Semiconductor electroplating device with good uniformity of wafer edge plating layer

Abstract

The application discloses a semiconductor electroplating device with good uniformity of wafer edge coating layer, which comprises an electroplating chamber; a wafer transfer device is arranged above the electroplating chamber and can move up and down and rotate; the wafer transfer device comprises a base; a rotating part is arranged on the base, and a rotatable rotating plate is arranged on the rotating part; an upper shell is arranged outside the rotating plate; a lower shell is arranged below the upper shell and can be lifted and lowered after rotating with the rotating plate; a placing ring is arranged below the lower shell and connected with the rotating plate; an electric slip ring is arranged on the rotating part; a ring electrode is arranged on the lower shell and arranged along the wafer on the placing ring; and the ring electrode is electrically connected with an external power supply through the electric slip ring. The ring electrode is arranged outside the circumference of the wafer, so that the partial power lines originally concentrated on the edge of the wafer are extended to the outside and redistributed, the current density distribution of the wafer surface tends to be consistent from the center to the edge, and the uniformity of the coating layer on the wafer surface is improved.

Description

Technical Field

[0001] This invention relates to the field of semiconductor electroplating technology, and in particular to a semiconductor electroplating apparatus with good uniformity of coating at the wafer edge. Background Technology

[0002] In semiconductor electroplating, the wafer is immersed in an electrolyte as the cathode, and the electroplating material acts as the anode, forming a metal coating on the wafer surface through the action of an electric field. However, due to the uneven distribution of the electric field, the current density in the wafer edge region is significantly higher than that in the center region, resulting in a thicker coating at the edge (especially in the radius range of 140 mm to 150 mm).

[0003] In existing technologies, adding a second or third cathode below the plating bath is commonly used to improve the uniformity of the edge plating layer, but the effect is limited and it is difficult to meet the high requirements for plating uniformity in advanced processes. In addition, the upper structure of existing technologies lacks effective means to optimize the end effect. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a semiconductor electroplating apparatus with good uniformity of wafer edge plating, resulting in good uniformity of the wafer edge plating after electroplating.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is: a semiconductor electroplating apparatus with good uniformity of wafer edge plating, comprising:

[0006] Electroplating chamber;

[0007] The wafer transfer device is mounted above the electroplating chamber and can move up and down and rotate.

[0008] The wafer transfer device includes a base, a rotating component, an upper housing, a lower housing, a placement ring, an electric slip ring, and an annular electrode. The rotating component is mounted on the base and has a rotatable rotating plate. The upper housing is sleeved on the outside of the rotating plate. The lower housing is vertically movable below the upper housing, following the rotation of the rotating plate. The placement ring is located below the lower housing and connected to the rotating plate. The electric slip ring is sleeved on the rotating component. The annular electrode is mounted on the lower housing and is positioned along the wafer located on the placement ring. The annular electrode is electrically connected to an external power source via the electric slip ring.

[0009] Optionally, the annular electrode has multiple upwardly oriented terminal blocks in the circumferential direction, and the terminal blocks are fitted into the lower housing; the terminal blocks have wiring holes, and wires are provided in the wiring holes, with the other end of the wires extending upward and connecting to the rotor side of the slip ring.

[0010] Optionally, the lower housing is connected to a lifting component located on the base via a transmission rod, thereby driving the lower housing to move up and down.

[0011] Optionally, the end face of the annular electrode facing the wafer is serrated.

[0012] Optionally, the number of the terminal blocks is four, and two are arranged in a group, respectively on both sides of the annular electrode.

[0013] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0014] The semiconductor electroplating apparatus of the present invention provides good uniformity of wafer edge plating. An annular electrode is provided outside the circumference of the wafer, which is equivalent to constructing an extended equipotential region. This attracts some of the electric field lines that were originally concentrated at the wafer edge to extend outward and redistribute them, thereby reducing the local current density at the wafer edge and making the current density distribution on the wafer surface from the center to the edge more uniform. This improves the uniformity of the wafer surface plating and meets the actual application requirements. Attached Figure Description

[0015] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0016] Figure 1 This is a schematic diagram of a structure according to an embodiment of the present invention;

[0017] Figure 2 for Figure 1 Sectional view of part A in the middle;

[0018] Figure 3 for Figure 2 Enlarged view of part B in the image;

[0019] Figure 4 This is a partial schematic diagram of a wafer transfer device in one embodiment of the present invention;

[0020] Figure 5 This is a three-dimensional structural diagram of the ring electrode in one embodiment of the present invention;

[0021] Figure 6 This is a schematic diagram of electric field lines in one embodiment of the present invention;

[0022] Figure 7 A comparison image showing the electroplating effect before and after adding a ring electrode;

[0023] The components are: 1. Electroplating chamber; 2. Wafer transfer device; 3. Wafer; 4. Edge region; 5. Electric field lines; 20. Base; 21. Rotating component; 22. Upper housing; 23. Lower housing; 24. Placement ring; 25. Electric slip ring; 26. Ring electrode; 27. Terminal block; 28. Lifting component; 29. ​​Wire; 30. Rotating plate. Detailed Implementation

[0024] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0025] This invention provides a semiconductor electroplating apparatus with good uniformity of wafer edge plating, thereby solving the problem of poor uniformity in wafer electroplating in the prior art.

[0026] For ease of understanding, the specific processes in the embodiments of this application are described below. Please refer to [link / reference]. Figures 1 to 4 A semiconductor electroplating apparatus with good uniformity of wafer edge plating in this application embodiment includes an electroplating chamber 1 and a wafer transfer device 2; the wafer transfer device 2 is disposed above the electroplating chamber 1 and can move up and down and rotate.

[0027] Specifically, the wafer transfer device 2 includes a base 20, a rotating component 21, an upper housing 22, a lower housing 23, a placement ring 24, an electric slip ring 25, and an annular electrode 26; the rotating component 21 is disposed on the base 20, and a rotatable rotating plate 30 is provided on the rotating component 21; the upper housing 22 is sleeved on the outside of the rotating plate 30; the lower housing 23 is disposed below the upper housing 22 after rotating with the rotating plate 30; the placement ring 24 is disposed below the lower housing 23 and connected to the rotating plate 30.

[0028] The slip ring 25 is sleeved on the rotating component 21; the annular electrode 26 is disposed on the lower housing 23 and is arranged along the wafer located on the placement ring 24; the annular electrode 26 is electrically connected to an external power supply through the slip ring 25, and its potential is set to the same cathode potential as the wafer. In this way, the annular electrode 26 is equivalent to forming an extended equipotential region on the outer edge of the wafer.

[0029] See Figure 6In traditional electroplating processes, electric field lines at the wafer edge are concentrated due to the geometric tip effect, resulting in a significantly higher current density in the edge region than in the center region, thus producing a thicker coating at the edge. This electroplating apparatus, however, utilizes an auxiliary cathode ring formed by annular electrodes 26, which effectively creates an extended equipotential region outside the wafer edge. This equipotential region attracts some of the electric field lines originally concentrated at the wafer edge to extend outward and redistribute them, thereby reducing the local current density at the wafer edge. This makes the current density distribution on the wafer surface more uniform from the center to the edge, resulting in a more uniform electric field between the wafer edge and the center, and improving the uniformity of the coating on the wafer surface.

[0030] See Figure 2 and Figure 5 The annular electrode 26 has multiple upward-facing terminal blocks 27 arranged around its circumference. The terminal blocks 27 are fitted inside the lower housing. Each terminal block 27 has a wiring hole with a wire 29 attached to it. The other end of the wire 29 extends upward and connects to the rotor side of the slip ring 25, so that both ends of the wire 29 rotate synchronously with the lower housing 23. Since the slip ring 25 is fitted onto the rotating component 21, this also eliminates the relative torsional motion between the wire 29 and the rotating component 21, effectively avoiding the problem of wire entanglement during rotation. At the same time, the multi-point parallel connection reduces the contact resistance, improves the uniformity of current distribution and the overall reliability of the system.

[0031] See Figure 5 The annular electrode 26 is circularly serrated, with the tips of the teeth facing the center of the wafer. This structure allows for the formation of multiple tiny tip discharge regions without significantly increasing the overall size of the annular electrode 26, smoothing the electric field transition curve and preventing the annular electrode 26 itself from introducing new current concentration points, thereby further improving the uniformity of the coating thickness.

[0032] Furthermore, the number of the terminal blocks 27 is four, although the number can be adjusted according to actual needs. In this embodiment, by setting the number of terminal blocks 27 to four and distributing them evenly along the circumference, the power supply access points of the ring electrode 26 are symmetrically distributed, improving the uniformity of the circumferential potential of the ring electrode 26 and further optimizing the symmetrical distribution of the electric field at the wafer edge.

[0033] Furthermore, the lower housing 23 is connected to the lifting component 28 located on the base 20 via a transmission rod, thereby driving the lower housing 23 to move up and down.

[0034] See Figure 6In use, the wafer is fixed on the placement ring 24, and then the same cathode potential as the wafer is applied to the annular electrode through the slip ring. After the wafer transfer mechanism 2 fixes the wafer, it is moved down to the electroplating chamber 1 and immersed in the electrolyte in the electroplating chamber. The rotating component is started, the wafer rotates, and electroplating is performed at the same time. The annular electrode attracts the edge electric lines to extend outward, making the edge position more uniform and optimizing the electric field distribution on the wafer surface. Finally, the uniformity of the coating on the wafer surface is good.

[0035] like Figure 7 As shown, the horizontal axis represents the coordinates of the cross-section passing through the wafer center, and the vertical axis represents the coating thickness on the wafer surface. Red represents the data before adding the ring electrode, and blue represents the data after adding the ring electrode. After adding the ring electrode, the distribution of blue points is more uniform than that of red points, especially in the edge region. The difference between the maximum and minimum thickness at the edge of the red points is more than twice that of the blue points. This demonstrates that adding the ring electrode improves the uniformity of the coating at the wafer edges.

[0036] In summary, the semiconductor electroplating apparatus of the present invention, which provides good uniformity of wafer edge plating, has an annular electrode set outside the circumference of the wafer, thereby making the electric field at the wafer edge and center more uniform, improving the uniformity of the wafer surface plating, and meeting practical application requirements.

[0037] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A semiconductor electroplating apparatus with good uniformity of coating at wafer edges, characterized in that, include: Electroplating chamber; The wafer transfer device is mounted above the electroplating chamber and can move up and down and rotate. The wafer transfer device includes a base, a rotating component, an upper housing, a lower housing, a placement ring, an electric slip ring, and an annular electrode. The rotating component is disposed on the base and has a rotatable rotating plate. The upper housing is sleeved on the outside of the rotating plate. The lower housing is vertically movable below the upper housing after rotating with the rotating plate. The placement ring is disposed below the lower housing and connected to the rotating plate. The electric slip ring is sleeved on the rotating component. The annular electrode is disposed on the lower housing and is arranged along the wafer located on the placement ring. The annular electrode is electrically connected to an external power source via an electric slip ring.

2. The semiconductor electroplating apparatus with good uniformity of wafer edge plating as described in claim 1, characterized in that: The annular electrode has multiple upward-facing terminal blocks along its circumference, and the terminal blocks are fitted inside the lower housing. The terminal blocks have wiring holes with wires attached to them, and the other end of the wires extends upward and connects to the rotor side of the slip ring.

3. The semiconductor electroplating apparatus with good uniformity of wafer edge plating as described in claim 1, characterized in that: The lower housing is connected to a lifting component located on the base via a transmission rod, thereby driving the lower housing to rise and fall.

4. The semiconductor electroplating apparatus with good uniformity of wafer edge plating as described in claim 1, characterized in that: The end face of the ring electrode facing the wafer is serrated.

5. The semiconductor electroplating apparatus with good uniformity of wafer edge plating as described in claim 2, characterized in that: The number of the terminal blocks is four, and they are arranged in pairs, one on each side of the annular electrode.

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