JPH09219404A - Method of forming bump electrode - Google Patents

Abstract

The present invention relates to a bump electrode forming method using an electric field plating method, and an object thereof is to make the heights of bump electrodes formed by the electric field plating method uniform. SOLUTION: A silicon wafer 1 on which a bump electrode is formed is dipped in a plating treatment cup 21 loaded with a plating solution 25, and the plating solution 25 is jetted from a jet nozzle 22 to the center of the silicon wafer 1 and a plating treatment cup is formed. 21
In the method of forming bump electrodes in which a bump electrode is formed on the silicon wafer 1 by the electric field plating method by applying an electric field by the anode electrode 23 disposed inside, a surface different from the bump electrode formation surface of the silicon wafer 1 is The silicon wafer 1 is immersed in a position deeper than the liquid surface of the plating solution 25 while maintaining the state where it does not come into contact with the plating solution 25, and electric field plating is performed in a state where the electric field wraps around the peripheral portion of the silicon wafer 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bump electrode forming method, and more particularly to a bump electrode forming method using an electroplating method. In recent years, as the density of semiconductor chips has increased, the number of electrodes included in the semiconductor chips has tended to increase. Further, there is a demand for miniaturization of semiconductor chips, and it is necessary to efficiently arrange a large number of electrodes on a narrow chip. A bump electrode is known as an electrode capable of coping with higher density and smaller size of this semiconductor device.

Various forming methods have been proposed as a method for forming the bump electrodes, and as one of them, a forming method for the bump electrodes using an electric field plating method is known. In the method of forming bump electrodes by using the electric field plating method, the bump electrodes can be collectively formed on the plurality of semiconductor chips formed on the wafer, so that the bump forming efficiency can be improved.

By the way, in a semiconductor chip in which bumps are formed and mounted by the electroplating method, the yield due to the variation in the bump height is poor, and it is required to reduce the variation in the bump height. Therefore, it is desired to improve the yield by reducing variations in bump height by improving the electric field plating method for forming bumps.

[0004]

2. Description of the Related Art Conventionally, plating electrodes 3 and 4 shown in FIG. 5 or 6 have been used to form bump electrodes on a substrate (silicon wafer) 1 shown in FIG.
First, the configuration of the silicon wafer 1 before the plating process is performed will be described. The silicon wafer 1 is shown in FIG.
As shown in FIG. 3, the semiconductor device has a chip forming region 6 in which a plurality of semiconductor chips 5 are formed, and the chip forming region 6
A plurality of plating current supply portions 7 to which a plating current is supplied at the time of electric field plating are formed at predetermined positions on the outer peripheral portion of the.

Further, as shown enlarged in FIG.
Bump forming electrodes 8 are formed on each semiconductor chip 5 formed in the chip forming region 6. The bump forming electrodes 8 are electrically connected to the plating current supply unit 7 described above. The silicon wafer 1 having the above-described configuration is used in the plating processing apparatus 3 shown in FIG. 5 or 6.
4 and bump electrodes are formed on the bump forming electrodes 8.

The plating apparatus 3 shown in FIG. 5 is a cup-type jet type plating apparatus, and a plating solution 10 (shown in satin) is filled inside a bottomed cylindrical (cup-shaped) plating cup 9. It has been configured. The silicon wafer 1 is mounted on the upper end of the plating cup 9.

Further, a jet nozzle 11 is provided at the center of the bottom surface of the plating cup 9, and the plating solution 10 is jetted from the jet nozzle 11 into the plating cup 9 (plating solution). The flow of 10 is shown in FIG. 5 by a dashed arrow). In addition, the excess plating solution 10
Flows out from the upper portion of the plating cup 9. Furthermore, at a position near the bottom surface of the plating cup 9, the anode electrode 1 is placed so as to face the mounted silicon wafer 1.
2 are provided.

In the plating apparatus 3 having the above structure, when the bump electrodes are to be formed by electrolytic plating, the silicon wafer 1 is first mounted in the upper opening of the plating cup 9. At this time, in the conventional plating apparatus 3, the diameter dimension in the upper opening of the plating cup 9 is set to a dimension sufficient to mount the silicon wafer 1.

When the silicon wafer 1 is mounted on the plating cup 9 as described above, the plating current supply unit 7 and the anode electrode 12 are connected to the current supply device, and an electric field is formed between the silicon wafer 1 and the anode electrode 12. (The state of the electric field formed between the silicon wafer 1 and the anode electrode 12 is shown by a solid line arrow in FIG. 5). This allows
The metal ions to be the bump electrodes in the plating solution 10 are deposited on the bump forming electrodes 8 to form the bump electrodes.

On the other hand, the plating processing apparatus 4 shown in FIG. 6 is a rack type plating processing apparatus. This rack type plating apparatus 4 has a plating solution 1 inside the plating tank 13.
Silicon wafer 1 filled with 0 (shown in satin)
Is immersed in the plating tank 13 while being mounted on the rack 14. As described above, by immersing the silicon wafer 1 in the plating bath 13 using the rack 14, the silicon wafer 1 is immersed at a position deeper than the liquid surface of the plating solution 10.

Further, the anode electrode 1 is placed in the plating tank 13.
5 are arranged, and the anode electrode 15 is the rack 1
4 is mounted at a predetermined position in the plating tank 13, the silicon wafer 1 mounted on the rack 14 is opposed to the silicon wafer 1. When the silicon wafer 1 mounted on the rack 14 as described above is immersed in the plating tank 13, the plating current supply unit 7 and the anode electrode 15 are connected to the current supply device, and the silicon wafer 1 and the anode electrode 1 are connected.
An electric field is formed between the silicon wafer 1 and the
The state of the electric field formed between the anode electrode 15 and the anode electrode 15 is indicated by a solid arrow). As a result, the metal ions serving as bump electrodes in the plating solution 10 are deposited on the bump forming electrodes 8 to form bump electrodes.

[0012]

Here, the experimental results of measuring the height of the bump electrodes formed by using the above-described plating treatment devices 3 and 4 are shown in FIGS. 7 and 8.
The experiment result shown in FIG. 7 shows the height of the bump electrode formed by the cup-type jet plating device 3, and the experiment result shown in FIG. 8 shows the bump electrode formed by the rack-type plating device 4. Shows the height of.

In each drawing, the horizontal axis corresponds to the position from Top to Bottom of the silicon wafer 1 shown in FIG. 1 (A), and the vertical axis shows the height of the formed bump electrode. Further, since a plurality of bump electrodes are formed at each position, the arrow A in each drawing indicates the highest bump electrode height (Max) at that position, and the arrow B indicates the lowest bump electrode. The height (Min) of the bump electrode is indicated by the arrow C, and the average height (Avg) of the bump electrode at that position
Further, the arrow D indicates the difference (Ma) between the highest bump electrode height (Max) and the lowest bump electrode height (Min).
x-Min) is shown.

First, paying attention to the height of the bump electrodes formed by the cup-type jet type plating apparatus 3 shown in FIG. 7, the cup-type jet type plating apparatus 3 is used.
It can be seen that the bump electrode formed by the method has a high bump electrode in the central position of the silicon wafer 1 and a low bump electrode in the peripheral portion.

Further, paying attention to the height of the bump electrode formed by the rack type plating apparatus 4 shown in FIG. 8, the bump electrode formed by the rack type plating apparatus 4 is located at the central position of the silicon wafer 1. It can be seen that the height of the bump electrode is low and the height of the bump electrode is high in the peripheral portion.

Therefore, as is apparent from the experimental results shown in FIGS. 7 and 8, in the conventional plating apparatuses 3 and 4,
There is a problem that bump electrodes having a uniform height cannot be formed on the entire surface of the silicon wafer 1. In this way, when the height of the bump electrode is different between the central portion and the peripheral portion of the silicon wafer 1, a large number of semiconductor chips 5 having different bump heights from the predetermined bumps are manufactured.
The number of non-defective semiconductor chips 5 manufactured from one silicon wafer 1 decreases, and the manufacturing yield decreases.

The present invention has been made in view of the above points, and it is an object of the present invention to provide a bump electrode forming method capable of making the heights of bump electrodes formed by the electroplating method uniform. .

[0018]

The above objects can be attained by taking the following means. Claim 1
In the invention described, the substrate for forming the bump electrode is immersed in a plating treatment tank loaded with a plating solution, the plating solution is jetted to the center of the substrate, and an anode disposed in the plating treatment tank is used. In a method of forming a bump electrode by applying an electric field to form a bump electrode on the substrate using an electric field plating method, while maintaining a state in which a surface different from a bump electrode formation surface of the substrate does not come into contact with the plating solution, It is characterized in that the substrate is immersed in a position deeper than the liquid surface of the plating solution, and the electric field plating is performed in a state where the electric field wraps around the peripheral portion of the substrate.

Further, the invention according to claim 2 is characterized in that, in the bump electrode forming method according to claim 1, a cup-type jet type plating treatment tank is used as the plating treatment tank. .

According to a third aspect of the present invention, in the bump electrode forming method according to the first or second aspect, the plating treatment is performed with the substrate on which the bump electrodes are formed being inclined at an angle of 30 degrees or less with respect to the horizontal. It is characterized by being immersed in a bath.

Further, in the invention according to claim 4, in the method for forming a bump electrode according to any one of claims 1 to 3, the substrate is dipped by 3 mm or more from the liquid surface of the plating solution. To do.

Each of the above means operates as follows. According to the invention of claim 1, in a method of forming a bump electrode in which a plating solution is jetted to the center of a substrate on which a bump electrode is formed, a state in which a surface of the substrate different from the bump electrode formation surface is not in contact with the plating solution is maintained. Meanwhile, the height of the bump electrodes to be formed can be made uniform by immersing the substrate in a position deeper than the liquid surface of the plating solution and performing the electric field plating in a state where the electric field wraps around the peripheral portion of the substrate.

The reason for this will be described below. First, focusing on FIG. 5, the reason why the bump electrode formed in the cup-type jet plating apparatus 3 is high in the center will be considered. In the cup-type jet-type plating apparatus 3, as shown in FIG. 5, a new plating solution flows into the plating cup 9 from the jet nozzle 11. The new plating solution that has flowed into the plating cup 9 hits the central portion of the mounted silicon wafer 1 as shown by the broken line in the figure, and then forms a flow path that flows toward the peripheral portion of the silicon wafer 1. .

Therefore, in the cup-type jet-type plating apparatus 3, a new plating solution containing a large amount of metal ions serving as bump electrodes is intensively jetted to the central portion of the silicon wafer 1 to cause the silicon wafer 1 It is estimated that a high bump electrode is formed in the central portion.

On the other hand, in the rack type plating apparatus 4, since the jet nozzle 11 is not provided, the above phenomenon does not occur. Next, paying attention to FIG. 6, the reason why the bump electrode formed in the rack type plating apparatus 4 becomes high in the peripheral portion will be considered.

The rack type plating apparatus 4 is shown in FIG.
By using the rack 14 as shown in FIG. 1, the bump electrode forming process (electrolytic plating process) is performed while the silicon wafer 1 is deeply immersed in the plating bath 13. At this time, paying attention to the electric field formed between the silicon wafer 1 and the anode electrode 15, since the silicon wafer 1 is deeply immersed in the plating bath 13, the electric field sneaking around in the peripheral portion of the silicon wafer 1 (see FIG. In the figure, reference numeral 16 indicates a wraparound electric field), which acts on the electric field plating.

Therefore, the rack type plating apparatus 4
Then, due to this wraparound electric field 16, a strong electric field acts on the peripheral portion of the silicon wafer 1 with respect to the central portion. The electric field plating increases the amount of metal deposited as the electric field is stronger. Therefore, in the rack type plating apparatus 4, it is estimated that high bump electrodes are formed in the peripheral portion of the silicon wafer 1.

On the other hand, in the cup-type jet type plating apparatus 3, the silicon wafer 1 is not immersed in the plating solution 10 but is electroplated while being placed on the plating cup 9. The sneak electric field does not act on the silicon wafer 1.

Next, the operation of the bump electrode forming method according to the first aspect will be considered based on the matters described above. In the bump electrode forming method according to the present invention, since the plating solution is jetted to the center of the substrate on which the bump electrode is formed,
Similar to the cup-type jet type plating apparatus 3, the height of the bump electrode formed in the central portion of the substrate becomes high.

Further, in the bump electrode forming method according to the present invention, the electric field plating is carried out in a state where the electric field wraps around the periphery of the substrate by immersing the substrate in a position deeper than the liquid surface of the plating solution. Therefore, similar to the rack type plating apparatus 4, the height of the bump electrode formed on the peripheral portion of the substrate becomes high.

Therefore, at the central position of the substrate, the height of the bump electrode is increased due to the jetting of the plating solution.
In addition, since the height of the bump electrode increases at the peripheral position of the substrate due to the electric field, the height of the bump electrode can be made uniform over the entire substrate.

According to the second aspect of the present invention, the cup-type jet type plating treatment tank is used as the plating treatment tank, so that a uniform height can be obtained without largely changing the conventional electric field plating equipment. It becomes possible to form bump electrodes.

According to the third aspect of the present invention, the substrate on which the bump electrode is formed is immersed in the plating bath while being inclined by 30 degrees or less with respect to the horizontal. Even if bubbles are generated in the cathode, the generated bubbles are guided by the inclined substrate and are removed from the substrate. Therefore, it is possible to prevent the plating failure from occurring due to the bubbles, and it is possible to perform high-quality plating processing.

According to the fourth aspect of the invention, the bump electrodes having a uniform height can be stably formed by appropriately setting the conditions of the plating apparatus.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration diagram showing a plating processing apparatus 20 used in a bump electrode forming method according to an embodiment of the present invention. The plating processing apparatus 20 shown in the figure has an improved configuration of the cup-type jet type plating processing apparatus 3 shown in FIG. 5. In general, the plating processing cup 21, the jet nozzle 22, and the anode are plating processing tanks. It is composed of an electrode 23, a wafer jig 24 and the like.

Further, the plating processing apparatus 20 according to this embodiment
Is to form bump electrodes on the 6-in silicon wafer 1 having the structure shown in FIG. The silicon wafer 1
Since the configuration has already been described with reference to FIG. 4, description thereof will be omitted here. The plating cup 21 has a bottomed cylindrical shape (cup shape), and its inner diameter is, for example, φ250 mm. Therefore, the plating cup 21
The inner diameter of is larger than that of the conventional cup-type jet type plating apparatus 3 shown in FIG.

A plating solution 25 (shown in satin) is loaded in the plating cup 21. In this embodiment,
Since the deposited metal to be the bump electrode is solder, a sulfonic acid-based Pb-Sn plating solution is used as the plating solution 25. In addition, a jet nozzle 22 is provided at the center of the bottom surface of the plating cup 21, and a new plating solution 25 is jetted from the jet nozzle 22 into the plating cup 21 (of the plating solution 25). The flow is shown in Figure 1 by the dashed arrows). In this embodiment, the flow rate of the plating solution 25 jetted from the jet nozzle 22 is 18 liters / min.

The jet nozzle 22 is connected to a plating solution supply device, and the plating solution 25 is supplied to the jet nozzle 22 from the plating solution supply device. However, this plating solution supply device is also provided in the conventional cup-type jet type plating processing device 3.

Therefore, the plating treatment apparatus 20 according to this embodiment can be incorporated into the plating treatment equipment without largely changing the equipment for the plating treatment including the plating solution supply device which has been used conventionally. The jet nozzle 2
The excess plating solution 25 due to the introduction of the new plating solution 25 from 2 flows out from the upper portion of the plating cup 21.

An anode electrode 23 is arranged near the bottom surface of the plating cup 21 so as to face the mounted silicon wafer 1. This anode electrode 23 has a size of φ150 mm and is made of titanium (T
The mesh of i) is plated with platinum (Pt). In the present embodiment, the anode electrode 23 is attached so as to be horizontal in the plating cup 21.

On the other hand, the wafer jig 24 is the silicon wafer 1
And has a function of immersing the mounted silicon wafer 1 in the plating solution 25 loaded in the plating processing cup 21. The wafer jig 24 has a cylindrical shape, and a supporting portion 26 for supporting the silicon wafer 1 is formed at the lower end portion. This wafer jig 24
Is configured so that it can be moved up and down substantially in the center of the plating cup 21.

The support portion 26 provided on the wafer jig 24 engages with and supports the outer peripheral portion of the silicon wafer 1, and the silicon wafer 1 is immersed in the plating solution 25. 25 is configured so as not to go around to the back surface side of the silicon wafer 1.

Further, the silicon wafer 1 is attached to the wafer jig 24 so that the bump electrode forming surface faces the plating cup 21, and in this embodiment, the silicon wafer 1 is placed horizontally on the wafer jig 24. It is installed. Next, a method of forming bump electrodes using the plating processing apparatus 20 having the above configuration will be described.

In order to form bump electrodes using the plating apparatus 20, first, the silicon wafer 1 is placed on the wafer jig 24.
Attach to Subsequently, the wafer jig 24 is moved toward the plating processing cup 21, and the silicon wafer 1 is immersed in the plating solution 25 loaded in the plating processing cup 21. FIG. 1 shows a state in which the silicon wafer 1 is immersed in the plating solution 25.

As is clear from the figure, the inner diameter of the plating cup 21 is 250 mm and the silicon wafer 1
Has a diameter of 6 inches, so the silicon wafer 1
Is completely submerged in the plating solution 25. That is,
The position of the silicon wafer 1 is located below the surface of the plating solution 25 by a predetermined amount (hereinafter, this amount is referred to as a depth amount, which is indicated by an arrow h in FIG. 1).

However, even if the silicon wafer 1 is positioned below the water surface of the plating solution 25 as described above, the plating solution 25 does not go around to the back surface of the silicon wafer 1 by the wafer jig 24. Therefore, it is not necessary to wash the back surface of the silicon wafer 1 with the plating solution 25 after the bump electrodes are formed, and since plating is not deposited on the back surface, the bump electrode forming process can be simplified. it can.

When the silicon wafer 1 is dipped in the plating solution 25 as described above, the plating current supply unit 7 and the anode electrode 23 are subsequently connected to the current supply device. This allows
An electric field is formed between the silicon wafer 1 and the anode electrode 23 (see the silicon wafer 1 and the anode electrode 23 in FIG. 1).
The state of the electric field formed between and is shown by the solid arrow).
As a result, the metal ions serving as bump electrodes in the plating solution 25 are deposited on the bump forming electrodes 8 to form bump electrodes.

Next, the operation of the above bump electrode forming method will be considered. In the bump electrode forming method according to the present embodiment, the plating solution 25 is jetted from the jet nozzle 22 to the center of the silicon wafer 1 on which the bump electrodes are formed. Therefore, the conventional cup-type jet type plating apparatus 3 (see FIG. 5) is used. The height of the bump electrode formed in the central portion of the silicon wafer 1 is increased similarly to the above.

In the method of forming bump electrodes according to this embodiment, the wafer jig 24 is used to immerse the silicon wafer 1 at a position deeper than the liquid surface of the plating solution 25, so that the plating current supply section 7 and the anode are formed. Of the electric field generated between the electrode 23 and the electrode 23, the wraparound electric field 27 formed in the peripheral portion of the silicon wafer 1 also acts on the electric field plating. Therefore,
Similar to the conventional rack type plating apparatus 4 (see FIG. 6), the height of the bump electrode formed in the peripheral portion of the silicon wafer 1 also becomes high.

Therefore, at the central position of the silicon wafer 1, the height of the bump electrode is increased by the jetting of the plating solution 25, and at the peripheral position of the silicon wafer 1, the wraparound electric field 27 acts and the bump electrode is applied. The height of the bump electrodes becomes high, which allows the bump electrodes to have a uniform height over the entire silicon wafer 1.

However, in the experiments conducted by the present inventor, it was found that the height of the bump electrode formed by using the forming method according to this embodiment is influenced by various conditions. The conditions are summarized below. (1) If the plating tank is not a cup-type jet type, it tends to deposit like the conventional rack type and the bump height cannot be made uniform. (2) When the inner diameter of the plating cup 21 exceeds three times the diameter of the silicon wafer 1, the precipitation tends to occur as in the conventional rack type, and the bump height cannot be made uniform. (3) When the depth h is less than 3 mm, the precipitation tends to occur as in the conventional cup-type jet type, and the bump height cannot be made uniform. (4) The spacing distance between the silicon wafer 1 and the anode electrode 23 (indicated by the arrow H in FIG. 1) is in the range of 10 to 150 mm, and good bump height uniformity can be realized. Further, in order to make the bump height uniform, it is necessary to arrange the silicon wafer 1 and the anode electrode 23 in parallel.

Therefore, by satisfying the above-mentioned conditions, bump electrodes having a uniform height can be formed over the entire silicon wafer 1. FIG. 2 is an experimental result of measuring the height of the bump electrode formed by using the bump electrode forming method according to the present embodiment. 7 and 8, the horizontal axis corresponds to the position from Top to Bottom of the silicon wafer 1 shown in FIG. 1 (A), and the vertical axis indicates the formed bump electrode. Shows the height.

Further, since a plurality of bump electrodes are formed at each position, the arrow A in the figure indicates the highest height (Max) of the bump electrode among the plurality of bumps formed at each position. The arrow B indicates the lowest bump electrode height (Min), the arrow C indicates the average bump electrode height (Avg) at that position, and the arrow D indicates Indicates the difference (Max-Min) between the highest bump electrode height (Max) and the lowest bump electrode height (Min).

As is apparent from the figure, by forming the bump electrodes by using the bump electrode forming method according to this embodiment, the heights of the bump electrodes are made uniform over the entire surface of the silicon wafer 1. I understand. Therefore, it is proved from the figure that the height of the bump electrodes formed can be made uniform by using the bump electrode forming method according to the present embodiment. As described above, since the bump electrode height can be made uniform by using the bump electrode forming method according to the present embodiment, the yield of the semiconductor chips 5 on which the bump electrodes are formed can be improved.

FIG. 3 shows another embodiment of the plating apparatus using the bump electrode forming method according to this embodiment.
In the figure, the components corresponding to those of the plating apparatus 20 shown in FIG. 1 are designated by the same reference numerals and the description thereof will be omitted. The plating apparatus 30 shown in the figure is configured such that the silicon wafer 1 is tilted so that the angle α with respect to the horizontal is 30 degrees or less, and can be immersed in the plating solution 25 in the plating cup 21 in this tilted state. It is a feature.

This structure can be easily realized by the structure that the silicon wafer 1 is supported by the wafer jig 24 in a state of being tilted by 30 degrees or less with respect to the horizontal. Further, in order to satisfy the above condition (4), the anode electrode 23 is also tilted with respect to the horizontal, and the silicon wafer 1
It is configured to be parallel to.

By tilting the silicon wafer 1 as described above, the bubbles 31 generated from the cathode (which may be generated from the anode) during the electroplating are likely to escape along the surface of the silicon wafer 1, and therefore, during the formation. It is possible to prevent the air bubbles 31 from adhering to the bump electrodes. If this bubble 31 adheres to the bump electrode in the process of forming, so-called plating chipping occurs, and it becomes impossible to form a uniform bump electrode (the bump electrode where the plating chipping occurs becomes lower than the normal bump electrode).

However, as described above, the silicon wafer 1
By tilting, it is possible to suppress the occurrence of plating chipping and to form uniform bump electrodes. Also,
The inclination angle of the silicon wafer 1 is set to 30 degrees or less for the following reason. That is, the tilt angle of the silicon wafer 1 is 3
When it exceeds 0 degrees, the jetting plating solution 25 does not uniformly hit the silicon wafer 1, and thus it becomes impossible to form bump electrodes having a uniform height. Therefore, the tilt angle of the silicon wafer 1 needs to be 30 degrees or less.

In the above embodiments, solder was used as the deposited metal for the bump electrodes. However, the method of forming bump electrodes according to this embodiment is not limited to the formation of solder bumps, and gold bumps may be formed. (Au), silver (Ag), copper (C
u), indium (In), bismuth (Bi), tin (S
It can also be applied to various metals such as n) alloys and lead (Pb) alloys.

In the above-mentioned embodiment, the silicon wafer 1 is used as the substrate, but the method of the present invention can be applied to other semiconductor substrates or insulating substrates. Furthermore, the method of the present invention is not limited to the formation of bump electrodes, but can be widely applied to electrolytic plating in which the height (thickness) of deposited metal is desired to be uniform.

[0061]

As described above, according to the present invention, the following effects can be realized. According to the first and fourth aspects of the present invention, the heights of the bump electrodes formed can be made uniform, so that the yield can be improved.

According to the second aspect of the present invention, it is possible to form bump electrodes having a uniform height without largely changing the conventional electric field plating equipment. According to the third aspect of the invention, even if bubbles are generated in the substrate during the plating process, the generated bubbles are guided by the inclined substrate and eliminated from the substrate. Can be prevented and high quality plating can be performed.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a plating apparatus used in a bump electrode forming method according to an embodiment of the present invention.

FIG. 2 is a diagram showing a height of a bump electrode formed by using the bump electrode forming method according to the first embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the plating apparatus used in the method for forming bump electrodes, which is one embodiment of the present invention.

FIG. 4 is a diagram for explaining the structure of a silicon wafer on which bump electrodes are formed.

FIG. 5 is a configuration diagram showing a cup-type jet type plating apparatus used in a conventional bump electrode forming method.

FIG. 6 is a configuration diagram showing a rack type plating apparatus used in a conventional bump electrode forming method.

FIG. 7 is a diagram showing the height of bump electrodes formed by a cup-type jet type plating apparatus.

FIG. 8 is a diagram showing the height of bump electrodes formed by a rack type plating apparatus.

[Explanation of symbols]

 1 Silicon Wafer 5 Semiconductor Chip 6 Chip Forming Area 7 Plating Current Supply Section 8 Bump Forming Electrode 20 Plating Processing Equipment 21 Plating Processing Cup 22 Jet Nozzle 23 Anode Electrode 24 Wafer Jig 25 Plating Solution 26 Supporting Section

Claims (4)

[Claims] 1. A substrate on which a bump electrode is to be formed is immersed in a plating treatment tank filled with a plating solution, the plating solution is jetted to the center of the substrate, and an anode disposed in the plating treatment tank is used. In a method of forming a bump electrode by applying an electric field to form a bump electrode on the substrate using an electric field plating method, while maintaining a state in which a surface different from the bump electrode formation surface of the substrate does not come into contact with the plating solution, A method of forming a bump electrode, characterized in that the substrate is immersed in a position deeper than the liquid surface of the plating solution, and the electric field plating is performed in a state where the electric field wraps around the periphery of the substrate. 2. The bump electrode forming method according to claim 1, wherein a cup-type jet plating tank is used as the plating tank. 3. The method of forming a bump electrode according to claim 1, wherein the substrate on which the bump electrode is formed is immersed in the plating bath in a state of being inclined at an angle of 30 degrees or less with respect to the horizontal. Method of forming bump electrode. 4. The method for forming bump electrodes according to claim 1, wherein the substrate is dipped by 3 mm or more from the liquid surface of the plating solution.