JP4480946B2 - Magnetic field generation method for magnetron plasma - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention, on a substrate to be processed such as a semiconductor wafer, to Ma grayed magnetron plasma for generating a magnetic field methods for by the action of the magnetron plasma subjected to processing such as etching.
[0002]
[Prior art]
Conventionally, in the field of manufacturing semiconductor devices, magnetron plasma is generated in a processing chamber, and this magnetron plasma is applied to a substrate to be processed, such as a semiconductor wafer, disposed in the processing chamber to perform predetermined processing, for example, etching, An apparatus for forming a film or the like is used.
[0003]
As a magnetic field generator for magnetron plasma for generating such magnetron plasma, a substrate to be processed such as a semiconductor wafer disposed horizontally with a surface to be processed facing upward is surrounded by a semiconductor wafer or the like. As described above, a multipole type in which a large number of N and S magnetic poles are alternately arranged adjacent to each other and a multipole magnetic field is formed so as to surround the periphery of the semiconductor wafer without forming a magnetic field. Are known (for example, see Patent Document 1).
[0004]
[Patent Document 1]
JP 2001-338912 A (page 4-5, FIG. 1-2).
[0005]
[Problems to be solved by the invention]
As described above, conventionally, a magnetron plasma magnetic field generating apparatus for forming a predetermined multipole magnetic field around a substrate to be processed such as a semiconductor wafer in a processing chamber and generating a magnetron plasma to perform an etching process or the like. Are known.
[0006]
By the way, in recent years, a substrate to be processed such as a semiconductor wafer tends to be gradually increased in size to, for example, a 12-inch diameter, and has been conventionally used while being able to process such a large substrate to be processed. For example, it is required to be able to cope with substrates to be processed having different sizes, such as processing of a substrate to be processed having a diameter of 8 inches or the like.
[0007]
However, in the magnetron plasma magnetic field generator using the multipole magnetic field as described above, as described above, a magnetic field is not formed above the substrate to be processed such as a semiconductor wafer, Since a multipole magnetic field that matches the size of the substrate to be processed is formed, it has been difficult to cope with substrates to be processed having different sizes.
[0008]
The present invention has been made in response to such a conventional situation, and can easily form a multipole magnetic field corresponding to a substrate to be processed having a different size. Te, it is intended to provide a luma grayed magnetron plasma for generating a magnetic field method can of doing each good processing.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 is provided outside the processing chamber for accommodating the substrate to be processed and performing a predetermined process, and is configured in an annular shape by arranging a plurality of magnet segments. A magnetron plasma magnetic field generation method using a magnetron plasma magnetic field generation device that forms a multipole magnetic field with a magnetic pole facing the processing chamber side around the substrate, when processing the substrate to be processed of a predetermined size Forming a multipole magnetic field having a predetermined number of magnetic poles arranged at predetermined intervals along the circumferential direction, and when processing the substrate to be processed having a size smaller than the predetermined size, A multi-pole magnetic field having a number of magnetic poles less than the predetermined number arranged at intervals wider than a predetermined interval and having magnetic lines of force entering the inside of the processing chamber is formed.
The invention according to claim 2 is the magnetic field generation method for magnetron plasma according to claim 1 , wherein the magnet segment is composed of a permanent magnet, and the magnet segment is rotated around a vertical rotation axis. The number of magnetic poles of the multipole magnetic field is increased or decreased by changing the direction of the magnetic poles.
Invention of Claim 3 is the magnetic field generation method for magnetron plasma of Claim 1 or 2 , Comprising: The said magnet segment is comprised from a permanent magnet, and consists of a magnetic body between the said magnet segment and the said process chamber. A magnetic field control member is inserted to control the state of the multipole magnetic field formed in the processing chamber.
A fourth aspect of the present invention, a claim 1 magnetron plasma for generating a magnetic field method, wherein the magnet segments, characterized in that it is composed of an electromagnet.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
The details of the present invention will be described below with reference to the drawings.
[0017]
FIG. 1 schematically shows an outline of a configuration of an embodiment in which the present invention is applied to a magnetron plasma etching apparatus for etching a semiconductor wafer. In FIG. 1, reference numeral 1 denotes a material such as aluminum. The figure shows a cylindrical vacuum chamber that is configured to be airtightly closed and that constitutes a processing chamber.
[0018]
The vacuum chamber 1 has a stepped cylindrical shape composed of a small-diameter upper portion 1a and a large-diameter lower portion 1b, and is connected to a ground potential. In addition, a support table (susceptor) 2 is provided inside the vacuum chamber 1 to support a semiconductor wafer W as a substrate to be processed substantially horizontally with the surface to be processed facing upward.
[0019]
The support table 2 is made of a material such as aluminum, for example, and is supported on a conductor support 4 via an insulating plate 3 made of ceramic or the like. A focus ring 5 made of a conductive material or an insulating material is provided on the outer peripheral portion of the upper surface of the support table 2.
[0020]
An electrostatic chuck 6 for electrostatically attracting the semiconductor wafer W is provided on the mounting surface of the semiconductor wafer W of the support table 2. The electrostatic chuck 6 is configured by disposing an electrode 6a between insulators 6b, and a DC power source 13 is connected to the electrode 6a. When a voltage is applied to the electrode 6a from the power source 13, the semiconductor wafer W is attracted by, for example, Coulomb force.
[0021]
Further, the support table 2 is supplied with a He gas to the back surface of the semiconductor wafer W in order to efficiently transmit the cooling flow from the refrigerant to the semiconductor wafer W and a refrigerant flow path (not shown) for circulating the refrigerant. A gas introduction mechanism (not shown) is provided so that the temperature of the semiconductor wafer W can be controlled to a desired temperature.
[0022]
The support table 2 and the support table 4 can be moved up and down by a ball screw mechanism including a ball screw 7, and a drive portion below the support table 4 is covered with a bellows 8 made of stainless steel (SUS). A bellows cover 9 is provided on the outer side of 8.
[0023]
A power supply line 12 for supplying high-frequency power is connected to substantially the center of the support table 2. A matching box 11 and a high frequency power source 10 are connected to the feeder line 12. From the high frequency power supply 10, high frequency power in the range of 13.56 to 150 MHz, preferably in the range of 13.56 to 100 MHz, for example, 100 MHz, is supplied to the support table 2.
[0024]
Further, a baffle plate 14 is provided outside the focus ring 5. The baffle plate 14 is electrically connected to the vacuum chamber 1 through the support 4 and the bellows 8.
[0025]
On the other hand, a shower head 16 is provided on the top wall portion of the vacuum chamber 1 above the support table 2 so as to face the support table 2 in parallel, and the shower head 16 is grounded. Therefore, the support table 2 and the shower head 16 function as a pair of electrodes.
[0026]
The shower head 16 is provided with a large number of gas discharge holes 18 on the lower surface thereof, and has a gas introduction part 16a on the upper part thereof. A gas diffusion space 17 is formed in the inside. A gas supply pipe 15a is connected to the gas introduction section 16a, and a processing gas supply system 15 for supplying a processing gas composed of a reactive gas for etching and a dilution gas is connected to the other end of the gas supply pipe 15a. Has been.
[0027]
As the reaction gas, for example, a halogen-based gas or the like can be used, and as the dilution gas, a gas usually used in this field such as Ar gas or He gas can be used. Such a processing gas reaches the gas diffusion gap 17 of the shower head 16 from the processing gas supply system 15 through the gas supply pipe 15a and the gas introduction portion 16a, and is discharged from the gas discharge hole 18 to be formed on the semiconductor wafer W. It is used for etching of the formed film.
[0028]
An exhaust port 19 is formed on the side wall of the lower portion 1 b of the vacuum chamber 1, and an exhaust system 20 is connected to the exhaust port 19. The vacuum chamber 1 can be depressurized to a predetermined degree of vacuum by operating a vacuum pump provided in the exhaust system 20. Further, a gate valve 24 that opens and closes the loading / unloading port of the semiconductor wafer W is provided on the upper side wall of the lower portion 1 b of the vacuum chamber 1.
[0029]
On the other hand, an annular magnetron plasma magnetic field generator (ring magnet) 21 is arranged around the outside of the upper portion 1 a of the vacuum chamber 1 concentrically with the vacuum chamber 1. A magnetic field is formed around the processing space. The entire magnetron plasma magnetic field generator 21 can be rotated around the vacuum chamber 1 at a predetermined rotational speed by a rotation mechanism 25.
[0030]
As shown in FIG. 2, the magnetron plasma magnetic field generator 21 is composed of a plurality (36 in FIG. 2) of magnet segments 22 made of permanent magnets supported by a support member (not shown). These magnet segments 22 constitute one magnetic pole by the two magnet segments 22, so that a total of 18 magnetic poles are formed, and these magnetic poles facing the vacuum chamber 1 side are S, N, S, N,... Are arranged alternately. In FIG. 2, the direction of the magnetic pole of each magnet segment 22 is indicated by the direction of the arrow.
[0031]
That is, in the magnetron plasma magnetic field generator 21, in the state shown in FIG. 2, the magnetic poles adjacent to each other (configured by two magnet segments 22) are arranged so that their directions are opposite to each other. Accordingly, magnetic field lines (only part of which are shown in FIG. 2) are formed between the adjacent magnetic poles, and a magnetic field having a predetermined strength is formed in the peripheral portion of the processing space, that is, in the vicinity of the inner wall of the vacuum chamber 1. Then, the multipole magnetic field is formed so as to be in a substantially magnetic-free state.
[0032]
Note that the substantially no magnetic field state above the semiconductor wafer W described above is desirably 0T in nature, but a magnetic field that affects the etching process is not formed in the arrangement portion of the semiconductor wafer W, so Any value that does not affect the processing of the semiconductor wafer W may be used.
[0033]
Furthermore, in the present embodiment, each magnet segment 22 of the magnetron plasma magnetic field generating device 21 is centered on a vertical axis in the magnetron plasma magnetic field generating device 21 by a magnet segment rotating mechanism (not shown). The magnet segments 22 are rotatable and the magnet segments 22 are detachable. When processing semiconductor wafers W having different diameters, the state of the multipole magnetic field formed by the magnetron plasma magnetic field generator 21 can be changed.
[0034]
That is, as described above, in the state shown in FIG. 2, 18 magnetic poles are formed. In this state, a multipole magnetic field is formed only on the periphery of the 12-inch diameter semiconductor wafer W, and this setting is used when processing the 12-inch diameter semiconductor wafer W. .
[0035]
If a multi-pole magnetic field in the above state is used when processing an 8-inch diameter semiconductor wafer W, the distance between the magnetic field and the semiconductor wafer W is increased, resulting in a weak plasma confinement effect. End up.
[0036]
Therefore, for example, as shown in FIG. 3, the direction of some magnet segments 22 is changed, and the intermediate magnet segment 22 is removed (thinned) (the thinned magnet segment 22 is indicated by a dotted line in the figure). .), Reducing the number of magnetic poles to twelve. As a result, the lines of magnetic force formed between adjacent magnetic poles (only part of which is shown in FIG. 3) enter the vacuum chamber 1 more than the state shown in FIG. A multipole magnetic field is formed in the periphery of the wafer W. Therefore, in this state, the 8-inch diameter semiconductor wafer W can be satisfactorily etched.
[0037]
In the above case, the magnet segment 22 positioned between the magnetic poles is removed. For example, as shown in FIG. 4, the magnet segment 22 positioned between the magnetic poles is directed in the circumferential direction toward the magnetic field lines. If it is made to rotate so that it may turn to a direction, the number of magnetic poles can be reduced, without removing the magnet segment 22 located between magnetic poles.
[0038]
Further, for example, as shown in FIG. 5, the number of magnetic poles can be reduced to, for example, six by simply removing the magnet segment 22 without rotating the magnet segment 22, and the magnetic field can be further reduced in the vacuum chamber 1. It can be in a state where it has entered inside.
[0039]
Further, as described above, instead of removing the magnet segment 22, a magnet such as an iron plate is provided between the magnet segment 22 and the vacuum chamber 1 (between the magnet segment indicated by the dotted line in FIG. 5 and the vacuum chamber). Also by arranging the body, as in the case shown in FIG. 5, the number of substantial magnetic poles can be reduced, and the magnetic field can be brought into the vacuum chamber 1.
[0040]
Further, as shown in FIG. 6, for example, the magnetron plasma magnetic field generator 21 includes an upper magnetron plasma magnetic field generator 21a provided on the upper side and a lower magnetron plasma magnetic field generator provided on the lower side. It can also be set as the structure divided into multiple, such as 21b. In the case of such a configuration, as indicated by arrows in the figure, the upper magnetron plasma magnetic field generator 21a and the lower magnetron plasma magnetic field generator 21b are moved so as to approach and separate in the vertical direction. The strength of the multipole magnetic field formed in the vacuum chamber 1 can be changed.
[0041]
Further, between the upper side magnetron plasma magnetic field generator 21a and the lower side magnetron plasma magnetic field generator 21b and the vacuum chamber 1, magnetic materials (for example, made of iron or the like in a cylindrical shape) 30a, respectively. The strength of the multipole magnetic field formed in the vacuum chamber 1 can also be increased by arranging 30b and moving these magnetic bodies 30a and 30b so as to approach and separate in the vertical direction as indicated by arrows in the figure. Can be changed. In this case, both the upper magnetron plasma magnetic field generator 21a and the lower magnetron plasma magnetic field generator 21b and the magnetic bodies 30a and 30b may be moved.
[0042]
By arranging the magnetic bodies 30a and 30b in this manner, the strength of the magnetic field is changed with a smaller moving distance than when only the upper magnetron plasma magnetic field generator 21a and the lower magnetron plasma magnetic field generator 21b are moved up and down. can do.
[0043]
When a permanent magnet is used as the magnet segment 22, it is possible to change the strength of the magnetic field by adopting the configuration as described above, and the change of the strength of the magnetic field can be performed, for example, in the middle of the process, if necessary. Can also be performed. In addition, when the magnetic bodies 30a and 30b are arranged as described above, the magnetic bodies 30a and 30b are moved in a direction in which they are brought close to each other so that they are in contact with each other. State.
[0044]
It should be noted that the number of magnet segments 22 and the number of magnetic poles as described above are examples, and it goes without saying that these numbers can be changed as appropriate. Further, in the above example, one magnetic pole is constituted by two magnet segments 22, but one magnetic segment 22 may constitute one magnetic pole, and more than two magnets. One magnetic pole may be constituted by the segment 22.
[0045]
In the above example, the case where a permanent magnet is used as the magnet segment 22 has been described. However, the magnet segment 22 is not limited to a permanent magnet, and an electromagnet can also be used. In this case, the direction of the current applied to the electromagnet is changed instead of rotating the magnet segment 22, and the energization to the electromagnet is stopped instead of removing the magnet segment 22, so that the multipole magnetic field can be The state can be changed.
[0046]
Next, processing in the magnetron plasma etching apparatus configured as described above will be described.
[0047]
First, the gate valve 24 is opened, and the semiconductor wafer W is loaded into the vacuum chamber 1 by a transfer mechanism (not shown) through a load lock chamber (not shown) arranged adjacent to the gate valve 24. And is placed on the support table 2 that has been lowered to a predetermined position in advance. Then, a predetermined voltage is applied from the DC power supply 13 to the electrode 6a of the electrostatic chuck 6, and the semiconductor wafer W is adsorbed by Coulomb force or the like.
[0048]
Thereafter, after the transport mechanism is retracted outside the vacuum chamber 1, the gate valve 24 is closed, the support table 2 is raised to the position shown in FIG. 1, and the vacuum chamber is passed through the exhaust port 19 by the vacuum pump of the exhaust system 20. 1 is exhausted.
[0049]
After the inside of the vacuum chamber 1 reaches a predetermined degree of vacuum, a predetermined processing gas is introduced into the vacuum chamber 1 from the processing gas supply system 15 at a flow rate of, for example, 100 to 1000 sccm. The pressure is maintained at about 1.33 to 133 Pa (10 to 1000 mTorr), preferably about 2.67 to 26.7 Pa (20 to 200 mTorr).
[0050]
In this state, high frequency power having a frequency of 13.56 to 150 MHz, for example, 100 MHz, and power of 100 to 3000 W is supplied from the high frequency power supply 10 to the support table 2. In this case, high frequency power is applied to the support table 2 that is the lower electrode as described above, so that a high frequency is generated in the processing space between the shower head 16 that is the upper electrode and the support table 2 that is the lower electrode. An electric field is formed, whereby the processing gas supplied to the processing space is turned into plasma, and a predetermined film on the semiconductor wafer W is etched by the plasma.
[0051]
At this time, as described above, the magnet segments 22 of the magnetron plasma magnetic field generator 21 are set in a predetermined arrangement state in advance according to the size (diameter) of the semiconductor wafer W to be processed. A predetermined multipole magnetic field is formed.
[0052]
If a multipole magnetic field is formed, there is a possibility that a portion corresponding to the magnetic pole of the side wall (depot shield) of the vacuum chamber 1 is locally cut. On the other hand, the magnetic pole moves relative to the wall of the vacuum chamber 1 by rotating the magnetron plasma magnetic field generator 21 around the vacuum chamber 1 by the rotation mechanism 25 having a drive source such as a motor. For this reason, the wall portion of the vacuum chamber 1 is prevented from being locally cut.
[0053]
Then, when the predetermined etching process is executed, the supply of the high frequency power from the high frequency power supply 10 is stopped, the etching process is stopped, and the semiconductor wafer W is removed from the vacuum chamber 1 by a procedure reverse to the above-described procedure. It is carried out to.
[0054]
In the above embodiment, the case where the present invention is applied to a magnetron plasma etching apparatus for etching a semiconductor wafer has been described. However, the present invention is not limited to this case. For example, a substrate other than a semiconductor wafer may be processed, and processing other than etching, for example, a film forming processing apparatus such as CVD can be applied.
[0055]
【The invention's effect】
As described above, according to the present invention, it is possible to easily form a multipole magnetic field corresponding to a substrate to be processed having a different size, and to perform a good process on each substrate having a different size. It can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall schematic configuration of a magnetron plasma processing apparatus in which a magnetron plasma magnetic field generator according to an embodiment of the present invention is arranged.
2 is a diagram showing a schematic configuration of the magnetron plasma magnetic field generator of FIG. 1;
3 is a diagram for explaining a state in which the number of magnetic poles of the magnetron plasma magnetic field generator of FIG. 2 is changed.
4 is a diagram for explaining a state in which the number of magnetic poles of the magnetron plasma magnetic field generator of FIG. 2 is changed.
FIG. 5 is a diagram for explaining a state in which the number of magnetic poles of the magnetron plasma magnetic field generator of FIG. 2 is changed.
FIG. 6 is a diagram showing a schematic configuration of a main part of another embodiment of the magnetic field generator for magnetron plasma according to the present invention.
[Explanation of symbols]
W ... Semiconductor wafer, 1 ... Vacuum chamber, 2 ... Support table, 3 ... Insulating plate, 4 ... Support base, 5 ... Focus ring, 6 ... Electrostatic chuck, 7 ... Ball screw, 8 ...... Bellows, 9 ... Bellows cover, 10 ... High frequency power supply, 11 ... Matching box, 12 ... Feed line, 13 ..., 14 ... Baffle plate, 15 ... Process gas supply system, 16 ... Shower Head, 17 ... Gas diffusion gap, 18 ... Gas discharge hole, 19 ... Exhaust port, 20 ... Exhaust system, 21 ... Magnetron plasma magnetic field generator, 22 ... Magnetic segment, 24 ... Gate valve 25 ...... Rotation mechanism.

Claims (4)

Provided outside a processing chamber for accommodating a substrate to be processed and performing a predetermined process, and a plurality of magnet segments are arranged to form an annular shape around the substrate to be processed in the processing chamber. A magnetic field generation method for magnetron plasma using a magnetic field generator for magnetron plasma that forms a multipole magnetic field facing a magnetic pole,
When processing the substrate to be processed having a predetermined size, a multipole magnetic field having a predetermined number of magnetic poles arranged at predetermined intervals along the circumferential direction is formed.
When processing the substrate to be processed having a size smaller than the predetermined size, the processing chamber has fewer magnetic poles than the predetermined number arranged in a circumferential direction and at a wider interval than the predetermined interval. A magnetic field generation method for magnetron plasma, characterized by forming a multipole magnetic field that penetrates into the interior of the magnetron. The method of generating a magnetic field for magnetron plasma according to claim 1 ,
The magnet segment is composed of a permanent magnet, and the number of magnetic poles of the multipole magnetic field is increased or decreased by changing the direction of the magnetic pole of the magnet segment by rotating the magnet segment around a vertical rotation axis. Magnetic field generation method for magnetron plasma. The method of generating a magnetic field for magnetron plasma according to claim 1 or 2 ,
The magnet segment is composed of a permanent magnet, and a magnetic field control member made of a magnetic material is inserted between the magnet segment and the processing chamber to control the state of the multipole magnetic field formed in the processing chamber. Magnetic field generation method for magnetron plasma. The method of generating a magnetic field for magnetron plasma according to claim 1 ,
A magnetron plasma magnetic field generating method, wherein the magnet segment is composed of an electromagnet.

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