Lower electrode assembly with focusing ring and semiconductor deposition equipment

Abstract

The present invention provides a lower electrode assembly with a focusing ring and a semiconductor precipitation device, which relate to the technical field of semiconductor device manufacturing, and include a lower electrode body and a focusing ring; the focusing ring is arranged in a ring shape along the circumferential edge of the lower electrode body, and the focusing ring is matched and connected with the side wall of the lower electrode body, and the focusing ring is used to balance the surface height of the lower electrode body, so as to balance the height match between the lower electrode body and a wafer; the shape of the focusing ring is designed according to the ring shape of the lower electrode body, and the focusing ring is directly assembled and connected with the side wall of the lower electrode body, and the plasma field at the edge of the wafer can be controlled by the focusing ring, thereby reducing the tolerance superposition in the assembly process, ensuring the gap tolerance range between the focusing ring and the lower electrode body, and alleviating the technical problems existing in the prior art that the height difference caused by the assembly tolerance superposition of the focusing ring is uncontrollable, which easily leads to the leakage of cooling helium on the back side of the wafer, and the reaction products are deposited on the surface of the lower electrode and the back side of the wafer.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor device manufacturing, and in particular to a lower electrode assembly with a focusing ring and semiconductor precipitation equipment. Background Art

[0002] Etching is a necessary step in the semiconductor device wafer manufacturing process. Generally, the etching process is used to remove the unnecessary parts from the wafer. The etching process mainly includes dry etching and wet etching. The uneven plasma density will affect the etching uniformity of each area of ​​the wafer, especially the uniformity of the wafer edge. In order to improve the uniformity of the wafer edge, a focus ring is usually designed on the outer ring of the lower electrode where the wafer is adsorbed.

[0003] In the prior art, in order to ensure the assembly of the focusing ring, a plurality of ceramic components are stacked along the side wall of the lower electrode; specifically, according to the use of different semiconductor precipitation equipment, ceramic rings of different thicknesses are preset, that is, the ceramic rings are arranged in a ring shape on the outside of the lower electrode, and the stacking height of the ceramic rings can ensure the assembly height of the focusing ring and the upper surface of the lower electrode.

[0004] However, since each ceramic ring has a tolerance, when multiple ceramic rings are assembled with the focusing ring, the total height difference after the tolerances are superimposed is uncontrollable. When the tolerances are superimposed and the height difference between the focusing ring and the upper surface of the lower electrode exceeds the etching critical value, it will cause leakage of cooling helium on the back of the wafer, and reaction products will be deposited on the surface of the lower electrode and the back of the wafer. When the reaction products are deposited to a certain extent, they will weaken the adsorption capacity of the supporting device and even directly affect the adsorption of the wafer. Summary of the invention

[0005] The purpose of the present invention is to provide a lower electrode assembly and semiconductor precipitation equipment with a focusing ring, so as to alleviate the technical problems existing in the prior art that the superposition of focusing ring assembly tolerances causes uncontrollable height differences, which easily leads to leakage of cooling helium on the back of the wafer, and deposition of reaction products on the surface of the lower electrode and the back of the wafer.

[0006] The present invention provides a lower electrode assembly with a focusing ring, comprising: a lower electrode body and a focusing ring;

[0007] The focusing ring is arranged in a ring shape along the circumferential edge of the lower electrode body and is connected to the side wall of the lower electrode body. The focusing ring is used to balance the surface height of the lower electrode body to balance the height coordination between the lower electrode body and the wafer.

[0008] In a preferred embodiment of the present invention, the electrode body comprises a lower electrode and an electrode support;

[0009] The electrode support has a receiving groove, the lower electrode is received in the receiving groove, and the focusing ring is arranged in a ring shape along the circumferential direction of the lower electrode, and the focusing ring is abutted and fixed against the side wall of the electrode support.

[0010] In a preferred embodiment of the present invention, the focusing ring includes a cover ring and a blocking ring;

[0011] The blocking ring is located between the lower electrode and the electrode support, the blocking ring is sleeved on the outside of the lower electrode, the cover ring is arranged in a ring along the side wall of the lower electrode, and the cover ring is covered at the edge of the lower electrode, and one end of the cover ring extends out of the lower electrode and abuts against the side wall of the electrode support for sealing.

[0012] In a preferred embodiment of the present invention, the cover ring includes a cover plate and a blocking plate;

[0013] The cover plate is connected to the blocking plate, and the cover plate and the blocking plate are arranged at an angle, the cover plate abuts against the surface of the lower electrode, the blocking plate cover is arranged at the end of the lower electrode, and the blocking plate abuts against the electrode support.

[0014] In a preferred embodiment of the present invention, the lower electrode has an extended protrusion, which extends along the side wall of the lower electrode, the cover plate is covered on the upper surface of the extended protrusion, and the blocking plate cover is provided at the end of the extended protrusion to balance the assembly height of the cover ring and the lower electrode through the extended protrusion.

[0015] In a preferred embodiment of the present invention, the blocking ring includes a ring body and an annular protrusion;

[0016] The ring body is fixedly connected to the annular protrusion, the ring body is arranged in an annular shape outside the lower electrode, and the annular protrusion is located between the extension protrusion and the blocking plate, and the annular protrusion abuts against the extension protrusion and the blocking plate respectively.

[0017] In a preferred embodiment of the present invention, a side of the annular protrusion corresponding to the blocking plate has an arc-shaped protrusion, and the blocking plate has a groove corresponding to the arc-shaped protrusion.

[0018] In a preferred embodiment of the present invention, a sealing step is provided at one end of the blocking plate away from the cover plate, and the blocking plate is abutted and sealed against the outer side wall of the electrode support via the sealing step.

[0019] In a preferred embodiment of the present invention, a boss is provided at one end of the cover plate away from the blocking plate, and the cover plate extends through the boss in the same plane as the surface of the lower electrode.

[0020] The invention provides a semiconductor precipitation device, comprising the lower electrode assembly with a focusing ring.

[0021] The lower electrode assembly with a focusing ring provided by the present invention comprises: a lower electrode body and a focusing ring; the focusing ring is arranged in a ring shape along the circumferential edge of the lower electrode body, and the focusing ring is matched and connected with the side wall of the lower electrode body, and the focusing ring is used to balance the surface height of the lower electrode body, so as to balance the height match between the lower electrode body and the wafer; the shape of the focusing ring is designed according to the ring shape of the lower electrode body, and the focusing ring is directly assembled and connected with the side wall of the lower electrode body, and the plasma field at the edge of the wafer can be controlled by the focusing ring, thereby reducing the tolerance superposition in the assembly process, ensuring the gap tolerance range between the focusing ring and the lower electrode body, and alleviating the technical problems existing in the prior art that the height difference caused by the tolerance superposition of the focusing ring assembly tolerance is uncontrollable, which easily leads to the leakage of cooling helium on the back side of the wafer, and the reaction products are deposited on the surface of the lower electrode and the back side of the wafer. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the overall structure of a lower electrode assembly with a focusing ring provided in an embodiment of the present invention;

[0024] Figure 2 A schematic diagram of a partially enlarged structure of a lower electrode assembly with a focusing ring provided in an embodiment of the present invention.

[0025] Icons: 100 - lower electrode body; 101 - lower electrode; 111 - extension protrusion; 102 - electrode support; 200 - focusing ring; 201 - cover ring; 211 - cover plate; 2111 - boss; 221 - blocking plate; 2211 - sealing step; 202 - blocking ring; 212 - ring body; 222 - annular protrusion; 2221 - arc-shaped protrusion. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] like Figure 1-Figure 2As shown, the present embodiment provides a lower electrode assembly with a focusing ring, comprising: a lower electrode body 100 and a focusing ring 200; the focusing ring 200 is arranged in a ring shape along the circumferential edge of the lower electrode body 100, and the focusing ring 200 is connected to the side wall of the lower electrode body 100, and the focusing ring 200 is used to balance the surface height of the lower electrode body 100, so as to balance the height coordination between the lower electrode body 100 and the wafer.

[0028] It should be noted that the lower electrode assembly with a focusing ring provided in the present embodiment serves as a structure for adsorbing wafers and controlling the temperature of wafers. It is directly connected to the lower electrode body 100 through the focusing ring 200, thereby reducing the multi-layer assembly of ceramic rings and avoiding the tolerance superposition in the process of superposing each ceramic ring, so that the gap between the wafer and the focusing ring 200 is controllable; specifically, the etching gas is excited by a plasma excitation device to form a plasma, and a bias electric field is generated by the radio frequency electrode to accelerate the plasma to the surface of the wafer to be etched, so as to etch the wafer to be etched; some reaction products generated by etching the wafer enter from the gap between the focusing ring 200 and the wafer; the shape of the focusing ring 200 in the present embodiment is designed according to the annular shape of the lower electrode body 100, thereby ensuring the gap tolerance range between the focusing ring 200 and the lower electrode body 100, avoiding the leakage of cooling helium on the back of the wafer, reducing the arc on the surface of the lower electrode body 100, and the deposition of reaction products on the back of the wafer, thereby ensuring that the wafer is smoothly etched.

[0029] Optionally, the focusing ring 200 may be made of ceramic material.

[0030] The lower electrode assembly with a focusing ring provided in the present embodiment comprises: a lower electrode body 100 and a focusing ring 200; the focusing ring 200 is arranged in a ring shape along the circumferential edge of the lower electrode body 100, and the focusing ring 200 is connected with the side wall of the lower electrode body 100, and the focusing ring 200 is used to balance the surface height of the lower electrode body 100, so as to balance the height matching between the lower electrode body 100 and the wafer; the shape of the focusing ring 200 is designed according to the ring shape of the lower electrode body 100, and the focusing ring 200 is directly assembled and connected with the side wall of the lower electrode body 100, and the focusing ring 200 can control the plasma field at the edge of the wafer, thereby reducing the tolerance superposition in the assembly process, ensuring the gap tolerance range between the focusing ring 200 and the lower electrode body 100, and alleviating the technical problems existing in the prior art that the height difference caused by the assembly tolerance superposition of the focusing ring 200 is uncontrollable, which easily leads to the leakage of cooling helium on the back side of the wafer, and the reaction products are deposited on the surface of the lower electrode 101 and the back side of the wafer.

[0031] On the basis of the above embodiments, further, in a preferred embodiment of the present invention, the electrode body includes a lower electrode 101 and an electrode support 102; the electrode support 102 has a receiving groove, the lower electrode 101 is received in the receiving groove, and the focusing ring 200 is arranged in a ring along the circumferential direction of the lower electrode 101, and the focusing ring 200 is fixed in contact with the side wall of the electrode support 102.

[0032] In the present embodiment, the electrode body serves as an adsorption structure for the wafer of the semiconductor precipitation equipment, the lower electrode 101 can be accommodated in the receiving groove of the electrode support 102, and the end of the lower electrode 101 extends out of the opening of the receiving groove, the lower electrode 101 can be used to adsorb the wafer and control the wafer temperature, the upper surface of the lower electrode 101 can be used as the adsorption surface of the wafer, and the focusing ring 200 can be arranged in a ring along the edge of the wafer, that is, the focusing ring 200 can be arranged in a ring along the outer circle of the edge of the lower electrode 101, and is connected to the outer circle of the edge of the lower electrode 101 through the focusing ring 200, and the focusing ring 200 can form a contact seal with the end of the side wall of the electrode support 102, thereby being able to control the plasma field at the edge of the wafer.

[0033] Optionally, the electrode body may further include an insulator, which is located between the lower electrode 101 and the electrode support 102. The insulator can be connected to the bottom walls of the lower electrode 101 and the electrode support 102 respectively, and the insulator can ensure the insulating support between the lower electrode 101 and the electrode support 102; further, after the focusing ring 200 is arranged in a ring shape outside the lower electrode 101, the focusing ring 200 and the insulator are matched, wherein the focusing ring 200 can be clamped and fixed with the bonding body by a step clamping method.

[0034] In a preferred embodiment of the present invention, the focusing ring 200 includes a cover ring 201 and a blocking ring 202; the blocking ring 202 is located between the lower electrode 101 and the electrode support 102, the blocking ring 202 is sleeved on the outside of the lower electrode 101, the cover ring 201 is arranged in a ring along the side wall of the lower electrode 101, and the cover ring 201 is covered at the edge of the lower electrode 101, and one end of the cover ring 201 extends out of the lower electrode 101 and abuts against the side wall of the electrode support 102 for sealing.

[0035] In this embodiment, the blocking ring 202 is located in the accommodating groove of the electrode support 102, and the blocking ring 202 is arranged in a ring shape along the circumferential direction of the lower electrode 101, and the blocking ring 202 can protect the side of the lower electrode 101 from being corroded in a stereoscopic manner; the blocking ring 202 can extend out of the end of the electrode support 102 to form a match with the lower electrode 101, and by arranging the cover ring 201 along the edge circumference of the lower electrode 101, the cover ring 201 can be covered at the edge position of the lower electrode 101, and a staggered match is formed between the cover ring 201 and the blocking ring 202, so that when the cover ring 201 passes over the end of the blocking ring 202 to form an abutment match with the electrode support 102, the circumferential direction of the lower electrode 101 can be completely sealed, and because the cover ring 201 is arranged at the surface position of the lower electrode 101, the plasma field at the edge of the wafer can be controlled by using the cover ring 201, and the cover ring 201 can form a contact sealing protection for the lower electrode 101 and the end of the electrode support 102.

[0036] In a preferred embodiment of the present invention, the cover ring 201 includes a cover plate 211 and a blocking plate 221; the cover plate 211 is connected to the blocking plate 221, and the cover plate 211 and the blocking plate 221 are arranged at an angle, the cover plate 211 abuts against the surface of the lower electrode 101, the blocking plate 221 is covered at the end of the lower electrode 101, and the blocking plate 221 abuts against the electrode support 102.

[0037] In this embodiment, the cover plate 211 and the blocking plate 221 can be arranged vertically, that is, the cover plate 211 and the blocking plate 221 are arranged in an "L" structure, the cover plate 211 can contact and cover the surface of the lower electrode 101, the blocking plate 221 can form a protection with the side wall of the lower electrode 101, and the end of the blocking plate 221 can form a contact connection with the electrode support 102, and the cover plate 211, the blocking plate 221 and the electrode support 102 are used to form a protection space for the lower electrode 101.

[0038] Optionally, a chamfer may be provided at the connection between the cover plate 211 and the blocking plate 221. The chamfer can ensure that an inclined surface is formed at the connection between the cover plate 211 and the blocking plate 221, and the discharge of the reaction products can be better achieved through the inclined surface.

[0039] Optionally, the cover plate 211 and the blocking plate 221 can be connected in various ways, such as: integral molding, plug-in or bonding, etc. Preferably, the cover plate 211 and the blocking plate 221 are integrally molded, wherein the cover ring 201 can be formed by injection molding the cover plate 211 and the blocking plate 221.

[0040] In a preferred embodiment of the present invention, the lower electrode 101 has an extended protrusion 111, which extends along the side wall of the lower electrode 101, the cover plate 211 is covered on the upper surface of the extended protrusion 111, and the blocking plate 221 is covered on the end of the extended protrusion 111 to balance the assembly height of the cover ring 201 and the lower electrode 101 through the extended protrusion 111.

[0041] In the present embodiment, since the assembly of the ceramic ring is cancelled, in order to ensure the covering connection of the cover ring 201, an extension protrusion 111 is provided along the side wall of the lower electrode 101, and the extension protrusion 111 can serve as the covering surface of the cover plate 211, and there is a height difference between the extension protrusion 111 and the surface of the lower electrode 101, and the cover plate 211 covers the surface of the extension protrusion 111, so that the cover plate 211 can ensure the height uniformity of the lower electrode 101, so that the gap between the wafer and the focusing ring 200 is controllable; further, the blocking plate 221 can form a protection with the end of the extension protrusion 111, and the blocking ring 202 can form a match with the end of the extension protrusion 111 away from the cover plate 211, that is, by changing the edge structure of the lower electrode 101, the assembly of the cover ring 201 and the lower electrode 101 is improved, and the gap range between the cover ring 201 and the surface of the lower electrode 101 is ensured.

[0042] In a preferred embodiment of the present invention, the blocking ring 202 includes a ring body 212 and an annular protrusion 222; the ring body 212 is fixedly connected to the annular protrusion 222, the ring body 212 is arranged in a ring shape outside the lower electrode 101, and the annular protrusion 222 is located between the extension protrusion 111 and the blocking plate 221, and the annular protrusion 222 is respectively abutted against the extension protrusion 111 and the blocking plate 221.

[0043] In this embodiment, the ring body 212 is connected to the circumference of the lower electrode 101, and the end of the ring body 212 away from the annular protrusion 222 can be fixedly abutted against the bottom wall of the electrode support 102. In order to ensure the supporting stability of the ring body 212, the ring body 212 can also form a stepped clamping connection with the insulator, that is, the ring body 212 is annularly clamped with the side wall of the lower electrode 101, and a stepped groove is provided at the position of the ring body 212 corresponding to the insulator, and the ring body 212 can form a fit with the edge of the insulator through the stepped groove; the annular protrusion 222 can extend out of the side wall position of the lower electrode 101, and the annular protrusion 222 can be located between the extended protrusion 111 and the blocking plate 221, and the annular protrusion 222 is used to ensure the clearance fit between the blocking plate 221 and the extended protrusion 111, and the annular protrusion 222 can form protection for the edge of the extended protrusion 111 to protect the side of the lower electrode 101 from being corroded by plasma.

[0044] In a preferred embodiment of the present invention, a side of the annular protrusion 222 corresponding to the blocking plate 221 has an arc-shaped protrusion 2221 , and a locking groove is formed on the blocking plate 221 corresponding to the arc-shaped protrusion 2221 .

[0045] In the present embodiment, in order to ensure that the blocking plate 221 forms contact protection on the side wall of the electrode support 102, the annular protrusion 222 abuts against the end of the extended protrusion 111, and a gap is provided between the annular protrusion 222 and the blocking plate 221. By providing an arc-shaped protrusion 2221 at the end of the annular protrusion 222, the arc-shaped protrusion 2221 can form an arc-shaped contact surface with the end of the arc-shaped protrusion 2221, that is, when the cover plate 211 contacts the upper surface of the extended protrusion 111, the blocking plate 221 can slide along the arc-shaped protrusion 2221, so that the blocking plate 221 is completely connected with the electrode support 102, and the sealing protection at the position of the lower electrode 101 is ensured by using the card slot to connect with the arc-shaped protrusion 2221.

[0046] In a preferred embodiment of the present invention, a sealing step 2211 is provided at one end of the blocking plate 221 away from the cover plate 211 , and the blocking plate 221 is abutted and sealed against the outer wall of the electrode support 102 via the sealing step 2211 .

[0047] In the present embodiment, after the blocking plate 221 abuts against the side wall of the electrode support 102, there is still a gap between the end positions of the blocking plate 221 and the electrode support 102. By providing a sealing step 2211 on the outer wall of the blocking plate 221, the sealing step 2211 can form an annular protection with the outer wall of the electrode support 102, thereby improving the protective abutment between the blocking plate 221 and the electrode support 102, and thus better protecting the side position of the lower electrode 101 from being corroded by plasma.

[0048] In a preferred embodiment of the present invention, a boss 2111 is disposed at one end of the cover plate 211 away from the blocking plate 221 , and the cover plate 211 extends in the same plane as the surface of the lower electrode 101 through the boss 2111 .

[0049] In this embodiment, when the cover plate 211 and the surface of the extended protrusion 111 are extended, there is a gap between the cover plate 211 and the surface of the lower electrode 101. By providing a boss 2111 at the end position of the cover plate 211, the boss 2111 can be clamped at the position of the extended protrusion 111 and the surface of the lower electrode 101. The boss 2111 ensures that the surface of the lower electrode 101 and the cover plate 211 are on the same height plane, thereby better improving the size chain gap between the focusing ring 200 and the wafer, thereby reducing the deposition of reaction products on the back of the wafer and between the focusing ring 200, and ensuring that the wafer is etched smoothly.

[0050] A semiconductor precipitation device provided in this embodiment includes the lower electrode assembly with a focusing ring. Since the technical effect of the semiconductor precipitation device provided in this embodiment is the same as the technical effect of the lower electrode assembly with a focusing ring provided in the above embodiment, it will not be repeated here.

[0051] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A lower electrode assembly having a focusing ring, characterized in that: include: A lower electrode body (100) and a focusing ring (200); The focusing ring (200) is arranged in a ring shape along the circumferential edge of the lower electrode body (100), and the focusing ring (200) is matched and connected with the side wall of the lower electrode body (100), and the focusing ring (200) is used to balance the surface height of the lower electrode body (100) so as to balance the height matching between the lower electrode body (100) and the wafer; The lower electrode body comprises a lower electrode (101) and an electrode support (102); The electrode support (102) has a receiving groove, the lower electrode (101) is received in the receiving groove, and the focusing ring (200) is arranged in a ring shape along the circumferential direction of the lower electrode (101), and the focusing ring (200) is abutted and fixed to the side wall of the electrode support (102).

2. The lower electrode assembly with a focusing ring according to claim 1, characterized in that: The focusing ring (200) comprises a cover ring (201) and a blocking ring (202); The blocking ring (202) is located between the lower electrode (101) and the electrode support (102), the blocking ring (202) is sleeved on the outside of the lower electrode (101), the cover ring (201) is arranged in a ring shape along the side wall of the lower electrode (101), and the cover ring (201) covers the edge of the lower electrode (101), and one end of the cover ring (201) protrudes from the lower electrode (101) and abuts against the side wall of the electrode support (102) for sealing.

3. The lower electrode assembly with a focusing ring according to claim 2, characterized in that: The cover ring (201) comprises a cover plate (211) and a blocking plate (221); The cover plate (211) is connected to the blocking plate (221), and the cover plate (211) and the blocking plate (221) are arranged at an angle, the cover plate (211) abuts against the surface of the lower electrode (101), the blocking plate (221) is covered at the end of the lower electrode (101), and the blocking plate (221) abuts against the electrode support (102).

4. The lower electrode assembly with a focusing ring according to claim 3, characterized in that: The lower electrode (101) has an extension protrusion (111), and the extension protrusion (111) extends along the side wall of the lower electrode (101). The cover plate (211) is covered on the upper surface of the extension protrusion (111), and the blocking plate (221) is covered on the end of the extension protrusion (111) to balance the assembly height of the cover ring (201) and the lower electrode (101) through the extension protrusion (111).

5. The lower electrode assembly with a focusing ring according to claim 4, characterized in that: The blocking ring (202) comprises a ring body (212) and an annular protrusion (222); The ring body (212) is fixedly connected to the annular protrusion (222); the ring body (212) is arranged in an annular shape outside the lower electrode (101); the annular protrusion (222) is located between the extending protrusion (111) and the blocking plate (221); the annular protrusion (222) is respectively in contact with the extending protrusion (111) and the blocking plate (221).

6. The lower electrode assembly with a focusing ring according to claim 5, characterized in that: The annular protrusion (222) has an arc-shaped protrusion (2221) on one side corresponding to the blocking plate (221), and the blocking plate (221) is provided with a slot corresponding to the arc-shaped protrusion (2221).

7. The lower electrode assembly with a focusing ring according to any one of claims 3 to 6, characterized in that: A sealing step (2211) is provided at one end of the blocking plate (221) away from the cover plate (211), and the blocking plate (221) is abutted and sealed against the outer wall of the electrode support (102) via the sealing step (2211).

8. The lower electrode assembly with a focusing ring according to any one of claims 3 to 6, characterized in that: A boss (2111) is provided at one end of the cover plate (211) away from the blocking plate (221), and the cover plate (211) extends through the boss (2111) in the same plane as the surface of the lower electrode (101).

9. A semiconductor precipitation device, characterized in that: It comprises a lower electrode assembly with a focusing ring as described in any one of claims 1 to 8.

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