Wafer electroplating device

Abstract

The utility model provides a wafer electroplating device. The wafer electroplating device comprises an electroplating pool, a pressure plate and an electromagnet, the electroplating pool is used for electroplating a wafer, the pressure plate is arranged above the electroplating pool and can move in the direction perpendicular to the surface of the wafer, and the pressure plate is provided with a front face and a back face which are opposite to each other; the front surface of the pressure plate is pressed on the wafer along the direction vertical to the surface of the wafer so as to fix the wafer in the electroplating pool, the electromagnet is fixedly arranged on the back surface of the pressure plate, and the electromagnet forms a magnetic field facing the electromagnet from the wafer. According to the wafer electroplating device, the movement speed of copper ions in the electroplating solution is increased, the problem that the hydrogen ion concentration and the copper ion concentration are unbalanced due to the fact that the movement speed of the hydrogen ions is larger than that of the copper ions is solved, and the copper ion concentration of the cathode plating area where the wafer is located is kept stable in the electroplating state; and the electroplating process data stability is ensured.

Description

Technical Field

[0001] This utility model relates to the semiconductor field, and more particularly to a wafer electroplating apparatus. Background Technology

[0002] In existing technology, when electroplating a wafer, the anode region is connected to the positive terminal of a power supply, and the cathode region is connected to the negative terminal. The electric field direction is from the anode region to the cathode region. The wafer is located in the cathode region, and the copper block is located in the anode region. The copper block undergoes an oxidation reaction in the anode region to generate copper ions. Under a certain potential, cations (hydrogen ions and copper ions) will pass from the anode through the ion membrane to the cathode.

[0003] Copper ions from the anode region, passing through the ion-exchange membrane to the cathode region, are reduced to copper on the wafer surface, while hydrogen ions remain in the cathode region. During continuous thick film deposition, the copper ion concentration in the cathode region continuously decreases, while the hydrogen ion concentration continuously increases. Furthermore, at the same potential, because hydrogen ions have a higher limiting equivalent conductivity, higher electromobility, and smaller hydration radius than copper ions, their velocity is several times that of copper ions. Hydrogen ions preferentially pass through the ion-exchange membrane, accumulating at the cathode, leading to a further increase in hydrogen ion concentration and a further decrease in copper ion concentration in the cathode region. Consequently, this affects the electroplating process data during high-voltage, long-term electroplating.

[0004] Providing a wafer electroplating apparatus that keeps the copper ion concentration in the cathode region stable is of great significance. Summary of the Invention

[0005] The technical problem to be solved by this invention is to provide a wafer electroplating apparatus that can keep the copper ion concentration in the electroplating solution in the electroplating cathode area stable.

[0006] To address the aforementioned problems, this utility model provides a wafer electroplating apparatus, comprising: an electroplating tank for electroplating wafers; a pressure plate disposed above the electroplating tank and movable in a direction perpendicular to the wafer surface, the pressure plate having a front and a back side, the front side of the pressure plate pressing against the wafer in a direction perpendicular to the wafer surface to fix the wafer within the electroplating tank; and an electromagnet fixedly disposed on the back side of the pressure plate, the electromagnet being capable of generating a magnetic field from the wafer toward the electromagnet.

[0007] In some embodiments, when the wafer electroplating apparatus is in electroplating operation, the electromagnet is subjected to current to form the magnetic field.

[0008] In some embodiments, the electromagnet is disc-shaped, and the electromagnet has the same outer diameter as the wafer.

[0009] In some embodiments, the thickness of the electromagnet is less than the thickness of the pressure plate.

[0010] In some embodiments, the back of the pressure plate has a groove into which the electromagnet can be embedded.

[0011] In some embodiments, a bearing is vertically fixed at the center of the pressure plate, and the bearing can drive the pressure plate to move in a direction perpendicular to the wafer surface.

[0012] In some embodiments, the electromagnet has a hole at its center, and the bearing passes through the hole through the electromagnet.

[0013] In some embodiments, the back of the pressure plate has a protrusion, and the electromagnet has at least one fixing hole, wherein the electromagnet is fixed to the back of the pressure plate by inserting the protrusion into the fixing hole.

[0014] In some embodiments, the shape of the fixing hole is one or more of the following: circular, triangular, rectangular, and cross-shaped.

[0015] In some embodiments, the fixing holes are evenly distributed on the electromagnet.

[0016] The above technical solution provides a wafer electroplating apparatus. The wafer electroplating apparatus includes an electroplating tank, a pressure plate, and an electromagnet. The electroplating tank is used for electroplating wafers. The pressure plate is positioned above the electroplating tank and can move in a direction perpendicular to the wafer surface. The pressure plate has a front and a back side. The front side of the pressure plate presses against the wafer in a direction perpendicular to the wafer surface to fix the wafer within the electroplating tank. The electromagnet is fixedly positioned on the back side of the pressure plate and forms a magnetic field from the wafer toward the electromagnet. By increasing the movement speed of copper ions in the electroplating solution through this wafer electroplating apparatus, the problem of an imbalance between hydrogen ion concentration and copper ion concentration caused by the greater movement speed of hydrogen ions than copper ions is avoided. During electroplating, the copper ion concentration in the cathode area where the wafer is located remains stable, ensuring stable electroplating process data.

[0017] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the present invention. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of a wafer electroplating apparatus provided in one embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the back of the pressure plate provided in one embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of an electromagnet provided in one embodiment of the present invention. Detailed Implementation

[0022] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0023] Figure 1 This is a schematic diagram of a wafer electroplating apparatus provided in one embodiment of the present invention. Figure 1 As shown, the wafer electroplating apparatus includes an electroplating tank 11, a pressure plate 12, and an electromagnet 13.

[0024] The electroplating tank 11 is used for electroplating the wafer 10. In this embodiment, the electroplating tank 11 is connected to the anode region in the electroplating chamber, and the wafer 10 is placed face down in the electroplating tank 11. When performing the electroplating process on the wafer 10, a robotic arm places the wafer 10 face down in the electroplating tank 11 and brings it into contact with the electroplating solution. The area of ​​the electroplating tank 11 near the wafer 10 is the cathode region, and the area away from the wafer 10 is the anode region. An ion exchange membrane exists between the cathode region and the anode region. During the electroplating process, the cathode region is connected to the negative terminal of the electroplating power supply, and the anode region is connected to the negative terminal of the electroplating power supply, forming an electric field E. Figure 1 As shown, the electric field E is directed towards the front side of the wafer 10. Under the action of the electric field E, copper ions and hydrogen ions in the anode region pass through the ion membrane to reach the cathode region.

[0025] The pressure plate 12 is positioned above the electroplating bath 11 and is movable in a direction perpendicular to the surface of the wafer 10. The pressure plate 12 has a front and a back side. The front side of the pressure plate 12 presses against the wafer 10 in a direction perpendicular to the surface of the wafer 10 to fix the wafer 10 within the electroplating bath 11. The side of the pressure plate 12 closest to the wafer 10 is the front side, and the side of the pressure plate 12 furthest from the wafer 10 is the back side. When the pressure plate 12 presses down and fixes the wafer 10 within the electroplating bath 11, as... Figure 1 As shown, the front of the pressure plate 12 is the lower surface of the pressure plate 12, and the back of the pressure plate 12 is the upper surface of the pressure plate 12.

[0026] In this embodiment, a bearing is vertically fixed to the center of the pressure plate 12, and the bearing can drive the pressure plate 12 to move in a direction perpendicular to the surface of the wafer 10. A motor (not shown) drives the bearing 14, thereby driving the pressure plate 12 to move in a direction perpendicular to the surface of the wafer 10. Figure 1 As shown, the wafer 10, the electroplating tank 11, and the pressure plate 12 are all horizontally arranged. When the pressure plate 12 presses down on the wafer 10, it fixes the wafer 10 in the electroplating tank 11.

[0027] The electromagnet 13 is fixedly disposed on the back side of the pressure plate 12, and the electromagnet 13 forms a magnetic field H from the wafer 10 toward the electromagnet 13.

[0028] Figure 2 This is a schematic diagram of the back of the pressure plate provided in one embodiment of this utility model. (See diagram below.) Figure 2 As shown, a bearing 14 is vertically fixed to the central region 123 of the pressure plate 12. Three protrusions 122 are evenly distributed on the back of the pressure plate 12. The bottom of each protrusion 122 is a cuboid.

[0029] The pressure plate 12 has a groove 121 on its back side, into which the electromagnet 13 can be embedded. In this embodiment, the groove 121 is a circular groove.

[0030] The thickness of the electromagnet 13 is less than the thickness of the pressure plate 12, and the electromagnet 13 can be completely embedded. Figure 2 The electromagnet 13 is placed in the groove 121 without affecting the process position. For example, the thickness of the electromagnet 13 is 10 mm.

[0031] Figure 3 This is a schematic diagram of an electromagnet provided in one embodiment of the present invention. Figure 3As shown, the electromagnet 13 is disk-shaped, and its outer diameter is the same as that of the wafer 12. For example, if the diameter of the wafer 10 is 300 mm, the outer diameter of the electromagnet 13 is also 300 mm. This ensures that the magnetic field H generated by the electromagnet 13 is perpendicular to the surface of the wafer 10 and is uniformly distributed on the surface of the wafer 10.

[0032] In some embodiments, the outer diameter of the electromagnet 13 is larger than the outer diameter of the wafer 12.

[0033] The electromagnet 13 can be of other shapes. For example, in some embodiments, the electromagnet 13 is square, but the magnetic field generated by the electromagnet 13 is directed from the wafer 10 toward the electromagnet 13.

[0034] Combination Figure 2 Since a bearing 14 is vertically fixed in the center area 121 of the pressure plate 12, there is a hole 131 in the center of the electromagnet 13.

[0035] In this embodiment, the hole 131 is circular in shape, making the electromagnet 13 itself symmetrical. The size of the hole 131 allows the bearing 14 to pass through the electromagnet 13, thereby bringing the electromagnet 13 into contact with the back of the pressure plate 12.

[0036] The pressure plate 12 has a protrusion 122 on its back side, and the electromagnet 13 has at least one fixing hole 132 for fixing the electromagnet 13 to the back side of the pressure plate 12. Figure 3 In the middle, the electromagnet 13 has 3 fixing holes 132.

[0037] The cross-sectional shape of the fixing hole 132 is one or more of the following: circular, triangular, rectangular, and cross-shaped. For example, in this embodiment, the cross-sectional shape of the fixing hole 132 is rectangular. The fixing hole 132 is adapted to the protrusion 122 on the back of the pressure plate 12. Specifically, the number of protrusions 122 on the back of the pressure plate 12 is the same as the number of fixing holes 132, the positional distribution of the protrusions 122 on the back of the pressure plate 12 is the same as the positional distribution of the fixing holes 132, and the shape of the protrusions 122 on the back of the pressure plate 12 is consistent with the shape of the fixing holes 132. Thus, the protrusions 122 on the back of the pressure plate 12 can be inserted into the fixing hole 132, so that the electromagnet 13 is fixed to the back of the pressure plate 12. The shape of the fixing hole 132 is consistent with the shape of the protrusion on the back of the pressure plate 12. It is not required that the shape of the fixing hole 132 is exactly the same as the shape of the protrusion on the back of the pressure plate 12. Rather, it means that when the protrusion is embedded in the fixing hole 132, there will be no displacement between the two.

[0038] contrast Figure 2 and Figure 3 The number of protrusions 122 on the back of the pressure plate 12 and the number of fixing holes 132 are both 3. The protrusions 122 on the back of the pressure plate 12 and the fixing holes 132 are distributed correspondingly. The bottom shape of the protrusions 122 on the back of the pressure plate 12 and the cross-sectional shape of the fixing holes 132 are both rectangular.

[0039] In this embodiment, the number of fixing holes is greater than or equal to 3. Figure 2 The number of fixing holes 132 is 3. In some embodiments, the number of fixing holes is 4 or 5.

[0040] The shape of the fixing hole 132 can be other shapes, such as one or more of circles, triangles, and crosses. The shapes of the fixing holes 132 can be the same or different. Correspondingly, the shape of the protrusion 122 on the back of the pressure plate 12 is consistent with the shape of the fixing hole 132, and when the protrusion 122 is inserted into the fixing hole 132, there will be no displacement between the two.

[0041] Continue to refer to Figure 3 The fixing holes 132 are evenly distributed on the electromagnet 13. For example, in this embodiment, the fixing holes 132 are equidistant from the center of the electromagnet 13, and the angle between the lines connecting any two adjacent fixing holes 132 and the center of the electromagnet 13 is 120°.

[0042] In some embodiments, the fixing holes are non-uniformly distributed on the electromagnet. The number and position of the fixing holes are determined according to the distribution of protrusions on the back of the pressure plate, with the aim of ensuring that the electromagnet can fit against the pressure plate and be fixed to the back of the pressure plate. For example, if the back of the pressure plate has three evenly distributed protrusions and a special protrusion near the center of the back of the pressure plate, then the electromagnet includes three evenly distributed fixing holes and a special fixing hole corresponding to the special protrusion.

[0043] Continue to refer to Figure 1 The electromagnet 13 is disc-shaped and fixed to the back of the pressure plate 12. The magnetic field H generated by the electromagnet 13 extends from the wafer 10 towards the electromagnet 13. Therefore, under the action of the magnetic field H, the copper ions in the electroplating solution experience a magnetic force towards the front of the wafer 10, which can accelerate the movement of copper ions to the cathode region, thereby increasing the copper ion concentration in the cathode region.

[0044] When the wafer electroplating apparatus is in electroplating operation, a current is applied to the electromagnet 13 to form the magnetic field H. Specifically, when the wafer electroplating apparatus is in electroplating operation, and the electroplating power applied to the cathode and anode regions is relatively high (e.g., 40.5V), copper ions from the anode region passing through the ion-exchange membrane to the cathode region are reduced to copper on the wafer surface, while hydrogen ions remain in the cathode region. During continuous thick film deposition, the copper ion concentration in the cathode region continuously decreases, while the hydrogen ion concentration continuously increases. At this time, the current applied to the electromagnet 13 gradually increases. As the magnetic force increases, the movement speed of copper ions in the electroplating solution increases accordingly, so that the copper ion supply and consumption in the cathode region reach a balance, thereby maintaining a stable copper ion concentration. In this embodiment, the current applied to the electromagnet 13 gradually increases to 10A within 10 seconds.

[0045] The above technical solution provides a wafer electroplating apparatus. The wafer electroplating apparatus includes an electroplating tank, a pressure plate, and an electromagnet. The electroplating tank is used for electroplating wafers. The pressure plate is positioned above the electroplating tank and can move in a direction perpendicular to the wafer surface. The pressure plate has a front and a back side. The front side of the pressure plate presses against the wafer in a direction perpendicular to the wafer surface to fix the wafer within the electroplating tank. The electromagnet is fixedly positioned on the back side of the pressure plate and forms a magnetic field from the wafer toward the electromagnet. By increasing the movement speed of copper ions in the electroplating solution through this wafer electroplating apparatus, the problem of an imbalance between hydrogen ion concentration and copper ion concentration caused by the greater movement speed of hydrogen ions than copper ions is avoided. During electroplating, the copper ion concentration in the cathode area where the wafer is located remains stable, ensuring stable electroplating process data.

[0046] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion. The various embodiments in this specification are described in a related manner, and similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments.

[0047] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of protection of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model.

Claims

1. A wafer electroplating apparatus, characterized in that, include: An electroplating bath used for electroplating wafers; A pressure plate is disposed above the electroplating bath and is movable in a direction perpendicular to the surface of the wafer. The pressure plate has a front and a back side. The front side of the pressure plate presses onto the wafer in a direction perpendicular to the surface of the wafer to fix the wafer in the electroplating bath. An electromagnet is fixedly disposed on the back of the pressure plate, and the electromagnet is capable of generating a magnetic field from the wafer toward the electromagnet.

2. The wafer electroplating apparatus according to claim 1, characterized in that, When the wafer electroplating apparatus is in electroplating operation, an electric current is applied to the electromagnet to form the magnetic field.

3. The wafer electroplating apparatus according to claim 1, characterized in that, The electromagnet is disc-shaped, and its outer diameter is the same as that of the wafer.

4. The wafer electroplating apparatus according to claim 1, characterized in that, The thickness of the electromagnet is less than the thickness of the pressure plate.

5. The wafer electroplating apparatus according to claim 1, characterized in that, The pressure plate has a groove on its back, into which the electromagnet can be inserted.

6. The wafer electroplating apparatus according to claim 1, characterized in that, A bearing is vertically fixed in the central region of the pressure plate, and the bearing can drive the pressure plate to move in a direction perpendicular to the surface of the wafer.

7. The wafer electroplating apparatus according to claim 6, characterized in that, The electromagnet has a hole in its central region, and the bearing passes through the electromagnet through the hole.

8. The wafer electroplating apparatus according to claim 1, characterized in that, The back of the pressure plate has a protrusion, and the electromagnet has at least one fixing hole. The electromagnet is fixed to the back of the pressure plate by inserting the protrusion into the fixing hole.

9. The wafer electroplating apparatus according to claim 8, characterized in that, The cross-sectional shape of the fixing hole is one or more of the following: circular, triangular, rectangular, and cross-shaped.

10. The wafer electroplating apparatus according to claim 8, characterized in that, The fixing holes are evenly distributed on the electromagnet.

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