TWI460790B - Apparatus and method for generating inductively coupled plasma - Google Patents

Description

Apparatus and method for generating inductively coupled plasma Field of invention

Embodiments of the present invention relate to a semiconductor processing apparatus, and more particularly to an inductively coupled plasma processing apparatus and a plasma forming method.

Background of the invention

In general, an inductively coupled plasma (ICP) process reactor applies a current to a process gas in a process chamber through one or more induction coils disposed outside the process chamber to form a plasma. The induction coil can be externally disposed from the process chamber by, for example, a dielectric cover or the like to achieve electrical separation. In certain plasma processes, heater elements can be placed on the dielectric cover to facilitate maintaining a certain temperature within the process chamber during or between processes.

The heater may be an open break heater (eg, a non-closed electrical circuit) or a no break heater (eg, a closed electrical circuit). In embodiments where the heater element is an open interrupt type heater element, the heater element employs, for example, a non-uniform etch rate of the substrate that results in processing or an asymmetric plasma non-uniformity that results in a pattern of moments. Such plasma non-uniformity can be eliminated by replacing the open interrupt type heater element with a non-interrupting heater element.

Summary of invention

The RF energy delivered to the induction coil is also inductively coupled to the non-interrupting heater element, even reducing the energy used to form the plasma within the process chamber (eg, the non-interrupting heater element reduces the plasma strike window).

Therefore, there is a need for an improved inductively coupled plasma reactor.

Embodiments of field enhanced inductively coupled plasma processing apparatus and plasma forming methods are provided.

In a specific embodiment, the field enhanced inductively coupled plasma processing apparatus includes: a process chamber having a dielectric cover; and a plasma source assembly disposed on the dielectric cover. The plasma source assembly comprises: at least one level induction coil, inductively combining RF energy into the process chamber to form and maintain plasma in the process chamber; at least one power application electrode electrically connected to the level induction coil to The RF energy is combined with the above-described process chamber capacity; the first position adjustment mechanism is coupled to the power application electrode and changes the level position of the application electrode; and the RF generator is coupled to the at least one or more power application electrodes.

In a specific embodiment, the field enhanced inductively coupled plasma processing apparatus includes: a vertical induction coil coupled to the level induction coil and disposed on a side of the dielectric cover; and a second position adjustment mechanism that integrally moves the vertical position of the vertical induction coil or Change the spacing of the vertical induction coils.

In a specific embodiment, the plasma forming method includes the steps of: providing a process gas to the interior of the process chamber, wherein the process chamber includes: at least one level induction coil, having a dielectric cover and disposed on the dielectric cover At least one vertical induction coil coupled to the level induction coil; and at least one power application electrode electrically coupled to the level induction coil; providing RF power from the RF power source to the power application electrode; utilizing the level sensing a coil and the vertical induction coil are supplied and capacitively coupled to the RF power of the process gas to form a plasma from the process gas; and changing a level position of the power application electrode, a spacing of the level induction coil, and a vertical position of the vertical induction coil And at least one of the intervals of the vertical induction coils to control at least one of plasma uniformity or ion density.

Accordingly, the present specification provides field enhanced inductively coupled plasma reactors and methods of utilization. The field enhanced inductively coupled plasma reactor of the present invention improves RF power for collision with plasma in the process chamber without changing other plasma characteristics such as plasma uniformity or ion density. The field enhanced inductively coupled plasma reactor of the present invention also controls and/or adjusts the uniformity and/or density plasma characteristics during processing.

The above is a description of the embodiments of the present invention, and other and additional embodiments of the present invention may be made without departing from the basic scope of the invention, and the scope of the invention is defined by the scope of the claims.

Simple illustration

1 is a schematic side view of a field-enhanced inductively coupled plasma reactor according to a specific embodiment of the present invention; and FIG. 2 is a schematic view of a level induction coil, a vertical induction coil, and a power application electrode of a field-enhanced inductively coupled plasma reactor according to an embodiment of the present invention; FIG. 3 is a schematic diagram of a level induction coil and a vertical induction coil of a field enhanced inductively coupled plasma reactor according to an embodiment of the present invention; FIG. 4 is a heater element of a field enhanced inductively coupled plasma reactor according to a specific embodiment of the present invention; A schematic plan view; FIG. 5 is a flow chart of a plasma forming method according to a specific embodiment of the present invention.

detailed description

The inductively coupled plasma reactor of the present invention provides increased radio frequency (RF) energy for impacting plasma. For example, provide an improved or enhanced plasma impact window. In addition, the inductively coupled plasma reactor of the present invention provides excellent plasma impact performance without changing other plasma characteristics such as plasma uniformity or ion density.

1 is a schematic side view of a field enhanced inductively coupled plasma reactor 100 in accordance with a same embodiment of the present invention. The field enhanced inductively coupled plasma reactor 100 is directly a processing module for a semiconductor substrate processing system and can be used alone or in conjunction with integrated devices such as semiconductor wafer processing systems. A variation of an embodiment of the invention includes an inductively coupled plasma etch reactor. The semiconductor devices listed above are merely examples and may be suitably modified for use in other etch reactors and CVD reactors or other semiconductor processing equipment as non-etching reactors.

The reactor 100 includes a conductive body 130 and a dielectric cover 120 that together form a processing volume, a substrate supporting pedestal 116 disposed in the processing volume, a plasma source assembly 160, and a process chamber 110 including a controller 140. The conductive body 130 is coupled to the electrical ground portion 134. A support pedestal (cathode) 116 can be coupled to the bias power source 122 via a first integrated network 124. While other frequencies and powers are preferred for a particular field, the bias supply 122 can be a 1000 W power source that generates continuous or pulsed power at a frequency of approximately 13.56 MHz. As another example, the bias power source 122 can be a DC or pulsed DC power source.

In a defined embodiment, the dielectric cover 120 can be substantially planar. The field enhanced inductively coupled plasma reactor 100 can have, for example, a convex dome or other form of cover. The plasma source assembly 160 is typically disposed over the dielectric cover 120 and inductively couples RF power into the process chamber 110. The plasma source assembly 160 includes at least one level induction coil, at least one vertical induction coil connected to at least one of the level induction coils, at least one power application electrode, and a plasma power source. At least one level induction coil may be disposed over the dielectric cover 120. At least one or more vertical induction coils are coupled to at least one of the level induction coils and disposed over the side of the dielectric cover 120. As shown in FIG. 1, at least one of the level induction coils 109, 111 is exemplarily disposed on the dielectric cover 120.

The multiple horizontal induction coils 109, 111 can be arranged, for example, in a spiral shape. If one end of the first level induction coil 109 is located on the left side with respect to the center, the other end is located on the right side with respect to the center. If one end of the second level induction coil 111 is located on the left side with respect to the center, the other end is located on the right side with respect to the center. At least one of the level sensing coils 109, 111 maintains a certain distance from each other and is matched. The spacing between the first level induction coil and the second level induction coil, the spacing between the vertical induction coils, and the number of windings of each coil can be appropriately selected to control the plasma density or distribution.

The first level induction coil 109 and the second level induction coil 111 are each coupled to the plasma power source 118 via an integrated network 119. While other frequencies and powers are suitable for a particular field, the plasma power source 118 generates up to 4000 W of power at an adjustable frequency in the range of 50 kHz to 13.56 MHz.

In a preferred embodiment, power distributor 104 is disposed between at least one of the level sensing coils to distribute the relative amount of RF power provided by plasma power source 118 to each coil by a combination of capacitors. For example, as shown in FIG. 1, the power distributor 104 may be disposed between the power application electrodes 102, 103 connected to the plasma power source 118 and the first level induction coil 109 and the second level induction coil 111, to provide control to each The amount of RF power of the coil.

As shown in FIG. 1, at least one or more of the power application electrodes 102, 103 can be electrically coupled to, for example, the first level induction coil 109 or the second level induction coil 111.

The RF power is supplied to the first level induction coil and the second level induction coil through the at least one power application electrodes 102, 103 at the plasma power source 118.

In a defined embodiment, at least one or more of the power application electrodes 102, 103 are movably coupled to one of the at least one level induction coils to facilitate positioning relative to each other and/or to the dielectric cover 120. For example, at least one or more first position adjustment mechanisms (not shown) are coupled to at least one of the power application electrodes 102, 103 to change the level position of the first level induction coil and the second level induction coil. The first position adjustment mechanism (not shown) may be a manual or automatic device including a guide screw, a linear bearing, a stepping motor, a wedge, or the like, and the level position setting of the power application electrodes 102, 103 may be changed.

In the predetermined embodiment, as shown in FIG. 1, first position adjustment mechanisms (not shown) are respectively coupled to the power application electrodes 102, 103 to independently control the level positions of the power application electrodes 102, 103 by the level arrow 102.

In a specific embodiment, the first position adjustment mechanism (not shown) is coupled to the first level induction coil 109 and the second level induction coil 111 to change the spacing between the first level induction coil 109 and the second level induction coil 111. .

Independent control of the level position of the power application electrodes and/or spacing control between the level induction coils facilitates the capacitive coupling of the relative RF power, thereby controlling the density of the plasma and/or the area of the plasma. For example, the closer the level of the power application electrode is to the center of the coil, the higher the density of the plasma, and the larger the spacing between the level induction coils, the lower the density of the plasma, but the area of the plasma increases.

The control of the amount of capacitive coupling of the RF power to the plasma source assembly 160 facilitates the control of the plasma characteristics in the process chamber. For example, by controlling the capacitive coupling of the plasma source assembly 160, the plasma strike window is altered to maintain the desired inductively coupled plasma characteristics. Selective control of the spacing between the leveling coils or the position of the electrodes for power application allows for the incorporation of excess RF energy into the plasma that forms a sufficient volumetric bond, as well as facilitating the impact with the plasma. Change plasma characteristics (eg, density, dissociation ratio, ion/neutron ratio, etc.) as needed. Further, by such a change, generation of non-uniform plasma such as uneven gas velocity in the process chamber due to asymmetric gas transfer and/or suction is reduced. For example, in the region of the plasma plasma density of the paste, the volumetric combination in the region of low plasma density is increased to form uniformity of the overall plasma distribution in the process chamber, thereby facilitating uniform processing.

One or more electrodes of the plasma source assembly station 160 may be symmetrically disposed on the upper portion of the dielectric cover 120 to increase uniform bonding of the RF energy to the plasma. In a given embodiment, one or more electrodes do not provide a continuous path that induces current flow into one or more of the electrodes. Thus, in embodiments that utilize a single electrode, the electrode can include a sensing break so that no inductive loop of the electrode is formed. However, such a specific break point may result in plasma non-uniformity due to the asymmetry of the shape. In electrodes utilizing a single electrode, the point of electrical discontinuity may be located at a location that compensates for the natural plasma distribution within the process chamber to approximate the suction enthalpy of the process chamber or a region corresponding to a relatively high plasma density.

In the specified embodiment, two or more level induction coils 109, 111 are arranged in line with each other to symmetrically distribute the influence of plasma generated in the dielectric space. For example, as shown in FIG. 2, two spiral level induction coils 109, 111 and two power application electrodes 102, 103 which are actually spaced at even intervals are included.

As shown in FIG. 1, the vertical induction coil 113 is connected to at least one of the level induction coils 109, 111. In the prescribed embodiment, the vertical induction coil 113 can integrally move the position in the vertical direction or the interval between the changes by the second position adjustment mechanism (not shown). For example, the second position adjustment mechanism (not shown) may be a manual or automatic device including a guide screw, a linear bearing, a stepper motor, a wedge, etc., which may change the position or spacing of the vertical induction coil 113.

As shown in FIG. 1, the heater element 121 is disposed on the upper portion of the dielectric cover 120 to facilitate internal heating of the process chamber 110. The heater element 121 may be disposed between the dielectric cover 120 and the level induction coils 109, 111 and the power application electrodes 102, 103. In a specified embodiment, the heater element 121 can include a resistive heating element and can be coupled to a power source 123 such as an AC power source that provides sufficient energy to control the temperature of the heater element 121 to between about 50 and 100 °C. In a defined embodiment, the heater element 121 can be an open interrupt type heater. In a prescribed embodiment, the heater element 121 may include a non-interrupting type of hot gas such as a ring element to facilitate uniform plasma formation within the process chamber 110.

For example, Figure 3 is a plan view of a heater element 121 in accordance with a prescribed embodiment of the present invention. The heater element 121 can include a hook portion 300 having a pin 302 that extends inwardly. In the illustrated embodiment, the hook portion 300 can be provided along the perimeter of the dielectric cover 120 as shown in FIG. For example, the hook portion 300 can have an outer diameter that is substantially the same as the outer diameter of the dielectric cover 120. In a prescribed embodiment, the hook portion 300 can have an outer diameter that is larger or smaller than the outer diameter of the dielectric cover 120. Other suitable structures that can substantially uniformly heat the hook portion 300 of the dielectric cover 120 can also be utilized. The pins 302 can have an appropriate width, length, number, and/or position relative to the hook portion 300 to control the amount and distribution of heat required by the process chamber 110. As shown in FIG. 3, the pin 302 is disposed to the vehicle with respect to the hook portion 300 of the heater element 121 so as to be elongated to the inner side.

As shown in FIG. 1, during operation, a substrate 114 (a suitable substrate suitable for semiconductor wafer or plasma processing, etc.) may be disposed on the susceptor, and a process gas may be supplied from the gas plate 138 through the inflow 埠 126 to form a process A mixture of gaseous states within chamber 110. As shown more specifically in FIG. 5, power is supplied from the plasma power source 118 to the level induction coils 109, 111 and the vertical induction coil 113, while the gaseous state mixture 150 is purged into the plasma 155 of the process chamber 110. In a prescribed embodiment, power may also be provided from the bias power source 122 to the pedestal 116. The internal pressure of the process chamber 110 can be controlled by a throttle valve 127 and a vacuum pump 136. The temperature of the conductive body 130 can be controlled by a conduit (not shown) formed along the conductive body 130.

The temperature of the wafer 114 can be controlled by stabilizing the temperature of the support pedestal 116. In one embodiment, helium gas from gas source 148 is supplied through a gas conduit to a channel disposed behind wafer 114 disposed on the surface of the substrate and between channels (not shown). The helium gas facilitates heat transfer between the susceptor 116 and the wafer 114. During the process, the support pedestal 116 is heated to a steady state temperature by its internal resistive heater (not shown), and helium gas facilitates uniform heating of the wafer 114. Through the above thermal control, the temperature of the wafer 114 can be maintained between 0 and 500 °C.

The controller includes a central processing unit (CPU) 144, a memory, and a support circuit 146 for the CPU 144, and facilitates control of the components of the reactor 100 and the plasma forming method. Controller 140 is used in industrial settings to control various process chambers and sub-processes. The memory or computer readable medium of the CPU 144 may be a combination of two or more of a random memory (RAM), a read only memory (ROM), a floppy disk, a hard disk, or various forms of local or remote data storage. . The support circuit 146 is coupled to the CPU 144 to support the processor in the conventional manner. The above circuits include a flash memory, a power supply, a clock circuit, input/output circuits, and subsystems. The software program of the present invention that controls the operation of the plasma reactor 100 can be stored in the memory 142 by the following means. The software program can also be saved and executed or operated from a hard disk controlled by the CPU 144 through a remote second CPU (not shown).

4 illustrates a method 400 of forming a plasma in a field enhanced inductively coupled reactor similar to the plasma reactor 100 described above, in accordance with a fixed embodiment. In general, the above method begins with the supply of process gas (or some gas) to "402" of process chamber 110. Process gas or some gas is supplied from gas plate 138 through inflow weir 126 to form a gaseous state mixture 150 within process chamber 110. The process chamber components such as the conductive body 130, the dielectric cover 120, and the support pedestal 116 can be heated to a desired temperature before or after the process gas cylinder by the above method.

The dielectric cover 120 can be heated by supplying power from the power source 123 to the heater element 121. The supplied power can maintain the process chamber 110 at a desired temperature during processing.

Next, at "404", RF power from the RF power source 118 is provided to the level induction coil and the vertical induction coil to be inductively and capacitively coupled to the process gas mixture 150. While other power and frequencies are used to form the plasma, RF power can be provided at adjustable frequencies up to 4000W and 50kHz to 13.56MHz.

In a defined embodiment, as indicated by "406", the first amount of RF power is coupled to the engineering gas via the level induction coil and the vertical induction coil. The first amount of RF power applied to the leveling induction coil 109 is inductively coupled to a portion of the first amount of RF power within the heater element 121 due to the non-interrupting type of heating element (eg, the heater element 121 is non-interrupting) The presence of the heating element) is reduced, thereby increasing the difficulty of plasma impact. However, as indicated by "508", the second amount of RF power applied to the leveling induction coil 11 is capacitively incorporated into the process gas and inductively coupled to the heater element 121 so as not to decrease, while the second amount of RF The performance of the plasma is improved to collide with the plasma over a wider range of conditions.

In "410", plasma 155 is formed from process gas mixture 150 using a first amount of RF power and a second amount of RF power provided to level sensing coils 109, 111 and vertical induction coils. When plasma stabilization is achieved by impact with the plasma, method 400 generally ends and the plasma continues to be processed as needed. For example, in a standard process, at least a portion of the process continues with current RF power settings and other process variables. The power application electrodes 102, 103 connected to the level shifting coil, either selectively or in combination, during the process, move horizontally to change the capacitive coupling of RF power into the process chamber, or change the pitch by the level shifting coil, vertically moving The coil changes its vertical position or spacing to change the capacitive coupling of RF power into the process chamber 110.

Accordingly, the present specification provides field enhanced inductively coupled plasma reactors and methods of utilization. The field enhanced inductively coupled plasma reactor of the present invention improves RF power for collision with plasma in the process chamber without changing other plasma characteristics such as plasma uniformity or ion density. The field enhanced inductively coupled plasma reactor of the present invention also controls and/or adjusts the uniformity and/or density plasma characteristics during processing.

The above is a description of the embodiments of the present invention, and other and additional embodiments of the present invention may be made without departing from the basic scope of the present invention, and the scope of the present invention is defined by the following claims. .

100. . . Plasma reactor

102, 103. . . Power application electrode

104. . . Power distributor

109. . . First level induction coil

110. . . Process room

111. . . Second level induction coil

113. . . Vertical induction coil

114. . . Substrate

116. . . Substrate support base

118. . . Plasma power supply

119. . . Integrated network

120. . . Dielectric cover

121. . . Heater element

122. . . Bias supply

123. . . power supply

124. . . First integrated network

126. . . Inflow

127. . . Throttle valve

130. . . Conductive body

134. . . Electrical grounding

136. . . Vacuum pump

138. . . Gas plate

140. . . Controller

142. . . Memory

144. . . CPU

146. . . Support circuit

148. . . Gas source

150. . . Gas state mixture, process gas mixture

155. . . Plasma

160. . . Plasma source assembly

300. . . Hook section

302. . . pin

1 is a schematic side view of a field enhanced inductively coupled plasma reactor in accordance with a prescribed embodiment of the present invention;

2 is a schematic plan view of a level induction coil, a vertical induction coil, and a power application electrode of a field-enhanced inductively coupled plasma reactor according to an embodiment of the present invention;

3 is a schematic view showing a level induction coil and a vertical induction coil of a field enhanced inductively coupled plasma reactor according to an embodiment of the present invention;

Figure 4 is a schematic plan view of a heater element of a field enhanced inductively coupled plasma reactor in accordance with a prescribed embodiment of the present invention;

Figure 5 is a flow chart of a plasma forming method in accordance with a prescribed embodiment of the present invention.

100. . . Plasma reactor

102, 103. . . Power application electrode

104. . . Power distributor

110. . . Process room

113. . . Vertical induction coil

114. . . Substrate

116. . . Substrate support base

118. . . Plasma power supply

119. . . Integrated network

120. . . Dielectric cover

121. . . Heater element

123. . . power supply

122. . . Bias supply

124. . . First integrated network

126. . . Inflow

127. . . Throttle valve

130. . . Conductive body

134. . . Electrical grounding

136. . . Vacuum pump

138. . . Gas plate

142. . . Memory

144. . . CPU

146. . . Support circuit

148. . . Gas source

150. . . Gas state mixture, process gas mixture

155. . . Plasma

160. . . Plasma source assembly

Claims (9)

A field-enhanced inductively coupled plasma processing apparatus includes: a process chamber having a dielectric cover; a plasma source assembly disposed on the dielectric cover; and the plasma source assembly comprising: a first level induction coil having a spiral shape One end is centered on the left side, and the other end is centered on the right side; the second level induction coil is spiral, one end is centered on the right side, and the other end is centered on the left side; the first power application electrode and a second power application electrode electrically connected to one of the first level induction coil and the second level induction coil to combine RF energy into the process chamber capacity; a first position adjustment mechanism coupled to the first power application electrode and a second power application electrode and changing a level position of the application electrode; and a power distributor connected to the first power application electrode and the second power application electrode and distributing a relative amount of RF power through a capacitor combination; and an RF generator, combined In the above power distributor. The field-enhanced inductively coupled plasma processing apparatus according to claim 1, wherein the first position adjusting mechanism is configured to change a level position of the power application electrode. The field-enhanced inductively coupled plasma processing apparatus according to claim 1, wherein the first position adjustment mechanism is coupled to The level sensing coil is used to change the pitch of the level induction coil. The field-enhanced inductively coupled plasma processing apparatus according to any one of claims 1 to 3, further comprising a vertical induction coil connected to the level induction coil and disposed on a side surface of the dielectric cover. The field-enhanced inductively coupled plasma processing apparatus according to claim 4, further comprising: a second position adjustment mechanism for integrally moving a vertical position of the vertical induction coil or changing a pitch of the vertical induction coil. The field-enhanced inductively coupled plasma processing apparatus according to claim 5, wherein the first position adjustment mechanism and the second position adjustment mechanism comprise at least one of a guide screw, a linear bearing, a stepping motor, and a wedge. One. The field-enhanced inductively coupled plasma processing apparatus according to any one of claims 1 to 3, further comprising: disposed between one or more electrodes of the plasma source assembly and the dielectric cover Heater element. A plasma forming method comprising the steps of: providing a process gas to a process chamber, wherein the process chamber comprises: at least one level induction coil, having a dielectric cover and disposed on the dielectric cover; at least one or more a vertical induction coil combined with the above level induction coil; and At least one or more power application electrodes are electrically connected to the level induction coil; RF power is supplied from the RF power source to the power application electrode; and the RF supplied to the process gas by the level induction coil and the vertical induction coil is used Generating a plasma from the process gas; and changing at least one of a level position of the power application electrode, a spacing of the level induction coil, a vertical position of the vertical induction coil, and an interval of the vertical induction coil to control plasma uniformity Or at least one of ion densities. The plasma forming method according to claim 8, wherein the process chamber further includes a non-interrupting heater element disposed on an upper portion of the dielectric cover, and further comprising supplying power to the heater element to The step of controlling the temperature of the process chamber described above.