electrode, comprising: 6. A resin layer is formed on a predetermined portion of a connection pad formed on a substrate, and a lower protruding electrode is formed on the connection pad including the resin layer and on an insulating film located around the connection pad. And forming an upper protruding electrode on a portion of the lower protruding electrode corresponding to at least a part of the resin layer. 7. The method according to claim 6, wherein the upper projecting electrode is formed such that the height of the upper projecting electrode is higher than the height of the lower projecting electrode. . 8. A semiconductor device comprising: a resin layer formed on a predetermined portion of a connection pad formed on a substrate; and an opening in a portion corresponding to the connection pad and an insulating film located around the connection pad. (1) forming a plating resist layer, forming a lower protruding electrode by plating in an opening of the first plating resist layer, and thereafter peeling off the first plating resist layer; Forming a second plating resist layer having an opening in a portion corresponding to at least a part of the layer, and forming an upper projecting electrode by plating in the opening of the second plating resist layer; Forming method. 9. A connection pad is formed on a substrate, and an insulating film having an opening at a portion corresponding to the center of the connection pad is formed on an upper surface thereof, whereby the center of the connection pad is formed by the insulating film. After the one exposed through the opening is prepared, a resin layer is formed on a predetermined part of the connection pad, and then a base metal layer is formed on the entire surface, and the connection pad and the periphery thereof are formed. A first plating resist layer having an opening in a portion corresponding to the insulating film is formed, and electroplating is performed using the base metal layer as a plating current path, thereby forming a lower protruding electrode in the opening of the first plating resist layer. And thereafter, the first plating resist layer is peeled off, and then a second plating resist layer having an opening in a portion on the lower projecting electrode corresponding to at least a part of the resin layer is formed. Then, an upper projecting electrode is formed in the opening of the second plating resist layer by performing electrolytic plating using the base metal layer as a plating current path, and thereafter, the second plating resist layer is peeled off. An etching method using an electrode as a mask to remove an unnecessary portion of the base metal layer, the method comprising forming a bump electrode.