JP3520213B2 - Semiconductor wafer with columnar electrode and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor wafer with columnar electrodes used for manufacturing a chip size package using a semiconductor wafer and a method for manufacturing the semiconductor wafer.

[0002]

2. Description of the Related Art FIG. 5 shows a method for manufacturing a semiconductor wafer having columnar electrodes used for manufacturing a chip size package using the semiconductor wafer. FIG. 5A is a sectional view showing the semiconductor wafer 10 in an enlarged manner.
2 shows a state in which the electrode terminals 12 and the passivation film 14 are formed on the surface of the. A polyimide film is coated on the surface of the semiconductor wafer 10 to form an insulating layer 16 exposing the electrode terminals 12 (FIG. 5 (b)). Next, sputtering is performed to form a conductor layer 18 serving as a plating power supply layer on the surfaces of the insulating layer 16 and the electrode terminal 12 (FIG. 5 (c)). next,
A resist is applied, a resist pattern 20 is formed according to the wiring pattern formed on the surface of the semiconductor wafer 10 (FIG. 5 (d)), and copper plating is performed using the conductor layer 18 as a plating power supply layer to form a wiring pattern 22. Yes (Fig. 5
(e)). The wiring pattern 22 has one end connected to the electrode terminal 12 and the other end formed with a pad portion for standingly providing a columnar electrode.

Next, electrolytic plating is performed to form columnar electrodes 24. Therefore, first, the resist pattern 20 is removed from the state of FIG.
A resist 26 is applied to the surface of the above, and the resist 26 in the portion where the columnar electrode 24 is formed by aligning with the pad portion of the wiring pattern 22 is removed to form an opening hole 26a. The columnar electrode 24 is formed to have a height of about 100 μm, and the resist 26 is formed to be slightly thicker than the height of the columnar electrode 24.

The columnar electrodes 24 are formed by electrolytic copper plating and raising the copper plating in the opening holes 26a. Figure 5 (f)
With the columnar electrode 24 formed, a plating film is formed on the top end surface of the columnar electrode 24. FIG. 5G shows a state in which after removing the resist 26, the conductor layer 18 exposed on the surface of the semiconductor wafer is removed by etching. By etching the conductor layer 18, the wiring pattern 22 electrically connected to the electrode terminal 12 at one end side is formed on the electrode terminal forming surface, and the columnar electrode 24 is formed at the other end side of the wiring pattern 22. The wafer 10 is obtained.

The semiconductor wafer 10 thus obtained has columnar electrodes 24 formed one by one corresponding to each electrode terminal 12, and a large number of columnar electrodes 24 are formed on the surface of the semiconductor wafer 10. ing. FIG. 6 shows a method of resin-sealing the semiconductor wafer 10 on which the columnar electrodes 24 are formed. The semiconductor wafer 10 is placed on the lower mold 31 with the columnar electrode 24 facing upward, and the resin material 28 for sealing is supplied onto the semiconductor wafer 10, and then the upper mold 32 that adsorbs the sealing film 30 on the clamp surface is used. The semiconductor wafer 10 is clamped between the lower die 31 and the lower die 31. By this clamping operation, the molten resin spreads on the surface of the semiconductor wafer 10 on which the electrode terminals are formed, and the resin is sealed. After the resin sealing, the semiconductor wafer 10 with the sealing film 30 adhered is taken out from the mold, and the sealing film 30 is peeled off from the semiconductor wafer 10. A chip size package is obtained by bonding a mounting terminal (for example, a solder ball) to the top end surface of the columnar electrode 24 and then cutting the semiconductor wafer into individual chip sizes.

[0006]

With the above-described manufacturing method,
Film 3 for sealing when the semiconductor wafer 10 is resin-sealed
The reason why the top end surface of the columnar electrode 24 is covered with 0 is to prevent the sealing resin from adhering to the top end surface of the columnar electrode 24. However, the height of the columnar electrode 24 varies. When the resin is sealed, the sealing resin may enter the top end surface of the columnar electrode 24, and the resin may adhere to and remain on the columnar electrode 24. After the semiconductor wafer 10 is resin-sealed, the sealing film 30 is peeled off from the semiconductor wafer 10. The resin remaining on the top end surface of the columnar electrode 24 is attached to the sealing film 30 and removed. This is because.

However, just peeling off the sealing film 30 from the semiconductor wafer 10 does not necessarily ensure that the resin remaining on the top end surface of the columnar electrode 24 is removed. Since the top end surface of the columnar electrode 24 is a joint surface for joining a mounting terminal such as a solder ball or the like, the fact that the resin is attached to the top end surface of the columnar electrode 24 indicates that the columnar electrode 24 and the terminal are joined together. There is a problem in terms. Therefore, the sealing film 30
After peeling off, the top end surface of the columnar electrode 24 is cleaned by blasting or the like.

However, such cleaning cannot always completely remove the resin remaining on the top end surface of the columnar electrode 24, and the columnar electrode 24
If the resin is excessively cleaned to completely remove the resin from the top end surface of the above, there is a problem that the sealing resin is deteriorated. As described above, in the conventional method for manufacturing a semiconductor wafer with columnar electrodes, the resin remains on the end faces of the columnar electrodes, which impairs the bondability between the columnar electrodes and the mounting terminals. The present invention has been made to solve these conventional problems, and an object thereof is to improve the bondability between a columnar electrode and a mounting terminal, thereby obtaining a highly reliable chip size package. It is an object of the present invention to provide a semiconductor wafer with a columnar electrode and a suitable method for manufacturing the semiconductor wafer.

[0009]

In order to achieve the above object, the present invention has the following constitution. That is, a wiring pattern whose one end side is connected to each electrode terminal is formed on an electrode terminal formation surface of a semiconductor wafer through an insulating layer, and a columnar electrode is formed on the other end side of each wiring pattern. In a semiconductor wafer with a columnar electrode having a top end face exposed and resin-sealed, a nickel plating film is formed on the top end face of the columnar electrode, and a palladium plating film and a gold plating film are sequentially formed on the nickel plating film. It is characterized by As the plating film, it is preferable that the palladium plating film is formed to a thickness of 0.1 μm or less and the gold plating film is formed to a thickness of 0.001 μm to 0.1 μm. It is more preferable that the gold plating film is formed to a thickness of 0.05 μm to 0.1 μm, and the gold plating film is formed to a thickness of 0.01 μm to 0.05 μm.

Further, as a method of manufacturing a semiconductor wafer with columnar electrodes, after the electrode terminal forming surface of the semiconductor wafer is exposed with an electrode layer and covered with an insulating layer, a conductor layer is formed on the surface of the electrode terminal and the insulating layer. A conductor pattern is formed on the surface of the conductor layer, and the conductor layer is subjected to copper plating as a plating power supply layer to form a wiring pattern whose one end side is connected to each electrode terminal, and after removing the resist pattern, the conductor A resist is applied to the surface of the layer and the wiring pattern, an opening hole is formed in the bottom surface of the wiring pattern where the other end of the wiring pattern is exposed, and the conductor layer is plated in the resist at the site where the columnar electrode is to be formed. Copper plating is performed in the opening hole as a power supply layer to form a columnar electrode in the opening hole, and then a nickel plating film is formed on the top end surface of the columnar electrode, A palladium plating film and a gold plating film are sequentially formed on the nickel plating film, the resist is removed, and the conductor layer exposed on the surface is removed, and then the surface of the gold plating film is exposed on the semiconductor wafer. It is characterized in that the electrode terminal formation surface side is resin-sealed.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. The semiconductor wafer with columnar electrodes according to the present invention is most characterized by the structure of columnar electrodes formed on the semiconductor wafer. FIG. 1 is an overall view showing the configuration of an embodiment of a semiconductor wafer with columnar electrodes according to the present invention, and FIG. 2 is an enlarged sectional view showing the configuration of columnar electrodes formed on a semiconductor wafer with columnar electrodes.

The semiconductor wafer with columnar electrodes of the present embodiment has the same structure as that of the conventional semiconductor wafer with columnar electrodes described above, except for the structure relating to the plating film on the columnar electrode portion. Therefore, in the following, the configuration of the columnar electrode portion that is characteristic of the present invention will be mainly described. In the following description, the same parts as those of the conventional semiconductor wafer with columnar electrodes are designated by the same reference numerals.

In the wafer with columnar electrodes, a wiring pattern 22 electrically connected to the electrode terminals 12 at one end side is formed on the electrode terminal formation surface of the semiconductor wafer 10 through the insulating layer 16, and the other end side of the wiring pattern 22 is formed. The columnar electrode 24 is erected on the surface of the semiconductor wafer 10, and the electrode terminal formation surface side of the semiconductor wafer 10 is sealed with a sealing resin 28 with the top end surface of the columnar electrode 24 exposed. As shown in FIG. 1, the resin 28 fills the space between all adjacent columnar electrodes 24 to seal the electrode terminal formation surface of the semiconductor wafer 10.

As shown in FIG. 2, the semiconductor wafer with a columnar electrode of the present embodiment is characterized in that a copper plated portion 40 is provided as a conductor portion of the columnar electrode 24 and a copper plated portion 4 is provided.
A plating film 4 including a nickel plating film 42, a palladium plating film 44, and a gold plating film 46 on the top end surface of 0.
1 is provided in this order.

It has been conventionally practiced to form a plating film on the top end surface of the copper plating portion 40 of the columnar electrode 24. In the columnar electrode 24 according to the present invention, the plating film 41 having a three-layer structure of the nickel plating film 42, the palladium plating film 44, and the gold plating film 46 is provided on the copper plating part 40, so that the external connection terminal for mounting is provided. (For example, a solder ball) and the columnar electrode 24 can be bonded well, and the thickness of the palladium plating film 44 formed on the plating film 41 can be reduced.

When the plating film provided on the columnar electrode 24 has a two-layer structure of a nickel plating film for preventing solder diffusion and a palladium plating film for improving solder wettability, the thickness of the nickel plating film is about 3 μm. The thickness of the palladium plating film needs to be about 0.1 to 0.15 μm. On the other hand, when the plating film 41 having the three-layer structure of the nickel plating film 42, the palladium plating film 44, and the gold plating film 46 is used as in the present embodiment, the thickness of the palladium plating film 44 is 0.1 μm. The thickness may be the following (preferably 0.05 μm to 0.1 μm), which is about half the thickness of the two-layer structure. Further, the thickness of the gold plating film 46 may be extremely thin such as 0.001 μm to 0.1 μm (preferably 0.01 μm to 0.05 μm). As described above, the reason why the thickness of the palladium plating film 44 can be reduced is that the wettability of the solder can be effectively improved by providing the gold plating film 46 as compared with the case where only the palladium plating film 44 is provided. .

When a solder ball is bonded to the columnar electrode as an external connection terminal, the gold plating film 46 and the palladium plating film 44 are both diffused in the molten solder and the solder ball is bonded to the nickel plating film 42. . Thus, the gold plating film 46 and the palladium plating film 44 contribute to the wettability of the solder,
When the gold plating film 46 is provided on the outer surface of the plating film as in the present embodiment, the solder wettability is sufficient even if the thickness of the palladium plating film 44 is reduced as compared with the case where the palladium plating film 44 is provided alone. It will be possible to obtain. Good solderability can be obtained by providing the gold plating film 46 as thin as flash plating.

By improving the solder wettability with the palladium plating film 44 and the gold plating film 46, the resin 28 is formed on the surface of the plating film formed on the top end face of the columnar electrode 24 when the semiconductor wafer 10 is sealed. Even if a small amount is attached, the external connection terminal for mounting such as a solder ball and the columnar electrode 24 can be reliably joined.
Thus, after sealing the semiconductor wafer 10, there is no need to excessively clean the plating film 41 formed on the top end surface of the columnar electrode 24 in order to completely remove the resin remaining on the surface of the plating film 41. .

Further, since the adhesion between the resin 28 and the surface of the gold plating film 46 is low, the surface of the plating film 46 is made the gold plating film 46 so that the surface of the semiconductor wafer 10 on which the electrode terminals are formed is sealed with resin. After stopping, sealing film 3
The resin 28 remaining on the surface of the gold plating film 46 when the 0 is peeled off is attached to the sealing film 30 to facilitate the peeling, and the resin 28 does not remain on the surface of the gold plating film 46. There is also the effect that you can.

FIG. 3 shows an embodiment of a method of manufacturing a semiconductor wafer with columnar electrodes. The method of manufacturing the semiconductor wafer with columnar electrodes is the same as the conventional method except for the configuration of the plating film 41 provided on the columnar electrodes 24. Therefore, FIG. 3 mainly shows the step of forming the plating film 41. Figure 3 (a)
Forms a wiring pattern 22 whose one end side is electrically connected to the electrode terminal 12 through the insulating layer 16 on the electrode terminal formation surface of the semiconductor wafer 10, and the conductor layer 18 and the wiring pattern 2 are formed.
The resist 26 is applied to the surface of No. 2 and the opening 26a where the other end side of the wiring pattern 22 is exposed on the bottom surface is formed in the resist 26 at the portion where the columnar electrode is formed on the other end side of the wiring pattern 22.
The state in which the is formed is shown.

After forming the opening hole 26a, electrolytic copper plating is performed using the conductor layer 18 as a plating power supply layer to form a copper plating portion 40 in the opening hole 26a (FIG. 3 (b)). Copper plating part 4
Reference numeral 0 indicates a conductor portion of the columnar electrode 24, and the opening hole 26a
Is formed by swelling the plating to a thickness that substantially fills the. The height of the columnar electrode 24 is about 100 μm, and the resist 26 is also formed to a thickness of about 100 μm in accordance with this.

Next, nickel plating, palladium plating and gold plating are performed in this order to form a plating film 41 on the copper plating portion 40 (FIG. 3 (c)). The plating film 41 is a nickel plating film 42, a palladium plating film 44,
It has a three-layer structure of the gold plating film 46. As previously mentioned,
The nickel plating film 42 has a thickness of 3 μm, the palladium plating film 44 has a thickness of 0.05 μm, and the gold plating film 46.
Has a thickness of 0.01 μm.

After forming the plating film 41, the resist 2
By removing 6 and etching the conductor layer 18 exposed on the surface of the semiconductor wafer 10, the nickel plating film 42, the palladium plating film 44, and the gold plating film 46.
The semiconductor wafer 10 having the columnar electrodes 24 having the plating film 41 having the three-layer structure formed on the top end face thereof is obtained. Since the conductor layer 18 has a thickness of about 0.05 μm and is formed extremely thinner than the columnar electrode 24 and the wiring pattern 22, the columnar electrode 24 and the wiring pattern 2 are formed.
Conductor layer 1 without covering 2 with resist or the like for protection
Only 8 can be removed by etching.

In the step of forming the plating film 41 in this embodiment, the conventional method of plating the copper plating portion 40 can be applied as it is, and the three layers of the nickel plating film 42, the palladium plating film 44 and the gold plating film 46 can be used. It is easy to stack plating layers. Thus, the semiconductor wafer 10
After the columnar electrode 24 is formed on the surface of the semiconductor wafer 10, the surface of the gold-plated coating formed on the top end surface of the columnar electrode 24 is exposed to seal the electrode terminal forming surface side of the semiconductor wafer 10 with resin, as shown in FIG. A semiconductor wafer with columnar electrodes is obtained.

The columnar electrodes 24 provided on the conventional semiconductor wafer with columnar electrodes are formed in a columnar shape. FIG. 4B is an enlarged perspective view showing the conventional columnar electrode 24, showing a state where the columnar columnar electrode 24 is erected on the pad portion 22 a of the wiring pattern 22. The semiconductor wafer with columnar electrodes is resin-sealed on the electrode terminal formation surface side on which the columnar electrodes 24 are formed, and resin 28 is filled between the adjacent columnar electrodes 24, as shown in FIGS. However,
Generally, resin and metal do not have good adhesion, so that when the external connection terminal for mounting such as a solder ball is joined to the columnar electrode 24, the side surface of the columnar electrode 24 and the resin 28 are bonded to each other. Solder may flow in or moisture may be adsorbed at the interface.

As a result, there is a problem in that the reliability of the connection between the external connection terminal joined to the columnar electrode 24 and the columnar electrode 24 is reduced. FIG. 4A shows the shape of the columnar electrode 24 that solves these problems, and is an example in which the side surface of the columnar electrode 24 has an uneven surface shape. In this way, the columnar electrode 24
If the side surface of the columnar electrode is formed into an uneven surface, the contact area between the side surface of the columnar electrode 24 and the resin 28 increases, and the clinging property between the resin 28 and the columnar electrode 24 on the side surface of the columnar electrode 24 improves.
Adhesion between the side surface of the columnar electrode 24 and the resin 28 is improved.

As shown in FIG. 3, the columnar electrode 24 has its side surface defined by the shape of the opening hole 26a formed in the resist 26. Therefore, the resist 26 is exposed and developed according to the shape of the opening hole 26a. At this time, the exposure may be performed so that the inner wall surface of the opening hole 26a becomes an uneven surface. Opening hole 26
It is easy to form a into an appropriate shape. By forming the side surface of the columnar electrode 24 in a concavo-convex shape in this way, the adhesion between the columnar electrode 24 and the resin 28 becomes good, and when the columnar electrode 24 is joined to an external connection terminal such as a solder ball, the columnar electrode 24 is formed. It is possible to effectively prevent the solder from flowing into the interface between the outer surface of the electrode 24 and the resin 28 and the intrusion of water.

In order to further improve the adhesion between the columnar electrode 24 and the resin 28, the columnar electrode 24 is formed, the resist 26 is removed, and then the side surface of the columnar electrode 24 is roughened by plasma ashing or the like. That is also effective.
Further, in addition to forming the side surface of the columnar electrode 24 into an uneven surface or a rough surface so as to improve the adhesion with the resin 28, the plating film 41 on the top of the columnar electrode 24 is formed in the same manner as described above. It is also possible to have a three-layer structure of a nickel plating film 42, a palladium plating film 44, and a gold plating film 46 in the configuration, and thereby a more reliable semiconductor device can be obtained.

[0029]

As described above, the semiconductor wafer with the columnar electrode according to the present invention has good solder wettability when the external connection terminal is joined to the columnar electrode, and thus can be used as an external connection terminal for mounting a solder ball or the like. It is possible to reliably bond the columnar electrode, and this makes it possible to manufacture a highly reliable semiconductor device. Further, according to the manufacturing method of the present invention, it is possible to preferably manufacture a semiconductor wafer with columnar electrodes for obtaining a highly reliable semiconductor device.

[Brief description of drawings]

FIG. 1 is a sectional view showing a configuration of a semiconductor wafer with columnar electrodes according to the present invention.

FIG. 2 is an enlarged sectional view showing a columnar electrode of a semiconductor wafer with a columnar electrode according to the present invention.

FIG. 3 is an explanatory view showing a method for manufacturing a semiconductor wafer with columnar electrodes according to the present invention.

FIG. 4 is a perspective view showing another example of forming columnar electrodes.

FIG. 5 is an explanatory diagram showing a conventional method for manufacturing a semiconductor wafer with columnar electrodes used in manufacturing a chip size package using a semiconductor wafer.

FIG. 6 is an explanatory view showing a method of manufacturing a semiconductor wafer with columnar electrodes used in manufacturing a chip size package using a semiconductor wafer.

[Explanation of symbols]

10 Semiconductor wafer 12 electrodes 18 Conductor layer 20 resist pattern 22 wiring pattern 24 columnar electrodes 26 Resist 26a Open hole 28 resin 30 Sealing film 40 Copper plating part 41 plating film 42 Nickel plating film 44 Palladium plating film 46 gold plating film

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-10-287994 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01L 21/288

Claims (4)

(57) [Claims] 1. A wiring pattern having one end side connected to each electrode terminal is formed on an electrode terminal formation surface of a semiconductor wafer through an insulating layer, and a columnar electrode is formed on the other end side of each wiring pattern. In a semiconductor wafer with a columnar electrode in which the top end face of the columnar electrode is exposed and resin-sealed, a nickel plating film is formed on the top end face of the columnar electrode, and a palladium plating film and a gold plating film are formed on the nickel plating film. A semiconductor wafer with columnar electrodes, which is sequentially formed. 2. A palladium plating film having a thickness of 0.1 μm or less, and a gold plating film having a thickness of 0.001 μm or more.
The semiconductor wafer with columnar electrodes according to claim 1, wherein the semiconductor wafer has a thickness of 0.1 μm. 3. The palladium plating film has a thickness of 0.05 μm or more.
Formed to a thickness of 0.1 μm, with a gold plating film of 0.01
The semiconductor wafer with a columnar electrode according to claim 1, wherein the semiconductor wafer has a thickness of μm to 0.05 μm. 4. A surface of the semiconductor wafer on which the electrode terminals are formed is exposed to cover the electrode terminals with an insulating layer, a conductor layer is formed on the surfaces of the electrode terminals and the insulating layer, and then a resist pattern is formed on the surface of the conductor layer. Then, a wiring pattern whose one end side is connected to each electrode terminal is formed by performing copper plating using the conductor layer as a plating power supply layer, and after removing the resist pattern, a resist is applied to the surface of the conductor layer and the wiring pattern. Then, in the resist of the portion forming the columnar electrode on the other end side of the wiring pattern, an opening hole is formed on the bottom surface where the other end side of the wiring pattern is exposed, and copper plating is performed in the opening hole using the conductor layer as a plating power supply layer. After forming a columnar electrode in the opening, a nickel plating film is formed on the top end surface of the columnar electrode, and a palladium plating film and a nickel plating film are formed on the nickel plating film. A gold plating film is sequentially formed, the resist is removed, and the conductor layer exposed on the surface is removed, and then the electrode terminal formation surface side of the semiconductor wafer is resin-sealed so that the surface of the gold plating film is exposed. A method for manufacturing a semiconductor wafer with a columnar electrode, comprising: