JP2003234430A - Semiconductor device and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an interface between a columnar electrode and a solder ball from cracking in a semiconductor device having the solder balls formed on the columnar electrodes. <P>SOLUTION: A recess 19 is formed into the top face of a sealing film 18 around a columnar electrode 17. A solder ball 20 is formed on the top of the electrode 17 and in the recess 19, including the top face of the electrode 17, thus covering the top end of the electrode 17 with the solder ball 20. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a columnar electrode and a method of manufacturing the same.

[0002]

2. Description of the Related Art For example, as a semiconductor device called CSP (chip size package), there is one shown in FIG. In this semiconductor device, the connection pad 2 is formed on the upper surface of the semiconductor substrate 1 made of silicon or the like, the insulating film 3 is formed on a portion of the upper surface except the central portion of the connection pad 2, and the opening formed in the insulating film 3 is formed. The base metal layer 5 is formed from the upper surface of the connection pad 2 exposed through the portion 4 to a predetermined position on the upper surface of the insulating film 3, and the rewiring 6 is formed on the upper surface of the base metal layer 5 to form the rewiring 6. The columnar electrode 7 is formed on the upper surface of the pad portion at the tip, and the sealing film 8 is formed on the entire upper surface excluding the columnar electrode 7 so that the upper surface thereof is flush with the upper surface of the columnar electrode 7. The structure is such that the solder balls 9 are formed.

[0003]

By the way, in the conventional semiconductor device described above, the solder ball 9 is formed on the upper surface of the columnar electrode 7 which is flush with the upper surface of the sealing film 8. After mounting on a substrate (not shown), the semiconductor substrate 1 is subjected to a temperature cycle test or the like.
There is a problem that cracks may occur at the interface between the columnar electrode 7 and the solder ball 9 due to the stress generated due to the difference in thermal expansion coefficient between the columnar electrode 7 and the circuit board. This also applies to the case where the solder balls 9 or the solder layer is previously formed on the connection terminals of the circuit board, instead of preliminarily forming the solder balls 9 on the columnar electrodes 7. An object of the present invention is to prevent cracks from easily occurring at the interface between a columnar electrode and a low melting point metal bonding material such as a solder ball.

[0004]

According to a first aspect of the present invention, there is provided a semiconductor device comprising a columnar electrode formed on a semiconductor substrate and a sealing formed on the semiconductor substrate in a region excluding the columnar electrode. In the semiconductor device including a film, a recess exposing the upper surface of the columnar electrode and the outer peripheral surface of the upper end is formed on the upper surface of the sealing film. A semiconductor device according to a second aspect of the present invention is the semiconductor device according to the first aspect, wherein the upper surface of the sealing film and the upper surface of the columnar electrode are substantially flush with each other. A semiconductor device according to the invention of claim 3 is
In the invention according to claim 1, the upper surface of the sealing film is higher than the upper surface of the columnar electrode. A semiconductor device according to a fourth aspect of the present invention is the semiconductor device according to the first aspect, wherein a low melting point metal ball is formed in the recess and on an upper side thereof including an upper surface of the columnar electrode. It is a thing. According to a fifth aspect of the present invention, there is provided a method of manufacturing a semiconductor device, wherein a columnar electrode is formed on a semiconductor substrate, a sealing film is formed on the semiconductor substrate including the columnar electrode, and It is characterized in that a recess is formed to expose the upper surface and the outer peripheral surface of the upper end of the columnar electrode. According to a sixth aspect of the present invention, in the method of manufacturing a semiconductor device according to the fifth aspect, after forming the sealing film, the upper surface of the sealing film and the upper surface of the columnar electrode are substantially flush with each other. It is characterized by performing uniform polishing. According to a seventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the fifth aspect, the sealing film is formed so that an upper surface of the sealing film is higher than an upper surface of the columnar electrode. In this state, the recess is formed in the sealing film. According to an eighth aspect of the present invention, in the method of manufacturing a semiconductor device according to the fifth aspect, the recess is formed by irradiating a laser beam. According to a ninth aspect of the present invention, in the method of manufacturing the semiconductor device according to the fifth aspect, the recess is formed by excavation. According to a tenth aspect of the present invention, in a method of manufacturing a semiconductor device, a columnar electrode is formed on a semiconductor substrate, a recess forming ball is formed at an upper end portion of the columnar electrode so as to cover the upper end portion, and the columnar electrode is formed. A sealing film is formed on the semiconductor substrate including the electrodes so that its upper surface is higher than the upper surface of the columnar electrode, and at least part of the recess forming ball remains around the upper end of the columnar electrode. Thus, the upper surface side of the sealing film and the recess forming balls are polished. According to an eleventh aspect of the present invention, in the method of manufacturing a semiconductor device according to the tenth aspect, polishing of the upper surface side of the sealing film and the recess forming ball does not expose the upper surface of the columnar electrode. It is characterized in that it is performed up to the position, and a part of the recess forming ball is left on the columnar electrode and around the upper end thereof. Claim 12
A method of manufacturing a semiconductor device according to the invention described in claim 1,
The invention according to 0 or 11 is characterized in that a part of the remaining recess-forming balls is removed to form a recess in the sealing film. According to a thirteenth aspect of the present invention, in the method of manufacturing a semiconductor device according to the tenth or eleventh aspect, the recess forming balls are formed of a low melting point metal, and a part of the recess forming balls that remains is formed. A low melting point metal ball made of the same material as the low melting point metal is formed on the upper surface of the. Further, according to the present invention, since the recess is formed on at least the upper surface of the sealing film around the columnar electrode, the low melting point metal bonding material such as a solder ball enters the recess and the upper end of the columnar electrode is Since it is covered with a low melting point metal bonding material such as a solder ball, it is possible to prevent cracks from easily occurring at the interface between the columnar electrode and the low melting point metal bonding material such as a solder ball.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention. In this semiconductor device, the connection pad 12 is formed on the upper surface of the semiconductor substrate 11 made of silicon or the like, and the insulating film 1 is formed on the upper surface of the connection pad 12 except the central portion.
3 is formed, and the base metal layer 15 is formed from the upper surface of the connection pad 12 exposed through the opening 14 formed in the insulating film 13 to a predetermined position on the upper surface of the insulating film 13.
The rewiring 16 is formed on the upper surface of the base metal layer 15, and the columnar electrode 17 is formed on the upper surface of the pad portion at the tip of the rewiring 16.
A sealing film 18 is formed on the entire upper surface excluding the columnar electrode 17 such that the upper surface is flush with the upper surface of the columnar electrode 17, and a recess 19 is formed on the upper surface of the sealing film 18 around the columnar electrode 17. The structure is such that solder balls (low melting point metal balls) 20 are formed in the recesses 19 and above the columnar electrodes 17 including the upper surfaces thereof.

As described above, in this semiconductor device, even if the upper surface of the columnar electrode 17 is flush with the upper surface of the sealing film 18, the recess 19 is formed in the upper surface of the sealing film 18 around the columnar electrode 17.
Since the solder balls 20 are formed in the recesses 19 and on the upper side thereof including the upper surfaces of the columnar electrodes 17, the upper ends of the columnar electrodes 17 can be covered with the solder balls 20.
As a result, when this semiconductor device is mounted on a circuit board (not shown) and then subjected to a temperature cycle test or the like, stress is generated due to the difference in thermal expansion coefficient between the semiconductor substrate 11 and the circuit board. Even if it occurs, it is possible to prevent cracks from easily occurring at the interface between the columnar electrode 17 and the solder ball 20.

Next, an example of a method of manufacturing this semiconductor device will be described with reference to FIGS. First, as shown in FIG. 2, the connection pads 12 are formed on the upper surface of the semiconductor substrate 11 in a wafer state, and the connection pads 12 on the upper surface are formed.
The insulating film 13 is formed on the portion except the central portion of the insulating film 1.
3, the underlying metal layer 15 is formed from the upper surface of the connection pad 12 exposed through the opening 14 formed in 3 to a predetermined position on the upper surface of the insulating film 13, and the rewiring 16 is formed on the upper surface of the underlying metal layer 15. Then, the electrode having the columnar electrode 17 formed on the upper surface of the pad portion at the tip of the rewiring 16 is prepared.

Next, as shown in FIG. 3, a sealing film 18 made of epoxy resin is formed on the entire upper surface of the insulating film 13 including the columnar electrodes 17 and the rewirings 16 by the transfer molding method,
It is formed by a dispenser method, a dipping method, a printing method or the like so that the thickness thereof is slightly larger than the height of the columnar electrodes 17. Therefore, in this state, the upper surface of the columnar electrode 17 is covered with the sealing film 18. Next, as shown in FIG. 4, the upper surface of the sealing film 18 is polished to expose the upper surface of the columnar electrode 17, and the exposed upper surface of the columnar electrode 7 is replaced with the upper surface of the sealing film 8. Be flush

Next, as shown in FIG. 5, the upper surface of the sealing film 18 around the columnar electrodes 17 is irradiated with laser light such as an ultraviolet laser or an excimer laser, or by excavation processing. The recess 19 is formed.
Next, as shown in FIG.
The solder balls 20 are formed on the upper surface of the solder ball 7 including the upper surface thereof.
In this case, the solder ball 20 is directly mounted on the upper surface of the columnar electrode 17 and reflowed, or a method of applying solder paste to the upper surface of the columnar electrode 17 by a printing method or a dispenser and then reflowing the solder paste is used. You can follow.
Solder balls 20 melted in the recesses 19 by reflow
Alternatively, as a part of the solder paste enters, the solder balls 20 or the solder paste becomes ball-shaped due to the surface tension, and includes not only the upper surface of the columnar electrode 17 but also the outer peripheral portion of the columnar electrode 17 as shown in FIG. The entire upper end is covered with the solder balls 20. The columnar electrode 17 may be a prism, but a column is more suitable for reducing the internal strain. Next, the semiconductor device shown in FIG. 1 is obtained after a dicing process.

(Second Embodiment) FIG. 7 is a sectional view of a semiconductor device according to a second embodiment of the present invention. In this figure, the same reference numerals are given to the same names as those in FIG. 1, and the description thereof will be omitted as appropriate. This semiconductor device is different from the case shown in FIG. 1 in that the upper surface of the sealing film 18 is higher than the upper surface of the columnar electrode 17.

Next, an example of a method of manufacturing this semiconductor device will be described. In this case, the steps up to the step shown in FIG. 3 are the same as those in the first embodiment. That is, the sealing film 18 is formed on the entire upper surface of the insulating film 13 including the columnar electrodes 17 and the redistribution lines 16 so that the thickness thereof is slightly larger than the height of the columnar electrodes 17.

Next, as shown in FIG. 8, a concave portion 19 is formed by irradiating the upper surface of the sealing film 18 on and around the columnar electrode 17 with a laser beam such as an ultraviolet laser or an excimer laser. The upper end of the columnar electrode 17 is exposed. Next, as shown in FIG. 9, solder balls 20 are formed in the recesses 19 and on the upper side including the upper surfaces of the columnar electrodes 17. The method of forming the solder balls 20 is the same as in the first embodiment. Next, after a dicing process, the semiconductor device shown in FIG. 7 is obtained. In this case, the polishing process shown in FIG. 4 can be omitted.

(Third Embodiment) FIG. 10 shows a third embodiment of the present invention.
1 is a cross-sectional view of a semiconductor device as an embodiment. In this figure, the same reference numerals are given to the same names as those in FIG. 1, and the description thereof will be omitted as appropriate. This semiconductor device is different from the case shown in FIG. 1 in that the recess 19 formed on the upper surface of the sealing film 18 around the columnar electrode 17 is formed so as to be a part of the spherical surface. Therefore, the solder ball 2 formed on the upper end of the columnar electrode 17
0 means that the inside of the concave portion 19 is formed into a spherical shape. As a result, the internal strain of the solder ball 20 is further reduced.

Next, an example of a method of manufacturing this semiconductor device will be described. Also in this case, first, the one shown in FIG. 2 is prepared. Next, although not shown, the tip end portion (upper end portion in FIG. 2) of the columnar electrode 17 is made up of the resist, polyimide, high melting point flux, etc. in the recess forming tank by turning upside down the one shown in FIG. By immersing in the recess forming liquid and then pulling it up and acting by surface tension and blowing hot air, the recess forming balls 21 are formed on the upper ends of the columnar electrodes 17, as shown in FIG. In this state,
The upper end of the columnar electrode 17 is covered with the recess forming ball 21.

Next, as shown in FIG. 12, a sealing film 18 made of epoxy resin is formed on the entire upper surface of the insulating film 13 including the recess forming balls 21 and the rewiring 16 by a transfer molding method, a dispenser method, or a dipping method. It is formed by a printing method or the like so that the thickness is at least larger than the height of the columnar electrodes 17. Next, as shown in FIG. 13, by polishing the upper surface side of the sealing film 18 and the recess forming balls 21, the upper surface of the columnar electrode 17 is exposed and the exposed upper surface of the columnar electrode 7 is sealed. It is flush with the upper surface of the stop film 8. In this case, a part of the recess forming ball 21 is left around the upper end of the columnar electrode 17.

Next, when the recess forming ball 21 remaining around the upper end of the columnar electrode 17 is removed, a part of the ball is formed on the upper surface of the sealing film 18 around the columnar electrode 17 as shown in FIG. A concave portion 19 made of is formed. next,
As shown in FIG. 15, solder balls 20 are formed in the recesses 19 and on the upper side thereof including the upper surfaces of the columnar electrodes 17. Next, after a dicing process, the semiconductor device shown in FIG. 10 is obtained.

(Fourth Embodiment) FIG. 16 shows a fourth embodiment of the present invention.
1 is a cross-sectional view of a semiconductor device as an embodiment. In this figure, parts having the same names as in FIG. 10 are assigned the same reference numerals and explanations thereof are omitted as appropriate. This semiconductor device is different from the case shown in FIG. 10 in that the sealing film 18
That is, the upper surface of is higher than the upper surface of the columnar electrode 17.

Next, an example of a method of manufacturing this semiconductor device will be described. In this case, the steps up to the step shown in FIG. 12 are the same as those in the third embodiment. That is, the sealing film 18 made of epoxy resin is formed on the entire upper surface of the insulating film 13 including the recess forming balls 21 and the rewirings 16 so that the thickness thereof is at least larger than the height of the columnar electrodes 17.

Next, as shown in FIG. 17, the upper surface side of the sealing film 18 and the upper half or more of the recess forming ball 21 are
The polishing is performed so that the upper surface of the columnar electrode 17 is not exposed. Therefore, in this state, the upper surface of the columnar electrode 17 is covered with the remaining recess forming balls 21. Next, when the remaining recess forming balls 21 are removed, recesses 19 are formed on the upper surface of the sealing film 18 on and around the columnar electrodes 17, as shown in FIG.

Next, as shown in FIG. 19, the solder ball 2 is formed in the recess 19 and on the upper side thereof including the upper surface of the columnar electrode 17.
Form 0. Next, after going through a dicing process, FIG.
The semiconductor device shown in is obtained. In this case, the polishing process shown in FIG. 17 can be shortened as compared with the case of the third embodiment.

(Other Embodiments) In the third and fourth embodiments, the recess forming balls 21 may be formed of a low melting point metal such as solder.
In this case, in particular, when the recess forming balls 21 are formed of solder, the solder balls 20 can be formed without removing the remaining recess forming balls 21. Further, in each of the above-described embodiments, the solder balls 20 may not be formed, and instead, although not shown, solder balls or a solder layer may be formed on the connection terminals of the circuit board.

[0022]

As described above, according to the present invention, since the recess is formed at least on the upper surface of the sealing film around the columnar electrodes, the low melting point metal bonding material such as a solder ball is formed in the recess. And the upper end of the columnar electrode is covered with a low melting point metal bonding material such as a solder ball, so that cracks are unlikely to occur at the interface between the columnar electrode and the low melting point metal bonding material such as a solder ball. You can

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of an initially prepared item in manufacturing the semiconductor device shown in FIG.

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

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

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

FIG. 6 is a diagram of a step that follows FIG.

FIG. 7 is a sectional view of a semiconductor device as a second embodiment of the present invention.

FIG. 8 is a cross-sectional view of a predetermined process in manufacturing the semiconductor device shown in FIG.

FIG. 9 is a diagram of a step following FIG. 8;

FIG. 10 is a sectional view of a semiconductor device as a third embodiment of the present invention.

11 is a sectional view of a predetermined process in manufacturing the semiconductor device shown in FIG.

12 is a sectional view of a step following FIG. 11. FIG.

FIG. 13 is a sectional view of a step following FIG. 12;

FIG. 14 is a sectional view of a step following FIG. 13;

FIG. 15 is a sectional view of a step following FIG. 14;

FIG. 16 is a sectional view of a semiconductor device as a fourth embodiment of the present invention.

17 is a sectional view of a predetermined process in manufacturing the semiconductor device shown in FIG.

FIG. 18 is a sectional view of a step following FIG. 17;

FIG. 19 is a sectional view of a step following FIG. 18;

FIG. 20 is a sectional view of an example of a conventional semiconductor device.

[Explanation of symbols]

11 Semiconductor substrate 12 connection pads 13 Insulating film 15 Base metal layer 16 Rewiring 17 Columnar electrode 18 Sealing film 19 recess 20 solder balls

Claims (13)

[Claims] 1. A columnar electrode formed on a semiconductor substrate,
In a semiconductor device including a sealing film formed on a region of the semiconductor substrate excluding the columnar electrode, a recess exposing the upper surface of the columnar electrode and the outer peripheral surface of the upper end is formed on the upper surface of the sealing film. A semiconductor device characterized by being provided. 2. The semiconductor device according to claim 1, wherein an upper surface of the sealing film and an upper surface of the columnar electrode are substantially flush with each other. 3. The semiconductor device according to claim 1, wherein an upper surface of the sealing film is higher than an upper surface of the columnar electrode. 4. The semiconductor device according to claim 1, wherein a low-melting-point metal ball is formed in the recess and on an upper side of the columnar electrode including an upper surface thereof. 5. A columnar electrode is formed on a semiconductor substrate, a sealing film is formed on the semiconductor substrate including the columnar electrode, and an upper surface of the columnar electrode and an outer peripheral surface of an upper end portion are formed on the sealing film. A method for manufacturing a semiconductor device, which comprises forming an exposed recess. 6. The invention according to claim 5, wherein after forming the sealing film, polishing is performed so that an upper surface of the sealing film and an upper surface of the columnar electrode are substantially flush with each other. Manufacturing method of semiconductor device. 7. The invention according to claim 5, wherein the sealing film is formed so that its upper surface is higher than the upper surface of the columnar electrode, and in this state, the recess is formed in the sealing film. A method of manufacturing a semiconductor device, which comprises forming the semiconductor device. 8. The method of manufacturing a semiconductor device according to claim 5, wherein the recess is formed by irradiation with laser light. 9. The method for manufacturing a semiconductor device according to claim 5, wherein the recess is formed by excavation. 10. A columnar electrode is formed on a semiconductor substrate, a recess forming ball is formed at an upper end portion of the columnar electrode so as to cover the upper end portion, and an upper surface thereof is formed on the semiconductor substrate including the columnar electrode. Is formed so that it is higher than the upper surface of the columnar electrode, and at least the upper surface side of the sealing film is formed so that at least a part of the recess forming ball remains around the upper end of the columnar electrode. A method of manufacturing a semiconductor device, comprising: polishing the recess forming ball. 11. The invention according to claim 10, wherein the upper surface side of the sealing film and the recess forming ball are polished until the upper surface of the columnar electrode is not exposed, and the upper surface of the columnar electrode and the upper end thereof are polished. A method of manufacturing a semiconductor device, characterized in that a part of the recess forming ball is left around the portion. 12. The method of manufacturing a semiconductor device according to claim 10, wherein a part of the remaining recess forming ball is removed to form a recess in the sealing film. . 13. The invention according to claim 10 or 11, wherein the recess forming balls are formed of a low melting point metal, and an upper surface of a portion of the remaining recess forming balls is formed.
A method of manufacturing a semiconductor device, comprising forming a low melting point metal ball made of the same material as the low melting point metal.