CN108588800B - Electroplating device and electroplating method - Google Patents

Abstract

The present invention enables the formation of bumps having a flat top shape or the formation of a metal film having good uniformity in the surface even under high current density conditions when plating an object to be plated (substrate) such as a semiconductor wafer. Comprising: a plating tank (10) for holding a plating solution (Q); an anode (26) disposed in the plating solution immersed in the plating tank; a holder (24) for holding an object to be plated (W) and disposed at a position facing the anode; a stirrer (32) which is disposed between the anode and the object to be plated held by the holder, reciprocates in parallel with the object to be plated, and stirs the plating solution; and a control unit (46) for controlling a stirrer drive unit (42) for driving the stirrer. The control unit controls the agitator drive unit so that the average value of the absolute value of the agitator movement speed is 70 to 100 cm/sec.

Description

Electroplating device and electroplating method

The present application is a divisional application, the original application of which is a patent application filed in the chinese patent office on 12/4/2008, and the application number is 200810178892.9(201210570167.2(201510813398.5)), entitled "electroplating apparatus and electroplating method".

Technical Field

The present invention relates to a plating apparatus and a plating method for plating a surface of a plating target (substrate) such as a semiconductor wafer; in particular, the present invention relates to a plating apparatus and a plating method suitable for forming a plating film in fine wiring grooves, holes, or openings of a resist provided on the surface of a semiconductor wafer, or forming bumps (bump electrodes) electrically connected to electrodes of a package on the surface of a semiconductor wafer.

Background

In TAB (Tape Automated Bonding) or flip chip, for example, it is widely carried out to form bump-like connection electrodes (bumps) of gold, copper, solder, nickel, or a multilayer of these materials at predetermined positions (electrodes) on the surface of a semiconductor chip on which wirings are formed, and to electrically connect the package electrodes or TAB electrodes through the bumps. Various methods such as plating, vapor deposition, printing, and rolling bump (ボールバンプ) are known as methods for forming such bumps, but as the number of I/O chips increases and the pitch becomes finer, a plating method that can be made finer and has relatively stable performance is often used.

By using the electroplating method, a high-purity metal film (plating film) can be easily obtained, and the thickness of the metal film can be relatively easily controlled in addition to a high film-forming speed of the metal film. In the process of forming a metal film on a conventional semiconductor wafer, uniformity of in-plane film thickness is also strictly required in order to achieve high-density mounting, high performance, and high yield. By adopting electroplating, it is expected that a metal film having excellent in-plane film thickness uniformity can be obtained by making uniform the distribution of the metal ion supply rate and the potential distribution in the plating liquid.

As a plating apparatus using a so-called immersion method, there is known an apparatus including a plating tank for storing a plating liquid therein, a substrate (object to be plated) whose peripheral edge is held by a substrate holder and an anode held by an anode holder are arranged in the plating tank so as to face each other and to be perpendicular to each other, an adjustment plate (adjustment plate) made of a dielectric material having a central hole formed in the center thereof is arranged between the anode and the substrate, and a stirrer for stirring the plating liquid is arranged between the adjustment plate and the substrate (see, for example, patent document 1).

In the plating apparatus described in patent document 1, a plating solution is contained in a plating tank, an anode, a substrate, and an adjustment plate are immersed in the plating solution, the anode is connected to an anode of a plating power supply via a lead, the substrate is connected to a cathode of the plating power supply, and a predetermined plating voltage is applied between the anode and the substrate, whereby a metal is deposited on the surface of the substrate to form a metal film (plating film). In addition, the plating solution is stirred by a stirrer disposed between the adjusting plate and the substrate during plating, and a sufficient amount of ions are uniformly supplied to the substrate, thereby forming a metal film having a more uniform thickness.

In the invention described in patent document 1, an adjustment plate having a plating liquid flow path inside a cylindrical body is disposed between an anode and a substrate disposed at a position facing the anode, and the adjustment plate is used to adjust the potential distribution in a plating tank, thereby adjusting the film thickness distribution of a metal film formed on the substrate surface.

Further, a plating apparatus has been proposed in which a distance between an adjustment plate disposed in a plating solution immersed in a plating tank and an object to be plated (object to be plated) is shortened as much as possible, thereby making a potential distribution of the entire surface of the object to be plated more uniform and thereby forming a metal film having a more uniform film thickness (see, for example, patent document 2).

In recent years, in order to achieve higher device productivity, it has been strongly demanded to shorten the plating time required for forming a plating film having a predetermined film thickness to about 2/3 times the conventional time. In order to perform plating of a predetermined film thickness on a certain plating area in a shorter time, it is necessary to perform plating at a high plating rate by applying a large current, that is, at a high current density. However, if the plating is performed under high current density conditions by a conventional general plating apparatus and operation method, the in-plane uniformity of the plating film thickness tends to be poor. The in-plane uniformity of the plating film thickness is required to be higher than that of the conventional one and to have a high level. Therefore, shortening the distance between the adjustment plate and the object to be plated as described in patent document 2 is more important when plating is performed under plating conditions of high current density.

As a problem of plating under a high current density condition, the present inventors have found that if plating is performed under a high current density condition by a conventional general plating apparatus and operation method, a bump formed by plating tends to have an uneven top shape and a sharp convex shape. While the WL-CSP (Wafer Level-Chip sizepack) technology under development covers the bumps with resin after the bumps are formed by electroplating, if the top ends of the bumps are pointed, an excessive amount of resin must be deposited to cover the entire bumps, which increases the cost. Further, when resin is deposited, the resin surface is flattened by a doctor blade called a squeegee in order to make the surface smooth, but if the resin surface is a high bump having a locally tapered protrusion, there is a problem that the bump collapses when the resin surface is flattened by a doctor blade (squeegee). Further, after the bump is coated with the resin, the resin and the bump are ground to a predetermined thickness by mechanical polishing, but in this case too, an excessive amount of the resin must be ground, which increases the cost.

There have been proposed plating apparatuses and plating methods for plating a printed wiring board having a through hole by driving one of a pair of stirring rods for stirring a plating solution at a speed of 5cm/sec to 20cm/sec and driving the other at a speed of 25cm/sec to 70cm/sec (see, for example, patent document 3). However, even if the plating is performed while moving the pair of stirring rods at such speeds, respectively, the bumps having a flat tip shape cannot be formed.

[ patent document 1] JP WO2004/009879 pamphlet

[ patent document 2] Japanese patent application laid-open No. 2001-329400

[ patent document 3] Japanese patent application laid-open No. 2006-41172

Disclosure of Invention

The present invention has been made in view of the above problems, and an object thereof is to provide a plating apparatus and a plating method capable of forming a bump having a flat top end shape and a metal film having good uniformity in a plating surface even when plating is performed under a high current density condition when a plating object (substrate) such as a semiconductor wafer is plated.

The invention of claim 1 is an electroplating apparatus, comprising: a plating bath for holding a plating solution; an anode disposed to be immersed in the plating solution in the plating tank; a holder configured to hold an object to be plated and disposed at a position facing the anode; a stirrer which is disposed between the anode and the object to be plated held by the holder, and which reciprocates in parallel with the object to be plated to stir the plating solution; and a control unit for controlling a stirrer driving unit for driving the stirrer; the control unit controls the agitator driving unit so that an average value of absolute values of moving speeds of the agitator is 70 to 100 cm/sec.

In this way, by operating the stirrer disposed between the anode and the object to be plated at a speed (high speed) having an average absolute value of the speed of 70 to 100cm/sec to stir the plating solution, it is possible to supply sufficient and uniform ions into the holes of the protective layer formed in advance for forming the bump, for example, when forming the bump, and to form the bump having a flat tip shape even under the plating condition of high current density.

The invention according to claim 2 is a plating apparatus according to claim 1, characterized in that: the stirrer is composed of a plate-like member having a lattice portion.

The invention according to claim 3 is a plating apparatus according to claim 2, characterized in that: the plate-like member has a constant thickness of 3 to 5 mm.

The invention according to claim 4 is a plating apparatus according to claim 2 or 3, characterized in that: the distance between the stirrer and the object to be plated is 5 to 11 mm.

The invention according to claim 5 is a plating apparatus according to claim 1, characterized in that: an adjustment plate made of a dielectric material and disposed between the anode and the stirrer; the adjusting plate has a cylindrical portion and a flange portion, and the inner diameter of the cylindrical portion is along the outer shape of the electroplated object; the flange portion is connected to an outer peripheral surface of the anode-side end portion of the cylindrical portion, and blocks an electric field formed between the anode and the object to be plated.

In this way, by disposing the adjustment plate between the anode and the agitator, the potential distribution over the entire surface of the object to be plated is made more uniform, and thereby the uniformity of the metal film (plating film) formed on the object to be plated in the plating surface can be improved even under the plating condition of high current density.

The present invention according to claim 6 is a plating apparatus according to claim 5, characterized in that: the distance between the end of the cylindrical part on the side of the object to be plated and the object to be plated is 8-25 mm.

The distance between the end of the cylindrical portion on the side of the object to be plated and the object to be plated is preferably 12 to 18 mm.

The invention according to claim 7 is a plating apparatus according to claim 1, characterized in that: the holder has an outwardly projecting holder arm, and the plating tank has a holder support portion that contacts the holder arm and supports the holder in a suspended manner; a fixing mechanism for fixing the holder arm to the holder support portion is provided at a contact portion between the holder arm and the holder support portion.

Thus, even if the holder is subjected to backward pressure by the flow of the plating liquid when the stirrer is moved at high speed, for example, when the holder is suspended and supported by the plating tank, the holder can be prevented from swinging or falling.

The 8 th aspect of the present invention is a plating apparatus according to the 7 th aspect having the following features: the fixing mechanism is constituted by a magnet provided on at least one of the holder arm and the holder support portion.

This can improve the holding force by the magnetic force.

The invention according to claim 9 is a plating apparatus according to claim 7 or 8, characterized in that: a contact point which is provided on a part of at least both of contact portions of the holder arm and the holder support portion, and which is brought into contact with and closed when the holder is suspended and supported in the plating tank; the power is supplied to the electroplated body through the contact closure.

In this way, by providing the contact points on at least a part of the contact portions of the holder arm and the holder support portion, when the holder is suspended and supported by the plating tank, the contact points on the holder arm side and the contact points on the holder support portion side can be reliably brought into contact with each other.

The invention provides an electroplating method according to claim 10, wherein an anode and an object to be electroplated are disposed in the electroplating solution in the electroplating bath so as to face each other; while applying a voltage between the anode and the object to be plated, a stirrer disposed between the anode and the object to be plated is reciprocated in parallel with the object to be plated at a moving speed of 70 to 100cm/sec as an average absolute value.

The 11 th aspect of the present invention is a plating method of the 10 th aspect having the following features: the stirrer is a plate-like member having a lattice portion.

The invention according to claim 12 is a plating method according to claim 11 having the following features: the plate-like member has a constant thickness of 3 to 5 mm.

The invention according to claim 13 is a plating method according to claim 11 or 12, characterized in that: the distance between the stirrer and the object to be plated is 5 to 11 mm.

The 14 th aspect of the present invention is a plating method according to the 10 th aspect, characterized in that: disposing an adjustment plate between the anode and the agitator, the adjustment plate being made of a dielectric material and having a cylindrical portion and a flange portion, the cylindrical portion having an inner diameter along an outer shape of the object to be plated; the flange portion is connected to an outer peripheral surface of the anode-side end portion of the cylindrical portion, thereby blocking an electric field formed between the anode and the object to be plated.

The 15 th aspect of the present invention is the plating method of the 14 th aspect having the following features: the distance between the end of the cylindrical part on the side of the object to be plated and the object to be plated is 8-25 mm.

The distance between the end of the cylindrical portion on the side of the object to be plated and the object to be plated is preferably 12 to 18 mm.

The invention according to claim 16 is a plating apparatus comprising: a plating bath for holding a plating solution; an anode disposed to be immersed in the plating solution in the plating tank; a holder for holding an object to be plated, the holder being disposed at a position facing the anode; a stirrer which is disposed between the anode and the object to be plated held by the holder, and which reciprocates in parallel with the object to be plated to stir the plating solution; and a control unit for controlling a stirrer driving unit for driving the stirrer; the plating bath is divided into an upper electroplating object processing chamber and a lower electroplating solution dispersing chamber by a partition plate with a plurality of electroplating solution through holes inside; the plating liquid dispersion chamber is provided with a shielding plate for ensuring the dispersion flow of the plating liquid and shielding an electric field.

In this way, the plating vessel is partitioned into the upper plating-target body treatment chamber and the lower plating liquid dispersion chamber by the partition plate, and the shielding plate is provided in the plating liquid dispersion chamber, whereby formation of the electric field from the anode to the plating target body in the plating liquid dispersion chamber is suppressed, and the electric field formed in the lower portion of the plating target body can be prevented from affecting the uniformity of the plating surface of the plating film. The influence of the electric field formed in the lower part of the object to be plated on the in-plane uniformity of the plating film is not a problem under the conventional low current density plating conditions, but is a problem because the plating film has a rapidly increased thickness in the portion near the bottom of the plating tank under the higher current density conditions than in the conventional cases.

The 17 th aspect of the present invention is a plating apparatus according to the 16 th aspect having the following features: an adjustment plate made of a dielectric material and disposed between the anode and the stirrer; the adjusting plate has a cylindrical portion and a flange portion, and the inner diameter of the cylindrical portion is along the outer shape of the electroplated object; a flange portion connected to an outer peripheral surface of the anode-side end portion of the cylindrical portion so as to block an electric field formed between the anode and the object to be plated; an electric field shielding member connected to the partition plate is attached to a lower end of the flange portion.

In this way, the electric field formed between the anode and the object to be plated can be suppressed by providing the adjustment plate, and the electric field can be prevented from leaking from the gap between the flange portion and the partition plate by providing the electric field shielding member between the flange portion and the partition plate.

The 18 th aspect of the present invention is a plating apparatus according to the 16 th aspect, characterized in that: the plating liquid dispersion chamber is partitioned into an anode side liquid dispersion chamber and a cathode side liquid dispersion chamber by the shield plate, and the plating liquid is supplied from a plating liquid supply passage to the anode side liquid dispersion chamber and the cathode side liquid dispersion chamber.

In this way, by completely partitioning the plating liquid dispersion chamber into the anode-side liquid dispersion chamber and the cathode-side liquid dispersion chamber by the shield plate, it is possible to reliably prevent the potential line generated at the anode from passing through the plating liquid in the plating liquid dispersion chamber to reach the object to be plated, which is the cathode.

The 19 th aspect of the present invention is a plating apparatus according to the 1 st aspect, characterized in that: the agitator is connected to a shaft extending from the agitator drive unit via a coupling.

Thus, the agitator can be easily separated from the shaft extending from the agitator drive shaft by the coupling, and the agitator replacement operation can be performed more quickly and easily.

The present invention in claim 20 provides an electroplating apparatus, comprising: a plating bath for holding a plating solution; an anode disposed to be immersed in the plating solution in the plating tank; a holder configured to hold an object to be plated and disposed at a position facing the anode; a stirrer which is disposed between the anode and the object to be plated held by the holder, and which reciprocates in parallel with the object to be plated to stir the plating solution; a control unit for controlling a stirrer driving unit for driving the stirrer; an adjustment plate made of a dielectric material and disposed between the anode and the stirrer; and an adjusting plate moving mechanism for moving the adjusting plate in a vertical or horizontal direction relative to the object to be plated.

Thus, the position of the adjusting plate relative to the object to be plated in the vertical direction or the horizontal direction is finely adjusted by the adjusting plate moving mechanism, and the in-plane uniformity of the plating film formed on the surface of the object to be plated can be improved. In particular, it is important to improve the in-plane uniformity of the thickness of the plating film formed on the surface of the object to be plated by finely adjusting the position of the adjusting plate relative to the object to be plated in the vertical or horizontal direction, which is arranged in the vicinity of the object to be plated.

The 21 st aspect of the present invention is a plating apparatus according to the 20 th aspect having the following features: the adjusting plate moving mechanism is provided with a pushing component which pushes the adjusting plate to move the adjusting plate.

The pushing member is constituted by, for example, a pushing bolt, and the amount of movement of the adjustment plate can be easily adjusted by managing the pushing amount of the pushing member, for example, in the case of using a pushing bolt having a predetermined pitch as the pushing member, by managing the number of rotations of the pushing bolt.

The invention according to claim 22 is a plating apparatus according to claim 20 or 21, characterized in that: the inner circumferential surface of the plating tank is provided with a guide part for guiding when the adjusting plate is moved.

Thus, the adjusting plate can be moved in parallel with the object to be plated using the guide portion as a guide in a state where the distance between the adjusting plate and the object to be plated is constant. Further, by using the guide portion having the recessed portion and into which the outer peripheral end portion of the adjustment plate can be inserted, leakage of the electric field from the outer periphery of the adjustment plate can be prevented.

The 23 rd aspect of the present invention is a plating apparatus according to the 20 th aspect having the following features: the adjusting plate has an auxiliary adjusting plate mounting portion to which an auxiliary adjusting plate for adjusting an electric field is mounted.

Thus, the adjustment plate and the auxiliary adjustment plate are combined without changing the installation position of the adjustment plate or replacing the adjustment plate, so that an optimum electric field can be formed according to the type of the object to be plated.

The 24 th aspect of the present invention is a plating apparatus according to the 20 th aspect, characterized in that: and a positioning and holding part for positioning and holding the holder, the adjusting plate and the anode holder for holding the anode.

Thus, by providing a positioning and holding member for positioning and holding the substrate holder, the adjustment plate, and the anode holder in the plating tank, the center positions of the substrate holder, the adjustment plate, and the anode holder in the vertical direction of the plating tank can be easily aligned.

The invention has the following effects: when the plating apparatus and the plating method of the present invention are used to plate an object to be plated (substrate) such as a semiconductor wafer, bumps having a flat top shape can be formed or a metal film having good in-plane uniformity can be formed even under high current density conditions.

Drawings

FIG. 1 is a front longitudinal sectional view showing a plating apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view showing a stirrer of the plating apparatus shown in FIG. 1.

Fig. 3 is a sectional view a-a of fig. 2.

Fig. 4 is a view corresponding to fig. 3 showing various modifications of the agitator.

FIG. 5 is a schematic view showing both a stirrer driving part and a plating tank of the plating apparatus shown in FIG. 1.

Fig. 6 is a plan view showing the relationship of the agitator at the end of the agitator stroke.

FIG. 7 is a perspective view showing an adjustment plate of the plating apparatus shown in FIG. 1.

Fig. 8 is a side view showing another example of the adjustment plate.

Fig. 9 is a view showing a relationship between a substrate holder and a holder support portion of a plating tank in the plating apparatus shown in fig. 1.

Fig. 10 is an enlarged perspective view of the periphery of a holder arm of the plating apparatus shown in fig. 1.

Fig. 11 is a sectional view showing a state in which the holder arm is in contact with the holder support portion.

Fig. 12 is a right side view of fig. 11.

Fig. 13 is a perspective view showing another example of the arm support portion.

FIG. 14 is a plan view showing a partition plate of the plating apparatus shown in FIG. 1.

Fig. 15 is a plan view showing another example of the partition plate.

FIG. 16 is a sectional view showing a state where a partition plate is provided on a side plate of a plating tank in the plating apparatus shown in FIG. 1.

FIG. 17 is a perspective view showing the relationship between a partition plate, a shield plate and the bottom of a plating tank in the plating apparatus shown in FIG. 1.

FIG. 18 is a perspective view showing another relationship of the partition plate, the shield plate and the bottom of the plating tank.

Fig. 19 is a sectional view showing a relationship between a flange portion of an adjusting plate and a partition plate in the plating apparatus shown in fig. 1.

Fig. 20 is a view showing a main part of an example in which an adjustment plate is attached so that the distance between the adjustment plate and a substrate can be adjusted, as viewed from above a plating tank.

FIG. 21 is a flowchart showing a process of copper electroplating in the process of forming a bump.

FIG. 22 is a view showing the shape of a bump formed by plating at a current density of 8ASD and an average absolute value of stirring speed of a stirrer of 20 cm/sec.

FIG. 23 is a view showing the shape of a bump formed by electroplating at a current density of 8ASD and an average absolute value of stirring speed of a stirrer of 83 cm/sec.

FIG. 24 is a photomicrograph of bumps formed by electroplating using a 2mm thick stirrer, with the average absolute value of the stirring speed of the stirrer set at 40 cm/sec.

FIG. 25 is a photomicrograph of bumps formed by electroplating using a 4mm thick stirrer, in which the average absolute value of the stirring speed of the stirrer was 40 cm/sec.

FIG. 26 is a photomicrograph of bumps formed by electroplating using a 4mm thick stirrer, with the average absolute value of the stirring speed of the stirrer set at 67 cm/sec.

FIG. 27 is a photomicrograph of bumps formed by electroplating using a 4mm thick stirrer, in which the average absolute value of the stirring speed of the stirrer was 83 cm/sec.

FIG. 28 is a photomicrograph of bumps formed by electroplating using a stirrer having a thickness of 3mm, with the average absolute value of the stirring speed of the stirrer set to 83 cm/sec.

FIG. 29 is a view showing the height distribution of bumps when bumps are formed by electroplating in a plating tank in which no shield plate is provided on the lower surface of the partition plate.

FIG. 30 is a view showing the height distribution of bumps when the bumps are formed by electroplating in a plating tank in which a shield plate is provided on the lower surface of a partition plate.

FIG. 31 is a graph showing in-plane uniformity of bump height when bumps are formed using a flat plate having a thickness of 5mm and a single opening at the center as an adjusting plate, with the average absolute value of the stirring speed of the stirrer set to 20cm/sec, and the distance between the adjusting plate and the substrate set to 35 mm.

FIG. 32 is a graph showing in-plane uniformity of bump height when bumps are formed using the adjusting plate shown in FIG. 7 with the average absolute value of the stirring speed of the stirrer set to 83cm/sec and the distance between the adjusting plate and the substrate set to 15 mm.

Fig. 33 is a diagram showing a relationship between the X axis and the Y axis in fig. 31 and 32.

FIG. 34 is a front longitudinal sectional view of a plating apparatus according to another embodiment of the present invention.

FIG. 35 is a plan view showing another driving mechanism of the stirrer and the plating tank.

Fig. 36 is a front view in longitudinal section of fig. 35.

FIG. 37 is a vertical cross-sectional side view showing another adjustment plate having an adjustment plate moving mechanism and another plating tank.

Fig. 38 is a sectional view taken along line B-B of fig. 37.

FIG. 39 is a view showing a main part of an adjusting plate and a plating tank provided with another adjusting plate moving mechanism.

Fig. 40 is a front view showing still another adjustment plate.

Fig. 41 is a top view of fig. 40.

FIG. 42 is a front elevation view showing a main part of a plating apparatus according to still another embodiment of the present invention.

FIG. 43 is a front view showing an anode holder and a positioning and holding portion used in the plating apparatus shown in FIG. 42.

Fig. 44 is a front view showing still another adjustment plate.

Fig. 45 is a cross-sectional view taken along line C-C of fig. 44.

Description of the symbols

10. An electroplating bath; 12. an overflow trough; 18. a plating solution supply port; 20. a constant temperature unit; 22. a filter; 24. a substrate holder; 26. an anode; 28. an anode holder; 32. a stirrer; a long hole; 32b. a lattice portion; 34. an adjustment plate; 42. a stirrer driving part; 44. an electric motor; 46. a control unit; 50. a cylindrical portion; 52. a flange portion; 60. a holder holding part; 62. a holder support portion; 64. a holder arm; 66. an arm-side contact; 68. a contact point on one side of the support part; 70. an arm-side magnet; 72. a magnet on the support side; 80. a partition plate; 80a plating solution through hole; 82. a shielding plate; 84. a substrate processing chamber; 86. an electroplating solution dispersing chamber; 90. a partition plate support portion; 94. an electric field shielding member (rubber sheet); 96. a slit plate for fixing the adjusting plate; 100. an electric field shielding member (rubber sheet); 110. an anode-side liquid dispersion chamber; 112. a cathode side liquid dispersion chamber; 120. a stirrer pressing member; 122a, 122b, coupling; 134. an adjustment plate; 136. a cylindrical portion; 140. a grip portion; 142. a regulating plate moving mechanism; 144. an adjusting plate support portion; 146. a cradle (blacket); 148. pushing the bolt left and right; 150. left and right fixing bolts; 152. a guide section; 158. an electric field shielding member (rubber sheet); 160. a regulating plate moving mechanism; 162. pushing the bolt up and down; 164. upper and lower fixing bolts; 170. an auxiliary adjusting plate; side hooks (auxiliary adjustment plate mount); 172b. bottom hook (auxiliary adjustment plate mount); 180. a fixed part; 182. a positioning and holding part; 188. partition wall

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In addition, the following examples describe examples of copper plating on the surface of a substrate as an object to be plated. In the following embodiments, the same or corresponding components are denoted by the same reference numerals, and redundant description thereof is omitted.

FIG. 1 is a front longitudinal sectional view showing a plating apparatus according to an embodiment of the present invention. As shown in fig. 1, the plating apparatus includes a plating tank 10 for holding a plating solution Q therein, and an overflow vessel 12 for receiving the plating solution Q overflowing from the edge of the plating tank 10 is provided on the outer periphery of the plating tank 10. One end of a plating bath supply channel 16 having a pump 14 is connected to the bottom of the overflow vessel 12, and the other end of the plating bath supply channel 16 is connected to a plating bath supply port 18 provided at the bottom of the plating vessel 10. Thus, the plating liquid Q stored in the overflow vessel 12 is returned to the plating vessel 10 by the driving of the pump 14. A thermostatic unit 20 for adjusting the temperature of the plating liquid Q and a filter 22 for filtering and removing foreign matters in the plating liquid Q are provided in the plating liquid supply passage 16 on the downstream side of the pump 14.

The plating apparatus includes a substrate holder 24 for detachably holding a substrate (object to be plated) W and immersing the substrate W in a plating liquid Q in the plating tank 10 in a state where the substrate W is vertical. An anode 26 is disposed at a position facing the substrate W held by the substrate holder 24 in the plating vessel 10 and immersed in the plating liquid Q, and the anode 26 is held by an anode holder 28 and immersed in the plating liquid Q. In this example, phosphorus-containing copper was used as the anode 26. The substrate W and the anode 26 are electrically connected by a plating power supply 30, and a plating film (copper film) is formed on the surface of the substrate W by passing a current between the substrate W and the anode 26.

Between the anode 26 and the substrate W held and immersed in the plating liquid Q by the substrate holder 24, a stirrer 32 is disposed to reciprocate parallel to the surface of the substrate W to stir the plating liquid Q. Thus, the plating liquid Q is stirred by the stirrer 32, whereby sufficient copper ions can be uniformly supplied to the surface of the substrate W. The distance between the stirrer 32 and the substrate W is preferably 5 to 11 mm. Between the stirrer 32 and the anode 26, a dielectric adjustment plate (adjustment plate)34 is disposed to make the potential distribution more uniform over the surface of the substrate W.

As shown in fig. 2 and 3, the agitator 32 is formed of a rectangular plate-shaped material having a constant thickness with a plate thickness t of 3 to 5mm, and has a plurality of cells 32b extending in the vertical direction by providing a plurality of elongated holes 32a in parallel inside. The stirrer 32 is made of titanium coated with teflon (registered trademark), for example. Length L of stirrer 32 in the vertical direction₁And the length-wise dimension L of the elongated hole 32a₂The dimension in the vertical direction of the substrate W is set to be much larger. The length H of the agitator 32 in the lateral direction is set to be sufficiently larger than the dimension of the substrate W in the lateral direction, in combination with the amplitude (stroke St) of the reciprocation of the agitator 32.

In order to efficiently stir the plating liquid in the grid portion 32b between the long holes 32a and the long holes 32a, the plating liquid is efficiently passed through the long holes 32a, and the width and number of the long holes 32a are preferably determined so that the grid portion 32b is as thin as possible within a range in which the grid portion 32b has the necessary rigidity. Further, it is also important to make the lattice portion 32b of the agitator 32 thin in order to reduce the influence of the shadow (a place not influenced by the electric field or less influenced by the electric field) of the electric field formed on the substrate W when the speed of the agitator 32 moving is slowed or stopped instantaneously in the vicinity of both ends of the reciprocating movement of the agitator 32.

In the present embodiment, as shown in fig. 3, the elongated holes 32a are vertically formed, and the cross section of each cell 32b is rectangular. The cross section of the lattice section 32b may be chamfered at four corners of the cross section of the lattice section 32b as shown in fig. 4(a), or the cross section of the lattice section 32b may be formed into a parallelogram by providing an angle to the lattice section 32b as shown in fig. 4 (b).

In order to bring the adjustment plate 34 closer to the substrate W, the thickness (plate thickness) t of the stirrer 32 is preferably 3 to 5 mm. In this example, the thickness is set to 4 mm. It has been confirmed that if the thickness (plate thickness) t of the stirrer 32 is made 1 or 2mm, there is not sufficient strength. Further, the stirrer 32 is made uniform in thickness, thereby preventing the plating liquid from splashing or shaking greatly.

FIG. 5 shows the driving mechanism of the stirrer 32 and the plating tank 10. The agitator 32 is fixed to a shaft 38 extending in the horizontal direction with a clamp 36 fixed to an upper end of the agitator 32, and the shaft 38 is held by a shaft holding portion 40 and can slide left and right. An end of the shaft 38 is connected to an agitator driving unit 42 that linearly reciprocates the agitator 32 in the left-right direction, and the agitator driving unit 42 converts the rotation of the motor 44 into the linear reciprocating motion of the shaft 38 by a crank mechanism (not shown). The present embodiment has a control unit 46 for controlling the speed at which the agitator 32 moves by controlling the rotational speed of the motor 44 of the agitator drive unit 42. The mechanism of the agitator drive unit 42 is not limited to the crank mechanism, and may be a mechanism that converts the rotation of a servo motor into linear reciprocating motion of a shaft by a ball screw or a mechanism that linearly reciprocates a shaft by using a linear motor.

In the present embodiment, as shown in fig. 6, the grid portions 32b of the agitator 32 are not positioned to overlap each other at the position where the agitator 32 has moved the left and right stroke ends of the stroke St. This can reduce the influence of the electric field shadow formed on the substrate W by the stirrer 32.

In the present embodiment, the average absolute value of the moving speed of the agitator 32 is 70 to 100cm/sec, and the agitator reciprocates at a higher speed than the conventional agitator. This is based on the fact that: the inventors confirmed through experiments that the current density was set to be lower than that of the conventional 5ASD (A/dm)²) In the case of a high 8ASD, the stirring is performed at a higher speed than the conventional one by the stirrer, whereby bumps having a flat top end shape can be formed. That is, the average value of the absolute values of the stirring speeds of the stirrers capable of forming the convex points having a flat tip shape is 70 to 100 cm/sec. In the present embodiment, the rotational motion of the motor 44 is converted into the linear reciprocating motion of the agitator 32 by a crank mechanism, and the agitator 32 reciprocates once with an amplitude of 10cm (stroke St) when the motor 44 rotates one revolution. In the present embodiment, the average value of the absolute values of the optimum stirring speeds of the stirrer 32 is 83cm/sec so that the optimum bump can be formed even when the motor 44 is rotated at 250 rpm.

The profile of the adjustment plate 34 shown in fig. 1 is shown in fig. 7. The adjustment plate 34 is composed of a cylindrical portion 50 and a rectangular flange portion 52, and is made of dielectric vinyl chloride. The adjustment plate 34 is provided in the plating tank 10 such that the tip of the cylindrical portion 50 is closer to the substrate side and the flange portion 52 is closer to the anode side. The cylindrical portion 50 has a size of an opening capable of sufficiently restricting the electric field expansion and a length along the axial center. In this embodiment, the length of the cylindrical portion 50 along the axial center is 20 mm. The flange portion 52 is provided in the plating tank 10 so as to shield an electric field formed between the anode 26 and the substrate W. In FIG. 1, the distance between the cylindrical portion 50 of the adjustment plate 34 and the substrate W is preferably 8 to 25mm, more preferably 12 to 18 mm.

In this embodiment, as shown in fig. 7, a member having a flange portion 52 attached to an end portion of the cylindrical portion 50 is used as the adjustment plate 34, but as shown in fig. 8, the cylindrical portion 50 may be extended to the anode side so that a part 50a of the cylindrical portion 50 protrudes to the anode side.

As shown in fig. 1, the substrate W is held by a substrate holder 24. The substrate holder 24 is configured to supply power from a peripheral portion of the substrate W to the substrate W with a substrate conductive film such as a copper sprayed film. The conductive contact of the substrate holder 24 has a multi-contact structure, and the total value of the contact widths is 60% or more of the circumference of the substrate on which the contact can be obtained. The contacts are distributed at equal intervals, and the contacts are arranged at equal distances from each other.

In the present embodiment, since the stirrer 32 is moved at a high speed, for example, with an average absolute value of 70 to 100cm/sec, the substrate holder 24 receives a backward pressure due to the flow of the plating liquid, and there is a new problem that the substrate holder 24 is swung or the substrate holder 24 is inclined at a more inclined angle than the original angle. When the substrate holder 24 is swung or tilted, the potential distribution becomes uneven, which affects the uniformity of the plating film.

As shown in fig. 9, when the substrate holder 24 is set in the plating vessel 10, the holder gripping portion 60 is held by a transport device (transporter), not shown, and suspended from above, and the holder arms 64 projecting outward are suspended and held by holder support portions 62 fixed to the plating vessel 10.

Fig. 10 is an enlarged view of the periphery of the holder arm 64, fig. 11 is a sectional view showing a state in which the holder arm 64 is in contact with the holder support portion 62, and fig. 12 is a right side view of fig. 11. As shown in fig. 10 to 12, an arm-side contact 66 is provided on a surface of the holder arm 64 facing the holder support portion 62, and the arm-side contact 66 is electrically connected to a cathode contact for supplying power to the substrate W by an electric wiring not shown in the drawings. A support portion side contact 68 is provided on a surface of the holder support portion 62 facing the holder arm 64, and the support portion side contact 68 is electrically connected to an external power supply not shown in the drawing. When the substrate holder 24 is suspended and supported in the plating tank 10, the arm-side contact 66 comes into contact with the support-side contact 68, and the contacts are closed, whereby the external power supply is electrically conducted to the cathode contact, and a cathode voltage can be applied to the cathode contact. In general, the arm-side contact 66 and the support-side contact 68 are provided on either one of the left and right holder arms 64 and the left and right holder supports 62.

An arm-side magnet 70 as a fixing means is provided on a surface of the holder arm 64 facing the holder support portion 62, and a support-portion-side magnet 72 as a fixing means is also provided on a surface of the holder support portion 62 facing the holder arm 64. Neodymium magnets, for example, are used as magnets 70, 72. Thus, when the substrate holder 24 is suspended and supported in the plating vessel 10, the arm-side magnet 70 and the support-side magnet 72 are brought into contact with each other and attracted, and the substrate holder 24 is more firmly fixed in the plating vessel 10 by the holder support 62 and the holder arm 64, whereby the substrate holder 24 can be prevented from being swung or tilted by the flow of the plating solution. The arm-side magnet 70 and the support-side magnet 72 are generally provided on both the right and left sides of the holder arm 64 and the holder support 62.

The position of the substrate holder 24 relative to the plating vessel 10 is determined by the conveyance by the conveyor, but as shown in fig. 13, an opening 62a having a groove shape or a slope at a corner may be provided in the holder support portion 62, and the holder arm 64 of the substrate holder 24 may be guided by the opening 62 a. Even if the opening (guide portion) 62a is provided in the holder support portion 62 in this manner to determine the position of the agitator 32 with respect to the plating tank 10, some dimensional play is required for positioning and transporting the substrate holder 24. When the substrate holder 24 swings or tilts within the range of the play, there is a risk that the contact between the arm-side contact 66 and the support-side contact 68 is intermittently separated, but the contact between the arm-side contact 66 and the support-side contact 68 can be stabilized by firmly supporting the substrate holder 24 in the plating vessel 10 near the contacts 66, 68 with the magnets 70, 72. Wear of the contacts 66, 68 due to friction between the contacts 66, 68 can be suppressed, and durability of the contacts 66, 68 can be improved.

One of the arm-side magnet 70 and the support-side magnet 72 may be made of a magnetic material instead of a magnet. Further, the surface of the magnet may be covered with a magnetic material to prevent damage due to contact. Further, the periphery of the magnet may be surrounded with a magnetic material so that the surface of the magnet is exposed, and a part of the magnetic material may protrude from the surface of the magnet to enhance the magnetic force.

As shown in fig. 1, a partition plate 80 and a shield plate 82 are provided at the bottom of the plating tank 10. In order to uniformly flow the plating liquid Q supplied from the plating liquid supply port 18 provided at the bottom of the plating tank 10 over the entire surface of the substrate W, a space for dispersing the plating liquid is provided at the bottom of the plating tank 10, and a partition plate 80 having a plurality of plating liquid through holes therein is horizontally disposed in the space, whereby the interior of the plating tank 10 is divided into an upper substrate processing chamber 84 and a lower plating liquid dispersion chamber 86.

Fig. 14 shows a plan view of partition plate 80. The partition plate 80 has substantially the same shape as the inside of the plating vessel 10, and is provided with a plating solution passage hole 80a having a plurality of small holes over the entire surface thereof. The plating vessel 10 is divided into a substrate treatment chamber 84 and a plating liquid dispersion chamber 86 by a partition plate 80, and a plurality of plating liquid passing holes 80a through which the plating liquid passes are provided in the partition plate 80, whereby the plating liquid Q is uniformly flowed toward the substrate W. If the plurality of plating liquid passing holes 80a provided in the partition plate 80 have a large diameter, the electric field leaks from the anode 26 to the substrate W side through the plating liquid dispersing chamber 86, which affects the uniformity of the plating film formed on the substrate W, so that the diameter of the plating liquid passing holes 80a is made to be 2.5mm in this embodiment.

Although plating liquid through-holes 80a are provided over the entire surface of partition plate 80 in the present embodiment, it is not necessary to provide plating liquid through-holes 80a over the entire surface of partition plate 80, and plating liquid through-holes 80a may be provided distributed only on the substrate side and plating liquid through-holes 80a may be provided only on the opposite side of the substrate (behind the anode) with position B where anode 26 is disposed, for example, as shown in fig. 15, with position a where adjustment plate 34 is disposed as a boundary. By using the partition plate 80 shown in FIG. 15, not only leakage of the electric field from the anode 26 to the substrate W side through the plating liquid dispersion chamber 86 can be more effectively prevented, but also by providing the plating liquid passage hole 80a also at the rear of the anode 26, particularly when the plating liquid Q is discharged from the plating tank 10, drainage can be reliably performed.

As shown in fig. 16, partition plate 80 is horizontally disposed so as to overlap partition plate support portion 90 provided on side plate 10a of plating tank 10, but partition plate 80 can be closely attached to partition plate support portion 90 by providing seal 92 between partition plate 80 and partition plate support portion 90.

Even if partition plate 80 is provided, the electric field may leak from anode 26 to the substrate W side through plating liquid dispersion chamber 86, and the uniformity of the plating film formed on substrate W may be impaired. Therefore, in the present embodiment, shield plate 82 extending downward in the vertical direction is attached to the lower surface of partition plate 80. Thus, by providing the shield plate 82, the plating liquid Q can be dispersed in the plating liquid dispersion chamber 86 in the plating tank 10 while effectively preventing the electric field from leaking from the anode 26 to the substrate W side through the plating liquid dispersion chamber 86, and can be uniformly flowed to the substrate processing chamber 84 in the plating tank 10. That is, as shown in fig. 17, the shield plate 82 is attached to a position directly above the plating liquid supply port 18 and to the lower surface of the partition plate 80, and a gap S is formed between the bottom of the plating vessel 10. In order to prevent leakage of the electric field, the gap S is preferably as small as possible.

As shown in fig. 18, the shield plate 82 may be brought into contact with the bottom of the plating vessel 10, and a semicircular opening 82a may be provided in the shield plate 82 to secure a flow path of the plating liquid. In the present embodiment, the opening 82a is preferably as small as possible in order to prevent electric field leakage. The shielding plate 82 is disposed on the lower surface of the partition plate 80 not having the plating liquid passing hole 80a, for example, on the lower surface of the partition plate 80 corresponding to the position immediately below the flange portion 52 of the adjustment plate 34.

In the present embodiment, the shielding plate 82 is provided directly above the plating liquid supply port 18, but it is not always necessary to provide it directly above the plating liquid supply port 18, and the shielding plate 82 may be provided in a plurality of pieces.

In the plating apparatus shown in fig. 1, the positional relationship among the substrate W, the anode 26, the adjustment plate 34, and the agitator 32 in the plating tank 10 affects the uniformity of the plating film formed on the substrate W. In the present embodiment, the substrate W, the anode 26, and the adjustment plate 34 are arranged such that the center of the substrate W, the center of the anode 26, and the axial center of the cylindrical portion 50 of the adjustment plate 34 are substantially aligned. The inter-electrode distance between the anode 26 and the substrate W is 90mm in the present embodiment, but the anode 26 may be provided within a range of 60 to 95 mm. The distance between the substrate W and the tip of the cylindrical portion 50 of the adjustment plate 34 on the substrate W side is 15mm in the present embodiment, but since the length of the cylindrical portion 50 is 20mm, the distance between the flange portion 52 of the adjustment plate 34 and the substrate W is 35 mm.

In order to prevent the electric field from leaking from the gap between partition plate 80 and flange portion 52, as shown in fig. 19, an electric field shielding member 94 made of, for example, a rubber sheet and having a lower end in elastic contact with partition plate 80 is provided at the anode-side lower end of flange portion 52 of adjustment plate 34. This prevents an electric field from leaking from the gap between partition plate 80 and flange 52. Further, the flange 52 itself may also serve as an electric field shielding member by bringing the lower end surface of the flange 52 into close contact with the upper surface of the partition plate 80.

The adjustment plate 34 may be attached so that the distance between the adjustment plate 34 and the substrate W is adjustable. That is, as shown in fig. 20, an adjusting plate fixing slit plate 96 having a plurality of slits 96a extending in the vertical direction at predetermined intervals is provided on the side plate 10a of the plating tank 10, and the end portion of the adjusting plate 34 on the flange portion 52 side is inserted into any of the slits 96a of the adjusting plate fixing slit plate 96. At this time, the adjustment plate fixing slit plate 96 is attached to the side plate 10a by the long hole 96b and the fixing screw 98, so that the distance between the adjustment plate 34 and the substrate W can be finely adjusted to an optimum position according to the type of the substrate to be processed by the plating apparatus.

Further, it is preferable to provide the electric field shielding member 100 made of a rubber sheet in the vicinity of the slit plate 96 for fixing the adjustment plate of the flange portion 52, thereby preventing an electric field from being formed from the anode 26 to the substrate W through a gap in the outer periphery of the flange portion 52. The electric field shielding member 100 may be provided only on the anode side of the adjustment plate fixing slit plate 96.

In the plating apparatus of the present invention, the bump diameter is 150 μm and the target plating film thickness is 110 μm, which are typical dimensions of the bump formed on the substrate. In order to form such bumps, it is desirable to use a plating solution having a copper sulfate concentration of 150g/L or more as the plating solution. Examples of the plating solution include a solution containing an organic additive polymer component (retarder), a carrier component (accelerator), and a leveling agent component (retarder) in a base solution of the following components.

The components of the base solution are as follows:

cupric sulfate pentahydrate (CuSO)₄·5H₂O) 200g/L

Sulfuric acid (H)₂SO₄) 100g/L

Chlorine (Cl) 60mg/L

In the conventional bump formation plating, the current density is generally 3 to 5ASD, and in the plating according to the embodiment of the present invention, the current density is, for example, 8 ASD. However, the plating apparatus and the plating method according to the embodiment of the present invention can achieve a current density of 14 ASD. The current density conditions in the following examples are 8ASD unless otherwise specified.

Next, a copper plating process step in the bump formation process is shown in fig. 21. First, the substrate is immersed in pure water, and is subjected to a preliminary washing for, for example, 10 minutes, and then immersed in 5 volume% sulfuric acid (vol%), and is subjected to a preliminary treatment for, for example, 1 minute. The washing with pure water for washing the substrate is performed, for example, 2 times for 30 seconds. Next, for example, after immersing the substrate in the plating liquid, the substrate is kept in a non-energized state for 1 minute, and then the substrate is subjected to a copper plating treatment by energization. The substrate is then washed with pure water and then dried with, for example, a nitrogen gas flow. After the plating step, the protective layer is peeled off by a special protective layer (レジスト) peeling liquid, and then washed with water and dried.

FIGS. 22 and 23 show the difference in the shape of the bump formed by plating when the speed of stirring the plating liquid by the stirrer was changed. The current density was 8 ASD. FIG. 22 shows a case where the plating was performed at a conventional ordinary speed of 20cm/sec as an average value of the absolute value of the stirring speed of the stirrer, and FIG. 23 shows a case where the plating was performed at an average value of about 83cm/sec as an average value of the absolute value of the stirring speed of the stirrer. As shown in FIG. 22, when the current density is as high as 8ASD, the height h of the top end projection of the bump formed at the stirring moving speed of the conventional general low stirrer is set to be as high as 8ASD₁30 μm, and as shown in FIG. 23, the height h of the convex portion at the tip end of the bump formed at a high stirrer moving speed such that the average value of the absolute values of the stirrer moving speeds was about 83cm/sec₂Is suppressed to 15 μm.

Fig. 24 to 28 are microscope photographs of bumps formed on the surface of a substrate (wafer) by using the plating apparatus shown in fig. 1 under conditions in which the stirrer and the stirring movement speed of the stirrer are changed. FIG. 24 shows defects in bumps formed on the entire surface of the substrate when the average absolute value of the stirring speed of the stirrer was 40cm/sec and the plating was performed using a stirrer having a thickness of 2 mm. FIG. 25 shows that when the average absolute value of the stirring speed of the stirrer was 40cm/sec and the plating was carried out using a stirrer having a thickness of 4mm, the bumps formed on the entire surface of the substrate had defects, and the shapes of the bumps were distorted by seven twists. As can be seen from fig. 24 and 25, merely increasing the thickness of the stirrer is not sufficient.

FIG. 26 shows defects in bumps formed on the entire surface of the substrate when the average absolute value of the stirring speed of the stirrer was 67cm/sec and the plating was performed using a stirrer having a thickness of 4 mm. FIG. 27 shows a case where the average value of the absolute values of the stirring speeds of the stirrers was 83cm/sec and the plating was performed using a stirrer having a thickness of 4mm, and good bumps having no defects were formed on the entire surface of the substrate. The reason for this is considered that when the stirring speed of the stirrer is low, the supply of copper ions at a high current density cannot follow up, and a bump defect is generated; when the stirrer moves at a high speed, the supply of copper ions is sufficient, and bumps having no defects can be formed. In addition, under the same high current density condition, when the average value of the absolute value of the stirring moving speed of the stirrer was set to 83cm/sec and the plating was performed by using a stirrer having a thickness of 3mm, as shown in FIG. 28, no defect was observed in the bump over the entire surface of the substrate, but the corner of the bump was rounded as compared with the case where the thickness of the stirrer was 4 mm.

FIGS. 29 and 30 show the height distribution of bumps formed on a substrate when plating is performed by a plating tank in which no shield plate is provided on the bottom surface of a partition plate of the plating tank (FIG. 29) and when plating is performed by a plating tank in which a shield plate is provided on the bottom surface of a partition plate of the plating tank (FIG. 30). The numerical values are in μm. As shown in fig. 29, when there is no shield plate, the thickness of the plating film is thicker in the vicinity of the substrate edge in the plating tank bottom direction than in the center portion of the substrate, but as shown in fig. 30, the thickness of the plating film is suppressed to be as thick as the center portion in the vicinity of the substrate edge in the plating tank bottom direction by inserting the shield plate.

Fig. 31 and 32 are graphs showing the uniformity of the height of the bump formed on the substrate in the plating plane when the stirring movement speed of the stirrer, the shape of the adjustment plate, and the distance between the adjustment plate and the substrate are simultaneously changed. In fig. 31 and 32, as shown in fig. 33, axes perpendicular to each other on a plane are taken as an X axis and a Y axis. FIG. 31 shows a tendency that the height of the bump (plating film) becomes W-shaped when the plating is performed by setting the average absolute value of the stirring speed of the stirrer to 20cm/sec and using a flat plate having no cylindrical portion, a thickness of 5mm and a single opening at the center portion as the adjusting plate and setting the distance between the adjusting plate and the substrate to 35 mm. FIG. 32 shows a case where the average absolute value of the stirring speed of the stirrer was 83cm/sec and the distance between the substrate and the distal end of the cylindrical portion was set to 15mm by using the adjusting plate shown in FIG. 7. At this time, the height of the bump (plating film) is flatter than that of fig. 31, and uniformity in the plating surface is improved.

FIG. 34 shows a plating apparatus according to another embodiment of the present invention. The plating apparatus of the present embodiment uses the shielding plate 82 extending vertically downward from the lower surface of the partition plate 80, with the lower end surface reaching the bottom wall of the plating tank 10, whereby the plating liquid dispersion chamber 86 formed below the partition plate 80 is completely partitioned into the anode-side liquid dispersion chamber 110 and the cathode-side liquid dispersion chamber 112 by the shielding plate 82. The lower end surface of the shield plate 82 is fixed to the bottom wall of the plating tank 10 by, for example, welding.

The plating liquid supply path 16 is provided with a conventional valve 114 and a conventional flow meter 116 between the thermostatic unit 20 and the filter 22. The plating liquid supply channel 16 is branched into 2 branch paths 16a and 16b on the downstream side of the filter 22, and the branch paths 16a and 16b are connected to the anode side liquid dispersion chamber 110 and the cathode side liquid dispersion chamber 112, respectively. Valves 118a and 118b are provided in the branch paths 16a and 16b, respectively.

By completely partitioning the plating liquid dispersion chamber 86 into the anode-side liquid dispersion chamber 110 and the cathode-side liquid dispersion chamber 112 by the shield plate 82 in this way, it is possible to reliably prevent potential lines generated at the anode 26 from leaking to the cathode (substrate) side through the plating liquid in the plating liquid dispersion chamber 86, and it is possible to supply the plating liquid to the anode-side liquid dispersion chamber 110 and the cathode-side liquid dispersion chamber 112 separately through the plating liquid supply channel 16.

FIGS. 35 and 36 show another drive mechanism for stirrer 32 and plating cell 10. In this embodiment, the agitator 32 has its upper end mounted to the agitator hold down 120. The shaft 38 extending from the agitator driving portion 42 is divided into 3 pieces, i.e., left and right end shafts 38a and 38b supported by the shaft holding portion 40, respectively, and an intermediate shaft 38c positioned between the end shafts 38a and 38b, and the intermediate shaft 38c passes through the inside of the agitator presser 120, and both ends thereof are exposed to the outside. One end of the intermediate shaft 38c and the end shaft 38a, and the other end of the intermediate shaft 38c and the end shaft 38b are connected by couplings 122a and 122b, respectively. Although the coupling members 122a and 122b are screw coupling members in the present embodiment, any coupling member such as a so-called quick-connect coupling member may be used.

Thus, for example, when the stirrer 32 needs to be replaced, the stirrer 32, the stirrer holding jig 120, and the intermediate shaft 38c can be removed from the plating apparatus through the coupling joints 122a and 122b without removing the shaft holding portion 40 from the plating apparatus. This enables the agitator 32 to be replaced easily and quickly. Further, when the stirrer 32 is mounted again to the plating apparatus, it can be mounted to a predetermined position with good reproducibility. Further, when the adjustment plate 34 is removed from the plating apparatus, the operation of removing and remounting the adjustment plate 34 can be easily performed by temporarily removing the agitator 32 from the plating apparatus.

FIG. 37 shows another adjusting plate having an adjusting plate moving mechanism and another plating tank. The plating tank 10 of this embodiment has an inner tank 130 and an outer tank 132 surrounding the inner tank 130. The adjustment plate 134 is configured by integrally connecting a grip portion 140 wider than a rectangular flat plate-shaped main body portion 138 to an upper portion of the main body portion 138, and the main body portion 138 has a cylindrical portion 136. The adjustment plate moving mechanism 142 according to the present embodiment determines the position of the adjustment plate 134 in the left-right (horizontal) direction parallel to the substrate W by the grip portion 140.

The adjustment plate moving mechanism 142 includes: an adjusting plate support portion 144 provided across an upper end opening portion of the plating tank 10, a pair of brackets 146 erected on an outer peripheral end portion of the adjusting plate support portion 144, left and right jack bolts 148 screwed into internal threads provided on each bracket 146 and moving in the horizontal direction, and left and right fixing bolts 150 extending horizontally through screw holes (free-dimension holes) provided in each bracket 146. When the grip portion 140 of the adjustment plate 134 is placed on the adjustment plate support portion 144 and the adjustment plate 134 is set to a predetermined position, the left and right jack bolts 148 and the left and right fixing bolts 150 are arranged at positions opposing the outer peripheral end surface of the grip portion 140. Further, female screws to be screwed with the left and right fixing bolts 150 are formed at positions facing the left and right fixing bolts 150 on the outer peripheral end surface of the grip portion 140, the left and right ejector bolts 148 are brought into contact with the outer peripheral end surface of the grip portion 140, and the adjustment plate 134 is pushed inward by tightening the left and right ejector bolts 148.

Accordingly, after the holding portion 140 of the adjustment plate 134 is placed on the adjustment plate moving mechanism 142 and the adjustment plate 134 is set at a predetermined position, the position of the adjustment plate 134 in the left-right direction parallel to the substrate W can be adjusted by the left-right ejector bolt 148, and the adjustment plate 134 can be fixed by the left-right fixing bolt 150. The position of the adjustment plate 134 to be positioned by the left and right jack bolts 148 and the left and right fixing bolts 150 may be other than the grip portion 140 and other portions of the adjustment plate 134. In addition, by managing the number of rotations of the left and right jack bolts 148 having a predetermined pitch, the amount of movement of the adjustment plate 134 in the left and right (horizontal) direction can be easily adjusted. The left and right fixing bolts 150 function as pull bolts in a state where the left and right push bolts 148 do not abut against the outer peripheral end surfaces of the grip portions 140 and do not push the adjustment plate 134.

In order to move the adjustment plate 134 in the right-and-left direction parallel to the substrate W, a gap is provided between the outer peripheral end surface of the main body portion 138 of the adjustment plate 134 and the inner peripheral surface of the inner tank 130 of the plating tank 10. In the present embodiment, a guide portion 152 having a groove-shaped recessed portion 152a opened inward is provided in a position of the inner groove 130 facing the outer peripheral end surface of the main body portion 138 of the adjustment plate 134, and the outer peripheral end portion of the main body portion 138 of the adjustment plate 134 is inserted into the recessed portion 152a of the guide portion 152. Thus, the adjustment plate 134 can be moved in the left-right (horizontal) direction parallel to the substrate W, guided by the guide portion 152, while keeping the distance between the adjustment plate 134 and the substrate W constant. Further, by inserting the outer peripheral end portion of the main body portion 138 of the adjustment plate 134 into the recessed portion 152a of the guide portion 152, leakage of an electric field from the outer periphery of the adjustment plate 134 can be prevented.

As shown in fig. 38, a movement gap t is provided between the bottom of the recessed portion 152a of the guide portion 152 and the outer peripheral end surface of the main body portion 138 of the adjustment plate 134₁. The moving gap t₁For example, 1 to 5mm, preferably 1 to 2 mm. Due to the convenience of construction, a gap t is generally formed between the guide 152 and the inner circumferential surface of the inner groove 130₂. In the present embodiment, in order to prevent the potential line from leaking from the gap t2, the free end of the electric field shielding member 158 made of, for example, a rubber sheet is pressed against the inner peripheral surface of the inner groove 130 using the seal holding plate 154 and the fixing bolt 156, and the electric field shielding member 158 is fixed to the guide section 152. Although the electric field shielding member 158 is disposed at the anode side of the guide portion 152 in the present embodiment, it may be disposed at the cathode (substrate) side of the guide portion 152 or disposed at both sides of the guide portion 152.

In the above-described embodiment, the adjustment plate 134 is moved in the horizontal direction parallel to the substrate W by the adjustment plate moving mechanism 142, but the adjustment plate 134 may be moved in the horizontal and vertical (vertical) directions parallel to the substrate W. Fig. 39 shows an adjusting plate moving mechanism 160 for moving the adjusting plate 134 in the left-right direction and up-down direction parallel to the substrate W. The difference between the adjustment plate moving mechanism 160 and the adjustment plate moving mechanism 142 shown in fig. 37 is that a projecting portion of the grip portion 140 of the adjustment plate, which projects outward, is provided with a female screw through which a high-precision screw lining is vertically passed, and a vertical jack bolt 162 is screwed into the female screw so that a lower end surface of the vertical jack bolt 162 is brought into contact with an upper end surface of the adjustment plate support portion 144; further, a long hole extending in the width direction of the plating vessel 10 is provided in an outwardly projecting end portion of the grip portion 140, and the upper and lower fixing bolts 164 are inserted into the long hole, and the lower portion of the upper and lower fixing bolts 164 is screwed into the female screw provided in the adjustment plate support portion 144. The left and right fixing bolts are omitted in this embodiment.

In this embodiment, when the up-down jack bolt 162 is rotated in the tightening direction, the tip end of the up-down jack bolt 162 abuts against the upper end surface of the adjustment plate support portion 144, and the reaction force pushing the upper end surface moves the adjustment plate 134 upward. Conversely, when the up-down jack bolt 162 is rotated in the loosening direction, the adjustment plate 134 moves downward. After the vertical and lateral directions of the adjustment plate 134 with respect to the substrate W are determined, the lower portion of the vertical fixing bolt 164 is screwed into the female screw provided in the adjustment plate support portion 144, and the adjustment plate 134 is fixed.

In addition, a pneumatic cylinder, a servo motor, or the like may be used instead of the ejector bolts 148 and 162. The adjustment plate moving mechanism 142 shown in fig. 37 and the adjustment plate moving mechanism 160 shown in fig. 39 may be combined to adjust the position of the adjustment plate 134 in the vertical and horizontal directions. At this time, by providing the bracket 146 with a vertically extending elongated hole through which the left and right fixing bolt 150 passes, the adjusting plate 134 can be fixed by the left and right fixing bolt 150 even if the position of the adjusting plate 134 is displaced in the vertical direction. In the adjusting plate moving mechanism 160 shown in fig. 39, the left and right knock-out bolts 148 may be omitted, and only the position of the adjusting plate 134 in the vertical direction with respect to the substrate W may be positioned.

In this way, the position of the adjustment plate 134 in the horizontal direction with respect to the substrate W is finely adjusted by the adjustment plate moving mechanism 148, or the position of the adjustment plate 134 in the horizontal and vertical directions with respect to the substrate W is finely adjusted by the adjustment plate moving mechanism 160, whereby the uniformity of the film thickness of the plating film formed on the surface of the substrate W in the plating plane can be improved. In particular, since the adjustment plate 134 is disposed at a position close to the substrate W, fine adjustment of the position of the adjustment plate 134 in the vertical direction or the horizontal direction with respect to the substrate W is important for improving the uniformity of the film thickness of the plating film formed on the surface of the substrate W on the plating surface.

Fig. 40 and 41 are views showing still another example of the adjustment plate, and the adjustment plate according to this example is configured as follows in addition to the adjustment plate 134 shown in fig. 37. That is, an auxiliary adjusting plate mounting portion for mounting the auxiliary adjusting plate 170 is provided on the surface of the main body portion 136 of the adjusting plate 134 on the anode side. The auxiliary adjustment plate mounting portion is constituted by a pair of side hooks 172a and a bottom hook 172b each having a hook-shaped cross section and fixed at a position corresponding to a side face and a lower end corner portion around the auxiliary adjustment plate 170. Thus, the auxiliary adjustment plate 170 can be set to a predetermined position with respect to the adjustment plate 134 by inserting the auxiliary adjustment plate 170 into the auxiliary adjustment plate attachment portion constituted by the side hooks 172a and the bottom hooks 172b of the adjustment plate 134.

In the present embodiment, an adjustment plate (8-inch adjustment plate for wafer) having an 8-inch opening 134a for wafer is used as the adjustment plate 134, and an adjustment plate (6-inch adjustment plate for wafer) having an 6-inch opening 170a for wafer is used as the auxiliary adjustment plate 170. Thus, when the substrate W is changed from an 8-inch wafer to a 6-inch wafer, the problem can be solved by merely providing the auxiliary adjustment plate (6-inch wafer adjustment plate) 170 on the adjustment plate (8-inch wafer adjustment plate) 134 without replacing the adjustment plate itself. An opening 170b for gripping is provided in an upper portion of the auxiliary adjustment plate 170.

Dimension t of horizontal overlap of adjustment plate 134 and auxiliary adjustment plate 170₃、t₄And a vertical lower overlap dimension t₅It is generally 5mm or more, preferably 10mm or more. Thus, when the auxiliary adjustment plate 170 is placed on the adjustment plate 134, the potential lines generated by the anode 26 do not pass through the opening 170a of the auxiliary adjustment plate 170, and can be prevented from leaking from the outside of the auxiliary adjustment plate 170 through the gap between the adjustment plate 134 and the auxiliary adjustment plate 170 and the opening 134a of the adjustment plate 134.

Although the above embodiment describes an example in which the 8-inch adjustment plate and the 6-inch adjustment plate for the wafer are combined, by adopting a configuration in which 2 adjustment plates (the 1 st adjustment plate and the 2 nd adjustment plate) can be combined, when plating is performed by using only the 1 st adjustment plate at ordinary times and there is a need to finely adjust the electric field distribution depending on the type of the substrate (object to be plated), such an operation can be performed in which the 2 nd adjustment plate is combined with the 1 st adjustment plate.

FIGS. 42 and 43 show a main part of a plating apparatus according to still another embodiment of the present invention. The present embodiment is different from the plating apparatus shown in fig. 1 in that the anode holder 28 having the wide grip portion 180 at the upper portion shown in fig. 43 and the adjustment plate 134 having the wide grip portion 140 shown in fig. 37 and the like are used, and the anode holder 28 is provided by the grip portion 180, the adjustment plate 134 is provided by the grip portion 140, and the substrate holder 24 is provided by the holder arm 64 (see fig. 9) in the single positioning and holding portion 182 provided across the upper end opening of the plating tank 10. That is, the grip portion 180 of the anode holder 28, the grip portion 140 of the adjustment plate 134, and the holder arm 64 of the substrate holder 24 are provided on the positioning and holding portion 182, which is the same component. This makes it possible to reliably align the central axes of the anode 26 held by the anode holder 28, the cylindrical portion 136 of the adjustment plate 134, and the substrate W held by the substrate holder 24.

Although the grip portion 180 of the anode holder 28, the grip portion 140 of the adjustment plate 134, and the holder arms 64 of the substrate holder 24 are placed on the positioning and holding portion 182, which is the same member, in the present embodiment, other portions of the anode holder 28, the adjustment plate 134, and the substrate holder 24 may be placed on the positioning and holding portion 182, respectively. In short, the positions of the anode holder 28, the adjustment plate 134, and the substrate holder 24 in the vertical direction may be determined with reference to the positioning and holding portion 182 as the same member.

Fig. 44 and 45 show still another example of the adjustment plate. In the present embodiment, the following structure is added to the adjustment plate 134 shown in fig. 7 and the like. That is, the partition 188 is fixed to the surface of the main body 138 on the anode side of the adjustment plate 134 by the fixing plate 184 and the fixing bolt 186 so as to cover the entire central opening 134 a. Since the partition 188 is formed of a cation exchanger or a functional membrane (neutral filtration membrane) that allows metal ions to pass therethrough but does not allow the additive to pass therethrough, the opening 134a of the adjustment plate 134 is covered with the partition 188, whereby the additive contained in the plating solution on the surface of the anode 26 can be prevented from being decomposed and consumed.

The embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments, and can be naturally implemented in various different forms within the scope of the technical idea.

Claims (5)

1. An apparatus for electroplating an object, comprising:

a plating bath for holding a plating solution;

an anode to be immersed in the plating solution in the plating tank;

a holder for holding an object to be plated and disposing the object to be plated at a position opposing the anode;

a stirrer disposed between the anode and the object to be plated held by the holder, the stirrer being reciprocated in parallel with the object to be plated to stir the plating liquid;

an adjustment plate having an opening for limiting electric field expansion, the adjustment plate being disposed between the agitator and the anode;

a guide member having a recessed portion in the shape of a groove opened inward, the guide member being provided in a position opposed to an outer peripheral end portion of the adjusting plate in the plating tank, for inserting the outer peripheral end portion of the adjusting plate into the recessed portion of the guide member to guide movement of the adjusting plate; and

an adjusting plate moving mechanism for moving the adjusting plate vertically or horizontally in parallel with the object to be plated, the adjusting plate moving mechanism comprising:

an adjusting plate supporting portion for supporting the adjusting plate above the surface of the plating liquid, an

A pushing member for pushing the adjusting plate supported by the adjusting plate supporting portion to move the adjusting plate vertically or horizontally while maintaining a constant distance between the adjusting plate and the object to be plated.

2. The apparatus of claim 1, wherein an electric field shielding member is provided at an anode side of the guide member so as to prevent leakage of electric current from between the plating tank and the guide member.

3. The apparatus of claim 1, wherein the adjustment plate comprises:

a cylindrical portion having an inner diameter suitable for an outer shape of the object to be plated; and

and a flange portion connected to an outer peripheral end portion of the cylindrical portion on the anode side.

4. The apparatus of claim 1, wherein the adjustment plate comprises:

a flange portion having the opening;

a membrane consisting of a cation exchanger capable of passing metal ions but not passing the additive or a neutral filtration membrane; and

a fixing plate for fixing the diaphragm to an anode-side surface of the flange portion such that the diaphragm covers the entire opening of the flange portion.

5. The apparatus of claim 1, wherein the adjustment plate comprises:

a flange portion having the opening; and

a mounting portion for mounting an auxiliary regulation plate on an anode-side surface of the flange portion such that a central axis of the opening of the flange portion and a central axis of an opening provided in the auxiliary regulation plate coincide with each other, the opening of the auxiliary regulation plate having a diameter smaller than a diameter of the opening of the flange portion.

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