JP2009120935A - Annular plating bath - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plating bath capable of forming a uniform plating layer on the whole surface of a substrate. <P>SOLUTION: The plating bath 100 has a cylindrical housing part housing a plating liquid 111 inside and having an opened upper part and a rotary shaft 110 extended vertically and attached to the center through the plating bath 100. A substrate fixing frame 120 having circular plane external form is attached to the rotary shaft 110 and a substrate fixing tool 121 arranged to make circular along the substrate fixing frame 120 and extended in the vertical direction is attached to the substrate fixing frame 120. The substrate 200 to be plated is attached to the substrate fixing tool 121 to be fixed at the upper and lower end part and a plurality of substrates 200 are arranged to form a circular shape to be immersed in the plating liquid 111. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a plating tank, and more particularly to a plating tank for forming a thin and uniform plating layer for forming a fine pattern on the surface of a substrate to be plated.

  In general, plating is a method in which a metal to be plated is placed in an electrolytic solution containing ions of the metal to be electrodeposited by using the metal to be plated as a cathode and the metal to be electrodeposited as an anode, and by conducting electricity. A method of depositing on the surface.

  A plating layer formed by such a plating method is more advantageous as it is thinner within a necessary range, and it is an important issue to form a thin plating layer while ensuring uniformity over the entire surface.

  In particular, a substrate used in a semiconductor process is mainly surface-treated by an electroplating apparatus, and a metal such as copper or gold is coated by electroplating to mainly form circuit patterns and bumps.

  Also, substrates used as electronic materials such as semiconductor processes are more limited in the characteristics required than other plating processes, and the main features are uniformity of plating thickness, smoothness of plating surface, and adhesion of plating. In particular, with respect to the plating thickness, it is strictly required that a uniform plating layer be formed on the entire surface to be plated so as to be advantageous for subsequent processes.

  Therefore, in order to improve the uniformity of the plating thickness, the current distribution of the plating current must be kept uniform in the plating tank.

  However, the conventional plating tank is mainly configured in a square box shape, and the distribution of ions to form a plating layer represented by the distribution of plating current by arranging a plurality of substrates in parallel inside There is a problem that it is difficult to obtain a uniform thin plating layer with uniform thickness.

  In particular, in the case of a substrate used as an electronic device material in various forms, since a fine pattern must be printed, a very thin plating layer must be formed on the surface of the substrate. In a conventional plating tank, it is technically difficult to form a plating layer having a thickness of about 30 μm or less capable of fine pattern printing.

  Next, the structure of the conventional plating tank and the plating method using the conventional plating tank will be briefly described as follows.

  FIG. 1 is a configuration diagram of a conventional plating tank. As shown in the figure, a conventional plating tank is filled with a plating solution 2 in a square plating tank 1, and a plurality of substrates 3 are filled in the filled plating solution. Are arranged in parallel.

  The plating tank 1 is configured as a square box having an open top, and is configured as a plating tank that contains a solution that is energized by a positive current from a positive charge terminal.

  Further, a conveying means (not shown) is provided on the upper part of the plating tank 1 and connected to a negative charge terminal, to which a negative current is passed, and a substrate 3 on which a plating layer is formed is coupled.

  In the conventional plating tank 1, the substrate to be plated is fixed to the conveying means by a suspension method, immersed in the plating solution in the plating tank 1, and reciprocated by the conveying means, thereby causing a chemical reaction by current conduction in the plating tank 1. Thus, a plating layer is formed as a thin film on the surface of the substrate 3.

  However, the conventional plating tank 1 is a process in which the substrate 2 is mainly formed in a thin plate shape in the process of plating, so that the substrate 2 is fixed to the transfer means and transferred in the plating solution. Due to the resistance force, the flow may occur in a portion that is not directly fixed to the conveying means.

  Therefore, there is a problem that a plating layer having a uniform thickness cannot be formed over the entire surface of the substrate 3.

  FIG. 2 is a diagram showing the ion distribution during plating in the conventional plating tank 1, and the time after the substrates 3 are arranged in parallel in the plating solution filled in the conventional plating tank 1. The ion distribution around the substrate 3 with the progress is shown.

  As shown in FIG. 2, when the substrates 3 are arranged in parallel in a plating solution that does not flow in the plating tank 1, ions around the substrate 3 are deposited and fixed on the surface of the substrate 3, so that the plating solution is obtained. Inside, the amount of ions gradually decreases.

  Therefore, as time passes, the distribution of ions distributed around the substrate 3 arranged at the outermost contour in the plating tank 1 and around the substrate 3 arranged inside thereof becomes non-uniform. Depending on the arrangement position, a problem arises that it becomes difficult to form a plating layer having a uniform thickness over the entire surface.

  Further, in order to simply improve such problems, a method for forcibly circulating the plating solution accommodated in the square plating tank 1 has been devised, but a complete solution to solve the above problems As described above, there may be a problem that the thickness of the plating layer may be non-uniform due to the shaking of the plating solution.

  In order to solve such a problem, the auxiliary cathode is brought into close contact with one surface of the substrate 3 arranged in parallel in the plating tank 1, and a shielding plate is arranged at a certain distance from the auxiliary cathode. A method has been proposed in which the electric field distribution of the substrate 3 is expanded so that a uniform plating layer is formed on the surface of the substrate 3.

  However, in the plating method using the shielding plate, it is difficult to fundamentally solve the problems and disadvantages described above, and the plating current is concentrated on the edge of the substrate 3 where the plating layer must be formed. Can be prevented by the shielding plate, but there is a problem that plating deviation must be generated when the plating area of the edge is large.

  Accordingly, the present invention was devised to solve the above disadvantages and problems occurring in conventional plating tanks, and provides a plating tank capable of forming a uniform plating layer on the entire surface of the substrate. With the goal.

  In addition, the present invention eliminates the deviation generated according to the position of the substrate so that the ions distributed in the circular plating tank are equally distributed around each substrate arranged along the wall of the plating tank. It is an object of the invention to provide a circular plating tank in which a fine plating layer having a thickness that can be formed is formed.

  The present invention for achieving the above object includes a circular plating tank in which a plating solution is accommodated, and a substrate disposed in the plating tank.

  The plating tank is configured in a circular water tank shape with an open top, and contains a plating solution so that the substrate can be completely immersed therein. At this time, as the plating solution, a solution in which a positive current is passed and the internal ions can flow is accommodated.

  The plating tank has an annular substrate fixing frame mounted therein, and the substrate fixing frame is provided with a substrate fixing tool capable of fixing a plurality of substrates.

  The substrate fixing frame is rotatably coupled on a rotating shaft vertically arranged at the center of the plating tank, and the substrate mounted on the substrate fixing frame is arranged in a polygon or a circle depending on the shape of the substrate fixing frame. Is done.

  Accordingly, the substrate is immersed in the plating solution while rotating in the direction of rotation of the substrate fixing frame, so that the substrate is uniformly affected by a disturbance source such as a heat source applied from the outside. Due to the internal driving, the influence of disturbance can be applied uniformly to the plating solution in the plating tank.

  Moreover, with respect to the influence of the disturbance in such a plating tank, the uniforming effect can be similarly obtained by circulating the plating solution in the plating tank.

  On the other hand, the substrate disposed in the plating tank is connected to the negative electrode and has a negative potential, and the plating solution immersed in the substrate is electrolyzed in the plating solution by energizing the anode having a positive potential. The positively charged ions in the electrolyte are deposited on the surface of the substrate.

  When the substrate has a negative potential, the anode can be placed in the center of the plating tank or in a circular shape inside the substrate in the plating tank.

  Moreover, the anode for electrolytic plating can also be arrange | positioned on the inner wall face of a board | substrate.

  At this time, a plurality of anodes may be arranged so as to have a constant interval with each other, or may be configured in a columnar shape without a gap.

  In the circular plating tank of the present invention having such a technical configuration, by arranging the substrate in a circular plating tank so as to form a circle or a polygon close to a circle, and rotating the substrate in the plating solution, By preventing the influence on external disturbances from being concentrated on some substrates and distributing them equally to each substrate, the plating deviation between the substrates is reduced, and a uniform plating layer is formed on the entire surface of the substrate. There is a technical feature that can be formed.

  In the circular plating tank of the present invention, a plurality of substrates are arranged so as to form a polygonal shape close to a circle in a circular plating tank in which a plating solution is accommodated, and the influence is made uniform when a disturbance occurs. There is an advantage that a uniform plating layer can be generated on the entire surface, and the deviation generated by the substrate position can be reduced, so that a fine plating layer having a thickness of 0.5 to 30 μm capable of forming a fine pattern can be formed. There are advantages.

  Matters relating to the operational effects including the technical configuration for the above-described object of the circular plating tank according to the present invention should be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention. It is.

  3 is a perspective view of a circular plating tank according to the present invention, and FIG. 4 is a plan view of the circular plating tank according to the present invention.

  As shown in the figure, the circular plating tank 100 of the present embodiment has a rotating shaft 110 attached to the center thereof, a substrate fixing frame 120 mounted on the rotating shaft 110 in the plating tank 100, and the inside of the substrate fixing frame 120. The substrate 200 to be plated is fixed to the substrate.

  The plating tank 100 is configured in a cylindrical shape with an open top, and contains an anode and a plating solution 111 that is an ion aqueous solution that can be energized. A plating solution inlet (not shown) for injecting the plating solution 111 is provided.

  At this time, the plating solution 111 accommodated in the plating tank 100 is filled up to a height at which the substrate 200 mounted on the substrate fixing frame 120 is sufficiently immersed.

  The rotating shaft 110 is attached so as to penetrate the inside of the plating tank 100 so that it can rotate at the center of the plating tank 100.

  Further, the substrate fixing frame 120 coupled to the rotating shaft 110 is formed in an annular shape, and is mounted on the upper and lower portions of the rotating shaft 110 in the plating tank 100. Is provided with a substrate fixture 121.

  The substrate 200 has upper and lower ends individually coupled to the substrate fixture 121, mounted along the frame portion of the annular substrate fixing frame 120, and rotated around the rotating shaft 110 while being immersed in the plating solution 111. Thus, the substrate fixing frame 120 rotates in the plating solution 111 in the rotation direction.

  On the other hand, a plurality of substrates 200 can be attached to the substrate fixing frame 120 in the plating solution 111 vertically and arranged along the frame portion of the substrate fixing frame 120, so that the substrate 200 can be changed according to the shape of the substrate fixing frame 120. As a whole, they are arranged so as to form a circle or a polygon close to a circle as shown in FIG.

  5a to 5c are diagrams showing examples of the substrate arrangement in the circular plating tank according to the present invention, and as shown in the figure, the substrates 200 are not arranged in parallel but arranged in a circle or a polygonal shape close to a circle. It is preferable to do.

  The arrangement structure of the substrate 200 can be appropriately changed according to the electrode arrangement structure and the rotation structure of the substrate 200 described below, and is most suitable in consideration of various conditions such as electrode arrangement through various simulations. A morphological arrangement is preferred.

  In the circular plating tank 100 having such a technical configuration, the substrate 200 is arranged in a circular shape or a nearly circular shape using the substrate fixing frame 120 in the circular plating tank 100, and an anode (anode) is formed at an arbitrary point inside. ) When the plating solution 111 is supplied into the plating tank 100 equipped with electrodes and the substrate 200 and the plating solution 111 are brought into contact with each other, and the plating current is supplied to the substrate 200, ions in the plating solution 111 are formed on the surface of the substrate 200. It is deposited and plated.

  Moreover, although the board | substrate 200 is arrange | positioned circularly in the inside along the shape of the plating tank 100, depending on the case, it can also arrange in one or two or more rows.

  As described above, the reason why the substrate 200 is arranged in a circular shape or a polygonal shape close to a circle in the circular plating tank 100 is that the influence of the outside of the substrate 200 due to an electromagnetic field, a heat source, and a flow rate change due to the circulation of the plating solution, This is to make uniform the influence of the disturbance applied to the substrate 200 by rotating the substrate 200 arranged close to a circle when a disturbance unnecessary for forming the plating layer occurs on one side in the plating tank 100.

  On the other hand, the plating tank 100 of the present invention rotates the rotating shaft 110, the substrate 200, or the plating tank 100 itself, circulates the plating solution 111 in the plating tank 100, and the substrate 200 disposed individually in the plating tank 100. The surface is plated uniformly.

  6A and 6B are configuration diagrams showing a plating solution circulation structure of a circular plating tank according to the present invention. As shown in the figure, in the present invention, the circular plating tank 100 has a predetermined interval from its inner wall surface. The substrate 200 is arranged so as to have a substantially circular shape, and the plating solution 111 accommodated so as to immerse the substrate 200 in the plating tank 100 circulates.

  The plating solution 111 is circulated so that ions contained in the plating solution 111 are evenly dispersed and uniformly deposited on the substrate 200 to be plated. As described above, disturbance is generated. This is also because a uniform plating layer is formed on the surface of the substrate 200 so that the influence on the disturbance at the time equally affects each substrate 200.

  For this reason, the plating solution 111 is attached to the rotating shaft 110 attached to the central portion of the plating tank 100 or another connecting member 300 as shown in FIG. The plating solution 111 is circulated by rotating the motor.

  In addition, as shown in FIG. 6B, a cylindrical cylinder 310 is provided inside the substrate 200 mounted inside the plating tank 100, and the plating solution 111 inside and outside of the substrate is rotated in the plating tank 100 by the rotation of the cylinder 310. It can also be.

  And when the board | substrate 200 with which it mounts in the plating tank 100 by this invention is mainly manufactured small, when the plating tank 100 which plates the board | substrate 200 is comprised as a small plating tank, it will be plated. The tank 100 itself can be rotated, and the influence of disturbance can be equally distributed to the substrates in the plating tank 100.

  Next, FIG. 7 a-e is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention, and the circular plating tank 100 of this invention was accommodated in the inside of the plating tank 100 as shown in these figures. Electrolysis generated in the plating tank 100 by causing the plating solution 111 to energize the anode and connecting the substrate 200 arranged in a substantially circular shape inside the plating tank 100 to the cathode. By the reaction, a thin coating layer is formed on the surface of the substrate 200.

  In order to generate an electromagnetic field in the plating tank 100 via the anode and the cathode, the cathode and the anode must be connected to the substrate 200 and the plating solution 111, but the substrate 200 described above. In consideration of the arrangement structure of the electrode, the electrodes can be arranged in various appropriate forms, and the most effective plating performance is substantially realized by the combination of the arrangement structure of the substrate 200 and the electrode arrangement structure. The arrangement structure can be selected when the plating tank is designed.

  The electrode disposed in the plating tank 100 is basically connected to the substrate 200 whose cathode is disposed in a polygonal shape close to a circle in the plating tank 100, and the anode is energized with the plating solution 111 in which the substrate 100 is immersed. Are arranged as follows.

  In a state where the cathode is connected to the substrate 200, the anode 400 is disposed at the center of the plating tank 100 together with the rotating shaft 110 penetratingly coupled to the plating tank 100 as shown in FIG.

  As another form of the anode, as shown in FIG. 7b, a cylindrical anode 410 is arranged between the center of the plating tank 100 and the substrate 200 arranged in a polygonal shape close to a circle, or in FIG. As described above, the cylindrical anode 420 may be disposed in close contact with the inner wall surface of the plating tank 100 or at a predetermined interval.

  At this time, the cylindrical anode 410 also functions as a cylinder (310) for rotating the plating solution 111 so that the circulation of the plating solution 111 and the electrical conduction with the plating solution 111 are performed simultaneously. You can also.

  7d and 7e, the anode 400 may be disposed at the center of the plating tank 100, and at the same time, the cylindrical anode 420 may be disposed on the inner wall of the plating tank 100. Alternatively, the cylinder-shaped anode 410 may be provided. A cylindrical anode 420 may be disposed on the inner wall surface of the plating tank 100 at the same time as being disposed between the wall of the plating tank 100 and the substrate 200.

  On the other hand, FIG. 8 is a diagram showing another embodiment of the electrode arrangement of the circular plating tank according to the present invention, in which the anode 500 is arranged at an arbitrary point outside the substrate 200 arranged in the circular plating tank 100. The plating solution 111 in which the substrate 200 is immersed is energized.

  The arrangement of the anodes 400 to 420 described above can be applied mainly when the substrate 200 is fixed to the plating tank 100. However, the arrangement of the anode 500 shown in FIG. By applying it when rotating at a speed, the electric field generated between the anode 500, the plating solution 111 to be energized and the substrate 200 can be applied to the substrate 200 equally.

  Finally, FIG. 9 is a drawing showing the ion distribution during the progress of plating using the circular plating tank according to the present invention. As shown in the figure, the circular plating tank 100 of the present invention has a circular plating tank 100. The ions contained in the plating solution 111 are evenly distributed around the surface of the substrate 200 arranged so as to form a substantially circular polygon inside the substrate 200, whereby the substrate 200 immersed in the plating solution 111 is The ions for forming the plating layer can be equally deposited on the surface.

  That is, as shown in FIG. 9, after the substrate 200 is mounted in the plating tank 100, the ions distributed around the substrate 200 are evenly distributed with respect to each substrate 200 even if time passes. Thereby, a plating layer is uniformly formed on the surface of the substrate 200.

  In addition, in the substrate 200 disposed in the circular plating tank 100, the influence on the disturbance generated inside and outside the plating tank 100 acts equally on both surfaces of the substrate 200, and the rotation of the substrate 200 and the flow of the plating solution 111 and A thin and uniform plating layer can be formed on the surface of the substrate 200 by dispersing external influence factors on each substrate 200 by rotating the plating tank 100 or the like.

  The form of the plating tank and the substrate arrangement in the plating tank can be applied to the electroless plating tank in addition to the electrolytic plating tank described above. Although the plating speed is somewhat slow, there is an advantage that a uniform distribution can be obtained on the surface of the substrate to be plated.

  The above-described preferred embodiments of the present invention are disclosed for the purpose of illustration, and those having ordinary knowledge in the technical field to which the present invention belongs do not depart from the technical idea of the present invention. Various substitutions, modifications, and alterations are possible within the scope, and such substitutions, alterations, and the like belong to the scope of the claims.

It is a block diagram of the conventional plating tank. It is a figure which shows ion distribution at the time of the plating progress of the conventional plating tank. It is a perspective view of the circular plating tank concerning the present invention. It is a top view of the circular plating tank concerning the present invention. It is a figure which shows embodiment of the board | substrate arrangement | sequence in the circular plating tank which concerns on this invention. It is a figure which shows embodiment of the board | substrate arrangement | sequence in the circular plating tank which concerns on this invention. It is a figure which shows embodiment of the board | substrate arrangement | sequence in the circular plating tank which concerns on this invention. It is a block diagram which shows the plating solution circulation structure of the circular plating tank which concerns on this invention. It is a block diagram which shows the plating solution circulation structure of the circular plating tank which concerns on this invention. It is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a block diagram which shows the electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a block diagram of other embodiment of electrode arrangement | positioning of the circular plating tank which concerns on this invention. It is a figure which shows the ion distribution at the time of plating progress using the circular plating tank which concerns on this invention.

Explanation of symbols

100 Plating tank 110 Rotating shaft 111 Plating solution 120 Substrate fixing frame 121 Substrate fixture 200 Substrate

Claims (15)

A circular plating tank containing a plating solution inside;
A substrate arranged to form a circle or a polygon close to a circle in the plating tank;
Including circular plating tank.   2. The plating tank according to claim 1, wherein the plating tank is formed in a cylindrical shape having an open top, and contains a plating solution that is a solution in which positive ions are electrolyzed when a positive current is applied. The circular plating tank described in 1.   3. The plating tank according to claim 1, wherein a rotating shaft is attached to a central portion of the plating tank, a substrate fixing frame is attached to the rotating shaft, and a substrate to be plated is fixed to the substrate fixing frame. The described circular plating tank.   The circular plating tank according to claim 3, wherein the substrate fixing frame is provided with a substrate fixing tool capable of fixing a plurality of substrates.   The substrate is mounted along a frame portion of an annular substrate fixing frame with upper and lower ends individually coupled to a substrate fixture, and the substrate is immersed in the plating solution by rotating a rotating shaft. It rotates in the rotation direction of a fixed frame, The circular plating tank as described in any one of Claim 1 to 4 characterized by the above-mentioned.   6. The circular plating tank according to claim 1, wherein the substrates are arranged in a plurality of rows so as to form a circle inside the plating tank along a shape of the plating tank.   The plating solution in the plating tank is circulated and flowed by a rotating shaft attached to a central portion of the plating tank or another rotating member attached to a connecting portion of the rotating shaft. The circular plating tank according to any one of 1 to 6.   2. The plating solution in the plating tank is circulated and flown inside and outside by rotation of a cylindrical cylinder provided inside the substrate mounted in the plating tank. To 7. The circular plating tank according to any one of 7 to 7.   The circular plating tank according to claim 1, wherein the plating solution in the plating tank is circulated and flowed by rotation of the plating tank itself.   The anode disposed in the plating tank so as to be able to energize the plating solution is formed on a rotating body attached so as to penetrate the plating tank, or is disposed at the center of the plating tank separately from the rotating body. The circular plating tank according to any one of claims 1 to 9, wherein:   The anode disposed in the plating tank so as to be able to energize the plating solution is disposed in a cylinder between the center of the plating tank and the substrate mounted in the plating tank. The circular plating tank according to any one of claims 1 to 10.   The anode disposed in the plating tank so as to be capable of energizing the plating solution is formed in close contact with an inner wall surface of the plating tank or at a predetermined interval. The circular plating tank as described in any one of these.   The anode disposed in the plating tank so as to be able to energize the plating solution is formed on the inner wall surface of the plating tank at the same time as being disposed at the center of the plating tank, or between the plating tank and the substrate. The circular plating tank according to any one of claims 1 to 12, wherein the circular plating tank is formed on the inner wall surface of the plating tank at the same time as being arranged in a cylindrical shape.   14. The anode according to claim 1, wherein the anode disposed in the plating tank so as to be capable of energizing with the plating solution is disposed at an arbitrary point outside the substrate disposed in the plating tank. The circular plating tank as described in any one.   The circular plating tank according to claim 1, wherein the plating tank is an electrolytic plating tank in which an anode and a cathode are connected, or an electroless plating tank in which an electrode is not connected.

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