JP2007134428A - Dry-etching method and its equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dry-etching method and its equipment for manufacturing a very accurate device with an etching cross section highly symmetrical in the plane of a wafer. <P>SOLUTION: A DC current is caused to flow in a coil 9 arranged outside a treatment chamber 14 to generate a magnetic field inside the treatment chamber 14. While controlling the deflection of plasma ions by the action of the magnetic field, an etched object 1 is etched vertically to the plane thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a dry etching method and apparatus using plasma used in the manufacture of a MEMS (micro electronic mechanical system) device or a semiconductor integrated circuit.

  In the dry etching method, a gas is introduced into a vacuum vessel, and the gas is excited by a high frequency, microwave, or the like to generate plasma and generate radicals and ions. It is performed by reacting radicals and ions generated by plasma with an object to be etched (wafer), converting the reaction product into a volatile gas, and exhausting it outside by a vacuum exhaust system. 6 has a configuration as shown in FIG. 6 (see, for example, Patent Document 1).

  In FIG. 6, a gas supply device 116 for supplying a gas used for the etching process and a high-frequency power source 108 for applying high-frequency power to the antenna 106 for generating plasma are connected to a processing chamber 114 via a matching circuit 107. The plasma chamber 115 is connected to the upper part. The processing chamber 114 has vacuum pumps 126 and 127 for exhausting the processing chamber 114 to a predetermined pressure, an orifice valve 125 for controlling the gas pressure to a predetermined level when gas is supplied, and the object 101 to be etched. And a bias power source 113 for applying bias power to the mounting electrode 102 are connected via a matching circuit 112. Furthermore, an electrostatic chuck 103 for mounting the object to be etched 101 on the mounting electrode 102, a guide ring 104 for controlling the flow of ions or electric field distribution around the object to be etched 101, In order to cool the etching body 101 or the mounting electrode 102, the refrigerant 128 is circulated inside the insulator 105 and the He gas 130 can be introduced directly under the body to be etched 101.

  Next, a dry etching method using this apparatus will be described. The object to be etched 101 is placed on the placement electrode 102 in the processing chamber 114 and is adsorbed thereon.

Thereafter, the orifice valve 125 is fully opened and the inside of the plasma chamber 115 is evacuated to a high vacuum, for example, 10 ⁻³ Pa or less, and then the orifice valve 125 is throttled, and the gas supply device 116 performs SF as an etching gas inside the plasma chamber 115. ₆ gas is introduced.

  Here, although only one gas supply device is shown in FIG. 6, of course, when a mixed gas is used, there are a plurality of gas supply devices. At this time, the orifice valve is set so that the gas pressure in the processing chamber 114 is 0.5 Pa. 125 is controlled.

Next, bias power is applied by the bias power supply 113. On the other hand, a high frequency power of 13.56 MHz is applied to the antenna 106 using a high frequency power source 108 to generate plasma in the plasma chamber 115. The plasma source 117 diffuses into the processing chamber 114 but diffuses with directivity (plasma direction) as indicated by an arrow 118. The directivity varies somewhat depending on gas pressure, gas flow rate, high-frequency power, bias power, etc., but becomes directivity specific to the apparatus depending on the size of the plasma chamber 115 and the processing chamber 114. For this reason, the etched cross section is processed vertically with high accuracy at the center of the object 101 to be etched, but the inner taper angle is larger than the outer taper angle toward the outer peripheral portion. And the angle difference is 1-2 degrees.
Japanese Unexamined Patent Publication No. Sho 63-99531

  However, in the conventional configuration, when the etching depth becomes deep like a MEMS device (for example, through etching of a standard thickness of 525 μm of a 4-inch wafer commonly used in MEMS processing), Is lost, and the dimensional difference is 10 μm. As described above, there is a problem that the symmetry of the wafer is greatly shifted in the plane of the wafer and the device characteristics are deteriorated.

  The present invention solves the above-described conventional problems, and an object of the present invention is to provide a dry etching method and apparatus capable of processing a processed cross-sectional shape with high dimensional accuracy within the surface of an object to be etched.

  In order to solve the conventional problems, the present invention has the following configuration.

  According to the first aspect of the present invention, a coil capable of passing a direct current is provided outside the processing chamber, and the coil is generated inside the processing chamber by the action of a magnetic field generated by the current applied to the coil. Thus, there is provided a dry etching method capable of processing the symmetry of the processed cross-sectional shape of the object to be etched uniformly and with high accuracy within the surface of the object to be etched. be able to.

  The invention according to claim 2 of the present invention is particularly generated in the processing chamber by the action of a magnetic field generated by the current applied to the coil provided with a coil capable of passing a direct current inside the processing chamber. Thus, there is provided a dry etching method capable of processing the symmetry of the processed cross-sectional shape of the object to be etched uniformly and with high accuracy within the surface of the object to be etched. be able to.

  According to the third aspect of the present invention, a coil capable of passing a direct current is provided outside the processing chamber, and the coil is generated inside the processing chamber by the action of a magnetic field generated by the current applied to the coil. It has a configuration that includes a means for deflecting the ions that have been processed, thereby deflecting the ions generated inside the processing chamber, and the symmetry of the processed cross-sectional shape of the object to be etched. It is possible to provide an apparatus capable of processing uniformly and with high accuracy in the plane of the film.

  In the invention according to claim 4 of the present invention, in particular, a coil capable of flowing a direct current is provided inside the processing chamber, and the coil is generated inside the processing chamber by the action of a magnetic field generated by the current applied to the coil. The apparatus has a configuration that includes a means for deflecting ions that are generated, and thus, the structure of the apparatus is simple, and ions generated inside the processing chamber can be easily deflected. It is possible to provide an etching apparatus capable of processing the symmetry of the processed cross-sectional shape uniformly and with high accuracy within the surface of the object to be etched.

  The invention described in claim 5 of the present invention has a configuration in which the means for generating a magnetic field inside the processing chamber has a configuration in which a magnet is arranged in a cylindrical shape around the mounting electrode. Thus, the structure of the apparatus is simpler, ions generated inside the processing chamber can be easily deflected, and the symmetry of the processed cross-sectional shape of the object to be etched can be increased uniformly and within the surface of the object to be etched. An etching apparatus that can be processed with high accuracy can be provided.

  The invention described in claim 6 of the present invention particularly has a configuration in which the means for generating a magnetic field inside the processing chamber has an annular magnet disposed above the mounting electrode, The device structure can be made extremely simple, the ions generated inside the processing chamber can be easily deflected, and the symmetry of the cross-sectional shape of the object to be etched can be processed uniformly and accurately within the surface of the object to be etched. An etching apparatus can be provided.

  In the dry etching method and apparatus of the present invention, a coil capable of flowing a direct current is provided outside the processing chamber, and a magnetic field can be generated by the coil current applied to the coil, or a coil is provided inside the processing chamber. By providing this structure, a magnetic field can be generated. By this, ions in the plasma generated inside the processing chamber are deflected, and the symmetry of the processed cross-sectional shape of the object to be etched is within the surface of the object to be etched (within the wafer). Therefore, it is possible to provide a dry etching method and an apparatus thereof that can be processed with high accuracy in a MEMS device or the like that can be made more uniform and the etching depth becomes deeper.

(Embodiment 1)
Hereinafter, the first and second aspects of the present invention will be described with reference to the drawings, using the first embodiment of the present invention.

  FIG. 1 is a schematic cross-sectional view of a dry etching apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a gas supply device 16 that supplies a gas used for the etching process and an antenna 6 that generates plasma outside the plasma chamber 15 are disposed in a processing chamber 14, and a high-frequency power source 8 is connected via a matching circuit 7. The plasma 17 is generated by being connected and applying high frequency power to the antenna 6.

  Then, vacuum pumps 26 and 27 for exhausting the processing chamber 14 to a predetermined pressure, and an orifice valve 25 for controlling the gas pressure to a predetermined level when gas is supplied are provided inside the processing chamber 14. A mounting electrode 2 for attracting and mounting the object to be etched 1 and a bias power source 13 for applying bias power to the mounting electrode 2 are connected via a matching circuit 12. Further, an electrostatic chuck 3 for mounting the object to be etched 1 on the mounting electrode 2 and an ion flow or electric field distribution around the electrostatic chuck 3 and the object to be etched 1 are controlled. The cooling ring 28 is circulated inside the insulator 5 and the He gas 30 can be introduced directly under the etched body 1 in order to cool the guide ring 4 and the etched body 1 or the mounting electrode 2. It is said.

  A coil 9 is disposed outside the processing chamber 14, and a DC power source 24 is connected to the coil 9. A magnetic field is formed inside the processing chamber 14 by passing a current through the coil 9.

  Next, a dry etching method using this etching apparatus will be described. The object to be etched 1 is placed on the placement electrode 2 inside the processing chamber 14 and is adsorbed thereon.

Next, the orifice valve 25 is fully opened, and the plasma chamber 15 is evacuated to a high vacuum, for example, 10 ⁻³ Pa or less, and then the orifice valve 25 is throttled to supply SF ₆ as an etching gas from the gas supply device 16 into the plasma chamber 15. Introduce gas. In FIG. 1, only one gas supply device is shown, but when a mixed gas is used, there are of course a plurality of gas supply devices. At this time, the orifice valve 25 is controlled so that the gas pressure in the processing chamber 14 becomes 0.5 Pa.

  Next, bias power is applied by the bias power source 13, and high frequency power of 13.56 MHz is applied to the antenna 6 using the high frequency power source 8 to generate plasma in the plasma chamber 15.

  Next, a process of plasma etching the object 1 using the generated plasma will be described with reference to FIGS.

  FIG. 2 is an etching cross-sectional view of the object 1 to be etched when ideal etching is performed, and FIG. 3 is an etching cross-sectional view when etching is performed by a conventional technique.

  In FIG. 1, gas is supplied to the plasma chamber 15 and high frequency power is applied to the antenna 6 to generate plasma. At this time, when the magnetic field is not generated by the coil 9, the plasma diffuses like the plasma direction 18 (the direction in which ions jump out). Here, when the DC power supply 24 is turned on and a current is passed through the coil 9, a magnetic field as shown by the magnetic flux line 21 is formed by the action of the coil 9, and ions existing inside the processing chamber 14 are plasma directed 20 (ion). Is deflected in the direction of By adjusting the intensity of the magnetic field and etching the object 1 to be etched with the plasma directing 18 component and the plasma directing 20 component, it is possible to control the ions to be incident on the etched object 1 perpendicularly. As a result, the etched surface of the object to be etched 1 can be etched in the state shown in FIG.

  On the other hand, if etching is performed by a conventional method in which such a coil 9 is not provided, the shape is processed as shown in FIG. That is, although it can be etched vertically in the central portion, it is etched obliquely in the vicinity of the outer peripheral portion of the wafer, making it difficult to achieve a predetermined dimension.

  As described above, in the first embodiment, the directivity of the plasma directivity 20 is adjusted by adjusting the direction of the ions in the plasma that greatly contributes to the etching from the outside by the DC power supply 24 according to the processing state of the object 1 to be etched. Can be adjusted.

  Next, Example 2 will be described with reference to FIG.

  In the structure of the etching apparatus of the second embodiment, the point that is greatly different from the structure of the etching apparatus shown in FIG. 1 is related to the arrangement of the coil 10, and the other structure is almost the same as in FIG. The contents are omitted.

  In FIG. 4, the coil 10 is disposed on the outer periphery of the mounting electrode 2, and the magnetic field generated by the coil 10 is indicated by magnetic flux lines 22. As described above, by providing the coil 10 capable of allowing a direct current to flow inside the processing chamber 14, the magnetic flux lines 22 can be controlled in the vicinity of the object 1 to be etched, so that the plasma directing 20 can be controlled more precisely. It becomes possible, and the precision of the etching cross-sectional shape of the to-be-etched body 1 can be controlled more precisely.

  The same effect can also be achieved by arranging a cylindrical magnet around the mounting electrode 2 instead of the coil 10. And by setting it as such a structure, the directivity of the plasma directivity 20 can be adjusted according to the processing state of the to-be-etched body 1 for the traveling direction of the ion in the plasma which contributes largely to etching from the outside. In addition, the configuration of the etching apparatus is simpler, and there is an advantage that an etching apparatus having a simple structure can be realized at low cost.

  Next, Example 3 will be described with reference to FIG. In FIG. 3, the magnet 11 is disposed on the placement electrode 2. A magnetic field generated by the magnet 11 is indicated by a magnetic flux line 23. By adopting such a configuration, the effect of the object to be etched 1 on the etching cross-sectional shape is the same as in the first and second embodiments. Here, the configuration in which the magnet 11 is disposed on the mounting electrode 2 is a plasma that greatly contributes to etching from the outside by replacing the magnet 11 in place of the generally used guide ring 4. In addition to the effect that the directivity of the plasma directing 20 can be adjusted in accordance with the processing state of the object 1 to be etched, the conventional apparatus can be used without any modification. This is because there is an effect that it can be mounted very easily at low cost. This is particularly effective when the diffusion state of the plasma directivity 18 is relatively weak.

  Further, in order to improve the etching resistance of the magnet 11, a rubber magnet or the like using an etching resistant material for the gas used for etching is effective.

  The dry etching method and apparatus according to the present invention are provided with a coil capable of passing a direct current outside the processing chamber, and can generate a magnetic field by the coil current applied to the coil, and are generated inside the processing chamber. This has the effect of controlling the deflection of the ions to be processed, making it possible to make the processing step surface shape symmetry of the object to be etched more uniform within the surface of the object to be etched, and is used when manufacturing MEMS devices and semiconductor integrated circuits. It is useful as a dry etching method using plasma and an apparatus thereof.

Schematic sectional view of a dry etching apparatus in Embodiment 1 of the present invention Cross section of ideal etching Normal etching cross section Sectional drawing of the structure which provided the coil inside the processing chamber Sectional drawing of another form which provided the magnet inside the processing chamber Schematic sectional view of a conventional dry etching system

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 To-be-etched body 2 Placement electrode 3 Electrostatic chuck 4 Guide ring 5 Insulator 6 Antenna 7 Matching circuit 8 High frequency power supply 9 Coil 10 Coil 11 Magnet 12 Matching circuit 13 Bias power supply 14 Processing chamber 15 Plasma chamber 16 Gas supply device 17 Plasma DESCRIPTION OF SYMBOLS 18 Plasma orientation 20 Plasma orientation 21 Magnetic flux line 22 Magnetic flux line 23 Magnetic flux line 24 DC power supply 25 Orifice valve 26 Vacuum pump 27 Vacuum pump 28 Refrigerant

Claims (6)

In a dry etching method in which high-frequency power is applied to an antenna and gas introduced into the processing chamber is turned into plasma to perform etching processing, a coil capable of flowing a direct current is provided outside the processing chamber, and current is supplied to the coil. A dry etching method in which etching is performed while controlling deflection of ions generated inside a processing chamber by the action of a magnetic field generated by flowing. In a dry etching method in which high-frequency power is applied to an antenna and gas introduced into the processing chamber is turned into plasma to perform etching processing, a coil capable of flowing a direct current is provided inside the processing chamber, and current is supplied to the coil. A dry etching method in which etching is performed while controlling deflection of ions generated inside a processing chamber by the action of a magnetic field generated by flowing. In a dry etching apparatus that applies high-frequency power to an antenna, converts the processing gas introduced into the processing chamber into plasma, and performs an etching process, a coil that can flow a direct current outside the processing chamber is provided. A dry etching apparatus comprising means for vertically etching an object to be etched by deflecting and controlling ions generated inside the processing chamber by the action of a magnetic field generated by passing a current through the substrate. In a dry etching apparatus that applies high-frequency power to an antenna, converts a processing gas introduced into the processing chamber into plasma, and performs an etching process, a coil that can flow a direct current is provided in the processing chamber. A dry etching apparatus comprising means for vertically etching an object to be etched by deflecting and controlling ions generated inside the processing chamber by the action of a magnetic field generated by passing a current through the substrate. The dry etching apparatus according to claim 4, wherein a cylindrical magnet is disposed around a mounting electrode on which an object to be etched is attracted and mounted as means for generating a magnetic field inside the processing chamber. The dry etching apparatus according to claim 4, wherein an annular magnet is disposed on an upper portion of a mounting electrode on which an object to be etched is mounted by suction as means for generating a magnetic field inside the processing chamber.

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