JP3386672B2 - Wafer plating equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer plating apparatus used for forming metal projection electrodes for connection by a flip chip method on an I / O pad of a wafer on which a semiconductor integrated circuit is formed by plating. It is a thing.

[0002]

2. Description of the Related Art An embodiment of the wafer plating apparatus that has been used conventionally will be described. FIG. 11 shows
It is sectional drawing which shows the structure of the wafer plating apparatus as a prior art example. As shown in the figure, a wafer 1 on which an integrated circuit is formed
00 is mounted on a wafer jig 102 for supporting the periphery thereof and sealing the peripheral portion of the wafer 100, and is immersed in a plating solution 104. This wafer 10
On 0, a plating electrode metal layer (barrier metal) for the cathode electrode is formed on the entire surface.

An anode electrode 106 is provided in the plating solution 104 at a position facing the wafer 100 in parallel, and the anode electrode 106 is connected to the positive electrode side of a power source 108. A cathode electrode contact 110 is provided around the wafer 100, and the cathode electrode contact 110 connects the plating electrode metal layer to the negative electrode side of the power supply 108.

In the thus configured wafer plating apparatus, the temperature of the plating solution 104 is adjusted by the circulation pump 112, and the plating solution 104 circulates in the wafer plating apparatus. That is, the plating solution 104 delivered by the circulation pump 112 flows from the bottom of the plating solution tank 104a, overflows from the top of the plating solution tank 104a, and flows out to the plating solution preliminary tank 104b to be stored therein. The plating solution 104 stored in the plating solution preliminary tank 104b is
The plating liquid tank 104 is passed from the bottom through the circulation pump 112.
It is sent to the lower part of a and flows into the plating solution tank 104a again from the bottom of the plating solution tank 104a.

In such a plating solution tank 104a,
A current flows through the plating solution 104 from the anode electrode 106 to the plating electrode metal layer serving as the cathode electrode, so that a metal such as solder grows as electrolytic plating at a desired position on the wafer 100.

FIG. 12 (a) is a plan view showing the shape of the anode electrode. FIG. 12B is a plan view showing the positions of the wafer and the contact point of the cathode electrode. As shown in FIG. 12A, the anode electrode 106 and the wafer 100 have almost the same size. Further, as shown in FIG. 12B, the cathode electrode contacts 110 are arranged at three points on the periphery of the wafer 100.

[0007]

However, the above-described wafer plating apparatus has a problem that the plating thickness varies within the wafer because the current flowing near the cathode electrode contact 110 is concentrated. The reason why the plating thickness varies is that the cathode electrode contact 110 exists at three points around the wafer. Therefore, the current path that flows from the anode electrode 106 to the vicinity of the cathode electrode contact 110 through the plating solution is the anode. Shorter than a current path that flows from the electrode 106 through the plating liquid to a position where the plating electrode metal layer is separated from the cathode electrode contact, and further flows through the plating electrode metal layer to the cathode electrode contact,
This is because the electric resistance is small, so that there is a difference in current density between the two.

Further, it is necessary to eliminate the unevenness of the plating thickness and make it uniform by increasing the wafer size in recent years and increasing the bump area, that is, the plating area.
It has become more difficult.

Therefore, the present invention has been made to solve the problem that the current flowing into the vicinity of the contact of the cathode electrode is concentrated and the plating thickness varies, and a metal projection electrode used for flip-chip connection or the like is formed on a wafer. An object is to provide a wafer plating apparatus that can be uniformly formed on the upper surface.

[0010]

In order to achieve the above object, a wafer plating apparatus according to the present invention comprises an electrode contact connected to an electrode film formed on a wafer, and a first power supply for the electrode contact. And a first electrode having a power source, and is disposed so as to face the first electrode at a predetermined interval, and between the electrode contact and a vicinity facing the electrode contact.
Is greater than the predetermined distance, and the electrode contact is
And the shortest distance between
A second electrode having the same outer shape and being connected to a second power supply.

Further, in the wafer plating apparatus according to a second aspect of the present invention, the second electrode has a shape in which the second electrode is concentrically removed around a point on the second electrode facing the electrode contact. It is characterized by

Further, in the wafer plating apparatus according to a third aspect of the present invention, the second electrode has a circular shape centered around a point facing the electrode contact from a circular shape equivalent to that of the first electrode. It is characterized by having a shape.

Further, in the wafer plating apparatus according to a fourth aspect, the second electrode has a shape obtained by cutting a circular shape smaller than the first electrode from a circular shape centered on a point facing the electrode contact. It is characterized by having.

Further, the wafer plating apparatus according to the present invention includes a first electrode having an electrode film formed on the wafer and an electrode contact for connecting the electrode film to a first power source, and the first electrode. Between the second electrode, which is installed so as to face each other and is connected to the second power source, and an insulator which shields a current, and between the electrode contact and the vicinity facing the electrode contact.
Is greater than the predetermined distance, and the electrode contact is
And the shortest distance between
And a current blocking means having the same opening shape and pressed against the second electrode.

Further, the wafer plating apparatus according to a sixth aspect is characterized in that the current shielding means has an opening shape which is concentrically removed around a point facing the electrode contact.

Further, in the wafer plating apparatus according to claim 7, the current shield means has a circular shape centered around a point facing the electrode contact from a circular shape equivalent to that of the first electrode. Is characterized by being open.

A wafer plating method according to the present invention
Forms a metal layer as a first electrode on the wafer
Process and forming bump electrodes on the metal layer on the wafer.
Process of forming a resist pattern with an opening for opening
And the electrode contact of the first electrode is provided on the periphery of the wafer.
Place the wafer in the plating solution as it is placed
Focusing on the process and the point facing the electrode contact of the first electrode
Second electrode having a shape obtained by cutting the circular shape
Is placed in the plating solution so as to face the wafer.
And a step of performing . In Wehamekki apparatus of the present invention, in the vicinity of the point on the second electrode facing the electrode contacts on the wafer, the second electrode, the
The distance between the electrode contact and the vicinity facing this electrode contact
It is larger than the facing distance, and the electrode contact and this electrode contact
It has an outer shape having the same shortest distance from the neighboring portion facing the point . As a result, a current path that flows from the second electrode through the plating solution to the vicinity of the electrode contact of the first electrode and a current path that passes through the plating solution from the second electrode and separates from the electrode contact of the first electrode Flow to the above-mentioned position, and by making the current paths that flow from this position to the electrode contact in the electrode film at substantially the same electrical distance, the difference in the current density that occurs between the two is eliminated, and the plating thickness becomes uniform. To be

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a wafer plating apparatus according to a first embodiment of the present invention. FIG. 2 is a perspective view showing a positional relationship between a wafer, which is a cathode electrode, and an anode electrode arranged in this wafer plating apparatus.

As shown in the figure, the wafer 2 on which the integrated circuit is formed is mounted on a wafer jig 4 for supporting the peripheral portion of the wafer 2 and sealing the peripheral portion of the wafer 2 in the plating solution 6. Is soaked in. A plated electrode metal layer (barrier metal) for the cathode electrode is formed on the entire surface of the wafer 2. Further, on the plated electrode metal layer, a resist pattern is formed in which a portion for forming a protruding electrode is opened.

An anode electrode 8 is provided in the plating solution 6 at a position facing the wafer 2 in parallel. The anode electrode 8 is connected to the positive electrode side of the power source 10. Further, a cathode electrode contact 12 is arranged around the wafer 2, and the cathode electrode contact 12 connects the negative electrode side of the power source 10 and the plated electrode metal layer on the wafer 2.

FIG. 3A is a plan view showing the shape of the anode electrode. FIG. 3B is a plan view showing the positions of the wafer and the cathode electrode contacts provided on the wafer. The outer peripheral diameter size of the anode electrode 8 and the wafer 2 are the same, and FIG.
The broken line 16 in the inside indicates the outer shape of the wafer 2 which is opposed thereto. Further, an arrow 18 in FIG. 3A indicates a position on the anode electrode 8 that faces, ie, faces, the cathode electrode contact 12 on the wafer 2. Wafer 2
As shown in FIG. 3B, the cathode electrode contacts 12 are arranged at three points on the periphery of the wafer 2 at substantially equal intervals.

As shown in FIG. 3A, the anode electrode 8
The shape is a shape that is cut along a locus at an equal distance from the position on the anode electrode 8 facing the cathode electrode contact 12 (the position shown by the arrow 18 in FIG. 3A). That is, the inner region of a concentric circle centered on the above position is cut out from the same circular shape as the wafer 2. The size of the radius of the concentric circles is determined by the electric resistance of the plating electrode metal layer (barrier metal) and the electric resistance of the plating solution. Specifically, the electric resistance value when a current flows from the vicinity of the edge of the concentric circle of the anode electrode 8 to the cathode electrode contact 12 and the plating electrode metal layer (barrier metal) not located in the vicinity of the anode electrode 8 to the cathode electrode contact 12 The size of the radius of the concentric circle is determined so that the electric resistance value when the current flows through the cathode electrode contact 12 becomes the same. That is, the electric resistance value when a current flows from the above-mentioned plated electrode metal layer (barrier metal) to the cathode electrode contact 12, and the cathode electrode contact 12 from the vicinity of the edge of the concentric circle of the anode electrode 8.
It is sufficient to determine the radius of the concentric circle so that the electric resistance value of the current path increased by cutting out the concentric circles among the current paths up to.

Next, the operation of the wafer plating apparatus according to the first embodiment will be described. In the thus configured wafer plating apparatus, the temperature of the plating solution 6 is adjusted by the circulation pump 14, and the plating solution 6 circulates in the wafer plating apparatus. That is, the plating liquid 6 delivered by the circulation pump 14 flows from the bottom of the plating liquid tank 6a,
It overflows from the upper portion of the plating solution tank 6a and flows into the plating solution preliminary tank 6b to be stored. Plating solution spare tank 6
The plating liquid 6 stored in b is supplied from the bottom to the circulation pump 1
It is sent out to the lower part of the plating solution tank 6a through 4 and again flows into the plating solution tank 6a from the bottom of the plating solution tank 6a. In such a plating liquid tank 6a, the anode electrode 8 is
From a cathode electrode to a plating electrode metal layer on the wafer, which is a current flowing through the plating solution 6,
A metal such as solder grows as electrolytic plating at a desired position on the wafer 2, that is, a portion on the plated electrode metal layer where the protruding electrode is formed.

In such a structure, the current path that flows from the anode electrode 8 through the plating solution 6 to the vicinity of the cathode electrode contacts 12 existing at three points on the peripheral portion of the wafer 2 is:
It is longer than the conventional one described above. That is, in the conventional example, the anode electrode 8 is present directly opposite the cathode electrode contact 12, but in the wafer plating apparatus of this embodiment, the anode electrode 8 is provided at a position away from the cathode electrode contact 12 directly. The current path becomes longer. On the other hand, the current path that flows through the plating liquid 6 from the anode electrode 8 on the surface of the wafer 2 away from the three cathode electrode contacts 12 is almost unchanged from the conventional one.

As a result, the electric resistance of the current path flowing from the anode electrode 8 to the vicinity of the cathode electrode contact 12 and the electric current flowing from the anode electrode 8 to the surface of the wafer 2 not near the cathode electrode contact 12 and from there to the cathode electrode contact 12. The difference from the electric resistance of the flowing current path becomes small.

Therefore, as described above, this first
According to the wafer plating apparatus of the above embodiment, it is possible to make the plating current density uniform within the wafer surface and reduce variations in plating thickness.

Next, a wafer plating apparatus according to the second embodiment will be described. This wafer plating apparatus shows a case where the wafer having three cathode electrode contacts in the first embodiment is a wafer having two cathode electrode contacts. Along with this, the shape of the anode electrode is a shape in which an inner region of a concentric circle centered on a position facing and facing the two cathode electrode contacts is cut out from the same circular shape as the wafer.

FIG. 4A is a plan view showing the shape of the anode electrode of this wafer plating apparatus. Figure 4 (b) shows
It is a top view which shows the position of the cathode electrode contact provided on the wafer.

The outer diameters of the anode electrode 20 and the wafer 22 are the same, and the broken line 16 in FIG. 4A extended from the outer shape of the anode electrode 20 shows the outer shape of the opposing wafer 22. In addition, the wafer 22 is shown in FIG.
As shown in FIG. 5, the cathode electrode contacts 12 are arranged at two points above and below the peripheral portion of the wafer 22. An arrow 18 in FIG. 4A indicates a position facing and corresponding to the cathode electrode contact 12 on the wafer 22. As described above, the shape of the anode electrode 20 is a shape obtained by cutting an inner region of a concentric circle centered on a position facing and facing two cathode electrode contacts from the same circular shape as the wafer.

In such a structure, the current path flowing from the anode electrode 20 through the plating solution to the vicinity of the cathode electrode contacts 12 existing at two upper and lower points around the wafer 22 is longer than that of the conventional one. . That is, in the conventional example, the anode electrode 20 was present directly opposite the cathode electrode contact 12, but in the wafer plating apparatus of this embodiment, the anode electrode 20 is provided at a position away from the cathode electrode contact 12 directly opposite. The current path becomes longer. On the other hand, the current path that flows through the plating solution from the anode electrode 20 on the surface of the wafer 22 separated from the two contact points 12 of the cathode electrode is almost unchanged from the conventional one.

As a result, the electric resistance of the current path flowing from the anode electrode 20 to the vicinity of the cathode electrode contact 12,
It flows from the anode electrode 20 onto the surface of the wafer 22 which is not near the cathode electrode contact 12, and from there, the cathode electrode contact 1
The difference from the electric resistance of the current path flowing in 2 becomes small.

Therefore, as described above, this second
According to the wafer plating apparatus of the above embodiment, it is possible to make the plating current density uniform within the wafer surface and reduce variations in plating thickness. Further, in this wafer plating apparatus, the number of cathode electrode contacts is reduced from three to two, so that it is easy to confirm the conduction state of the cathode electrode contacts and the maintenance of this apparatus can be easily performed.

Next, the wafer plating apparatus of the third embodiment will be described. This wafer plating apparatus shows a case where the wafer having three cathode electrode contacts in the first embodiment is changed to a wafer having eight cathode electrode contacts. Along with this, the shape of the anode electrode is such that the inner region of a concentric circle centered on the position facing and corresponding to the eight cathode electrode contacts is cut out from the same circular shape as the wafer.

FIG. 5A is a plan view showing the shape of the anode electrode of this wafer plating apparatus. FIG. 5 (b) shows
It is a top view which shows the position of the cathode electrode contact provided on the wafer.

The outer peripheral diameter size of the anode electrode 30 and the wafer 32 are the same, and the broken line 16 in FIG. 5A extended from the outer shape of the anode electrode 30 shows the outer shape of the opposing wafer 32. In addition, the wafer 32 is shown in FIG.
As shown in FIG. 5, the cathode electrode contacts 12 are arranged at eight points on the peripheral portion of the wafer 32 at substantially equal intervals. Figure 5
The arrow 18 in (a) indicates the position facing and corresponding to the cathode electrode contact 12 on the wafer 32. As described above, the shape of the anode electrode 30 is a shape obtained by cutting an inner region of a concentric circle centered on a position facing and facing the eight cathode electrode contacts from the same circular shape as the wafer.

In such a structure, the current path flowing from the anode electrode 30 through the plating solution to the vicinity of the cathode electrode contacts 12 existing at eight points around the wafer 32 is longer than that of the conventional one. That is, in the conventional example, the anode electrode 30 exists directly opposite the cathode electrode contact 12, but in the wafer plating apparatus of this embodiment, the anode electrode 30 is provided at a position away from the cathode electrode contact 12 directly. The current path becomes longer. On the other hand, the current path flowing from the anode electrode 30 through the plating solution on the surface of the wafer 32 away from the eight cathode contact points 12 is almost unchanged from the conventional one.

As a result, the electric resistance of the current path flowing from the anode electrode 30 to the vicinity of the cathode electrode contact 12,
It flows from the anode electrode 30 onto the surface of the wafer 2 that is not near the cathode electrode contact 12, and from there, the cathode electrode contact 12
The difference from the electric resistance of the current path flowing in the direction becomes small.

Therefore, as described above, this third
According to the wafer plating apparatus of the above embodiment, it is possible to make the plating current density uniform within the wafer surface and reduce variations in plating thickness. Further, since the third embodiment has more cathode electrode contacts than the first and second embodiments, it has an effect of further relaxing and dispersing current concentration near the cathode electrode contacts. is doing.

Next, a wafer plating apparatus according to the fourth embodiment will be described. This wafer plating apparatus has three cathode electrode contacts on the wafer as in the case of the first embodiment, and further, the outer peripheral diameter size of the anode electrode is smaller than the outer peripheral diameter size of the wafer.

FIG. 6 is a plan view showing the shape of the anode electrode of this wafer plating apparatus. The position of the wafer and the contact of the cathode electrode provided on this wafer are shown in FIG.
Is the same as that shown in.

The outer peripheral diameter size of the anode electrode 40 is smaller than the outer peripheral diameter size of the wafer 2, and the broken line 16 in FIG. 6 drawn on the outer side of the anode electrode 40 indicates the outer periphery of the wafer 2 which faces the anode electrode 40. Further, on the wafer 2, as shown in FIG. 3B, the cathode electrode contacts 12 are arranged at three points on the periphery of the wafer 2 at substantially equal intervals. Arrow 1 in FIG.
Reference numeral 8 indicates a position facing the cathode electrode contact 12 on the wafer 2 and corresponding thereto. As described above, the shape of the anode electrode 40 is such that the inner region of a concentric circle centered on the corresponding position facing the three cathode electrode contacts,
It has a shape cut out from a circular shape smaller than the wafer 2.

In such a structure, the current path flowing from the anode electrode 40 through the plating solution to the vicinity of the cathode electrode contacts 12 existing at three points around the wafer 2 is longer than that of the conventional example described above. That is, in the conventional example, the anode electrode exists directly opposite the cathode electrode contact 12, but in the wafer plating apparatus of this embodiment, the anode electrode 40 is provided at a position away from the cathode electrode contact 12 directly, so that the current The route becomes longer. On the other hand, the current path flowing from the anode electrode 40 through the plating solution on the surface of the wafer 2 away from the three cathode electrode contacts 12 is almost unchanged from the conventional one.

As a result, the electric resistance of the current path flowing from the anode electrode 40 to the vicinity of the cathode electrode contact 12,
It flows from the anode electrode 40 onto the surface of the wafer 2 which is not in the vicinity of the cathode electrode contact 12, and from there, the cathode electrode contact 12
The difference from the electric resistance of the current path flowing in the direction becomes small.

Therefore, as described above, this fourth
According to the wafer plating apparatus of the embodiment of, it is possible to make the plating current density more uniform in the wafer surface,
Variations in plating thickness can be reduced.

In addition, in the first embodiment, since a part of the peripheral portion of the anode electrode and the peripheral portion of the wafer are arranged in parallel and directly opposite to each other, the current density is increased in the peripheral portion due to the current sneak in the peripheral portion. Existed. However, in the fourth embodiment, the shape of the anode electrode 40 is a shape obtained by cutting an inner region of a concentric circle centered on a position facing the cathode electrode contact 12 from a circular shape smaller than the outer circumference of the wafer. , And has an effect of alleviating and dispersing current concentration in the peripheral portion of the wafer and in the vicinity of the contact of the cathode electrode.

Next, a wafer plating apparatus of the fifth embodiment will be described. In this wafer plating apparatus, the anode electrode has a circular shape equivalent to that of a wafer, and a current-shielding mask plate made of an insulator for shielding current is provided in front of the anode electrode. This is the same as the first embodiment.

FIG. 7 is a diagram showing the structure of the wafer plating apparatus according to the fifth embodiment. As shown in FIG. 7, the anode electrode 50 between the anode electrode 50 and the wafer 52 is
In front of the current shield mask plate 54 made of an insulator and pressed against the anode electrode 50 to shield the current.
Is provided. Other configurations are similar to those of the above-described first embodiment, and therefore description thereof will be omitted.

FIG. 8A is a plan view showing the shape of the current shielding mask plate 54 of the wafer plating apparatus.
FIG. 8B is a plan view showing the position of the wafer and the cathode electrode contact provided on the wafer from the front side of the wafer.

On the wafer 52, as shown in FIG. 8B, the cathode electrode contacts 12 are arranged at three points on the periphery of the wafer 52 at substantially equal intervals. Arrow 1 in FIG. 8 (a)
Reference numeral 8 indicates a position on the wafer 52 which faces and corresponds to the cathode electrode contact 12. The opening 56 of the current shielding mask plate 54 has an inner region of a concentric circle centered on the position indicated by the arrow 18 as shown in FIG. 8A with respect to a circular opening equivalent to the wafer 52. It has a protruding shape. That is, the current shielding mask plate 54 is provided with the opening 56 having the same shape as the anode electrode 8 shown in FIG.

In such a structure, the current path flowing from the anode electrode 50 through the plating solution 6 to the vicinity of the cathode electrode contacts 12 existing at three points on the periphery of the wafer 52 is more than that of the conventional one. become longer. That is, in the conventional example, the anode electrode 50 is present directly opposite the cathode electrode contact 12, but in the wafer plating apparatus of this embodiment, the anode electrode 50 is provided at a position away from the cathode electrode contact 12 directly. The current path becomes longer. On the other hand, the current path flowing from the anode electrode 50 through the plating solution 6 on the surface of the wafer 52 away from the three cathode electrode contacts 12 is almost unchanged from the conventional one.

As a result, the electric resistance of the current path flowing from the anode electrode 50 to the vicinity of the cathode electrode contact 12,
It flows from the anode electrode 50 onto the surface of the wafer 52 which is not in the vicinity of the cathode electrode contact 12, and from there, the cathode electrode contact 1
The difference from the electric resistance of the current path flowing in 2 becomes small.

Therefore, as described above, this fifth
According to the wafer plating apparatus of the embodiment, by pressing the current shielding mask plate in front of the anode electrode,
This is the same as the presence of the anode electrode as shown in FIG. 3, so that the plating current density can be made uniform within the wafer surface, and the variation in the plating thickness can be reduced.

Further, as compared with the first embodiment, it is not necessary to process the anode electrode itself into a desired shape, and a current shielding mask may be prepared. Therefore, the anode electrodes of various shapes can be formed. It's easy. In addition, in the fifth embodiment, the current shielding mask plate having the opening having the same shape as that of the anode electrode shown in FIG. 3 is used, but the present invention is not limited to this, and FIGS. A current-shielding mask plate having an opening having the same shape as the anode electrode shown in FIG. 6 may be used.

Next, a wetting apparatus of the sixth embodiment will be described. FIG. 9 is a diagram showing the configuration of a wafer plating apparatus according to the sixth embodiment of the present invention. Figure 9
As shown in FIG. 3, the wafer 60 on which the integrated circuit is formed is supported horizontally around the wafer 60 and installed horizontally. This wafer 6
0, a plating electrode metal layer (barrier metal) for the cathode electrode is formed on the entire surface, and a resist pattern in which a portion for forming a protruding electrode is opened is formed on the plating electrode metal layer. .

An anode electrode 62 is provided on the lower side facing the wafer 60 in parallel. A current-shielding mask plate 64 made of an insulator and pressed against the anode electrode 62 is provided on the anode electrode 62 to shield the current.

The anode electrode 62 has a power source 66.
Is connected to the positive electrode side of. Further, a cathode electrode contact is provided around the wafer 60, and the cathode electrode contact connects the negative electrode side of the power source 66 and the plated electrode metal layer on the wafer 60. The temperature and the like of the plating solution 68 in the wafer plating apparatus are adjusted by a circulation pump 70, and the plating solution tank 68a and the plating solution preliminary tank 6 are provided.
8b and 8b.

FIG. 10A is a plan view showing the shape of the anode electrode of this wafer plating apparatus. The positions of the wafer 60 and the cathode electrode contact provided on the wafer 60 are the same as those shown in FIG. 3B.

The anode electrode 62 has a circular shape larger than that of the wafer 60, and the broken line 16 in FIG. 10A drawn inside the anode electrode 62 indicates the outer periphery of the opposing wafer 60. . In addition, the wafer 60 is shown in FIG.
As shown in (b), the cathode electrode contacts 12 are arranged at three points around the wafer at substantially equal intervals. Figure 10
An arrow 18 in (a) indicates a position facing and corresponding to the cathode electrode contact 12 on the wafer 60. Further, the anode electrode 62 has six holes 72 through which the plating solution passes. The shape of the arrangement of the holes 72 may be other shapes.

FIG. 10B is a plan view showing the shape of the current shielding mask plate 64 of the wafer plating apparatus. The wafer 60 has a cathode electrode contact.
They are arranged at three points on the periphery of 0 at substantially equal intervals. Figure 1
An arrow 18 in 0 (b) indicates a position facing and corresponding to the cathode electrode contact on the wafer 60. The opening 74 of the current shielding mask plate 64 is shown in FIG.
As shown in FIG. 5, the inner region of a concentric circle centered on the position indicated by the arrow 18 is projected into the circular opening equivalent to the wafer 60. That is, the current shielding mask plate 64 is the same as the anode electrode 8 shown in FIG.
It has an opening 74 of the same shape as. In addition, this 6th
In the above embodiment, the example in which the anode electrode 62 is larger than the wafer 60 is shown, but it may be the same size as the wafer 60 or smaller than the wafer 60.

The operation of the wafer plating apparatus of the sixth embodiment will be described next. In the wafer plating apparatus configured as described above, the plating liquid 68 is supplied to the circulation pump 70.
The temperature and the like are adjusted by the method, and the wafer is circulated in the wafer plating apparatus. That is, the plating solution 68 delivered by the circulation pump 70 becomes a jet from the lower part of the plating solution tank 68a and flows into the plating growth surface side of the wafer 60. The plating solution 68 that has flowed in overflows from the upper portion of the plating solution tank 68a, flows into the plating solution preliminary tank 68b, and is stored therein. The plating solution 68 stored in the plating solution reserve tank 68b
From the bottom through the circulation pump 70 to the plating liquid tank 68.
It is sent to the lower part of a and supplied again between the anode electrode 62 and the wafer 60.

In the plating solution tank 68a, a current flows from the anode electrode 62 to the plating electrode metal layer, which is the cathode electrode, in the plating solution 68, so that the desired position of the wafer 60, that is, the plating electrode is obtained. A metal such as solder grows as electrolytic plating on the portion of the metal layer where the protruding electrode is formed.

As described above, according to the wafer plating apparatus of the sixth embodiment, the anode electrode as shown in FIG. 3 is formed by pressing the current shielding mask plate against the front portion of the anode electrode. As is the case with the above, the plating current density can be made uniform within the wafer surface, and the variation in the plating thickness can be reduced.

Further, as compared with the first embodiment, the shape itself of the anode electrode does not need to be processed into a desired shape, and a current shielding mask for shielding an electric current may be prepared. It is easy to form an anode electrode having a uniform shape. Although the current shield mask plate corresponding to the anode electrode shown in FIG. 3 is used in the sixth embodiment, the present invention is not limited to this, and the anode shown in FIGS. 4, 5 and 6 is used. A current shielding mask plate corresponding to the electrodes may be used.

[0064]

As described above, according to the present invention, it is possible to provide a wafer plating apparatus capable of uniformly forming metal projection electrodes used for flip chip connection or the like on a wafer.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a wafer plating apparatus according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a positional relationship between a wafer, which is a cathode electrode, and an anode electrode arranged in the wafer plating apparatus.

FIG. 3 shows the shape of the anode electrode of the wafer plating apparatus,
FIG. 3 is a plan view showing the positions of cathode electrode contacts provided on the wafer.

FIG. 4 is a plan view showing a shape of an anode electrode and a position of a cathode electrode contact provided on a wafer of a wafer plating apparatus according to a second embodiment.

FIG. 5 is a plan view showing a shape of an anode electrode and a position of a cathode electrode contact provided on a wafer of a wafer plating apparatus according to a third embodiment.

FIG. 6 is a plan view showing the shape of an anode electrode of a wafer plating apparatus according to a fourth embodiment.

FIG. 7 is a diagram showing a configuration of a wafer plating apparatus according to a fifth embodiment.

FIG. 8 is a plan view showing the shape of a current-shielding mask plate of a wafer plating apparatus according to a fifth embodiment and the positions of cathode electrode contacts provided on the wafer.

FIG. 9 is a diagram showing a configuration of a wafer plating apparatus according to a sixth embodiment.

FIG. 10 is a plan view showing a shape of an anode electrode and a shape of a current shielding mask plate of a wafer plating apparatus according to a sixth embodiment.

FIG. 11 is a cross-sectional view showing a structure of a wafer plating apparatus as a conventional example.

FIG. 12 is a plan view showing a shape of an anode electrode of the wafer plating apparatus and a position of a cathode electrode contact provided on the wafer.

[Explanation of symbols]

2 wafers 4 Wafer jig 6,68 plating solution 6a, 68a plating bath 6b, 68b Plating solution spare tank 8 Anode electrode 10, 66 power supply 12 Cathode electrode contact 14,70 Circulation pump 16 dashed line 18 arrows 20, 30, 40, 50, 62 Anode electrode 22, 32, 52, 60 wafers 54, 64 Mask plate for current shielding 56,74 opening 72 holes

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 21/60 C25D 7/12 C25D 17/12 H01L 21/288

Claims (9)

(57) [Claims] 1. A first electrode having an electrode contact connected to an electrode film formed on a wafer and a first power supply serving as a power supply for the electrode contact; and a first electrode having a predetermined interval. It is disposed so as to face, in the neighborhood opposed to the electrode contact and the electrode contact
The distance between them is larger than the predetermined distance and the electrode contact is
The shortest distance between the point and the adjacent part facing this electrode contact
Have the same outer shape and are connected to a second power source.
A wafer plating apparatus, comprising: 2. The second electrode according to claim 1, wherein the second electrode has a shape that is deleted in a concentric shape around a point on the second electrode facing the electrode contact. Wafer plating equipment. 3. The second electrode has a shape obtained by cutting out a circular shape equivalent to the first electrode from a circular shape centered on a point facing the electrode contact. The wafer plating apparatus described in 1. 4. The second electrode has a shape obtained by cutting a circular shape smaller than the first electrode from a circular shape centered on a point facing the electrode contact. The described wafer plating apparatus. 5. A first electrode having an electrode film formed on a wafer and an electrode contact connecting the electrode film to a first power supply; and a first electrode provided so as to face the first electrode. a second electrode connected to a second power source, an insulating member for shielding the electric current, the electric and the electrode contact
The distance from the vicinity facing the pole contact is
Large and facing the electrode contact and this electrode contact
A wafer plating device, comprising: an opening shape having an equal shortest distance to a neighboring portion, and a current shield means pressed against the second electrode. 6. The wafer plating apparatus according to claim 5, wherein the current shielding means has an opening shape that is removed in a concentric circle shape centered on a point facing the electrode contact. 7. The current shield means has an opening formed by cutting out a circular shape centered around a point facing the electrode contact from a circular shape equivalent to the first electrode. Item 5. The wafer plating apparatus according to Item 5. 8. A metal layer as a first electrode on a wafer
And a part for forming a bump electrode on the metal layer on the wafer.
A step of forming a resist pattern having an opening, and disposing an electrode contact of the first electrode on the peripheral portion of the wafer.
Of placing the wafer in a plating solution, as described above
And a circle centered on the point facing the electrode contact of the first electrode
The second electrode having a shape obtained by cutting the shape is
Placing the plating solution in the plating solution so as to face the wafer.
And a wafer plating method comprising: 9. The first electrode is a cathode electrode,
The second electrode is an anode electrode
The wafer plating method according to claim 8 .