JP2725249B2 - Electroplating electrode observation and automatic plating equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention observes an electrode surface while energizing, and further controls and monitors an electrode supply voltage or current in accordance with the state of the electrode surface. The present invention relates to an automatic plating apparatus.

[Conventional technology]

In general, when a hydrogen storage metal is used as a cathode and a current is passed between the anode and the electrolyte in the electrolyte, hydrogen ions are transported in the electrolyte to generate hydrogen atoms at the cathode, and this is occluded by the cathode. Has the property of increasing the hardness while increasing the brittleness. The electroplating technique of electroplating hydrogen-absorbing alloys using hydrogen as a plating material metal for the anode and the anode or using a plating solution containing metal ions as the electrolyte is a field with a wide range of industrial applications. Recently, plating technology for plating ICs and LSIs has also been developed.

[Problems to be solved by the invention]

By the way, in electrolytic plating, as described above, hydrogen atoms are generated on the plating substrate serving as the cathode, and the generated hydrogen atoms are combined with each other or the generated hydrogen atoms and the hydrogen atoms in the cathode to generate hydrogen gas. Since air bubbles are generated from the cathode surface, pores are scattered and formed on the surface to be plated, and it is often difficult to realize uniform and high-quality plating.

The present invention has been made to solve the above problems, and enables in-situ observation of an electrode during energization, performs image processing on a captured electrode surface image, and adjusts a voltage or a current supplied to the electrode according to a processing result. An object of the present invention is to provide an electroplating electrode observation and automatic plating apparatus capable of automatically performing uniform and high-quality plating by controlling the apparatus.

[Means for solving the problem]

The present invention is an apparatus for energizing between an anode and a cathode disposed in an electrolytic cell filled with an electrolytic solution, a device for continuously observing changes in the electrode surface with a microscope, and a means for imaging the electrode surface through a microscope, With an image processing means for processing image information obtained by imaging, an electrolytic plating electrode observation device so as to observe the electrode surface state while energizing, and an anode disposed in an electrolytic tank filled with an electrolyte Apply electricity between the cathodes,
An image pickup means for picking up an image of an electrode surface through a microscope, an image processing means for processing image information obtained by image pick-up, and a means for controlling a voltage or a current supplied to the electrode in accordance with a result of the image processing; It features a plating device.

[Action]

In the present invention, by observing the surface of the electrode with a light microscope through a window provided in the electrolytic cell while energizing, it is possible to observe the state of hydrogen absorption and plating at the cathode and the state of oxidation of the anode material at the anode. it can. In addition, since a microscope image is continuously captured by an imaging device such as a TV camera and image processing is performed, and a supply voltage or a current to the electrode is controlled according to a processing result, electroplating having desired characteristics can be performed. It is also possible to change the polarity of the voltage to polish the electrode surface when bubbles are generated and pores are generated, and to repeat plating when the pores disappear by changing the polarity of voltage or current again. As a result, uniform and high-quality plating can be performed.

〔Example〕

 Hereinafter, examples will be described.

FIG. 1 is a cross-sectional view of a main part of an electroplating electrode observation apparatus according to the present invention, FIG. 2 is a view showing the overall configuration of the electroplating apparatus, and FIG. 3 is a waveform diagram. In the figure, 1 is an optical microscope, 2
Is a lens barrel, 3 is an objective lens, 4 is an electrolytic tank, 5 is an electrolytic solution, 6
Is a plating substrate, 7 is a platinum electrode, 8 is a cover glass, 9 is a water flow pump, 10 is a thermocouple, 11 is a bubble, 21 is a TV camera, 22
Is a monitor, 23 is a computer, and 24 is a voltage generator.

In FIG. 1, an electrolytic cell 4 is mounted on an XY stage 12, and a plating substrate (cathode) 6 which is energized between a plating material metal and a platinum electrode (anode) 7 is covered in an electrolytic solution 5. The XY stage is located opposite the window of glass 8
While the field of view is determined at 12, the surface of the plated substrate during energization is observed by the optical microscope 1 through the window of the cover glass. This change in the substrate surface can be imaged by a TV camera attached to a microscope as described later. The objective lens 3 uses a long-distance focusing lens because the distance from the sample decreases as the magnification increases, and it becomes difficult to insert an electrolytic solution during this. However, if the magnification is up to about 200 times, a normal objective lens is sufficient.

When energized, hydrogen gas is generated on the cathode side by hydrogen ions transported through the electrolytic solution.
At an angle of 5 ° to 30 ° so as to guide bubbles out of the visual field by buoyancy. Of course, the cover glass may be provided horizontally without being inclined, and the air bubbles may be guided out of the field of view by obliquely tilting the entire apparatus. In addition, a water flow pump or screw 9 is provided in the electrolytic cell 4 to force the electrolytic solution toward the plating substrate to similarly guide generated bubbles out of the field of view. The generated gas is released from the gas discharge port 12 to prevent the pressure in the electrolytic cell from rising. Further, plating is performed while measuring the temperature of the electrolytic solution with the thermocouple 10.

With such a configuration, it is possible to continuously observe the state of the cathode plating surface while energizing, and also observe the state of occlusion of hydrogen.

In the above description, observation of the cathode has been described.
Of course, it is also possible to observe the anode, in which case the oxidation state of the anode surface due to electrolysis is observed.

Next, an automatic plating apparatus using the observation apparatus shown in FIG. 1 will be described with reference to FIGS.

When performing fine plating for ICs on semiconductor wafers and the like, in order to control the adhesion state of plating, instead of simply applying a constant voltage to the electrodes, change the voltage or current waveform,
It is preferable to repeat electrodeposition and electrolytic polishing.

2, the electrode surface image observed by the optical microscope 1 with the TV camera 21 is continuously captured, and the computer 23 performs image processing while observing the electrode surface image with the monitor 22 as necessary. Then, the voltage applied to the electrodes is controlled by the voltage generator 24 according to the image processing result. For example, in the early stage of plating, “metal adhesion” is observed interspersed. Therefore, the amount of metal adhesion is calculated from the number, the adhesion area, and the adhesion thickness estimated from the depth of focus, and the supply voltage waveform is calculated. The plating speed is controlled optimally by changing it by the computer 23.

When it is recognized that pores are generated on the electrode surface, for example, by observing the electrode surface with a monitor and performing image processing, the computer 23 controls the voltage generator 24 to control the voltage generator 24 as shown in FIG. Then, the polarity of the voltage applied to the electrode is changed, and the electrode surface is polished by changing from the electrodeposition mode to the electropolishing mode to eliminate pores. When it is observed that the pores have almost disappeared or disappeared, the polarity is changed again and the electrodeposition mode is set. By performing plating while repeating electrodeposition and polishing in this manner, uniform and favorable plating can be performed. Of course, a current generator may be used instead of the voltage generator 24.

In addition, since the generation of bubbles is an important factor for uniform plating, the position, number, size, growth rate, etc., of the bubbles are also captured as data and immediately processed by a computer to determine the electrode state. The current waveform is changed and the current waveform is changed immediately by feedback. In this case, since the voltage or current waveform is synthesized and generated by a computer, electroplating having desired characteristics can be performed. If the generated bubbles are left untreated, large pores are formed on the metal surface, so it is necessary to remove the bubbles at an early stage after the generation of the bubbles. Therefore, when the generation of air bubbles is recognized as a result of the image processing, the above-described water flow pump or screw is driven with feedback, or the use of ultrasonic waves or the application of vibration to electrodes (not shown) is performed,
Alternatively, it is desirable to remove bubbles early by using these methods in combination.

Also, prepare a plurality of metal pieces for electrolytic plating on the anode,
It is also possible to control different types of metals and electrodeposit them as a multilayer film.

By changing the voltage or current supplied to the electrode in combination with observing the electrode surface and analyzing the surface state by further image processing, the plating process can be performed automatically in the optimum state. It becomes possible.

In the above description, electroplating has been described.
The same is true for hydrogen storage, and therefore it is also effective in that the surface state of the cathode electrode and the surface state of the metal or alloy for hydrogen storage, which has recently been talked about, can be continuously observed during electrolytic hydrogen storage. It is. In this case, in the case of palladium metal, a hydride phase such as palladium hydride, swelling (blistering), peeling (flakes) of the metal surface, and generation of bubbles from the position can be continuously recorded on a video. It is also effective for basic research on hydrogen embrittlement prevention by electrolytic hydrogen storage.

〔The invention's effect〕

As described above, according to the present invention, it is possible to observe the surface of the electrode while energizing, observe the hydrogen occlusion and plating state at the cathode, and observe the oxidation state of the anode material at the anode. In addition, by automatically capturing images with a TV camera and performing image processing, controlling the supply voltage or current to the electrodes according to the processing results, and taking measures to remove air bubbles, automatically uniform and high-quality plating Can be performed.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an electrolytic plating apparatus according to the present invention,
FIG. 2 is a diagram showing the overall configuration of the electrolytic plating apparatus, and FIG. 3 is a waveform diagram. 1 ... optical microscope, 2 ... barrel, 3 ... objective lens, 4
... electrolytic bath, 5 ... electrolytic solution, 6 ... plating substrate, 7 ...
Platinum electrode, 8 Cover glass, 9 Water pump, 10
…… Thermocouple, 11 …… Bubble, 21 …… Video camera, 22 ……
Monitor, 23 ... Computer, 24 ... Voltage generator.

Claims (3)

(57) [Claims] An apparatus for continuously observing a change in an electrode surface with a microscope by applying a current between an anode and a cathode disposed in an electrolytic cell filled with an electrolyte, and means for imaging the electrode surface through a microscope. And an image processing means for processing image information obtained by imaging, and observing the state of the electrode surface while applying power. 2. An imaging device for energizing between an anode and a cathode disposed in an electrolytic cell filled with an electrolytic solution and imaging an electrode surface through a microscope, and an image processing device for processing image information obtained by imaging. Means for controlling the voltage or current supplied to the electrodes according to the image processing result. 3. An anode comprising a plurality of different metals.
Or the apparatus according to 2.