JPS6396292A - Device for electrolytic plating - Google Patents

Abstract

PURPOSE:To perform electroplating of a fine pattern without damaging a substrate at the stage of electroplating of the metallic fine pattern on a fragile circular substrate of semiconductor, by supporting the substrate with plural cathode needles and holding it on a surface of a plating liq. with a specific holder. CONSTITUTION:The plating liq. 3 is received in a cup part 2 in a plating tank 1. The fragile circular substrate 6 of semiconductor is supported on the surface of the liq. 3 with an annular substrate holder 120 consisting of a stopper 111 and a main holder 112, is brought into contact with plural cathode needles 5 at the position where the substrate contacts with the surface of the gilding liq. and is pressurized with gaseous N2 100 blowing against the substrate from an injection opening 10a of a nozzle 10 fitted on the top cover 12. Then, the fine pattern is formed with the cathode needle 5 without damaging GaAs substrate by supplying electric current between an anode 4 in the plating liq. and the GaAs substrate 6 as the cathode, and by electroplating while allowing the plating liq. to overflow 3a at the position of the lower surface of the substrate 6.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an electrolytic plating apparatus for forming a metal layer on the main surface of a substrate, particularly on the main surface of a semi-quadramid circular substrate made of GaAs or the like which is easily broken. The present invention relates to an electrolytic plating apparatus that forms fine metal patterns on surfaces.

[Conventional technology]

FIG. 4 is a longitudinal cross-sectional view showing an example of a conventional electrolytic plating apparatus. In the figure, 1 is a plating tank, 2 is a cup portion, and 3
is the plating solution, 3a is the plating solution level, 4 is the anode electrode,
5 is a cathode needle, 6 is a circular substrate, 7 is a voltmeter, 8 is a constant current power supply, 9 is a pump, 10 is a nozzle, 10a is a nitrogen gas blowing hole of the nozzle 10, 11 is an elastic metal fitting, 12 is a plating tank lid It is. Further, arrow 33 indicates the flow of plating solution 3, and arrow 100 indicates the flow of nitrogen gas.

5(al) and (b) are a plan view showing the cup part 2 of the conventional electrolytic plating apparatus, and its AOA' vertical cross-sectional view. FIG. 6(al) and (b) are 4 is a side view and a bottom view showing a nozzle of an electrolytic plating apparatus and its attached parts. Note that parts having the same functions as those in FIG. 4 are given the same symbols, and explanations thereof will be omitted.

In FIGS. 5(a) and (b), 55 is a cathode needle support part, and in FIGS. 6(a) and (b), 10b is a male thread.

Next, the process flow before proceeding to electrolytic plating will be explained based on the process diagram shown in FIG.

First, the substrate 6 is placed on the tips of the three cathode needles 5 located near the upper opening of the cup portion 2 (FIGS. 4 and 5) (Step 1 in FIG. 8). Next, by closing the plating tank lid 12 (FIG. 4), the nozzle 10 (FIG. 4) is installed at the bottom of the plating tank lid 12 (FIG. 4).

The substrate 6 is pressed and fixed from above by a propeller-shaped elastic fitting 11 attached to the substrate (FIG. 6), and the substrate 6 and the cathode needle 5 are brought into contact (Step 2 in FIG. 8).

At this time, the three wings of the elastic fitting 11 are located at the cathode needle 5.
Next, measure the voltage between the three cathode needles 5 using the voltmeter 7 (Fig. 4), and make sure that all three cathode needles 5 are connected to the board 6 (Step 3 in Figure 8). If the contact is good, proceed to Steps 1 to 3.
This process is repeated until the contact is good, and if the contact is good, the process moves on to the electrolytic plating process.

Next, the electrolytic plating process will be explained.

The electrolytic plating apparatus shown in FIG. 4 makes electrical contact between the tip of the cathode needle 5 and the substrate 6, that is, a conductive substrate or a power supply metal layer formed on the substrate, so that the substrate 6 itself becomes a cathode electrode. A constant current power source 8 is used to pass a current through the plating solution 3 to deposit metal on the main surface of the substrate 6 for plating. The height of the cathode needle 5 is adjusted so that the plating liquid level 3a is in contact with the main surface of the substrate 6, and the nitrogen gas blowing hole 10a of the nozzle 10 is adjusted so that the plating liquid 3 does not go around the back surface of the substrate 6. A flow 100 of nitrogen gas is constantly blown onto the back surface of the substrate 6 from the beginning. The plating solution 3 overflows from the upper opening of the cup portion 2 at an appropriate flow rate as shown by an arrow 33 by driving the pump 9, so that the composition of the plating solution 3 hitting the substrate 6 is always constant.

[Problem that the invention seeks to solve]

In the conventional electrolytic plating apparatus configured as described above, the cathode needle 5 of the cup portion 2 and the substrate 6 are in contact with each other at three points as shown in FIG. 5(a), and as shown in FIG. 6(b). The substrate 6 is pressed down from above by three blades of a propeller-shaped elastic fitting 11. For this reason, pressure is locally applied near the contact point between the tip of the cathode needle 5 and the substrate 6, resulting in a problem that the substrate cracks. In particular, if the positions of the three cathode needles 5 and the three blades of the propeller-shaped elastic metal fitting 11 did not match, this alone would lead to substrate cracking.

The above problem will be specifically explained below with reference to FIGS. 7 and 9. 7(a) to (d) are cross-sectional views showing the process of forming a metal layer on a semiconductor substrate by electrolytic plating. In the figure, 66 is a semiconductor substrate, 67 is a power supply metal layer, and is formed thinly by sputtering, vapor deposition, or electroless plating. 6
Reference numeral 8 indicates a photoresist, and reference numeral 69 indicates a metal layer formed by electrolytic plating.

Next, the above process will be explained. First, a photoresist 68 is patterned on the power supply metal layer 67 (FIG. 7(al)), and electrolytic plating is performed (FIG. 7(b)).
Then, the resist is removed (FIG. 7(C)), and the unnecessary part of the power supply metal layer 67 (the part that was under the resist pattern) is removed.
etching to obtain a fine metal pattern (7th
Figure (d)).

Further, FIG. 9 is a cross-sectional view showing a portion where a resist pattern is formed in the state of FIG. 7(a).
is the cathode needle. FIG. 7 (Al, in the part where there is no resist on the semiconductor substrate 66, the cathode needle 5 and the power supply metal formed on the semiconductor substrate 66) It is easy to make electrical contact with the mm 67, but as shown in FIG. A condition for electrical contact is that the cathode needle 5 is able to penetrate through the photoresist 68 and come into contact with the power supply metal layer 67 in a certain portion of the photoresist 68.

However, in the conventional electrolytic plating apparatus, considering the local pressure exerted on the semiconductor substrate 66 by the tip of the cathode needle 5 and the strength and cleavage of the semiconductor substrate 66, the elastic metal fitting 11 attached to the nozzle 10 in FIG. Therefore, the force for pressing down the semiconductor substrate 66 from above is considerably limited.

For this reason, the cathode needle cannot penetrate the photoresist 68 and electrical contact cannot be established in many cases. However, in order not to reduce the number of chips that can be removed from the semiconductor substrate 66 too much, the area of the cutout pattern must be made small, so the alignment of the cathode needle 5 and the cutout pattern requires redoing. There are many things involved.

In addition, in the conventional electrolytic plating apparatus, in FIG. 4, the main wiring connecting the contact check system (voltmeter 7, etc.) outside the plating tank and the cathode needle 5 side is connected to the plating tank M1.
2, and a contact check cannot be performed until after the lid 12 is closed and the two are connected. Therefore, for the reason mentioned above, the contact between the power supply metal layer 67 and the cathode needle 5 is If electrical contact cannot be made, it is necessary to repeat steps 1 to 3 shown in FIG. If stress is applied repeatedly to the substrate 66, the substrate may crack.

As is clear from the above explanation, in conventional electrolytic plating equipment, the substrate is unstable, making it difficult to make electrical contact between the substrate and the cathode needle, easily resulting in substrate cracking, and the work before electrolytic plating takes a long time. There was a problem that it took a lot of time.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to provide an electrolytic plating apparatus that can prevent substrate cracking and reduce work time loss.

[Means for solving problems]

The electrolytic plating apparatus according to the present invention has a substrate holder for mounting the substrate on the cup portion so as to be in contact with the surface of the plating solution in the cup portion, that is, a ring shape capable of accommodating the substrate; A substrate holder main body that has a plurality of contact portions that contact the side surface of the substrate and holds three or more cathode needles that support the substrate thereon, a gas blowing hole to the substrate, and the substrate and cathode needles. and a contact check circuit for checking electrical contact with the cathode needle, and a holding part that is attached and fixed to the substrate holder body and elastically presses the substrate against the tip of the cathode needle. It is.

[Effect]

In this invention, a plurality of contact portions that contact the side surfaces of the substrate are provided on the inner periphery of the ring-shaped substrate holder body capable of accommodating the substrate, so that the substrate can be stably installed, and the substrate can be pressed and fixed by the holding portion. It is possible to prevent the substrate from shifting laterally.

Furthermore, since the substrate is fixed in a holder format by the holding portion and the substrate holder main body, handling of the substrate after the substrate is installed can be reduced.

Further, since a contact check circuit is provided in the holding portion, electrical contact between the substrate and the cathode needle can be checked regardless of whether the plating tank lid is opened or closed, and the working time can be shortened.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an electrolytic plating apparatus according to an embodiment of the present invention. In the figure, 1 is a plating bath, 2 is a cup portion, 3 is a plating solution, 3a is a plating solution level, and 4 is an anode. electrode, 5 is a cathode needle, 6 is a circular substrate, 7 is a voltmeter, 8 is a constant current power supply, 9 is a pump, 10 is a nozzle, 10
a is a nitrogen gas blowing hole of the nozzle 10, 111 is a holding part, 111d is a nitrogen gas blowing hole of the holding part 111,
112 is the substrate holder body, 112b is the substrate contact part, 1
20 is a substrate holder consisting of a holding part 111 and a substrate holder main body 112, 12 is a plating tank lid, 12a is a viewing window, 13 is a substrate installation state observation device, and 13a is a fiberscope with illumination. Further, arrow 33 represents the flow of the plating solution, and arrow 100 represents the flow of nitrogen gas.

Further, FIG. 2 shows each part of the electrolytic plating apparatus in this embodiment. FIG. 2(a) is a top view of the substrate holder main body 112 of the electrolytic plating apparatus of this embodiment,
55 is a cathode needle support part, 112a is a ring-shaped main body, 1
12b is a substrate contact part, 112C is a cathode needle insertion hole, 1
12d is a slot for inserting tweezers, etc., and a broken line 6a is a slot for inserting the board 6.
Indicates the position when placed. Figure 2 (bl is cup part 2
2a is a substrate holder support pillar provided in the cup part 2.

FIG. 2(C) is a top view of the holding part 111.
e is a hole into which the transport rod 113 is inserted. FIG. 2(d) is a bottom view of the holding portion 111, in which 111a is the holding portion main body, 111b is a chemical-resistant rubber cushion, and 111c is an elastic spring. FIG. 2(e) shows a substrate holder 12 consisting of the holding part 111 and the substrate holder main body 112.
0 and the cup portion 2, the cup portion showing an AOA' cross section. FIG. 2(f) shows a state in which the substrate holder 120 is attached to the cup portion 2. As shown in FIG.

In addition, in FIG. 2, the same reference numerals as in FIG. 1 indicate the same or corresponding parts. In FIG. 1 11 a) in the figure is omitted.

In the electrolytic plating apparatus of this embodiment, the substrate holder main body 11
2, three cathode needle support parts 55 made of metal are attached to a ring-shaped main body 112a made of polypropylene at positions 120'' from each other as shown in FIG. Three cathode needles 5 are supported by each of the cathode needle support parts 55.The lower part of the substrate holder main body 112 is shown in FIG. 2(e) and FIG. 2(f). 3 of cup part 2 as shown
It has a shape that can be fitted into the book board holder support column 2a (FIG. 2(b)). Further, a total of nine cathode needles 5 are provided so that their tips are approximately 2n inward from the circumference of the substrate 6. In addition, the cathode needle support portion 55 and the cathode needle 5 are made of Ti plated with Pt, and the tip of the cathode needle 5 and the portion of the cathode needle support portion 55 other than the contact check wiring connection portion are further coated with Teflon. It is designed to prevent plating metal from adhering during electrolytic plating. The heights of the tips of the cathode needles 5 are uniform, and the tips of all the cathode needles 5 uniformly contact the main surface of the substrate 6 to support the substrate 6 horizontally. In addition, even if the height of the tip of the cathode needle 5 slightly varies due to wear of the tip of the cathode needle 5 due to long-term use of the device, the cathode needle of the cathode needle support portion 55 can be fixed as shown in FIG. 2(a). By setting an appropriate distance from the base of the cathode needle 5 to the tip of the cathode needle 5, the elasticity of the cathode needle 5 itself can absorb variations in height of the tip of the cathode needle 5 and make the height uniform. . The three cathode needle supports 55 are insulated from each other by a ring-shaped body 112a made of polypropylene, and the three cathode needles are used as one set to perform a contact check on each of the three parts of the substrate 60 in the same manner as in the past. It is now possible to do this. Since the substrate contact portion 112b is provided on the inner periphery of the ring-shaped main body 112a, the substrate 6 is fixed by preventing the substrate 6 from shifting laterally on the cathode needles 5, and the substrate 6 and the cathode needles 5 are connected to each other. It is possible to make electrical contact easier and prevent substrate cracking. Further, the tip (inner side) of the substrate contacting portion 112b has a streamlined shape so as not to impede the flow of the plating solution 3 as much as possible.

In addition, the holding part 111 whose details are shown in FIG. 2(C) and FIG.
A chemical-resistant rubber cushion 1 having the same diameter as the substrate 6 is attached to 1a.
11b and an elastic spring 111C.
As shown in the cross-sectional views of FIG. 2(e) and FIG. 2(f), the elastic spring 111C holds the board 6 by fitting it into the board contacting part 112b of the board holder main body 112 and fastening the holding part main body 111a with a bottle or the like. It is pressed and fixed with appropriate pressure. In this embodiment, the substrate 6 is held in a holder format using the substrate holder main body 112 and the holding part 111, so that the substrate 6 can be fixed with less handling, and substrate cracking can be prevented. can do.

FIG. 3 shows a simple circuit for checking the electrical contact between the substrate 6 and the cathode needle 5.
a, 5b, 5c are the tips of the cathode needles, 6 is the substrate, 1
4 is a light emitting diode, 15 is a switch, and 88 is a battery. In this circuit, two light emitting diodes 14 are turned on at the same time only when the tips 5a, 5b, 5c of the cathode needles are all in electrical contact with the substrate 6. Since the holding part 111 is provided with such a simple circuit, the contact check can be performed by the substrate holder 120 itself, regardless of whether the plating tank lid 12 is opened or closed, and the contact check can be performed before the plating process. The working time can be reduced.

In addition, in this example, FIGS. 2(C), (e), (f)
As shown in FIG.
Since a transport rod insertion hole 111e is provided in , the transport rod 113 can be inserted to attach, remove, and transport the substrate holder 120 to the cup portion 2, and furthermore, each substrate holder 120 can be washed with water. It is configured as follows.

In addition, in this embodiment, as shown in FIG.
2 is provided with a peephole 12a, so that the installed state of the substrate holder 120 can be observed after the lid 12 is closed.
Furthermore, since a substrate installation state observation device 13 equipped with an illuminated fiberscope 13a is provided, it is also possible to check how the plating solution 3 is applied to the substrate 6.

〔Effect of the invention〕

As described above, according to the electrolytic plating apparatus of the present invention, the substrate holder for mounting the substrate on the cup portion so as to come into contact with the plating liquid surface of the cup portion, that is, the substrate holder is formed in a ring shape capable of accommodating the substrate; a substrate holder main body having a plurality of contact portions on its inner periphery for contacting the side surface of the substrate, and holding three or more cathode needles supporting the substrate thereon;
It has a gas blowing hole to the substrate and a contact check circuit for checking electrical contact between the substrate and the cathode needle, and is mounted and fixed on the substrate holder main body to connect the substrate to the tip of the cathode needle. Since it is equipped with a holding part that presses elastically, it is possible to stably fix the board, make it easier to make electrical contact between the board and the cathode needle, prevent the board from cracking, and reduce work time. This has the effect of shortening the time. This effect is particularly noticeable in an electrolytic plating apparatus that performs electrolytic plating on a semiconductor substrate that has cleavability and is easily broken, such as a GaAs substrate.

[Brief explanation of the drawing]

FIG. 1 is a vertical sectional view showing an electrolytic plating apparatus according to an embodiment of the present invention, FIG. 2(a) is a top view showing the substrate holder main body of the above embodiment, and FIG. FIG. 2 (C) and (dl are top and bottom views respectively showing the holding part of the above embodiment, FIG.
e) is a sectional view showing a substrate holder in which the holding portion is attached to the substrate holder main body, and a cup portion;
Figure (f) is a sectional view showing the board holder attached to the cup part, Figure 3 is a circuit diagram showing the contact check circuit provided in the holding part of the above embodiment, and Figure 4 is a conventional electrolytic A vertical cross-sectional view showing an example of a plating apparatus, FIGS. 5(a) and (b) are a top view and an AOA' cross-sectional view of the cup portion of the conventional example, and FIGS. 6(a) and (b) are the above-mentioned A side view and a bottom view showing a conventional nozzle and its attached parts, FIGS. 7(a) to 7(d) are cross-sectional views showing the process of forming a metal layer on a semiconductor substrate by electrolytic plating, and FIG. FIG. 9, a process diagram showing the process flow before the plating step, is a sectional view showing a portion where a resist pattern is formed on the substrate in the state of FIG. 7(a). In the figure, 1... plating tank, 2... cup part, 2
a... Substrate holder support pillar, 3... Plating solution, 3a
...Plating liquid level, 33...Flow of plating liquid, 4
...Anode electrode, 5...Cathode needle, 5a, 5b
, 5c... Tip of cathode needle, 6... Substrate, 7...
・Voltmeter, 8... Constant current power supply, 88... Battery, 9.
... Pump, 10... Nozzle, 10a... Nitrogen gas blowout hole, 100... Nitrogen gas flow, 111.
... Holding part, 111a... Holding part main body, 111b
...Chemical-resistant rubber cushion, 111C...Elastic spring, 111d...Nitrogen gas blowout hole, 111e...
・Function rod insertion hole, 112... Board holder body,
112a... Ring-shaped main body, 112b... Substrate contact portion, 112c... Cathode needle insertion hole, 113... Transport rod, 12... Plating tank lid, 13... Substrate installation state observation device, 13a...Fiberscope with illumination, 14
...Light emitting diode, 15...Switch. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (5)

[Claims] (1) A plating tank and a plating tank lid having a gas blowing nozzle; A cup part provided in the plating tank and containing a plating solution that always overflows and circulates from the upper opening of the plating tank; This cup part is used to hold the substrate. An electrolytic plating apparatus comprising: a cathode needle that is supported so as to be in contact with the surface of the plating solution; and a power supply means that applies a current to the cathode needle to form a metal layer on the surface of the substrate by plating. a substrate holder to be attached to the cup portion so as to be in contact with the plating liquid surface of the portion, the substrate holder being formed in a ring shape capable of accommodating the substrate, and having an inner periphery in contact with a side surface of the substrate. A substrate holder body having a plurality of contact parts and holding three or more cathode needles supporting the substrate thereon, gas blowing holes to the substrate and electrical contact between the substrate and the cathode needles. 1. An electrolytic plating apparatus comprising: a contact check circuit for checking; and a holding part that is attached and fixed to the substrate holder body and elastically presses the substrate against the tip of the cathode needle. (2) The electrolytic plating apparatus according to claim 1, wherein the contact portion has a streamlined outer shape. (3) The electrolytic plating apparatus according to claim 1 or 2, wherein the plating tank lid has a window for observing the inside of the plating tank. (4) The apparatus according to any one of claims 1 to 3, further comprising a fiber scope for observing the contact status between the substrate and the cathode needle, and the substrate and the plating solution. Electrolytic plating equipment. (5) The substrate holder is characterized in that it has a transport rod insertion hole into which a transport rod for transporting the substrate is inserted. electrolytic plating equipment.