TW201445632A - Inductive coupling plasma device - Google Patents

Abstract

The present invention relates to an inductive coupling plasma device, which includes: a reaction chamber for performing a plasma processing reaction with a chip placed therein; a gas sprinkling head arranged above the reaction chamber and including at least one air inlet for guiding reaction gas into the reaction chamber; at least one set of inductive coupling coil arranged to be adjacent to the reaction chamber for applying radio frequency power to the reaction chamber by an adapter externally connected with a radio frequency power source; and a shielding device arranged to be adjacent to the inductive coupling coil for shielding and restricting the radio frequency power in a first space and causing the radio frequency power to react with the reaction gas so as to generate plasma which is freely diffused to react with the chip through a second space, wherein the first space and the second space are respectively located in the reaction chamber, and are distributed up and down and communicated with each other. With the present invention, the temperature of the electrons in the plasma is obviously lowered so as to greatly weaken the physical etching reaction, which also advantageously enables the plasma in the reaction chamber to achieve a uniform distribution.

Description

Inductively coupled plasma device

The present invention relates to the field of semiconductor manufacturing equipment, and more particularly to an inductively coupled plasma device.

Inductively Coupled Plasma (ICP) devices are widely used in processes such as semiconductor etching. The reaction gas is ionized to generate a plasma under excitation of radio frequency power, and contains active particles such as electrons, ions, excited atoms, molecules, and radicals, and the active particles react with the surface material of the object to be etched, thereby A plasma etching process is implemented. The RF electric field is generated by the inductive coupling coil acting on the response chamber. Specifically, the inductive coupling coil is externally connected to a radio frequency power source having a frequency of 13.56 MHz, for example, an RF current is passed through the inductive coupling coil, thereby generating a changing magnetic field, and the changed magnetic field induces an electric field, thereby responding to the response gas inside the chamber. Convert to plasma.

In the prior art, the inductively coupled plasma device is shown in FIG. 1. The upper portion of the response chamber 10 is provided with a shower head 11 which passes through a plurality of air inlets 110 to the response chamber 10 to receive a response gas, and responds to the bottom of the chamber. There is an electrostatic chuck 13 on which the wafer 20 to be etched is placed; an outer wall portion of the response chamber 10 is provided with an inductive coupling coil 12, and an external RF power source is used for applying RF power to the entire response chamber 10 to generate an RF electric field. Under the action of the electric field, the response gas is converted into a plasma, but the RF electric field is distributed between the top and the bottom of the response chamber, so that the plasma is excited by the RF electric field before reaching the wafer 20, and the electrons therein Will have a higher temperature.

However, on the one hand, in some etching processes (such as polycrystalline engraving) Eclipse), especially in processes requiring chemical etching, it is desirable that the temperature of the electrons in the plasma be lower to avoid excessive bombardment energy, which makes the physical etching dominate, and the process is not available. The state of the control.

On the other hand, the electromagnetic field in the response chamber is unevenly distributed, and the density in the central portion is large, and the density at the edge portion is small, causing the plasma in the response chamber to be unevenly distributed, which will etch the wafer. Uniformity has an adverse effect.

Therefore, according to the requirements of a specific etching process, generating a plasma having a uniform distribution and a low electron temperature in the response chamber is a technical problem to be solved by the present invention.

It is an object of the present invention to provide an inductively coupled plasma device that produces a plasma having a uniform distribution and a low electron temperature in the response chamber.

In order to achieve the above object, the technical solution of the present invention is as follows:

An inductively coupled plasma device comprising: an responsive chamber for plasma processing response with a wafer placed therein; and a venting head disposed at an upper portion of the response chamber, the at least one air inlet for responding The chamber is responsive to the gas; at least one set of inductive coupling coils are adjacent to the response chamber setting for externally applying RF power through the matcher to apply RF power to the response chamber; and shielding means adjacent to the inductive coupling coil setting The RF power is shielded in the first space to act on the response gas to generate a plasma, and the plasma is freely diffused through the second space to respond to the wafer; wherein the first space and the second space are respectively located in the response chamber. It is distributed up and down and connected to each other.

Preferably, the bottom surface of the air shower head comprises at least one convex portion, the inductive coupling coil and the shielding device are embedded in the convex portion, the first space is a concave space surrounded by the convex portion, and the second space is a response below the first space Chamber space.

Preferably, the shielding device comprises at least one set of metal cross-sections corresponding to the inductive coupling coils, disposed directly below the inductive coupling coil, and the metal cross-section extends along the length of the inductive coupling coil.

Preferably, the protrusions are two and are separately disposed, respectively being a first protrusion and a second protrusion, and the second protrusion surrounds the first protrusion from the periphery; the inductive coupling coil comprises two groups respectively embedded in The coils in the first raised portion and the second raised portion are respectively a first coil and a second coil, and the shielding device comprises two sets of metal horizontal sheets corresponding to the inductive coupling coils, and two sets of inductive coupling coils. Corresponding metal risers are respectively a first horizontal piece, a second horizontal piece, a first vertical piece and a second vertical piece, and the first horizontal piece and the first vertical piece are embedded in the first convex part for The RF power generated by one coil is shielded in the third space, and the second horizontal piece and the second vertical piece are embedded in the second convex portion for shielding the RF power generated by the second coil from the fourth space; wherein, the third The space is a recessed space surrounded by the first convex portion, and the fourth space is a recessed space surrounded by the second convex portion and not including the third space, and the third space and the fourth space are respectively connected to the second space.

Preferably, the shielding device further comprises a metal disc, the metal disc is in close contact with the first and second vertical pieces, and covers the first and second coils from the upper portion, and the metal disc is provided with at least one through hole for respectively connecting the air inlet .

The inductively coupled plasma device provided by the present invention shields the radio frequency electric field in the first space of the response chamber through the setting shielding device, and does not function as the radio frequency electric field in the second space. The plasma generated in the first space is freely diffused through the second space to reach the surface of the wafer, and in the second space, the plasma undergoes a cooling process, so that the temperature of the electrons in the plasma is significantly reduced, thereby significantly weakening the physical etching. Respond. In addition, the inductively coupled plasma device can shield different RF electric fields generated by different coils into different response chamber spaces, thereby regulating the uniform distribution of plasma in the response chamber, and facilitating wafer etching. Uniformity.

10‧‧‧Response chamber

101‧‧‧First space

1010‧‧‧ fourth space

1011‧‧‧ third space

102‧‧‧Second space

11‧‧‧Lip head

110‧‧‧air inlet

111‧‧‧ raised parts

112‧‧‧ raised parts

12‧‧‧Inductive Coupling Coil

121‧‧‧Inductive Coupling Coil

122‧‧‧Inductive Coupling Coil

13‧‧‧Electrostatic chuck

14‧‧‧metal crosspiece

141‧‧‧metal crosspiece

142‧‧‧metal crosspiece

151‧‧‧Metal risers

152‧‧‧Metal risers

16‧‧‧Metal wafer

20‧‧‧Processed wafers

1 is a schematic structural view of an inductively coupled plasma device in the prior art; FIG. 2 is a schematic view showing the structure of an inductively coupled plasma device according to a first embodiment of the present invention; FIG. 3 is a schematic structural view of an inductively coupled plasma device according to a second embodiment of the present invention; and FIG. 4 is a schematic structural view of an inductively coupled plasma device according to a third embodiment of the present invention.

The specific implementation mode of the present invention will be further described in detail below with reference to the accompanying drawings.

As shown in FIG. 2, the inductively coupled plasma device provided by the first embodiment of the present invention includes an response chamber 10, a shower head 11, an inductive coupling coil 12, and a shielding device. The air shower head 11 is disposed at the top of the response chamber 10, and an electrostatic chuck 13 is disposed at the bottom of the response chamber for fixing the wafer 20 to be processed; the air shower head 11 includes a plurality of air inlets 110 for the response chamber The chamber 10 is provided with a response gas, and the bottom surface of the shower head 11 has a continuous extending protrusion 111, which may be spirally distributed, or a plurality of U-shaped distributions connected end to end; the inductive coupling coil 12 is externally connected to the RF through a matching device. The power source applies RF source power to the response chamber 10 to convert the response gas into a plasma.

The inductive coupling coil 12 and the shielding device are both laid inside the boss portion 111 and are vertically distributed. The shielding device shields the RF source power generated by the inductive coupling coil 12 from the first space 101 in the upper portion of the response chamber, in response to the gas being ionized into a plasma therein, and the plasma is freely diffused through the second space 102 in the lower portion of the response chamber 10 to The surface of the wafer 20 is etched in response to the wafer 20.

The first space 101 is a recessed space between the convex portions 111 or a recessed space surrounded by the convex portions 111, and the second space 102 is an responsive cavity space below the first space 101. That is, the first space and the second space 101, 102 are vertically distributed vertically.

Specifically, the shielding device is a set of metal cross-pieces 14 that are in one-to-one correspondence with the inductive coupling coils 12. The inductive coupling coil 12 laid inside the boss 111 extends in accordance with the extending direction of the boss 111, and similarly, the metal rail 14 is inductively coupled. The coil 12 extends in the longitudinal direction, that is, the inductive coupling coil 12 laid inside the boss portion 111, the metal cross piece 14 is spirally distributed like the boss portion 111, or a plurality of U-shaped ends are connected to the air shower head 11 The lower surface, wherein the metal lateral piece 14 is laid directly under the inductive coupling coil 12, shields the RF source power applied by the inductive coupling coil 12 into the first space 101.

The inductively coupled plasma device generates a plasma in the first space 101, and the plasma is freely diffused to the surface of the wafer 20 via the second space 102, because the radio frequency electric field is only distributed in the first space 101, and the plasma is in the second space 102. Without accelerating or exciting, it undergoes a cooling process, so the electrons therein have a lower temperature, which significantly weakens the effect of the physical etching response with the wafer 20, making the chemical etching response dominant and satisfying The requirements of a specific etching process.

At the same time, in response to the uneven distribution of the plasma in the chamber 10, there is a mixing process when freely diffusing in the second space 102, so that the second space 102 corresponds to a pre-treatment chamber in which the plasma is made more It is evenly distributed to facilitate uniformity of etching of the wafer 20.

As shown in FIG. 3, the inductively coupled plasma device according to the second embodiment of the present invention includes: an response chamber 10, a shower head 11, two sets of inductive coupling coils 121, 122, and two metal lateral sheets 141, 142, two Block metal risers 151, 152. An electrostatic chuck 13 and a wafer to be processed 20 are provided at the bottom of the response chamber. The bottom surface of the air shower head 11 has a continuous extending protrusion 111.

Specifically, two sets of inductive coupling coils 121, 122 and two metal horizontal pieces 141, 142, two metal vertical pieces 151, 152 are laid inside the convex portion 111; the inductive coupling coils 121, 122 follow the convex portion 111 Extends in the direction of extension. The metal risers 151, 152 are separately disposed and extend in the longitudinal direction of the inductive coupling coils 121, 122, respectively, and the metal risers 152 are disposed on the peripheral side of the metal risers 151. The metal horizontal sheets 141 and 142 may be integrally provided or may be separately disposed and extended along the longitudinal direction of the inductive coupling coils 121 and 122, respectively.

The metal cross piece 141 and the metal riser 151 are integrally shielded The RF source power generated by the inductive coupling coil 121 is shielded from the third space 1011 of the response chamber. The metal horizontal piece 142 and the metal vertical piece 152 are used as another integral shielding device, and are disposed outside the inductive coupling coil 122. The shielding device formed by the metal horizontal piece 141 and the metal vertical piece 151 is located inside the inductive coupling coil 122, and the two shielding devices work together. The RF source power generated by the inductive coupling coil 122 is shielded in the fourth space 1010 of the response chamber 10.

The third space 1011 is a recessed space surrounded by the metal lateral piece 141 and the convex portion 111 where the metal vertical piece 151 is located, and the fourth space 1010 is surrounded by the convex portion 112 where the metal horizontal piece 142 and the metal vertical piece 152 are located. The recessed space, the third and fourth spaces 1011, 1010 can all be regarded as part of the first space 101 in the first embodiment of the present invention, or the third and fourth spaces 1011, 1010 are combined together to form the first space 101. The second space 102 is a response chamber space vertically distributed below the third and fourth spaces 1011, 1010. That is, the third and fourth spaces 1011 and 1010 are both located inside the response chamber 10 and are both in communication with the second space 102. The fourth space 1010 surrounds the third space 1011 from the periphery, and the two are distributed inside and outside. Wherein, the convex portion 111 and the convex portion 112 are detachably set.

The RF power applied by the inductive coupling coil 121 acts on the response gas generated in the third space 1011 to generate plasma, and the RF power applied by the inductive coupling coil 122 acts on the response gas in the fourth space 1010 to generate a plasma, which is transmitted through the plasma. The second space 102 is freely diffused to the surface of the wafer 20. In the second space 102, the plasma undergoes a cooling process due to the absence of an RF electric field, and the wafer 20 is etched back so that the electrons in the plasma have a higher The low temperature, and thus the physical etching response of the wafer 20 is significantly weakened, and the chemical etching response is dominant, which is advantageous for specific process occasions such as polysilicon etching.

In addition, plasma is generated in the third and fourth spaces 1011, 1010, and density unevenness occurs. When the plasma is freely diffused in the second space 102, there is a mixing process, so that the second space 102 is equivalent to a pretreatment. The chamber, in which the plasma is more evenly distributed, facilitates uniformity of etching of the wafer 20.

According to the second embodiment described above, one of the main functions of the metal riser 151 is to shield the mutual electromagnetic interference between the inductive coupling coil 121 and the inductive coupling coil 122, so that the radio frequency powers in the third space 1011 and the fourth space 1010 are shielded from each other.

Further, the inductive coupling coils 121 and 122 can be connected to the same power RF power source through the matching device, thereby generating the same intensity of the RF source power in the third space 1011 and the fourth space 1010, and can also connect the RF powers of different powers through the matching device. The power source thus produces different intensity RF source powers in the third space 1011, the fourth space 1010.

Preferably, the inductive coupling coils 121, 122 are connected to different power RF power sources, so that the inductive coupling coil 121 applies a first intensity of radio frequency power in the third space 1011 to generate a first concentration of plasma therein, so that the inductive coupling coil 122 applies a second intensity of radio frequency power in the fourth space 1010 to generate a second concentration of plasma therein, the first intensity being different from the second intensity.

Those skilled in the art understand that due to the distribution of the inductive coupling coil and the physical structure of the response chamber, the RF electric field in the response chamber is generally unevenly distributed, with a large density at the center portion and a small density at the edge portion, resulting in a response cavity. The plasma in the chamber is also in a state of uneven distribution, which adversely affects the uniformity of wafer etching. Even if the second space 102 is set for the plasma to pass through a mixing process to promote uniform plasma distribution, it is necessary to find other effective solutions to further optimize the uniform distribution of the plasma.

The inductively coupled plasma device provided by the second embodiment of the present invention can respectively connect different sets of inductive coupling coils 121 and 122 through the matching device to respectively connect different RF power sources, and can apply different RF powers to different parts of the response chamber 10. . By applying a weaker RF power selectively in the center of the response chamber, such as the third space 1011, and applying a relatively strong RF power in response to the edge portion of the chamber, such as the fourth space 1010, the response chamber can be made The RF electric field is in a more evenly distributed state, which in turn allows the plasma to be evenly distributed, ultimately The uniformity of wafer etching brings about extremely favorable conditions.

According to the above second embodiment of the present invention, the first intensity is less than the second intensity, and the first concentration may be slightly lower or closer to the second concentration.

Further, the inductive coupling coils 121, 122 are respectively connected to two output ends of a power distributor, and the power distributor input is connected to a common RF power source through a matching device. This setup further simplifies the system architecture.

Further, the power distributor includes an adjustment unit for adjusting the radio frequency power distributed to the inductive coupling coils 121, 122. Through the adjustment unit, the distribution of the RF electric field in the response chamber can be adjusted in real time, thereby adjusting the plasma distribution.

Preferably, the power distribution device distributes the RF power to the inductive coupling coil 121 less than the RF power it distributes to the inductive coupling coil 122.

Further, the power distribution of the power distribution device to the inductive coupling coil 122 is 52%-65% of the total power of the external RF power supply.

Further, the RF power source provides RF source power with a power of 700W-10kW.

As shown in FIG. 4, the inductively coupled plasma device according to the third embodiment of the present invention includes: an response chamber 10, a shower head 11, two sets of inductive coupling coils 121, 122, and two metal lateral sheets 141, 142, two Block metal risers 151, 152, and a metal wafer 16. An electrostatic chuck 13 and a wafer to be processed 20 are provided at the bottom of the response chamber. The bottom surface of the air shower head 11 has two continuous extending protrusions 111 and 112. The inductive coupling coil 121 and the metal cross piece 141 and the metal vertical piece 151 are laid inside the convex portion 111, and along with the extending direction of the convex portion 111. Similarly, the inductive coupling coil 122 and the metal cross piece 142 and the metal riser 152 are laid inside the boss 112 and extend along the extending direction of the boss 112. The metal disk 16 is horizontally laid on the portion of the air shower head 11 and the non-protrusion portion 111.

The third embodiment is a further improved implementation mode of the second embodiment described above, and different from the first and second embodiments, the metal wafer 16 and the two metal verticals The sheet 151 is closely connected, and the inductive coupling coils 121 and 122 are covered from the upper portion, and the metal wafer 16 is provided with a plurality of through holes to connect the air inlets set on the air shower head 11 in a one-to-one correspondence.

By setting the metal wafer 16, the RF power can be further shielded from the third space 1011 and the fourth space 1010 in the response chamber 10, preventing the RF power from leaking out from the top of the response chamber 10, which is beneficial in the response chamber. Producing a high concentration of plasma increases energy efficiency.

It should be understood that the present invention or shielding device shields RF power in a space in the response chamber, allowing it to diffuse freely to the surface of the wafer, reducing the temperature of the electrons in the plasma to facilitate a specific process; or responding with a shielding device The RF power intensity at different locations in the chamber is adjusted to distribute the plasma more evenly therein. These inventive ideas should not be limited to the architecture or position of the shielding device, and the inductively coupled plasma devices that achieve the same function with other shielding devices do not depart from the idea of the present invention.

The above are only the preferred embodiments of the present invention, and the embodiments are not intended to limit the scope of the patent protection of the present invention. Therefore, equivalent structural changes made by using the description of the present invention and the contents of the drawings should be included in the same manner. Within the scope of protection of the present invention.

10‧‧‧Response chamber

1010‧‧‧ fourth space

1011‧‧‧ third space

102‧‧‧Second space

11‧‧‧Lip head

110‧‧‧air inlet

111‧‧‧ raised parts

112‧‧‧ raised parts

121‧‧‧Inductive Coupling Coil

122‧‧‧Inductive Coupling Coil

13‧‧‧Electrostatic chuck

141‧‧‧metal crosspiece

142‧‧‧metal crosspiece

151‧‧‧Metal risers

152‧‧‧Metal risers

20‧‧‧Processed wafers

Claims (15)

An inductively coupled plasma device comprising: an responsive chamber for plasma processing response with a wafer placed therein; and a venting head disposed at an upper portion of the responsive chamber, including at least one air inlet for Transmitting a response gas to the response chamber; at least one set of inductive coupling coils adjacent to the response chamber setting for externally receiving a RF power source through the matcher to apply RF power to the response chamber; and shielding means, Adjacent to the inductive coupling coil setting for shielding the radio frequency power in the first space to act on the response gas to generate a plasma, the plasma being freely diffused through the second space and the wafer In response, wherein the first space and the second space are respectively located in the response chamber, and are vertically distributed and connected to each other. The inductively coupled plasma device according to claim 1, wherein the bottom surface of the gas shower head comprises at least one convex portion, and the inductive coupling coil and the shielding device are embedded in the convex portion, and the first space is The concave portion encloses a recessed space, and the second space is an responsive chamber space below the first space. The inductively coupled plasma device of claim 2, wherein the shielding device comprises at least one set of metal crosspieces corresponding to the inductive coupling coils, disposed directly below the inductive coupling coil, the metal cross The sheet extends along the length of the inductive coupling coil. The inductively coupled plasma device of claim 2, wherein the raised portions are two and are separately disposed, respectively being a first raised portion and a second raised portion, the second raised portion being surrounded by the periphery The first protruding portion; the inductive coupling coil includes two sets of coils respectively embedded in the first raised portion and the second raised portion, respectively being first a coil and a second coil, the shielding device comprises two sets of metal crosspieces corresponding to the inductive coupling coils, and two sets of metal vertical pieces corresponding to the inductive coupling coils, respectively being a first horizontal piece, a second horizontal piece, a first vertical piece and a second vertical piece, the first horizontal piece and the first vertical piece being embedded in the first convex portion for shielding RF power generated by the first coil In the third space, the second horizontal piece and the second vertical piece are embedded in the second raised portion for shielding the RF power generated by the second coil from the fourth space; wherein the The third space is a recessed space surrounded by the first convex portion, and the fourth space is a recessed space surrounded by the second convex portion and not including the third space, the third space, The fourth space is in communication with the second space. The inductively coupled plasma device of claim 4, wherein the first horizontal piece and the second horizontal piece are respectively disposed directly under the first coil and the second coil, and respectively along the first coil, The two coils extend in the length direction. The inductively coupled plasma device of claim 4, wherein the first riser and the second riser respectively extend along a length direction of the first coil and the second coil, and the first riser surrounds from a peripheral side The first coil is shielded from the third coil by RF power generated by the first coil at least one week, and the second riser surrounds the second coil from the peripheral side at least one week to the first vertical The sheets together shield the RF power generated by the second coil to the fourth space. The inductively coupled plasma device of claim 4, wherein the shielding device further comprises a metal wafer, the metal wafer is in close contact with the first and second vertical sheets, and covers the first portion from an upper portion And a second coil, wherein the metal disc is provided with at least one through hole to respectively connect the air inlet. An inductively coupled plasma device according to any one of claims 1 to 7, The radio frequency power is the radio frequency source power. The inductively coupled plasma device of any one of claims 4 to 7, wherein the first coil applies a first intensity of radio frequency power in the third space to generate a first concentration of plasma, the first The second coil applies a second intensity of radio frequency power in the fourth space to produce a second concentration of plasma, the first intensity being different from the second intensity. The inductively coupled plasma device of claim 9, wherein the first intensity is lower than the second intensity. The inductively coupled plasma device of any one of claims 4 to 7, wherein the first coil and the second coil are respectively connected to two outputs of a power distributor, the power distributor input being connected In the matcher, the matcher externally connects the RF power source. The inductively coupled plasma device of claim 11, wherein the power distributor includes an adjustment unit for adjusting radio frequency power distributed to the first coil and the second coil. The inductively coupled plasma device of claim 12, wherein the power distributor distributes the RF power to the first coil less than the RF power it distributes to the second coil. The inductively coupled plasma device of claim 13, wherein the RF power distributed by the power distributor to the second coil is 52% to 65% of the power supplied by the RF power source. The inductively coupled plasma device of claim 14, wherein the radio frequency power source provides radio frequency source power having a power of 700 W to 10 kW.