JP3182821B2 - Plating treatment method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating method capable of uniformly plating a portion to be plated in an opening of a substrate to be plated without bubbles generated during the plating process remaining in the opening of the plating resist on the substrate to be plated. .

[0002]

2. Description of the Related Art A conventional plating method, for example, a jet plating method of bump plating will be described with reference to a schematic vertical sectional side view of FIG. Net-shaped anode electrode 1
On the other hand, a semiconductor substrate 140 serving as a substrate to be plated is placed in the opening at the upper end of the plating tank 110 with the surface 150 on the side to be plated facing downward. A conductor 160 made of aluminum (Al) or the like is arranged on the surface 150 on the plating side, and a cathode electrode pin 170 is connected to the conductor 160. Are formed on the surface of the conductor 160 by forming openings 181, 181,... Of a predetermined shape in the plating resist 180.
, Are formed with plated portions 161, 161,. Then, a plating solution 120 is blown up from the bottom of the plating tank 110 as shown by an arrow in the same figure, and a plating current is applied to the anode electrode 130 and the cathode electrode 170 to perform a plating process. .

[0003]

However, the plating solution 12
0, especially in the case of a solder plating solution, the current density is
Even when the standard current density is set to 0, air bubbles are generated, and these air bubbles accumulate in the surface 150 on the side to be plated of the semiconductor substrate 140 and the opening 181 of the plating resist 180 and are hard to be removed, so that poor plating (poor bump shape) is caused. generate. For this reason, the current density must be kept low, and the plating time per batch becomes long, and the efficiency of the plating process is poor. The present invention has been made in view of such circumstances,
Even if bubbles are generated during the plating process, plating can be performed evenly on the portion to be plated in the opening without the bubbles remaining in the opening of the plating resist on the substrate to be plated. It is an object of the present invention to provide a plating method with high processing efficiency.

[0004]

In order to achieve the above object, a plating method according to the present invention has a plating resist applied to a surface thereof, and an opening having a predetermined shape is formed in the plating resist. The substrate to be plated, which is the portion to be plated, is placed in a plating solution in which the plating solution is jetted substantially vertically from the bottom side to the top side, and the portion to be plated is raised.
On the surface side, and immersed in a predetermined inclined state with respect to the jet flow direction , and perform plating at least at a predetermined angular position and an angle position which is inverted by 180 degrees in the same plane from the predetermined angular position. I try to make it. The substrate to be plated may be a semiconductor substrate. Then, a bump electrode may be plated on a portion to be plated of the semiconductor substrate. Further, the plating process may be performed while rotating the substrate to be plated in the same plane, or a forced flow may be formed in the plating solution.

[0005]

According to the plating method of the present invention, a plating resist is applied to the surface, an opening having a predetermined shape is formed in the plating resist, and the opening serves as a portion to be plated. the substrate, the object main in a plating solution in the plating solution is jet in a substantially vertical direction to the top surface side from the bottom side
With the jack part on the upper surface side, and immersed in a predetermined inclination state with respect to the jet flow direction, at least at a predetermined angle position and an angle position which is inverted by 180 degrees in the same plane from the predetermined angle position Since the plating process is performed, even if bubbles are generated during the plating process, the bubbles do not accumulate in the openings of the plating resist on the substrate to be plated, and plating can be uniformly performed on the portions to be plated in the openings. If the plating process is performed while rotating the substrate to be plated in the same plane, the bubbles are less likely to collect due to the opening of the plating resist of the substrate to be plated, and the plating on the portion to be plated is more uniform. You. Furthermore, if a forced flow is formed in the plating solution, the bubbles are less likely to collect in the openings of the plating resist, and the plating on the portion to be plated is made more uniform.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the illustrated embodiments. FIG. 1 is a vertical sectional side view of a plating tank in which a substrate to be plated is set, and FIG. 2 is a front view of a substrate to be plated and a driving pulley for rotating the substrate to be plated.

The plating tank 1 includes a plating chamber 10 for performing a plating process, a jet chamber 20 for feeding a jet of a plating solution 41 (for example, a solder plating solution) into the plating chamber 10, and a plating chamber 10 in the plating chamber 10. A recovery chamber 30 for recovering the plating solution 41 and sending it into the jet chamber 20;

Then, the plating chamber 10 and the jet chamber 20 are connected to each other through the jet port 21.
Are in communication with each other via the collection port 31.

The recovery chamber 30 and the jet chamber 20 communicate with each other via a bypass 81, and a pump 80 is provided in the middle of the bypass 81.

By the pump 80, the plating solution 41 is forcibly circulated in the order of the recovery chamber 30, the jet chamber 20, the plating chamber 10, and the recovery chamber 30.

Further, in the plating chamber 10, an object-to-be-plated installation section 11 which is obliquely upward and an object-to-be-plated installation section 11.
And an anode electrode installation section 12 facing the above.

A driving pulley 31 for rotationally driving a substrate 50 to be plated, such as a semiconductor substrate, is arranged on the substrate 11 along the same circumference. These driving pulleys 31 are large diameter portions 31 for support.
a and a rotatable small diameter portion 31b.
Are rotationally driven in the same direction by a motor (not shown) installed in the plating tank 1.

A cathode electrode pin 60 is installed on the upper side of the plating object installation section 11 in the same circumferential arrangement as the driving bully 31. The tip of the cathode electrode pin 60 is connected to the substrate 50 to be plated as described later.
Is in contact with the peripheral portion of the plating base layer 53 formed on the substrate.

On the other hand, an anode electrode 70 is installed on the anode electrode installation section 12 side.

The substrate 50 to be plated is formed, for example, in a disk shape, and an orientation flat 51 is formed on a part of an outer peripheral edge thereof.

In the substrate 50 to be plated, for example, a plating base layer 53 is provided on a semiconductor substrate 52, and a coating layer 54 of a plating resist is formed on the plating base layer 53. Openings 54a, 54a,... Are formed in the coating layer 53, and portions of the plating base layer 53 exposed from the openings 54a, 54a,.

The plating tank 1 and the substrate to be plated 50 are configured as described above, and are subjected to plating as follows.

That is, first, with the surface to be plated of the substrate 50 to be plated facing the anode electrode 70, the outer peripheral edge thereof is driven by the driving pulleys 31, 3 of the substrate mounting portion 11.
The cathode electrode pins 6 fit into the small diameter portions 31b of the
0 is brought into contact with the periphery of the plating base layer 53. Thereby, the substrate to be plated 50 is driven by the driving pulleys 31 and 3.
1 and 31 are supported by the large diameter portions 31a. In this state, the plate 50 is set so that the portion of the orientation flat 51 of the substrate to be plated 50 comes to the reference position (uppermost position).

Next, the plating chamber 41, the jet chamber 20, and the recovery chamber 30 are filled with an appropriate amount of a plating solution 41, so that the entire plating portion 35 of the substrate 50 to be plated is immersed in the plating solution 41.

Thereafter, the pump 80 is operated to circulate the plating solution 41 in the order of the recovery chamber 30, the jet chamber 20, the plating chamber 10, and the recovery chamber 30, so that the plating liquid 41 is supplied to the cathode electrode pin 60 and the anode electrode 70. An electric current is applied to start the plating process. At the same time, the driving pulley 31 is operated to rotate the substrate to be plated 50 at a constant speed.

During the plating process, air bubbles are generated in the plating solution 41. However, since the surface to be plated of the substrate to be plated 50 is obliquely upward and is rotating, the air bubbles are generated at the opening of the coating layer 54 of the plating resist. It escapes upward without collecting in 54a. Therefore, plating on the portion to be plated 55 in the opening 54 is not hindered by the bubbles.

Next, the plating film thickness distribution at each rotational angle position of the substrate 50 during the plating process will be described with reference to FIGS. FIGS. 3 and 4, FIGS. 5 and 6, FIGS. 7 and 8, and FIGS. 9 and 10 show the relationship between the rotation angle position of the substrate to be plated and the plating film thickness distribution at the rotation angle position. It is. 4, FIG. 6, FIG. 8, FIG. 10, and FIG.
The axis indicating the position on the line B and the vertical axis indicate the plating film thickness.

First, when a portion of the orientation flat 51 of the substrate 50 to be plated is plated at a reference position (the highest position in this embodiment) as shown in FIG. 3, a solid line graph shown in FIG. To be plated 5
The plating is performed such that the plating thickness t on the A side on the center line AB passing through the center of the 0 orientation flat 51 is large and the plating thickness t on the B side is small. This becomes the initial plating film thickness distribution.

When plating is performed in a state of reaching an angular position rotated 90 degrees clockwise from the reference position (the position shown in FIG. 5), along the AB line of the substrate 50 to be plated, as shown in FIG.
Then, a plating layer having the same thickness as shown by the dashed line graph is newly formed. This plating layer is laminated on the previous plating layer (shown by a dotted line in FIG. 6), and
The plating thickness distribution along the AB line 0 is such that the plating thickness is large and the plating thickness on the B side is small.

When plating is performed in a state where the position is further rotated clockwise by 90 degrees (the position shown in FIG. 7), the plating thickness on the A side is taken along the line AB of the substrate 50 to be plated. A plating layer (shown by a two-dot chain line in FIG. 8) in which t is small and plating thickness t on the B side is large is newly formed. This plating layer is laminated on the previous plating layer (shown by a dotted line in FIG. 8), and the plating thickness distribution along the AB line of the substrate 50 to be plated is indicated by a solid line in FIG. 8 as a whole. It will be the same thickness as shown. That is, 18
The distribution of the plating film thickness performed at the position where the phase is different by 0 degrees is canceled out to obtain the same thickness distribution.

In a state in which the position is further rotated clockwise by 90 degrees (position shown in FIG. 9),
A plating layer having the same thickness (shown by a three-dot chain line in FIG. 10) is newly formed. This plating layer is laminated on the previous plating layer (shown by the dotted line graph in FIG. 10), and the plating thickness distribution along the AB line of the substrate to be plated 50 becomes the same as a whole. (It is shown by a solid line graph in FIG. 10).

As described above, in the process of plating the substrate 50 while rotating it by 360 degrees, the difference in the plating film thickness distribution at positions 180 degrees out of phase with each other is canceled out, and The plating film thicknesses of the plated portions 55, 55,... Have the same distribution.

As described above, the plating method according to this embodiment is such that the surface to be plated of the substrate 50 to be plated is turned obliquely upward, and is rotated in the same plane. Since the forced flow is applied, even if bubbles are generated during the plating process, the bubbles are generated by the openings 54a, 54a of the plating resist 54 of the substrate 50 to be plated.
4a,... Are not accumulated, and plating can be uniformly applied to the plated portions 55, 55,... In the openings 54a, 54a,.

The installation angle of the substrate 50 to be plated is shown in FIG.
The angle may be set to any angle as long as the surface to be plated faces upward. In this case, the installation angle of the anode electrode 70 is changed correspondingly.

The means for rotating the substrate 50 to be plated is not limited to the driving pulley 31, and any means may be used.

Further, the plating process does not necessarily have to be performed while the substrate to be plated 50 is being rotated, and the plating process may be performed at a predetermined angular position and an angular position inverted by 180 degrees from the position at the same time. .

In the above embodiment, a forced flow is formed in the plating solution 41 in the plating chamber 10, but this is not always necessary. Further, the type of plating solution is not limited.

[0033]

According to the plating method of the present invention, a plating resist is applied to the surface, an opening having a predetermined shape is formed in the plating resist, and the opening is formed as a portion to be plated. the object to be plated substrate, the plating liquid which plating liquid is jet substantially perpendicularly to the top surface side from the bottom side
With the plating part on the upper surface side and immersed in a predetermined inclined state with respect to the jet direction , plating is performed at least at a predetermined angle position and an angle position which is inverted by 180 degrees in the same plane from the predetermined angle position. Because the process is performed, even if bubbles are generated during the plating process, the bubbles do not collect in the opening of the plating resist on the substrate to be plated, and plating is performed by plating the portion to be plated in the opening. Characteristic plating method.

If the plating process is performed while rotating the substrate to be plated in the same plane, the bubbles are less likely to collect in the openings of the plating resist on the substrate to be plated, and plating on the portion to be plated is performed. Is more uniform.

Furthermore, if a forced flow is formed in the plating solution, the bubbles are less likely to collect in the openings of the plating resist, and the plating on the portion to be plated is made more uniform.

[Brief description of the drawings]

FIG. 1 is a vertical sectional side view of a plating tank in which a substrate to be plated is set.

FIG. 2 is a front view of a substrate to be plated and the substrate to be plated;

FIG. 3 is a front view of a substrate to be plated at a reference position.

FIG. 4 is a graph showing a plating film thickness distribution along a line AB when a substrate to be plated is at a reference position.

FIG. 5 is a front view of the substrate to be plated at a position rotated 90 degrees clockwise from a reference position.

FIG. 6 is a graph showing a plating film thickness distribution along the line AB when the substrate to be plated is at a position rotated 90 degrees from a reference position.

FIG. 7 is a front view of a substrate to be plated at a position rotated clockwise by 180 degrees from a reference position.

FIG. 8 is a graph showing a plating film thickness distribution along the line AB when the substrate to be plated is at a position rotated by 180 degrees from a reference position.

FIG. 9 is a front view of the substrate to be plated at a position rotated 270 degrees clockwise from a reference position.

FIG. 10 is a graph showing a plating film thickness distribution along the line AB when the substrate to be plated is at a position rotated by 270 degrees from the reference position.

FIG. 11 is a schematic vertical sectional side view of a conventional plating tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Plating tank 41 Plating liquid 50 Substrate to be plated 54 Plating resist 54a Opening 55 Part to be plated

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-255684 (JP, A) JP-A-2-310393 (JP, A) JP-A-4-28897 (JP, A) JP-A-58-58 64394 (JP, A) JP-A-63-238283 (JP, A) JP-A-57-65968 (JP, U) JP-A-64-7271 (JP, U) (58) Fields investigated (Int. ⁷ , DB name) C25D 5/00-7/12 H01L 21/288

Claims (5)

(57) [Claims] 1. A plating resist is adhered to a surface, an opening having a predetermined shape is formed in the plating resist, and a plating substrate which is a portion to be plated is formed in the opening. The portion to be plated is immersed in a plating solution which is jetted substantially vertically to the upper surface side, and is immersed in a predetermined inclined state with respect to the jet flow direction, at least at a predetermined angle. From the position and the predetermined angular position in the same plane.
A plating method, wherein plating is performed at an angle position inverted by 0 degrees. 2. The plating method according to claim 1, wherein the substrate to be plated is a semiconductor substrate. 3. The plating method according to claim 2, wherein a bump electrode is plated on the portion to be plated. 4. The plating method according to claim 1, wherein the plating is performed while rotating the substrate to be plated in the same plane. 5. The plating method according to claim 1, wherein a forced flow is formed in the plating solution.