JP3096296B1 - Electroplating equipment - Google Patents

Abstract

Kind Code: A1 An object to be plated having a conductive underlayer in various film formation states without troublesome work such as replacement of an auxiliary part of a processing tank such as an anode electrode and a shielding plate, and change of a mounting position. To provide an electrolytic plating apparatus capable of performing electrolytic plating with a uniform film thickness distribution. SOLUTION: A main anode 1 is provided in a plating tank 11.
3 and the sub-anode 14 are arranged.
3 and the sub-anode 14 are independently controlled by the current controller 16 and the current control conditions can be changed to a plurality.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrolytic plating apparatus used for performing an electrolytic plating wiring process on a surface of a semiconductor wafer, for example, in a semiconductor manufacturing process.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional electrolytic plating apparatus of this kind. In this figure, reference numeral 1 denotes a plating tank to which a plating solution (not shown) is supplied. At the bottom of the plating bath 1, a workpiece 2 to be plated such as a semiconductor wafer is arranged with the plating surface facing upward.
On the other hand, an anode electrode 3 is provided in the upper part of the plating bath 1, and a plating power source 4 is connected between the anode electrode 3 and the object 2 to be plated.

[0003] In the electrolytic plating apparatus configured as described above, a plating solution is supplied into the plating tank 1.
When the plating solution fills the surface of the workpiece 2 from the surface of the workpiece 2, a current flows between the anode electrode 3 and the workpiece 2 by the plating power supply 4, and the current flows to the processing surface of the workpiece 2. Electroplating is performed.

[0004]

However, in the conventional electroplating apparatus as described above, the electroplating process having a uniform film thickness distribution can be performed on the workpiece 2 having a conductive underlayer in various film formation states. Cannot be performed. More specifically, in the conventional electrolytic plating apparatus as described above, since the anode electrode is constituted by one, the anode electrode diameter and the interelectrode distance (the distance between the anode electrode 3 and the workpiece 3 to be plated) are once determined. When the distance is fixed, the condition of the electric field distribution on the object to be plated 2 cannot be largely changed at the time of plating, and if the electric field distribution condition is to be changed by any means, the apparatus is disassembled and the anode electrode 3 and a shielding not shown are not shown. It requires time-consuming operations such as replacing the processing tank auxiliary parts such as plates and changing their mounting positions.

On the other hand, a conductive underlayer is formed on the object to be plated 2 in a previous step.
The state of film formation (physical properties of film formation, film thickness distribution) may vary depending on the conditions, and this is one of the causes of non-uniformity of the electrolytic plating film thickness. Therefore, even if the above-mentioned electric field distribution is set so that electrolytic plating having a uniform film thickness distribution can be obtained for a workpiece to be plated having a conductive underlayer in a certain film formation state, the conductivity under another film formation state can be reduced. The electric field distribution is not appropriate for the object to be plated having the underlayer, and uniform electrolytic plating cannot be performed. Therefore, it is necessary to change the electric field distribution according to the film formation state of the conductive underlayer, but it is difficult to easily change the electric field distribution with the conventional electrolytic plating apparatus as described above. It was not possible to perform electrolytic plating with a uniform film thickness distribution on an object to be plated having a conductive underlayer in a film-formed state.

[0006] The present invention has been made in view of the above points,
The electric field distribution on the object to be plated can be changed arbitrarily without troublesome work such as replacement of the auxiliary parts of the processing tank such as the anode electrode and shield plate and change of the mounting position. It is an object of the present invention to provide an electrolytic plating apparatus capable of performing electrolytic plating with a uniform film thickness distribution on an object to be plated having the same.

[0007]

According to the present invention, there is provided an electrolytic plating apparatus comprising: a plurality of anode electrodes disposed in a plating bath; current control is performed independently for each of the plurality of anode electrodes; It is characterized in that the current control condition can be changed.

In the above electrolytic plating apparatus, the plurality of anode electrodes may be, for example, a small-diameter anode electrode and a ring-shaped large-diameter anode electrode on the outside of which is electrically insulated from the small-diameter anode electrode. And Alternatively, a plurality of electrically insulated anode electrodes are arranged at different distances from the object to be plated. This method of changing the distance to the object to be plated can be applied to the small-diameter anode electrode and the ring-shaped large-diameter anode electrode.
Further, the anode electrode may be formed in a mesh shape, or may have a plurality of slits or small holes. Further, a plurality of types of current control conditions for a plurality of anode electrodes are stored in the current control unit in advance, and any one of them can be selected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of an electrolytic plating apparatus according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a configuration diagram showing a first embodiment of the electrolytic plating apparatus of the present invention. In this figure, reference numeral 11 denotes a plating tank to which a plating solution (not shown) is supplied. At the bottom of the plating bath 11, a plating target 12 such as a semiconductor wafer is disposed with the plating surface facing upward. On the other hand, a main anode electrode (hereinafter, referred to as a main anode) 13 having a size corresponding to the object to be plated 12 is disposed in an upper portion of the plating tank 11. An intermediate portion of the plating tank 11 between the main anode 13 and the plating target 12 has a size corresponding to the central portion of the plating target 12 and has a size corresponding to that of the main anode 13.
An auxiliary anode electrode (hereinafter, referred to as a sub-anode) 14 having a smaller size is arranged so as to be electrically insulated from the main anode 13. These two anodes 13,1
A plating power supply 15 is connected between the plating object 4 and the workpiece 12. At this time, a current control unit 16 is interposed between the plating power supply 15 and the anodes 13 and 14. This current controller 16
Is for independently controlling the current for each of the main anode 13 and the sub-anode 14, and the current control condition can be changed. A plurality of types of current control conditions for the anodes 13 and 14 are created and stored in advance in the current control unit 16 as shown in FIGS. 2 to 4, for example, and are optionally set by switches (not shown) on the panel surface of the current control unit 16. You can choose one.

In the electroplating apparatus configured as described above, a plating solution is supplied into a plating tank 11 in which an object to be plated 12 is disposed at the bottom. When the plating solution fills from the surface of the object to be plated 12 to the sub-anode 14 close to the surface, FIG.
Alternatively, as shown in FIG. 4, the current control unit 16 starts energizing the sub-anode 14 with a predetermined current value. Therefore, a current flows between the sub-anode 14 and the plating target 12, and the electrolytic plating is started on the processing surface of the plating target 12. Then, the plating solution is applied to the main anode 1
When the condition of FIG. 2 is reached, the current control unit 16 cuts off the current supply to the sub-anode 14 when the condition of FIG. 2 is selected, and continues the current supply when the other condition of FIG. 3 or 4 is selected. At the same time, energization of the main anode 13 with a predetermined current value is performed by the current control unit 1.
6 is started. Therefore, the main anode 13
The current is switched between the current and the object to be plated 12 (FIG. 2).
), Or the sub and main anodes 14, 1
3 and the current to be plated 12 (FIG. 3 or FIG. 4), a current flows between the anode and the workpiece to be plated, and the electrolytic plating on the processing surface of the workpiece 12 to be plated is continued. . Then, the above-described energization is continued until a desired plating film thickness is obtained. During this time, the main anode 13
The current applied to the sub-anode 14 is controlled to be constant under the conditions of FIG. 2 or FIG. 3 and to change stepwise on the way under the conditions of FIG. In FIG. 4, when the energization of the main anode 13 is started, the current value of the sub-anode 14 is increased, and thereafter, after a certain time, the current value is controlled to decrease to a current value lower than the first time. On the other hand, the main anode 13
After the current value of the sub-anode 14 decreases, the current is controlled to increase after a certain period of time.

As described above, according to the above-mentioned electrolytic plating apparatus, the main anode 1 is placed in one plating tank 11.
3 and the sub-anode 14 are arranged, and their current control can be performed independently and by changing a plurality of current control conditions. Therefore, by changing the current control conditions (current value and energizing time) as shown in, for example, FIG. 2, FIG. 3 or FIG. It is possible to always obtain the optimal electric field distribution for the object to be plated having the conductive underlayer in various film formation states without performing troublesome operations such as the above, and always perform the electrolytic plating with a uniform film thickness distribution. be able to. In particular, in the above-described apparatus, when the energization of the sub-anode 14 is performed in addition to the energization of the main anode 13 or when the energization of the sub-anode 14 precedes the energization of the main anode 13, the electric field is affected by the sub-anode 14. Since it is possible to increase the plating film thickness of the portion, it is possible to perform uniform electrolytic plating even on the workpiece 12 in which the plating film tends to be thin in the central portion where the sub-anode 14 is disposed. Become. The sub-anode 1
4 can be arranged corresponding to a portion other than the central portion of the workpiece 12 to be plated.

FIG. 5 shows a second embodiment of the electrolytic plating apparatus of the present invention.
An embodiment will be described. In the second embodiment, FIG.
As shown in FIG. 1, the anode is composed of a small-diameter disk-shaped anode (hereinafter referred to as small-diameter anode) 21 and a large-diameter ring-shaped anode (hereinafter referred to as large-diameter ring anode) 22. The small-diameter anode 21 is disposed on the upper part of the plating tank 11 sufficiently away from the workpiece 12 to face the central surface of the workpiece 12. The large-diameter ring anode 22 is provided outside the small-diameter anode 21 so as to be electrically insulated from the small-diameter anode 21. In addition, the large-diameter ring anode 22 is disposed at the bottom of the plating bath 11 and close to the outer peripheral surface of the plating target 12 at the bottom. These small-diameter anodes 21
As in the first embodiment, the current control of the large-diameter ring anode 22 is independently performed by the current control unit 16 and the current control condition can be changed.

In the second embodiment configured as described above, a plating solution is supplied into a plating tank 11 in which the object to be plated 12 is disposed at the bottom, and the plating solution is supplied to the plating object 12. When injected from the surface to the small-diameter anode 21 via the large-diameter ring anode 22, the small-diameter anode 21
The current control unit 16 starts energizing the large-diameter ring anode 22 with a predetermined current value. This energization is performed independently by the small-diameter anode 21 and the large-diameter ring anode 22, and is performed, for example, under one of the control conditions shown in FIGS. 7 to 11 according to the selection state of the current control unit 16. When the control condition of FIG. 7 is selected, the small-diameter anode 21 and the large-diameter ring anode 22 are energized with the same constant current value and the same constant time. When the control condition of FIG. 8 is selected, power is supplied to the small-diameter anode 21 and the large-diameter ring anode 22 by applying the same constant current value for different fixed times. When the control condition of FIG. 9 is selected, current is supplied to the small-diameter anode 21 and the large-diameter ring anode 22 by applying a different constant current value for the same constant time. When the control condition of FIG. 10 is selected, power is supplied to the small-diameter anode 21 and the large-diameter ring anode 22 by applying different constant current values for different fixed times. When the control condition of FIG. 11 is selected, the current is supplied to the small-diameter anode 21 and the large-diameter ring anode 22 by applying a different current value and a different time at an arbitrary stepwise rate.

In the second embodiment as described above, the small-diameter anode 21 and the large-diameter ring anode 22 are arranged in one plating tank 11 and their currents are controlled independently and by the current control. Since it can be carried out by changing the conditions to a plurality of conditions, it is possible to conduct the conductive film in various film formation states without performing troublesome work such as replacing the processing tank auxiliary parts such as the anode electrode and a shielding plate (not shown) and changing the mounting position. An optimal electric field distribution can always be obtained for the object to be plated having the underlayer, and electrolytic plating with a uniform film thickness distribution can always be performed.

In the above embodiment, two anode electrodes are arranged as a plurality of anode electrodes in one plating tank 11, but three or more anode electrodes can be arranged to more finely adjust the electric field distribution. You can also do so. Further, the distance (inter-electrode distance) of each anode electrode from the object to be plated is not limited to the above-described embodiment, and can be arbitrarily changed. Furthermore, the shape of the anode electrode to be used is not necessarily uniform in order to make it possible to adjust the local current density, and a mesh of an arbitrary size through which a plating solution can pass, or a slit, a small hole, or the like is provided at an arbitrary position. May have a plurality of structures.

[0016]

As described above in detail, according to the electrolytic plating apparatus of the present invention, it is possible to replace the auxiliary parts of the processing tank such as the anode electrode and the shielding plate and change the mounting position without performing any troublesome work. Electroplating with a uniform film thickness distribution can be performed on an object to be plated having a conductive underlayer in various film formation states.

[Brief description of the drawings]

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

FIG. 2 is a characteristic diagram showing current control conditions according to the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing other current control conditions according to the first embodiment of the present invention.

FIG. 4 is a characteristic diagram showing still another current control condition according to the first embodiment of the present invention.

FIG. 5 is a configuration diagram showing a second embodiment of the electrolytic plating apparatus of the present invention.

FIG. 6 is a perspective view showing an anode electrode according to a second embodiment of the present invention.

FIG. 7 is a characteristic diagram showing current control conditions according to the second embodiment of the present invention.

FIG. 8 is a characteristic diagram showing another current control condition according to the second embodiment of the present invention.

FIG. 9 is a characteristic diagram showing still another current control condition according to the second embodiment of the present invention.

FIG. 10 is a characteristic diagram showing still another current control condition according to the second embodiment of the present invention.

FIG. 11 is a characteristic diagram showing still another current control condition according to the second embodiment of the present invention.

FIG. 12 is a configuration diagram showing a conventional electrolytic plating apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Plating tank 12 Plating object 13 Main anode electrode 14 Auxiliary anode electrode 15 Plating power supply 16 Current control part

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yoshito Tachibana 2-3-1, Shibasaki, Chofu-shi, Tokyo Shimada Rika Kogyo Co., Ltd. (72) Inventor Yasuomi Morito 25 Achigaya, Shimada-shi, Shizuoka Shimada Rika Kogyo Co., Ltd. (56) References JP-A-3-134195 (JP, A) JP-A-2-200800 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C25D 7/12 , 21 / 00,21 / 12

Claims (4)

(57) [Claims] 1. A plurality of anode electrodes are arranged in a plating bath, current control is independently performed on each of the plurality of anode electrodes, and current control conditions can be changed .
And the plurality of anode electrodes correspond to an object to be plated.
And an electroplating apparatus arranged at different distances . 2. A plurality of anode electrodes, comprising a small-diameter anode electrode and a ring-shaped large-diameter anode electrode electrically insulated from the small-diameter anode electrode on the outside thereof. An electrolytic plating apparatus according to item 1. 3. The anode electrode is formed in a mesh shape,
Or electrolytic plating apparatus according to claim 1 or 2, characterized in that it has a plurality of slits or small holes. 4. A plurality of types of current control conditions for a plurality of anode electrodes are stored in advance in a current control unit, and any one of them can be selected.
3. The electrolytic plating apparatus according to any one of 3 .