WO2006033508A1

WO2006033508A1 - Inductively coupled plasma treatment apparatus

Info

Publication number: WO2006033508A1
Application number: PCT/KR2005/000270
Authority: WO
Inventors: Chang-Hun Hwang; Jeong-Su Ahn; Ha-Jin Song
Original assignee: Doosan Dnd Co., Ltd.
Priority date: 2004-09-25
Filing date: 2005-01-29
Publication date: 2006-03-30
Also published as: KR100631479B1; KR20060028346A

Abstract

Disclosed herein is an inductively coupled plasma treatment apparatus configured such that a substrate chuck thereof is vertically movable with a high accuracy and a plasma is discharged from the center of a bottom wall of a chamber, thereby performing a substrate plasma treatment under optimum process conditions.

Description

INDUCTIVELY COUPLED PLASMA TREATMENT

APPARATUS

Technical Field

[1] The present invention relates to an inductively coupled plasma treatment apparatus to perform a substrate plasma treatment under optimum process conditions on the basis of the vertical movement of a substrate chuck. Background Art

[2] Plasma, that is generated upon application of a high frequency, is classified into ca- pacitively coupled plasma (CCP) and inductively coupled plasma. As well known in the art, the inductively coupled plasma is preferable in the treatment of substrates because the capacitively coupled plasma tends to damage the substrates. Con¬ ventionally, there have been used inductively coupled plasma treatment apparatuses to perform certain treatments upon substrates using the inductively coupled plasma.

[3] Such inductively coupled plasma treatment apparatuses are capable of performing etching, ashing, chemical vapor deposition (CVD), ion injection treatments, etc. upon semiconductor wafers, organic substrates, or the like.

[4] In the inductively coupled plasma treatment apparatuses, a processing ratio and uniformity of substrates are largely affected by specific process conditions, for example, a distance between a substrate chuck, onto which a substrate is disposed within a chamber, and a source unit that supplies a process gas to the substrate from the upper side of the substrate.

[5] Further, during a substrate plasma treatment process, plasma generated inside of the chamber of the apparatus is continuously suctioned and discharged to the outside to perform a treatment upon the substrate while flowing in a constant direction. In this case, it is preferable to keep the plasma at a constant flow rate throughout a substrate for the uniform treatment of a large-area substrate. Disclosure of Invention Technical Problem

[6] Currently, the area of a substrate to be processed is increasing, so a plasma treatment apparatus having a vertically moveable substrate chuck is strongly required to achieve a uniform treatment throughout the surface of a large-area substrate. Technical Solution

[7] The present invention has been made in view of the above mentioned problems, and an aspect of the present invention is to provide an inductively coupled plasma treatment apparatus to achieve a uniform plasma treatment throughout the surface of a large-area substrate.

Brief Description of the Drawings

[8] The above aspect, and other features and advantages of the exemplary embodiments of the present invention will become more apparent after reading the following detailed description when taken in conjunction with the drawings, in which:

[9] FlG. 1 is a vertical sectional view of an inductively coupled plasma treatment apparatus consistent with an exemplary embodiment of the present invention;

[10] FIGS. 2a and 2b are vertical sectional views illustrating the vertical movement of a substrate chuck provided in the inductively coupled plasma treatment apparatus of FIG. 1;

[11] FlG. 3 is a vertical sectional view illustrating the operation of an exhaust unit provided in the inductively coupled plasma treatment apparatus of FlG. 1 ; and

[12] FIGS. 4 to 7 are vertical sectional views explaining the operating sequence of the inductively coupled plasma treatment apparatus of FlG. 1. Best Mode for Carrying Out the Invention

[13] In accordance with an aspect of the present invention, an inductively coupled plasma treatment apparatus is provided, comprising a chamber having a vacuum pressure, a source unit provided in an upper region of the chamber to inject a process gas into the chamber, a substrate chuck provided in a lower region of the chamber to support a substrate at an upper surface thereof during a substrate plasma treatment, and an exhaust unit to suction and discharge the gas inside of the chamber to the outside, wherein the substrate chuck is vertically movable by means of a substrate chuck lifting mechanism, and the substrate chuck lifting mechanism includes a cylindrical shaft coupled at an upper end thereof to a lower surface of the substrate chuck to protrude to the outside of the chamber by penetrating through a bottom wall of the chamber, a shaft drive unit connected to a lower end of the shaft to verticaly move the shaft, and a bellows unit surrounding a lower region of the shaft and configured to be expanded or contracted in a flexible manner, thereby serving to keep the interior of the chamber in an air tight state during a vertical movement of the shaft.

[14] Preferably, a power line, coolant supply line, and radio frequency (RF) supply line, that are connected to the substrate chuck, may extend in an interior space of the shaft, thereby preventing damage thereto and enabling easy repair and maintenance thereof.

[15] Preferably, the shaft drive unit may include a ball screw coupled to the lower end of the shaft, a motor located at a side of the ball screw to provide a power required to rotate the ball screw, and a power transmission member to transmit the power of the motor to the ball screw. With such a configuration, the height of the substrate chuck is closely adjustable, and the substrate chuck is vertically movable without an increase in the overall height of the plasma treatment apparatus.

[16] Preferably, the exhaust unit may include a plasma outlet formed through the bottom wall of the chamber around a center shaft penetrating region of the bottom wall, a duct plate spaced apart downward from the bottom wall of the chamber by a predetermined distance and having a center shaft penetrating hole, a duct lateral wall extending between the duct plate and the bottom wall of the chamber to coincide with an outer circumference of the plasma outlet, the duct lateral wall defining an isolated space between the duct plate and the bottom wall of the chamber, and an exhaust pump connected to a certain portion of the duct lateral wall to discharge a gas inside of the exhaust unit to the outside. As a result of discharging the plasma from the bottom center of the chamber, the uniform treatment of the substrate is possible. Further, the exhaust pump is provided at the side of the vertically moving shaft, achieving a reduction in the overall height of the apparatus.

[17] Preferably, a movable plate may be coupled to a lower portion of the shaft to guide a vertical movement of the shaft while moving along with the shaft, and the movable plate may be vertically moved by means of one or more linear guides and linear blocks, the linear guides vertically extending between a lower surface of the duct plate and a bottom surface of the apparatus, and the linear blocks being inserted around the respective linear guides and coupled to the movable plate to guide a vertical movement direction of the shaft along the linear guides. Thereby, the substrate chuck is vertically movable in an accurate direction, thereby keeping the substrate in a horizontal plane. This enables an uniform treatment of the substrate.

[18] Preferably, the bellows unit may extend between the lower surface of the duct plate and an upper surface of the movable plate, thereby surely keeping the interior of the chamber in an air tight state in spite of the vertical movement of the substrate chuck.

[19] Preferably, the inductively coupled plasma treatment apparatus may further comprise one or more cylindrical substrate transfer pins extending vertically to penetrate through the substrate chuck and be affixed at lower ends thereof to an upper surface of the bottom wall of the chamber, thereby serving to support the substrate at upper ends thereof. The substrate transfer pins have the effect of reducing a process time and simplifying the structure of the apparatus.

[20] Now, an exemplary embodiment of the present invention will be described in detail with reference to the annexed drawings.

[21] FIG. 1 is a vertical sectional view of an inductively coupled plasma treatment apparatus consistent with an exemplary embodiment of the present invention. Referring to FIG. 1, the inductively coupled plasma treatment apparatus 1 comprises a chamber 10, a source unit 20, a substrate chuck 30, and an exhaust unit 40.

[22] The chamber 10 is designed to produce a vacuum pressure therein and is a body component of the inductively coupled plasma treatment apparatus consistent with the exemplary embodiment of the present invention. The source unit 20 is provided in the upper region of the chamber 10 and is used to inject a process gas into the chamber 10. In the exemplary embodiment of the present invention, the source unit 20 has a linear antenna (not shown) and a magnet array (not shown).

[23] The substrate chuck 30 is provided in the lower region of the chamber 10 and is used to support a substrate S at an upper surface thereof during a certain substrate treatment. For this, the substrate chuck 30 has a plurality of substrate contactors 32 arranged thereon to come into direct contact with the substrate S. The substrate contactors 32 minimize a contact area between the substrate chuck 30 and the substrate S to thereby prevent damage or contamination to a contact surface of the substrate S. RF power supply line 34 is connected to the substrate chuck 30 to apply a radio frequency to the substrate chuck 30 in order to generate a plasma inside of the chamber 10, more particularly, in a specific space between the substrate chuck 30 and the source unit 20. To prevent an excessive temperature increase during a substrate plasma treatment, the substrate chuck 30 further has a coolant circulation passage 36, and a coolant supply line 38 connected to the substrate chuck 30.

[24] FIGS. 2a and 2b are vertical sectional views of the substrate chuck 30 consistent with the exemplary embodiment of the present invention. As shown in FIGS. 2a and 2b, the substrate chuck 30 is vertically movable. For this, a substrate chuck lifting mechanism 50 is provided below the substrate chuck 30. The substrate chuck lifting mechanism 50 includes a shaft 52, a shaft drive unit 54 and a bellows unit 56.

[25] The shaft 52 is coupled at an upper end thereof to the center of a lower surface of the substrate chuck 30, and a lower end of the shaft 52 protrudes to the outside of the chamber 10 by penetrating through a bottom wall of the chamber 10. In the exemplary embodiment of the present invention, the shaft 52 has a cylindrical shape and is vertically movable in a coupled state with the substrate chuck 30. As shown in FIGS. 1, 2a and 2b, the coolant supply line 38, the RF supply line 34, and an additional power line (not shown), which are connected to certain portions of the substrate chuck 30, extend in a hollow interior space of the shaft 52 to prevent the coolant supply line 38, RF supply line 34 and power line from being affected by the vertical movement of the substrate chuck, thereby having no damage to connecting portions therebetween. Even if certain portions of the coolant supply line 38, RF supply line 34 and power line, that protrude downward from the shaft 52 to be exposed to the outside, are displaced from their correct positions when the substrate chuck 30 vertically moves, the exposed portions are easy to repair because they are located at the outside of the chamber 10. Therefore, with the exemplary embodiment of the present invention, the coolant supply line 38, RF supply line 34 and power line are safely and stably stored regardless of the vertical movement of the substrate chuck 30. This consequently facilitates the maintenance and operation of the substrate S.

[26] The shaft drive unit 54 is connected to the lower end of the shaft 52 to vertically move the shaft 52 to thereby vertically move the substrate chuck 30. The shaft drive unit 54 has a ball screw 54a, a motor 54b, and a power transmission member 54c. The ball screw 54a is coupled to the lower end of the shaft 52 to vertically move the shaft 52 while being rotated by the motor 54b. The ball screw 54a is effective to closely adjust a vertical movement length of the shaft 52, thereby enabling an accurate detailed adjustment of a distance between the substrate chuck 30 and the source unit 20 and consequently achieving optimum process conditions suitable to a substrate to be processed. The motor 54b is a component to provide a power required to rotate the ball screw 54a. In the exemplary embodiment of the present invention, the motor 54b is a servo motor to closely control a rotating speed, etc. The power transmission member 54c serves to connect the motor 54b to the ball screw 54a for the transmission of power. The reason why the motor 54b is indirectly connected to the ball screw 54a by interposing the power transmission member 54c is as follows. That is, in order to directly connect the motor 54c to the ball screw 54a, the motor 54b should be located at a lower end of the ball screw 54a, but this inevitably causes an increase in the overall height of the plasma treatment apparatus 1. For this reason, the motor 54b is disposed at a side of the ball screw 54a and is connected to the ball screw 54a by in¬ terposing the separate power transmission member 54c to ensure a free rotation of the ball screw 54a without increasing the overall height of the plasma treatment apparatus 1. In the exemplary embodiment of the present invention, a timing belt is used as the power transmission member 54c.

[27] Referring to FIG. 1, a movable plate 58 is coupled around a lower portion of the shaft 52. The movable plate 58 is located at a certain height between a duct plate 44 and a bottom surface of the plasma treatment apparatus 1 so that it is vertically movable under operation of linear guides 56a and linear blocks 56b. The linear guides 56a extend vertically between the duct plate 44 and the bottom surface of the plasma treatment apparatus 1, and the linear blocks 56b are inserted around the respective linear guides 56a in a vertically movable manner. With such a configuration, the movable plate 58 accurately guides the vertical movement of the shaft 52, and in turn, the linear guides 56a and the linear blocks 56b guide a movement direction of the movable plate 58.

[28] The bellows unit 56 surrounds the lower region of the shaft 52 and is expandable or contractable in a flexible manner. The bellows unit 56 serves to keep the interior of the chamber 10 in an air tight state regardless of the vertical movement of the shaft 52. As shown in FIG. 1, the bellows unit 56 is coupled at an upper end thereof to a lower surface of the duct plate 44 and at a lower end thereof to an upper surface of the movable plate 58 to be vertically expanded or contracted according to the vertical movement of the movable plate 58.

[29] The exhaust unit 40 is used to suction and discharge a resulting gas inside of the chamber 10 to the outside. When a process gas is supplied and a radio frequency is applied to generate a plasma in a state wherein a substrate is disposed in a space between the substrate chuck 30 and the source unit 20, the exhaust unit 40 produce a plasma stream inside of the chamber 10 so that the plasma continuously flows in a constant direction to process the substrate.

[30] FlG. 3 is a vertical sectional view of the exhaust unit 40 consistent with the exemplary embodiment of the present invention. Referring to FIGS. 1 and 3, the exhaust unit 40 includes a plasma outlet 42, the duct plate 44, a duct lateral wall 45, and an exhaust pump 48. The plasma outlet 42 is a through-hole formed around a shaft penetrating region of the bottom wall of the chamber 10. As will be easily understood by those skilled in the art, for the uniform treatment of a substrate, the plasma must flow throughout the substrate by a constant flow rate. In order to achieve such a constant flow rate of the plasma throughout the substrate, it is preferable that the plasma is discharged from a bottom center position of the chamber 10. For this reason, in the exemplary embodiment of the present invention, the plasma outlet 42 is formed around the shaft 52 centrally located in the chamber 10 to discharge the plasma. The duct plate 44 is spaced apart downward from the bottom wall of the chamber 10 to define a plasma induction space therebetween to induce the plasma to the outside of the chamber 10. The duct plate 44 has a center hole for the penetration of the shaft 52.

[31] The duct lateral wall 46 is a cylindrical wall member extending vertically between an upper surface of the duct plate 44 and a lower surface of the bottom wall of the chamber 10 to coincide with an outer circumference of the plasma outlet 42. The duct lateral wall 46 serves to isolate the plasma induction space between the duct plate 44 and the bottom wall of the chamber 10 from the outside. That is, the plasma induction space for the discharge of the plasma is defined under the chamber 10 by the duct plate 44 and the duct lateral wall 46. The duct lateral wall 46 has a mount hole formed at a certain portion thereof so that the exhaust pump 48 is mounted through the mount hole of the duct lateral wall 46 to discharge the plasma from the induction space defined by the duct plate 44 and the duct lateral wall 46.

[32] The duct lateral wall 46 has a pair of O-rings interposed at connecting portions between upper and lower ends thereof and the bottom wall of the chamber 10 and the duct plate 44. In the exemplary embodiment of the present invention, the exhaust pump 48 is positioned at a side of the shaft 52. This has an advantage in that the plasma is able to be discharged from the bottom center of the chamber 10 without an increase in the overall height of the plasma treatment apparatus 1.

[33] The inductively coupled plasma treatment apparatus 1 consistent with the exemplary embodiment of the present invention further comprises substrate transfer pins 70. When a substrate is carried into or carried out from the chamber 10, the substrate transfer pins 70 serve to receive the substrate from a substrate transfer unit provided at the outside of the chamber 10 or from the substrate chuck 30 to facilitate a substrate transfer operation.

[34] The substrate transfer pins 70 extend vertically by penetrating through the substrate chuck 30. Lower ends of the substrate transfer pins 70 are affixed to an upper surface of the bottom wall of the chamber 10 so as not to vertically move, thereby assisting the stable transfer of the substrate. Upper ends of the substrate transfer pins 70 have curved surface to minimize a contact area with the substrate S. The reason why the substrate transfer pins 70 are affixed to the bottom wall of the chamber 10 is that it is effective to eliminate some unnecessary processes during the transfer and operation of the substrate chuck 30, thereby reducing a process time and simplifying the structure of the plasma treatment apparatus 1.

[35] Now, a substrate treatment process of the inductively coupled plasma treatment apparatus 1 consistent with the exemplary embodiment of the present embodiment will be explained.

[36] Referring to FlG. 4, first, a gate valve 60, provided at a lateral wall of the chamber

10, is opened to allow the introduction of the substrate S into the chamber 10. In an opened state of the gate valve 60, a substrate transfer unit 80, provided at the outside of the chamber 10 (see. FlG. 7), enters the chamber 10, with the substrate S supported thereon, to position the substrate S at the upper ends of the substrate transfer pins 70. After positioning, the substrate transfer unit 80 exits the chamber 10. In this course, the substrate chuck 30 is kept at its lowered position close to the bottom wall of the chamber 10.

[37] After the closure of the gate valve 60, as shown in FlG. 5, the motor 54b is driven to lift the substrate chuck 30 until the substrate chuck 30 is positioned higher than the substrate transfer pins 70. If the substrate chuck 30 is positioned on the substrate transfer pins 70, the substrate S, disposed on the substrate transfer pins 70, is shifted onto the substrate chuck 30. After shifting, the substrate chuck 30 is further lifted to be positioned at an optimum height based on a preset input value.

[38] In a state wherein the substrate is positioned at the optimum height, electric power is applied to the source unit 20 and the substrate chuck 30 to drive them, and a process gas is supplied into the chamber 10 to generate a plasma. In this case, the exhaust pump 48 operates to discharge the plasma, used in the treatment of the substrate S, from the chamber 10 by a constant flow rate. [39] After a substrate treatment completion, as shown in FlG. 6, the motor 54b is driven to lower the substrate chuck 30 until the substrate chuck 30 is positioned lower than the substrate transfer pins 70. Then, the substrate S is shifted onto the substrate transfer pins 70.

[40] Finally, as shown in FlG. 7, the gate valve 60 is again opened and the substrate transfer unit 80, kept at a waiting position at the outside of the chamber 10, is introduced into the chamber 10 to discharge the substrate, supported on the substrate transfer pins 70, to the outside and to introduce a new substrate into the chamber 10 for the repetition of a new process.

[41] Although the exemplary embodiment of the invention have been disclosed for il¬ lustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and sprit of the invention as disclosed in the accompanying drawings. Industrial Applicability

[42] As apparent from the above description, the present invention provides an in¬ ductively coupled plasma treatment apparatus in which a substrate chuck is vertically movable with a high accuracy, thereby enabling the implementation of a substrate plasma treatment under optimum process conditions.

[43] Further, in accordance with the present invention, a power line, coolant supply line,

RF line, etc. extend in a hollow interior space of a shaft that vertically moves along with the vertically movable substrate chuck. This has the effect of preventing damage to the respective lines due to the vertical movement of the substrate chuck.

[44] Furthermore, in the inductively coupled plasma treatment apparatus of the present invention, a plasma outlet is formed at the center of the bottom wall of the chamber to thereby achieve a constant plasma flow rate throughout a substrate. Further, an exhaust pump is provided at a side of the shaft to reduce the overall height of the plasma treatment apparatus.

[45]

[46]

Claims

[1] An inductively coupled plasma treatment apparatus comprising a chamber having a vacuum pressure, a source unit provided in an upper region of the chamber to inject a process gas into the chamber, a substrate chuck provided in a lower region of the chamber to support a substrate at an upper surface thereof during a substrate plasma treatment, and an exhaust unit to suction and discharge the gas inside of the chamber to the outside, wherein the substrate chuck is vertically moved by means of a substrate chuck lifting mechanism, and wherein the substrate chuck lifting mechanism includes: a cylindrical shaft coupled at an upper end thereof to a lower surface of the substrate chuck to protrude to the outside of the chamber by penetrating through a bottom wall of the chamber; a shaft drive unit connected to a lower end of the shaft to vertically move the shaft; and a bellows unit surrounding a lower region of the shaft and configured to be expanded or contracted in a flexible manner, thereby serving to keep the interior of the chamber in an air tight state during a vertical movement of the shaft.

[2] The apparatus as set forth in claim 1, wherein a power line, coolant supply line, and RF power supply line, that are connected to the substrate chuck, extend in an interior space of the shaft.

[3] The apparatus as set forth in claim 1, wherein the shaft drive unit includes: a ball screw coupled to the lower end of the shaft: a motor located at a side of the ball screw to provide a power required to rotate the ball screw; and a power transmission member to transmit the power of the motor to the ball screw.

[4] The apparatus as set forth in claim 1, wherein the exhaust unit includes: a plasma outlet formed through the bottom wall of the chamber around a center shaft penetrating region of the bottom wall; a duct plate spaced apart downward from the bottom wall of the chamber by a predetermined distance and having a center shaft penetrating hole; a duct lateral wall extending between the duct plate and the bottom wall of the chamber to coincide with an outer circumference of the plasma outlet, the duct lateral wall defining an isolated space between the duct plate and the bottom wall of the chamber; and an exhaust pump connected to a certain portion of the duct lateral wall to discharge the gas inside of the exhaust unit to the outside.

[5] The apparatus as set forth in claim 4, wherein a movable plate is coupled to a lower portion of the shaft to guide a vertical movement of the shaft while moving along with the shaft, and wherein the movable plate is vertically movable by means of one or more linear guides and linear blocks, the linear guides vertically extending between a lower surface of the duct plate and a bottom surface of the apparatus, and the linear blocks being inserted around the respective linear guides and coupled to the movable plate to guide a vertical movement direction of the shaft along with the linear guides.

[6] The apparatus as set forth in claim 5, wherein the bellows unit extends between the lower surface of the duct plate and an upper surface of the movable plate.

[7] The apparatus as set forth in claim 1, further comprising: one or more cylindrical substrate transfer pins extending vertically to penetrate through the substrate chuck and be fixed at lower ends thereof to an upper surface of the bottom wall of the chamber, thereby serving to support the substrate at upper ends thereof.