Plating Equipment

Abstract

Disturbances in the electric field formed between the anode and the substrate are detected. The plating apparatus 10 includes a plating tank 50 for containing a plating solution Q, an anode 21 disposed in the plating tank 50, a substrate holder 40 for holding a substrate WF such that a surface WF1 to be plated faces the anode 21, an anode mask 70 disposed between the anode 21 and the substrate holder 40, the anode mask 70 having an anode opening 70a penetrating from the anode 21 side to the substrate holder 40 side and configured so that the size of the anode opening 70a can be adjusted, a regulation plate 30 disposed between the anode mask 70 and the substrate holder 40, a measurement electrode 74 disposed between the anode mask 70 and the regulation plate 30, a reference electrode 75 disposed in the plating solution Q contained in the plating tank 50, and a measuring instrument 76 for measuring a voltage between the reference electrode 75 and the measurement electrode 74.

Description

[Technical field]

[0001] The present application relates to a plating apparatus. [Background technology]

[0002] Known examples of electrolytic plating equipment include dip-type plating equipment and cup-type plating equipment. Both have in common that a substrate (e.g., a semiconductor wafer) is held in a substrate holder and immersed in a plating solution, and a voltage is applied between the substrate (cathode) and an anode to deposit a conductive film on the substrate surface. The two types differ in the direction in which the substrate's surface to be plated faces. In a dip-type plating equipment, the substrate is immersed in the plating solution so that the surface to be plated faces sideways, while in a cup-type plating equipment, the substrate is immersed in the plating solution so that the surface to be plated faces downwards.

[0003] Patent Document 1 discloses a dip-type plating apparatus. This plating apparatus is equipped with an anode mask for adjusting the electric field between the anode and the substrate. The anode mask is a plate-like member disposed between the anode and the substrate holder, and has an opening in the center through which the current flowing between the anode and the substrate passes, and is configured to be adjustable in diameter. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6335763 Summary of the Invention [Problem to be solved by the invention]

[0005] The plating apparatus disclosed in Patent Document 1 does not take into consideration detection of disturbances in the electric field formed between the anode and the substrate.

[0006] That is, a part of the anode mask (e.g., a member for adjusting the diameter of the opening of the anode mask) may deteriorate and be damaged due to chemical changes caused by the plating solution. When a part of the anode mask is damaged, the electric field between the anode and the substrate is disturbed, making it difficult to form a desired plating film thickness distribution on the surface to be plated. In addition, not only the anode mask but also other members placed in the plating tank may be damaged due to chemical changes caused by the plating solution.

[0007] Furthermore, in a plating apparatus, the anode, anode mask, and substrate (substrate holder) must be positioned in appropriate axial alignment. However, if any of the components is misaligned, the electric field between the anode and substrate is disturbed, making it difficult to achieve the desired plating thickness distribution.

[0008] Therefore, one object of the present invention is to detect disturbances in the electric field formed between the anode and the substrate. [Means for solving the problem]

[0009] According to one embodiment, a plating apparatus is disclosed that includes a plating tank for containing a plating solution, an anode disposed in the plating tank, a substrate holder for holding a substrate such that the surface to be plated faces the anode, an anode mask disposed between the anode and the substrate holder, the anode mask having an anode opening penetrating the anode side and the substrate holder side and configured to be able to adjust the size of the anode opening, an electric field adjusting member disposed between the anode mask and the substrate holder, a measurement electrode disposed between the anode mask and the electric field adjusting member, a reference electrode disposed in the plating solution contained in the plating tank, and a measuring instrument for measuring a voltage between the reference electrode and the measurement electrode. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a cross-sectional view showing the overall configuration of a plating apparatus according to one embodiment. [Diagram 2] FIG. 2 is a schematic front view of an anode mask according to one embodiment. [Diagram 3] FIG. 3 is a vertical cross-sectional view of an embodiment of an anode mask. [Figure 4] FIG. 4 is a schematic front view of an anode mask according to one embodiment. [Diagram 5] FIG. 5 is a schematic front view of an anode mask according to one embodiment. [Figure 6] FIG. 6 is a cross-sectional view showing the overall configuration of a plating apparatus according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings described below, the same or corresponding components are designated by the same reference numerals and redundant description will be omitted.

[0012] 1 is a cross-sectional view showing the overall configuration of a plating apparatus according to one embodiment. As shown in the figure, a plating apparatus 10 according to this embodiment includes an anode holder 20 configured to hold an anode 21, a substrate holder 40 configured to hold a substrate WF, and a plating tank 50 that houses the anode holder 20 and the substrate holder 40 therein. In this embodiment, the substrate WF is formed in a disk shape, and the anode 21 is formed in a disk shape corresponding to the shape of the substrate WF.

[0013] As shown in FIG. 1, the plating tank 50 has a plating treatment tank 52 that contains plating solution Q containing an additive, a plating solution discharge tank 54 that receives and discharges plating solution Q that has overflowed from the plating treatment tank 52, and a partition wall 55 that separates the plating treatment tank 52 from the plating solution discharge tank 54.

[0014] The anode holder 20 holding the anode 21 and the substrate holder 40 holding the substrate WF are immersed in the plating solution Q in the plating tank 52, and are provided facing each other so that the anode 21 and the plating surface WF1 of the substrate WF are approximately parallel to each other. In other words, the substrate holder 40 holds the substrate WF with the plating surface WF1 facing sideways. A voltage is applied to the anode 21 and the substrate WF while they are immersed in the plating solution Q in the plating tank 52. As a result, metal ions are reduced on the plating surface WF1 of the substrate WF, and a film is formed on the plating surface WF1.

[0015] The plating treatment tank 52 has a plating solution supply port 56 for supplying the plating solution Q into the tank. The plating solution discharge tank 54 has a plating solution discharge port 57 for discharging the plating solution Q that has overflowed from the plating treatment tank 52. The plating solution supply port 56 is disposed at the bottom of the plating treatment tank 52, and the plating solution discharge port 57 is disposed at the bottom of the plating solution discharge tank 54.

[0016] When plating solution Q is supplied to plating tank 52 from plating solution supply port 56, plating solution Q overflows from plating tank 52, passes over partition wall 55, and flows into plating solution discharge tank 54. Plating solution Q that has flowed into plating solution discharge tank 54 is discharged from plating solution discharge port 57, and impurities are removed by a filter or the like of plating solution circulation device 58. The plating solution Q from which impurities have been removed is supplied to plating tank 52 via plating solution supply port 56 by plating solution circulation device 58.

[0017] The plating apparatus 10 has an anode mask 70 for adjusting the electric field between the anode 21 and the substrate WF. The anode mask 70 is, for example, a substantially plate-shaped member made of a dielectric material, and is provided on the front surface of the anode holder 20. Here, the front surface of the anode holder 20 refers to the surface facing the substrate holder 40. That is, the anode mask 70 is disposed between the anode 21 and the substrate holder 40. The anode mask 70 has an anode opening 70a at the substantially central portion thereof, which penetrates between the anode 21 side and the substrate holder 40 side, in other words, through which the current flowing between the anode 21 and the substrate WF passes. The diameter of the anode opening 70a is preferably smaller than the diameter of the anode 21. The anode mask 70 is configured to be able to adjust the diameter of the anode opening 70a. This point will be described below.

[0018] FIG. 2 is a schematic front view of the anode mask 70. FIG. 2 is a view taken along the line AA in FIG. 1. As shown in FIG. 2, the anode mask 70 has a plate-shaped anode mask body 71 and a substantially annular edge portion 73 formed in the center of the anode mask body 71. The anode mask 70 has a plurality of diaphragm blades 72 configured to adjust the anode opening 70a. The diaphragm blades 72 are attached to the edge portion 73 and cooperate to define the anode opening 70a. Each of the diaphragm blades 72 has a structure similar to that of the diaphragm mechanism of a camera to expand or reduce the diameter of the anode opening 70a (adjust the diameter of the anode opening 70a). The anode opening 70a of the anode mask 70 shown in FIG. 2 is formed into a non-circular shape (for example, a polygonal shape) by the diaphragm blades 72. In this case, the diameter of the anode opening 70a refers to the shortest distance between the opposing sides of the polygon or the diameter of the inscribed circle. Alternatively, the diameter of the anode opening 70a can be defined as the diameter of a circle having an area equivalent to the opening area.

[0019] Each of the diaphragm blades 72 is adapted to enlarge or reduce the diameter of the anode opening 70a, for example, manually. Each of the diaphragm blades 72 may be configured to be driven using air pressure or an electric driving force.

[0020] 1, the plating apparatus 10 has a regulation plate 30, which is an example of an electric field adjusting member for adjusting the electric field between the anode 21 and the substrate WF. The regulation plate 30 is a substantially plate-shaped member made of, for example, a dielectric material, and is disposed between the anode mask 70 and the substrate holder 40 (substrate WF). The regulation plate 30 has a regulation opening 30a that penetrates between the anode 21 side and the substrate holder 40 side, in other words, through which a current flows between the anode 21 and the substrate WF. The diameter of the regulation opening 30a is preferably smaller than the diameter of the substrate WF.

[0021] The regulation plate 30 may be configured to adjust the diameter of the regulation opening 30a by an aperture blade, similar to the anode mask 70. However, the adjustment of the diameter of the regulation opening 30a is not limited to the aperture blade. For example, the diameter of the regulation opening 30a can be adjusted by attaching an elastic tube to the substantially annular edge and expanding / contracting the elastic tube by feeding a fluid (gas such as air or nitrogen, or fluid such as water) into and out of the internal cavity of the elastic tube.

[0022] The regulation plate 30 is preferably located closer to the substrate holder 40 than the intermediate position between the anode holder 20 and the substrate holder 40. The closer the regulation plate 30 is located to the substrate holder 40, the more accurately the film thickness at the peripheral portion of the substrate WF can be controlled by adjusting the diameter of the regulation opening 30a of the regulation plate 30.

[0023] A paddle 18 for stirring the plating solution Q in the vicinity of the plating surface WF1 of the substrate WF is provided between the regulation plate 30 and the substrate holder 40. One end of the paddle 18 is fixed to a paddle driving device 19. The paddle 18 is moved along the plating surface WF1 of the substrate WF by the paddle driving device 19, thereby stirring the plating solution Q.

[0024] The plating apparatus 10 further includes a membrane box 60. The membrane box 60 is a box-shaped member for accommodating the anode holder 20 (anode 21) and the anode mask 70 in the plating tank 50. The membrane box 60 includes a membrane 62 disposed between the anode mask 70 and the regulation plate 30. The membrane 62 is a film that separates an anode region in which the anode 21 is disposed and a cathode region in which the substrate WF is disposed. The membrane box 60 includes a plug 64 for discharging the plating solution Q from the membrane box 60 when the membrane box 60 is lifted from the plating tank 50.

[0025] Next, a description will be given of a detection mode of disturbance in the electric field of the plating apparatus 10. As shown in Fig. 2, the plating apparatus 10 has a measurement electrode 74 (three measurement electrodes 74-1, 74-2, and 74-3 in the embodiment of Fig. 2), a reference electrode 75, and a measuring instrument 76 that measures the voltage between the reference electrode 75 and the measurement electrode 74.

[0026] In the embodiment of FIG. 2, the measurement electrodes 74-1, 74-2, and 74-3 are arranged on the surface of the anode mask 70 facing the substrate holder 40 at equal intervals (120° intervals) on a circumference with respect to the center of the anode opening 70a. More specifically, the measurement electrodes 74-1, 74-2, and 74-3 are arranged on the surface of the aperture blade 72 facing the substrate holder 40. However, the measurement electrodes 74 are not limited to the arrangement as in the embodiment of FIG. 2, and may be arranged between the anode mask 70 and the regulation plate 30 (electric field adjustment member). When there are multiple measurement electrodes 74, each measurement electrode 74 may be arranged at equal intervals on a circumference with a virtual axis connecting the center of the anode 21 and the center of the substrate WF as the center. The number of measurement electrodes 74 may be one.

[0027] The reference electrode 75 is disposed on the surface of the anode mask 70 facing the substrate holder 40, at a location farther from the center of the anode mask 70 than the measurement electrodes 74-1, 74-2, and 74-3. However, the arrangement of the reference electrode 75 is not limited to that of the embodiment in FIG. 2, and it is sufficient that the reference electrode 75 is disposed in the plating solution Q contained in the plating tank 50. The measurement electrode 74 and the reference electrode 75 are each connected to a measuring instrument 76 via a pattern wiring 77.

[0028] FIG. 3 is a perspective cross-sectional view of the anode mask 70 and the membrane 62 of one embodiment. As shown in FIG. 3, the anode mask body 71 has a plate-shaped first anode mask body 71-1 and a plate-shaped second anode mask body 71-2. The first anode mask body 71-1 and the second anode mask body 71-2 are arranged to face each other with a gap therebetween. The pattern wiring 77 is arranged in the space between the first anode mask body 71-1 and the second anode mask body 71-2. The pattern wiring 77 can be formed by patterning copper foil on a substrate such as epoxy. The first anode mask body 71-1 and the second anode mask body 71-2 function as a sealant, and therefore can prevent the plating solution Q from entering the internal space that accommodates the pattern wiring 77.

[0029] The plating apparatus 10 can measure the voltage of the measurement electrode 74 relative to the reference electrode 75 using the measuring device 76, and can therefore detect disturbances in the electric field formed between the anode 21 and the substrate WF. An example of detection of the disturbances in the electric field will be described below.

[0030] 2, the plating apparatus 10 has a detection member 80 configured to detect damage to the anode mask 70 or the regulation plate 30 (electric field adjustment member) based on the time change of the voltage measured by the measuring instrument 76. That is, a part of the anode mask 70 (for example, the aperture blade 72 for adjusting the diameter of the anode opening) may be damaged due to deterioration of the member caused by chemical changes caused by the plating solution. When a part of the anode mask is damaged, the electric field between the anode and the substrate is disturbed, making it difficult to form a desired plating film thickness distribution on the plated surface. In addition, not only the anode mask 70 but also the regulation plate 30 may be damaged due to chemical changes caused by the plating solution.

[0031] In response to this, the detection member 80 detects that the voltage of at least one of the measurement electrodes 74-1, 74-2, and 74-3 has changed from the normal state based on the time change in the voltage measured by the measuring device 76. For example, if the aperture blade 72 arranged near the measurement electrode 74-1 is damaged, the voltage of the measurement electrode 74-1 changes from the normal state. When the detection member 80 detects that the voltage of the measurement electrode 74-1 has changed from the normal state, it can issue an alarm indicating the possibility of damage to the aperture blade 72 arranged near the measurement electrode 74-1. Furthermore, the detection member 80 can issue an alarm and stop the operation of the plating apparatus 10.

[0032] Fig. 4 is a schematic front view of an anode mask according to one embodiment. As shown in Fig. 4, the plating apparatus 10 may have six measurement electrodes 74-1 to 74-6. In this case, the measurement electrodes 74-1 to 74-6 are disposed on the surface of the anode mask 70 facing the substrate holder 40 at equal intervals (60° intervals) on a circle about the center of the anode opening 70a.

[0033] The detection member 80 is configured to detect damage to the anode mask 70 or the regulation plate 30 (electric field adjusting member) based on the time change of the voltage measured by the measuring instrument 76 for each of the measurement electrodes 74-1 to 74-6. By increasing the number of measurement electrodes 74 as in this embodiment, it is possible to more specifically detect the location where the disturbance of the electric field formed between the anode 21 and the substrate WF occurs. As a result, for example, when damage occurs in the diaphragm blade 72, the location where the damage occurs can be more specifically identified.

[0034] 5 is a schematic front view of an anode mask according to an embodiment. This embodiment is an embodiment of a plating apparatus for performing plating processing on a rectangular substrate WF. As shown in FIG. 5, the anode opening 70a is formed in a rectangular shape corresponding to the shape of the rectangular substrate WF.

[0035] As shown in Fig. 5, the anode mask 70 has a plurality of shielding members 79 (shielding members 79-1, 79-2, 79-3, 79-4) provided on each side of the rectangular anode opening 70a. Each shielding member 79 is movable toward and away from the center of the anode opening 70a. Also, as shown in Fig. 5, the plating apparatus 10 includes a plurality (four) of measurement electrodes 74-1, 74-2, 74-3, 74-4 respectively disposed on each side of the rectangular anode opening 70a.

[0036] The plating apparatus 10 has an aperture adjustment member 90 configured to move the shielding member 79 based on the voltages of the multiple measurement electrodes measured by the measuring instrument 76. The aperture adjustment member 90 can adjust the anode aperture 70a when the axial alignment of the anode 21, the anode mask 70, and the substrate WF (substrate holder 40) is misaligned.

[0037] That is, the anode 21, the anode mask 70, and the substrate WF (substrate holder 40) are required to be arranged in appropriate positions with their axes aligned with each other. However, if any of the members is misaligned, the electric field between the anode and the substrate is disturbed, making it difficult to form a desired plating film thickness distribution.

[0038] In response to this, the aperture adjustment member 90 compares the voltage values ​​of the measurement electrodes on the opposing sides of the anode aperture 70a, and adjusts the position of the anode aperture 70a by moving the shielding members 79-1, 79-2, 79-3, and 79-4 based on the comparison result. For example, assume that the substrate holder 40 is placed at a position lower than the appropriate position. In this case, the electric field between the anode and the substrate is disturbed, and when the voltage of the measurement electrode 74-1 is compared with the voltage of the measurement electrode 74-3, the voltage of the measurement electrode 74-3 may be higher. Based on this comparison result, the aperture adjustment member 90 moves the shielding members 79-1 and 79-3 downward to move the anode aperture 70a downward. The aperture adjustment member 90 can move the shielding members 79-1 and 79-3 downward until the voltage of the measurement electrode 74-1 and the voltage of the measurement electrode 74-3 become equal. As a result, the disturbance of the electric field between the anode and the substrate is suppressed, and it becomes easier to form a desired plating film thickness distribution.

[0039] In the above embodiment, a dip-type plating apparatus in which the substrate WF is immersed in the plating solution so that the surface WF1 to be plated faces sideways has been described as an example, but the present invention is not limited to this. The present invention can also be applied to a cup-type plating apparatus in which the substrate WF is immersed in the plating solution so that the surface WF1 to be plated faces downward. This point will be described below.

[0040] 6 is a cross-sectional view showing the overall configuration of a plating apparatus according to one embodiment. Members having the same functions as those in the above embodiment are given the same reference numerals and their explanations are omitted.

[0041] 6, the substrate holder 40 is configured to hold the substrate WF with the plating surface WF1 facing downward. The plating apparatus 10 has a resistor 32 (electric field adjusting member) that is disposed between the anode mask 70 and the substrate holder 40 and has a plurality of openings 32a penetrating between the anode 21 side and the substrate holder 40 side. The resistor 32 can be, for example, a punched plate in which a plurality of punched openings are formed, but is not limited thereto.

[0042] According to this embodiment, as in the above embodiment, the plating apparatus 10 can measure the voltage of the measurement electrode 74 relative to the reference electrode 75 by the measuring instrument 76, and therefore can detect disturbances in the electric field formed between the anode 21 and the substrate WF. The plating apparatus 10 also has a detection member 80 configured to detect damage to the anode mask 70 or the resistor 32 (electric field adjusting member) based on the time change in the voltage measured by the measuring instrument 76. When the detection member 80 detects that the voltage of the measurement electrode 74 has changed from the normal state, it can issue an alarm indicating the possibility of damage to the aperture blade 72 arranged near the measurement electrode 74. The detection member 80 can also issue an alarm and stop the operation of the plating apparatus 10.

[0043] Although several embodiments of the present invention have been described above, the above-mentioned embodiments of the present invention are intended to facilitate understanding of the present invention and do not limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and the present invention naturally includes equivalents thereof. Furthermore, any combination or omission of each component described in the claims and specification is possible within the scope of solving at least a part of the above-mentioned problems or achieving at least a part of the effects.

[0044] The present application discloses, as one embodiment, a plating apparatus including: a plating tank for containing a plating solution; an anode disposed in the plating tank; a substrate holder for holding a substrate such that a surface to be plated faces the anode; an anode mask disposed between the anode and the substrate holder, the anode mask having an anode opening penetrating the anode side and the substrate holder side and configured to be able to adjust the size of the anode opening; an electric field adjusting member disposed between the anode mask and the substrate holder; a measurement electrode disposed between the anode mask and the electric field adjusting member; a reference electrode disposed in the plating solution contained in the plating tank; and a measuring instrument for measuring a voltage between the reference electrode and the measurement electrode.

[0045] The present application also discloses, as one embodiment, a plating apparatus in which the measurement electrode includes a plurality of measurement electrodes equally spaced on a circumference centered on an imaginary axis connecting the center of the anode and the center of the substrate.

[0046] Furthermore, the present application discloses, as one embodiment, a plating apparatus in which the plurality of measurement electrodes are disposed on a surface of the anode mask facing the substrate holder.

[0047] In addition, as one embodiment, the present application discloses a plating apparatus further including a detection member configured to detect damage to the anode mask or the electric field adjusting member based on a time change in the voltage measured by the measuring device.

[0048] The present application also discloses, as one embodiment, a plating apparatus in which the anode opening is formed into a rectangle corresponding to the shape of a rectangular substrate held by the substrate holder, the multiple measurement electrodes are each arranged on each side of the rectangular anode opening, the anode mask includes multiple shielding members provided on each side of the rectangular anode opening, and the anode mask further includes an opening adjustment member configured to move the multiple shielding members toward or away from the center of the anode opening based on the voltage measured by the measuring instrument.

[0049] The present application also discloses, as one embodiment, a plating apparatus in which the substrate holder is configured to hold a substrate with the surface to be plated facing sideways, and the electric field adjustment member includes a regulation plate having a single regulation opening penetrating the anode side and the substrate holder side.

[0050] The present application also discloses, as one embodiment, a plating apparatus in which the substrate holder is configured to hold a substrate with the surface to be plated facing downward, and the electric field adjustment member includes a resistor having a plurality of openings penetrating between the anode side and the substrate holder side. [Explanation of symbols]

[0051] 10 Plating Equipment 21 Anode 30 Regulation Plate 30a Regulation Aperture 32 Resistor 32a aperture 40 Substrate holder 50 Plating tank 70 Anode Mask 70a Anode opening 74 Measuring electrode 75 Reference electrode 76 Measuring Instruments 79 Shielding material 80 Detection member 90 Opening adjustment member Q Plating solution WF board WF1 Plated surface

Claims

1. A plating tank for containing a plating solution; an anode disposed in the plating tank; a substrate holder for holding a substrate such that a surface to be plated faces the anode; an anode mask disposed between the anode and the substrate holder, the anode mask having an anode opening penetrating the anode side and the substrate holder side, the anode mask being configured to be adjustable in size; an electric field adjusting member disposed between the anode mask and the substrate holder; a measurement electrode disposed between the anode mask and the electric field adjusting member; a reference electrode disposed in the plating solution contained in the plating tank; a meter for measuring a voltage between the reference electrode and the measurement electrode; Including, Plating equipment.

2. The measurement electrodes include a plurality of measurement electrodes arranged at equal intervals on a circumference centered on a virtual axis connecting the center of the anode and the center of the substrate.

2. The plating apparatus according to claim 1.

3. the plurality of measurement electrodes are disposed on a surface of the anode mask facing the substrate holder; 3. The plating apparatus according to claim 2.

4. and a detection member configured to detect damage to the anode mask or the electric field adjusting member based on a time change in the voltage measured by the measuring device. The plating apparatus according to claim 1 .

5. the anode opening is formed in a rectangular shape corresponding to the shape of a rectangular substrate held by the substrate holder; The plurality of measurement electrodes are disposed on each side of a rectangular anode opening, the anode mask includes a plurality of shielding members provided on each side of a rectangular anode opening, and an aperture adjustment member configured to move the plurality of shielding members in a direction toward or away from the center of the anode aperture based on the voltage measured by the measuring device.

4. The plating apparatus according to claim 2 or 3.

6. The substrate holder is configured to hold the substrate with the surface to be plated facing sideways, the electric field adjusting member includes a regulating plate having a single regulating opening extending through the anode side and the substrate holder side; 2. The plating apparatus according to claim 1.

7. the substrate holder is configured to hold the substrate with the surface to be plated facing downward; The electric field adjusting member includes a resistor having a plurality of openings extending from the anode side to the substrate holder side.

2. The plating apparatus according to claim 1.