JP2005002432A - Plasma etching system, method of producing matrix used for die for forming optical element using the same, die for forming optical element, method of producing die for forming optical element, method of producing optical element, and optical element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a plasma etching system by which a variance in shape is reduced as much as possible when the shape of a diffraction lens having a prescribed height or more is formed as a multi-wavelength compatible lens, and the diffraction lens with high precision can be formed, to provide a method of producing a matrix used for a die for forming an optical element, to provide a die for forming an optical element, to provide a method of producing an optical element, and to provide an optical element. <P>SOLUTION: The method for producing a matrix used for a die for forming an optical element comprises: a shape working stage where a resist layer arranged on a base material is worked so as to be in a prescribed shape; a plasma generation stage where plasma particles are generated; and a plasma control stage where the value of bias voltage is controlled based on an etching selective ratio as a ratio between the height of the shape of the resist layer formed by the shape working stage and the height of a desired shape formed on the surface of the base material, the bias voltage is applied to the base material so that the plasma particles are made to go straight to the surface of the base material so as to be made incident, and further, the bias voltage is detected to control the bias voltage so as to be made almost fixed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma etching apparatus and a manufacturing method of a mother die used for an optical element molding die using the same, an optical element molding die, a manufacturing method of an optical element molding die, an optical element manufacturing method, and an optical device. In particular, the manufacturing method relates to a method for forming an arbitrary shape on a substrate such as silicon by dry etching.
[0002]
[Prior art]
In recent years, for example, CDs and DVDs are widely used as information recording media, and many optical elements are used in precision instruments such as reading devices that read these recording media. Optical elements used in these devices, such as optical lenses, use glass or resin optical lenses. From the viewpoint of cost reduction and miniaturization, in particular, resin optical lenses are frequently used. Yes. Such resin optical lenses are manufactured by general injection molding.
[0003]
By the way, recently, specifications and performance required for optical elements have been improved. For example, when manufacturing an optical element having a diffractive structure on an optical functional surface, in order to injection-mold the optical element. It is necessary to form a surface for giving such a diffractive structure to the molding die.
[0004]
When forming a pattern such as a diffractive structure on a substrate such as an optical element, not limited to the pattern formation step of a semiconductor element, the substrate with a resist layer having a predetermined pattern formed on one surface A so-called transfer is performed in which the pattern is transferred onto the base material by performing an etching process or the like using an etching apparatus or the like (see, for example, Patent Document 1).
[0005]
[Patent Document 1]
JP 2002-333722 (paragraph [0168], FIG. 1)
[0006]
[Problems to be solved by the invention]
The improvement in the capacity recorded on a recording medium has been remarkable in recent years. In particular, as a next-generation optical disk medium, a large amount of information can be read by using a blue-violet laser light source (oscillation wavelength of 405 nm). Possible recording media are being used.
[0007]
As a matter of course, not only the information recorded on the next generation optical disc using such a blue-violet laser light source but also a lens that can read information recorded on the conventional CD and the current DVD (hereinafter, referred to as “lens”). A multi-wavelength compatible lens).
[0008]
However, since the multi-wavelength compatible lens is required to have a blazed shape having a height of 3 μm or more, for example, about 3.0 μm to 6.0 μm, even if a drawing method using an exposure machine is adopted, a mask required for this is also required. In addition to being enormous and costly, there is a drawback in that it is necessary to perform alignment many times, and the accuracy decreases as the shape becomes complicated.
[0009]
In addition, even when using an electron beam drawing method that can be processed while maintaining pattern accuracy, the height of the blazed shape to be manufactured is usually about 1.5 μm. It was difficult.
[0010]
For example, in the drawing method using an electron beam, it is possible to process a blazed shape with a height of 1.5 μm or more by increasing the acceleration voltage, but this is not only costly but also increases the acceleration voltage. As the blaze becomes deeper, the shape of the bottom of the resist layer is rounded, which makes it difficult to control. That is, when a deep shape is manufactured with an electron beam, means of (1) lengthening the drawing time or (2) increasing the acceleration voltage of the electron beam can be considered. The shape is greatly blunted at the troughs, and the desired high shape cannot be formed.
[0011]
As a method of forming a blazed shape having a height higher than a predetermined level on the substrate, not only the generation of plasma particles for etching the surface of the substrate, but also the provision of a high-frequency power source for application to the substrate is performed. There is an etching method using an inductively coupled plasma etching apparatus in which plasma particles have directivity and etching efficiency is improved. The output from the high frequency power source applied to the substrate may be “power” or “voltage”.
[0012]
However, not only to ensure the height of the blazed shape, but when there is a demand to accurately form the blazed shape, the blazed shape is formed on the substrate surface using a conventional inductively coupled plasma etching apparatus. In this case, since the output of the high-frequency power source set in advance is only controlled to be constant, the self-bias generated between the substrate and the ground due to the type of etching object, the type of process gas, and the chemical reaction accompanying the etching. The voltage fluctuated, and as a result, there was a possibility that the blazed shape might vary although it was fine.
[0013]
The present invention has been made in view of the above circumstances, and an object thereof is, for example, a multi-wavelength compatible lens having a height of 3 μm or more (about 3.0 μm to 6.0 μm), for example, diffraction. A plasma etching apparatus capable of manufacturing a shape of an optical element such as a lens and reducing variations as much as possible when manufacturing such a shape, and an optical element using the plasma etching apparatus An object of the present invention is to provide a manufacturing method of a mother die used for an element molding die, an optical element molding die, a manufacturing method of an optical element molding die, an optical element manufacturing method, and an optical element.
[0014]
[Means for Solving the Problems]
In order to achieve the above object, a plasma etching apparatus according to claim 1 is a plasma etching apparatus comprising a substrate holder for mounting a substrate on which a blazed resist layer is formed, and an etching gas. A first power supply device for supplying power for etching the base material and a ratio between a height of the blaze shape formed on the surface of the resist layer and a height of the blaze shape to be formed on the surface of the base material A second power supply device that applies a bias output based on an etching selection ratio indicating the above to the substrate holder so as to cause the particles into plasma to enter the substrate in a straight line, and to apply the bias output to the substrate. And a control device for controlling the second power supply device so as to keep a constant self-bias voltage generated between the holder and the ground as a result of being applied to the holder.
[0015]
By adopting such a configuration, the control device controls the bias output (high-frequency power output) from the second power supply device so that the fluctuation of the self-bias voltage is detected and the self-bias voltage is kept constant. It is possible to provide a highly accurate optical element in which the thickness of the sheath region generated on the base material is constant and stable etching without variation is applied.
[0016]
According to a second aspect of the present invention, in the plasma etching apparatus of the first aspect, the control device detects the self-bias voltage and is stable over time within a predetermined range. And a bias output (high frequency power output) by the second power supply device is controlled based on a result determined by the determination means.
[0017]
Further, a manufacturing method of a mother die used for the optical element molding die according to the invention of claim 3 includes a shape processing step of processing so that a resist layer formed on a substrate has a predetermined shape, A plasma generation step for generating plasma particles, and an etching selection ratio which is a ratio of a height of a resist layer shape formed by the shape processing step and a height of a desired shape to be formed on the substrate surface. The bias output is applied to the substrate so that the plasma particles are caused to enter the surface in a straight line, and a self-bias voltage generated between the substrate and the ground is applied as a result of applying the bias output to the substrate holder. And a plasma control step of detecting and controlling the self-bias voltage to be constant.
[0018]
Etching using a dry etching apparatus that can separately control chemical etching that is affected by the plasma generation process, such as inductively coupled plasma etching, and physical etching that is affected by the plasma control process, as in this method. Since the process is adopted, there are many parameters, and even under complicated etching conditions, the etching selectivity can be accurately controlled by paying attention only to the self-bias voltage, and the drawing surface can be processed smoothly, etc. Thus, it is possible to manufacture an optical element having a three-dimensional fine shape processing in which the height can be freely controlled based on the point that can be precisely processed.
[0019]
According to a fourth aspect of the present invention, there is provided a manufacturing method of a mother die used for the optical element molding die according to the invention of the third aspect. 5. The optical element according to claim 4, wherein the step includes a drawing step of drawing a predetermined shape on the resist layer by an electron beam and a developing step of developing the predetermined shape drawn by the drawing step. A method of manufacturing a mother die used for a molding die.
[0020]
A manufacturing method of a mother die used for the optical element molding die according to the invention described in claim 5 is the manufacturing method of the mother die used in the optical element molding die according to claim 3 or 4, The plasma generation step and the plasma control step are performed using an inductively coupled plasma etching apparatus.
[0021]
According to a sixth aspect of the present invention, a mother die according to the invention is manufactured by the method of manufacturing a mother die used for the optical element molding die according to any one of the third to fifth aspects.
[0022]
A manufacturing method of a mother die used for an optical element molding die according to the invention of claim 7 is a manufacturing method of a mother die used for the optical element molding die of any of claims 3 to 5. The method includes a transfer step of obtaining an optical element molding die by transferring the shape of the mother die manufactured by the above method.
[0023]
According to an eighth aspect of the present invention, there is provided a manufacturing method of a mother die used for an optical element molding die according to the invention. The shape of the mother die is transferred to the die by electroforming.
[0024]
A method for manufacturing an optical element molding die according to the invention described in claim 9 is the method for manufacturing an optical element according to claim 7 or 8, wherein the surface of the base material subjected to dry etching is It has the process of forming a surface protective film.
[0025]
An optical element molding die according to the invention of claim 10 is manufactured by the method for manufacturing an optical element molding die according to any one of claims 7 to 9.
[0026]
An optical element manufacturing method according to an eleventh aspect of the invention is an optical element molding die manufactured by the optical element molding die manufacturing method according to any one of the seventh to ninth aspects. An optical element is formed by using the optical element.
[0027]
An optical element according to the invention described in claim 12 is manufactured by the optical element molding die described in claim 10.
[0028]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0029]
(Outline of etching process using etching selectivity)
First, the outline of the etching process based on the etching selectivity in the present invention will be described. In the present embodiment, when an etching process is performed on a base material (silicon layer) having a resist layer formed on the surface (upper surface), the target first dimension to be formed on the base material is set. Assuming that a pattern (for example, a groove) to be processed into the resist layer is set as the etching selectivity and the second dimension. That is, the shape of the groove portion of the resist layer is manufactured in advance with a size corresponding to the degree of progress of the etching so that the shape of the groove portion of the substrate after the etching process becomes a specific size shape. Is.
[0030]
The base material having the groove after etching obtained in this way is called a mother die, and a die for optical element molding is manufactured by transferring the shape of this mother die.
[0031]
The structure of the base material in the etching process of the present invention will be described below with reference to FIGS.
[0032]
Specifically, the substrate 12 of the present embodiment is preferably formed of a member such as an optical element or a semiconductor element, for example, and a coating material such as a resist is applied to the surface (upper surface) of the substrate 12 made of silicon or the like. And a resist layer 13 that is spin-coated with a liquid and heat-treated.
[0033]
The resist layer 13 has a resist shape drawn by, for example, an electron beam from an electron beam drawing apparatus or the like. For example, in the example of FIG. 1A, a groove 13a is formed.
[0034]
Here, b represents the thickness of the resist layer from the boundary surface between the resist layer 13 and the substrate 12 to the bottom wall of the groove 13a (groove resist thickness), and the thickness of the resist layer 13 to which etching should proceed (resist etching depth). Is c.
[0035]
When the etching process is performed on the base material 12 having the above configuration, the base material 12 having a configuration as shown in FIG. 1B can be generated.
[0036]
The base material 12 has a groove 12a obtained by etching the resist layer 13 having the groove 13a. Here, the distance from the bottom wall of the groove 12a to the boundary surface (the groove depth of the groove of the silicon (Si) layer) is a.
[0037]
(Manufacture of molds for molding optical elements)
Next, fabrication of a mold for molding an optical element according to an embodiment of the present invention will be described with reference to FIGS. Specifically, a description will be given of the manufacture of a mold for injection-molding an optical element using a base material having a groove portion obtained as described above as a mother mold. 2A to 2F are cross-sectional views illustrating the configuration of the base material of the present embodiment.
[0038]
In the present embodiment, not only the process of processing the substrate by electron beam drawing and etching processes, but also the mother mold and mold for molding optical elements etc. are manufactured by the process of the entire process including those processes. A process for manufacturing an optical element or the like by injection molding based on the mold will be described. The drawing process will be described later.
[0039]
First, as shown in FIG. 2A, the aspherical surface processing of the base material 300 having the curved surface portion 306 on one surface of the base material (silicon material or the like) is performed by machining (cutting process).
[0040]
Next, a treatment on the surface of the resin substrate 300 is performed. Specifically, as shown in FIG. 2B, the base material 300 is positioned, the spinner is rotated while dropping the resist L, spin coating is performed, and baking is performed to obtain a resist layer. .
[0041]
Note that after spin coating, the thickness of the resist layer is measured to evaluate the resist layer (resist film evaluation step).
[0042]
Subsequently, as shown in FIG. 2 (C), the base material 300 is positioned, and the base material 300 is controlled by the X, Y, and Z axes, respectively, and the base material changes in shape three-dimensionally. Similarly to the above-described embodiments, drawing is performed with an electron beam so as to obtain a shape that takes correction calculation into account. Thereby, for example, a diffraction grating structure can be formed in the curved resist layer.
[0043]
Further, as shown in FIG. 2D, the base material 300 is developed (development process). Furthermore, a surface hardening process is performed. Next, a step of evaluating the resist shape is performed by SEM observation or a film thickness measuring instrument (resist shape evaluation step).
[0044]
Then, an etching process is performed by dry etching or the like to obtain a diffraction grating structure 302 on the base material as shown in FIG. Here, as indicated by the dotted line K, it is preferable that the peripheral surface portion is cut out so that only the curved surface portion is formed.
[0045]
Furthermore, the present invention provides a mold for electroforming or releasing a molded article formed by direct pressing by forming a protective film on the surface of the dry-etched substrate so that it is not difficult to remove the mold. Suggest measures to improve the performance.
[0046]
Specifically, the substrate surface is coated with a DLC (Diamond Like Carbon) film or the like. The film thickness is considered to have a protective effect as long as the fine pattern is not destroyed, but as an example, the film thickness may be controlled with a film thickness variation of 100 nm or less and within 5%.
[0047]
As the formulation of the protective film, since the hardness of the substrate (Si) is about Hv280, if the hardness is higher than this (preferably Hv500 or higher), the surface shape maintaining effect is increased.
[0048]
This is because the above-described DLC film has good releasability and has a protective effect because it has a hardness of Hv1500 or more. In addition, since the film can be easily removed by oxygen ashing, repeated film formation can be performed, and the film can be used over and over again, so that significant cost reduction can be achieved.
[0049]
In addition, since silicon nitride has a hardness of about Hv 1600, it is also effective to fluorinate or nitride the base material surface. Specifically, the durability of the surface is increased by fluorinating or nitriding the surface of the base material (Si) to a depth of about several nm to 1 μm, and the same effect as the surface protective film can be obtained.
[0050]
Next, in order to manufacture a mold 330 for the base material 300 having only the curved surface portion provided with the diffraction grating structure 302, as shown in FIG. A process etc. are performed and the process which peels the base material 300 and the metal mold | die 330 is performed as shown in FIG.2 (F).
[0051]
A surface treatment is performed on the mold 330 peeled from the surface-treated substrate (mold surface treatment step). Then, the mold 330 is evaluated. After the evaluation, an optical element is manufactured using the mold 330.
[0052]
In this manner, a mold for injection molding the above-described optical element can be manufactured, and the optical element can be easily manufactured using the mold. It is also possible to directly transfer the shape to a curable resin or the like using the base material performed in the step of FIG. 2D as a stamp.
[0053]
(Resist shape on curved surface)
Next, the resist shape on the curved surface according to the embodiment of the present invention will be described with reference to FIGS. FIGS. 3A to 3C are explanatory diagrams showing this embodiment.
[0054]
In the present embodiment, a case where a desired drawing pattern, for example, a diffraction grating structure is formed on a resist layer on a base material that changes to a three-dimensional shape is disclosed.
[0055]
Specifically, as shown in FIG. 3C, the base material 190 before etching is a diffraction grating made of a base material 192 having a curved surface on one surface and a resist formed on the base material 192. It has a structure 191.
[0056]
More specifically, as shown in FIG. 3A, the substrate has a base material 192 and a resist layer 194 formed on the base material 192. The inclined surface of the blaze 195 of the resist layer 194 has a curved surface. As it goes to the periphery of the part, the inclination angle becomes steep and the pitch width becomes shorter.
[0057]
The base material after etching the base material 190 has a base material 192 on the curved surface portion as shown in FIG. 3B, and a blaze 193 having a diffraction grating structure for each pitch is formed on the base material 192. It is formed.
[0058]
Here, in the present embodiment, when the blaze 195 having the diffraction grating structure on the curved surface portion is formed by electron beam drawing or the like to obtain a resist shape, the blaze 195 is previously set to the second dimension having a predetermined shape. Set and input so that the second dimension is corrected with the above-described correction coefficient as the first dimension, and the dose amount and the like are adjusted and controlled so that the blaze 193 becomes the first dimension. draw. As a result, even if the etching process is performed on the diffraction grating structure on the curved surface under the same conditions, it does not progress more than the target first dimension or does not progress sufficiently. Thereby, for example, when a diffraction grating structure or the like is formed on a base material (for example, an optical element or the like) having a curved surface on one surface, the final structure can be obtained accurately.
[0059]
Hereinafter, the manufacturing method of the mother die used for the optical element molding die in this embodiment and the manufacturing method of the optical element will be described with reference to FIG. First, a resist solution is applied onto a substrate by spin coating and baked to form a resist layer (step, hereinafter “S” 201).
[0060]
Next, a base material is set on the X and YZ stages of the electron beam drawing apparatus (S202).
[0061]
Subsequently, based on the input of the target dimension or the like, electron beam drawing is performed with the corresponding dose amount (S203), and the resist layer after drawing is developed to obtain the resist shape of the substrate (S204).
[0062]
(Plasma etching process)
(Plasma generation process)
After placing the substrate on the susceptor of the inductively coupled plasma etching apparatus, the substrate is fixed by the holding member (S206).
[0063]
Subsequently, the etching conditions are acquired from the table based on the input of the combination of the resist layer constituting the base material and the material of the base material, and setting based on the etching conditions is performed (S207). Next, dry etching is performed to transfer the resist shape to the substrate (S208).
[0064]
(Plasma control process)
Here, in the present embodiment, the shape of the groove portion of the original resist layer is manufactured in advance to the desired shape, and the resist layer and the material of the base material that constitute the base material when this is etched. From these combinations, an etching selectivity is determined, and etching is performed under the etching conditions. At this time, a characteristic table prepared in advance by experiment, a table in which the ratio of the etching progress of both corresponding to the combination of the resist layer and the material of the base material is related, etc., are manufactured. Etching conditions (a high-frequency output value for plasma generation and a high-frequency output value for bias supplied to a high-frequency antenna, a pressure value of a processing gas containing an etching gas in a processing chamber, an etching gas, for example, SF ₆ And O ₂ It is determined whether the etching process is performed based on the mixing ratio), and a desired shape is formed on the substrate by performing the etching process under the etching conditions. That is, by controlling the high-frequency output value so that the self-bias voltage is constant based on the table, the blazed shape having a predetermined height is maintained while maintaining the accuracy of the shape formed in the resist layer. Can be formed into a material. Note that the electron beam drawing conditions (depth of focus, dose) are set as appropriate, and the description thereof is omitted in this embodiment.
[0065]
(About the configuration of the plasma etching system)
Next, a schematic configuration of a plasma etching apparatus for performing a dry (plasma) etching process on a substrate will be described. In the embodiment of the present invention, an inductively coupled plasma processing apparatus capable of generating high density plasma is used.
[0066]
In a typical structure of an inductively coupled plasma processing apparatus, a dielectric wall (window plate) is disposed on the ceiling of an airtight processing chamber, and a radio frequency (RF) antenna is disposed on the dielectric wall. An induction electric field is formed in the processing chamber by the high-frequency antenna, and the processing gas is converted into plasma by the electric field. By using the plasma of the processing gas generated in this way, the substrate disposed in the processing chamber is subjected to processing such as etching.
[0067]
FIG. 5 is a diagram showing the configuration of the inductively coupled plasma etching apparatus according to the present embodiment. This apparatus is used, for example, for forming a blazed shape or the like on a substrate in the production of an optical element.
[0068]
As shown in FIG. 5, the plasma etching apparatus 1 includes an airtight container 20 that is assembled from a casing made of a conductive material such as aluminum. The container 20 is grounded by a ground wire 21. Note that the inner wall surface of the container 20 is anodized by anodization so that contaminants are not generated from the wall surface.
[0069]
The inside of the container 20 is preferably airtightly divided into an upper antenna chamber 24 and a processing chamber 26. The partition structure partitioned upon partitioning is formed by a support portion 34 including a dielectric wall 32 formed by combining segments made of quartz or the like. The lower surface of the support part 34 is formed in a substantially uniform state on a horizontal plane.
[0070]
The lower surface of the support portion 34 is preferably further covered with a dielectric cover (not shown) made of quartz or the like having a smooth lower surface. On the other hand, the upper side of the dielectric wall 32 is made of PTFE (polyethylene). It is preferable to dispose a resin plate (not shown) made of tetrafluoroethylene) or the like.
[0071]
A heater 61 is disposed in the antenna chamber 24 and is connected to a power source 62. The partition structure including the dielectric wall 32 is heated by the heater 61 via the support portion 34, and thereby, by-products are prevented from adhering to the lower surface of the partition structure exposed to the processing chamber 26.
[0072]
The support portion 34 is made of a hollow member made of a conductive material, preferably a metal, for example, an aluminum housing, and is also used as a shower housing for constituting a shower head. The inner and outer surfaces of the housing constituting the support portion 34 are anodized by anodization so that contaminants are not generated from the wall surface. The support / shower housing 34 has a gas flow path formed therein, and a plurality of gas supply holes that communicate with the gas flow path and open to a susceptor 71 described later are formed on the lower surface.
[0073]
A gas supply pipe 51 communicating with a gas flow path in the support portion 34 is disposed in a tubular tube portion 35 connected to the center of the support portion 34. The gas supply pipe 51 penetrates the ceiling of the container 20 and is connected to the processing gas source unit 50 disposed outside the container 20. That is, during the plasma processing, the processing gas is supplied from the processing gas source unit 50 through the gas supply pipe 51 into the support / shower casing 34 and is released into the processing chamber 26 from the gas supply hole on the lower surface thereof. The
[0074]
In the antenna chamber 24, a radio frequency (RF) antenna 31 disposed on the partition structure is disposed so as to face the dielectric wall 32.
[0075]
The antenna 31 is formed of a planar coil antenna whose part on the partition structure forms, for example, a spiral shape. One end of the antenna 31 is led out from substantially the center of the ceiling of the container 20, and is connected to a first power supply device (high frequency power supply) 42 through a matching unit 41. On the other hand, the other end is connected to the container 20 and thereby grounded.
[0076]
During the plasma processing, the first power supply 42 supplies the antenna 31 with a high-frequency voltage for forming an induction electric field. An induction electric field is formed in the processing chamber 26 by the antenna 31, and the processing gas supplied from the supporter / shower casing 34 is converted into plasma by the induction electric field. For this reason, the first power supply device 42 is set so as to supply a high-frequency voltage with an output sufficient to generate plasma.
[0077]
A susceptor 71, which is a mounting table (base material holder) for placing a base material, is disposed in the processing chamber 26 so as to face the high-frequency antenna 31 with the dielectric wall 32 interposed therebetween. The susceptor 71 is made of a conductive material, for example, an aluminum member, and the surface thereof is anodized by anodization so as not to generate contaminants. A holding member 73 for fixing the base material is disposed around the susceptor 71.
[0078]
The susceptor 71 is accommodated in the insulator frame 72 and further supported on a hollow column. The support column penetrates the bottom of the container 20 in an airtight manner and is supported by driving means 74 disposed outside the container 20. That is, the susceptor 71 is driven, for example, in the vertical direction by the driving means 74 when the substrate is loaded / unloaded.
[0079]
The susceptor 71 is connected to a second power supply device 82 that is grounded via a matching unit 81 and a detection device 83 that measures a self-bias voltage, by a power supply rod arranged in a hollow column. During the plasma processing, the second power supply device 82 applies a high frequency power output for bias to the susceptor 71. This bias high-frequency power output is used to effectively attract ions in the plasma excited in the processing chamber 26 to the substrate. Further, the detection device 83 measures the self-bias voltage in real time, and transmits the measurement result to the control device 94. Here, the self-bias voltage is a potential difference generated between the susceptor 71 on which the substrate is placed and the ground during the dry etching process. Further, the high-frequency power output that the second power supply device 82 applies to the susceptor 71 may be “power” or “voltage”. In this embodiment, the output is performed by “power”. .
[0080]
Further, in the susceptor 71, in order to control the temperature of the base material, a temperature adjusting means 75 and a temperature sensor (not shown) including a heating means such as a heater and a refrigerant flow path are disposed. Is connected to a temperature control means 76 for controlling. Pipes and wirings for these mechanisms and members are all led out of the container 20 through hollow columns.
[0081]
A vacuum exhaust mechanism including a vacuum pump and the like is connected to the bottom of the processing chamber 26 through an exhaust pipe 77. The inside of the processing chamber 26 is evacuated by the vacuum exhaust mechanism, and the inside of the processing chamber 26 is set and maintained in a vacuum atmosphere and a predetermined pressure atmosphere during the plasma processing.
[0082]
On the other hand, the control means 94 is also connected to the first power supply 42 for generating plasma that outputs a plasma generation voltage having a frequency relatively higher than the self-bias voltage. The supply of voltage is controlled. The control means 94 includes a display means 93 for displaying various setting input values, an operation input means 92 for performing operation inputs, and a storage means 91 for storing various tables, various control programs, setting information, and the like. Is connected. Information including the correction coefficient set and calculated in the electron beam drawing apparatus by connecting the control means 94 and the control circuit of the electron beam drawing apparatus to the network via various communication means. Is preferably stored in the storage means 91 so that it can be used for control.
[0083]
As described above, the control means 94 in the present embodiment controls not only the first power supply device 42 but also the second power supply device 82 that applies the high-frequency power output to the susceptor 71, and in particular, the second power supply device. As for the control of 82, the measurement result transmitted from the detection device 83 provided between the susceptor 71 and the second power supply device 82 is based on the set value of the high-frequency power output input in advance by the operation input means 92. And is controlled by the control device 94.
[0084]
That is, the present invention applies a high-frequency power output to the base material in order to assist the incidence straightness of the plasma particles on the surface of the base material, and monitors the self-bias voltage generated thereby in real time. The second power supply device 82 is controlled so that the voltage (self-bias voltage) is stabilized within a predetermined range.
[0085]
Then, as a specific configuration, the control means 94 in the present embodiment monitors the actual self-bias voltage value by the detection device 83 over time, and controls the second power supply device 82 so as to be constant. Therefore, the second power supply device 82 should calculate the difference (deviation) from the self-bias voltage value over time, compare the deviation amount, and compare the signal given from the storage device 91 and output it. Comparison / calculation means (not shown) for calculating a value corresponding to the output value, and a control signal for controlling the second power supply device 82 based on the value obtained thereby is converted into the second control signal. It is desirable that a control unit (not shown) for sending to the power supply apparatus and a storage means 91 are provided. The storage unit 91 not only stores the calculation result and the control signal calculated by the comparison / calculation unit, but also enables accurate and fine adjustment by feeding back the latest stored data to the calculation result. .
[0086]
Next, an operation of performing a plasma etching process on the substrate using the inductively coupled plasma etching apparatus of FIG. 5 will be described with reference to FIG.
[0087]
First, as a starting operation of the plasma etching process, after the base material is placed on the placement surface of the susceptor 71 by the conveying means through the gate valve 22, the base material is fixed to the susceptor 71 by the holding member 73. Next, various conditions are set according to the substrate to be processed using the operation input means 92 (S301). Then, based on the set contents, an etching gas (for example, SF) is supplied from the gas supply source 50 into the processing chamber 26. ₆ And O ₂ And the processing chamber 26 is maintained in a predetermined pressure atmosphere by evacuating the processing chamber 26 through the exhaust pipe 77.
[0088]
Next, the control means 94 instructs the first power supply device 42 to apply a predetermined high-frequency voltage based on the set contents to the antenna 31 (S302), so that the processing chamber 26 is passed through the partition wall structure. A uniform induction electric field is formed inside. Due to the induction electric field, the processing gas is in a plasma state in the processing chamber 26, and high-density inductively coupled plasma is generated.
[0089]
Similarly, the control means 94 instructs the second power supply device 82 to apply a predetermined high-frequency voltage based on the set contents to the antenna 31 (S303). As a result, a predetermined high-frequency power output is applied from the second power supply device 82 to the susceptor 71, and ions in the generated plasma are effectively drawn into the base material, and a desired etching process is performed on the base material. Is given.
[0090]
Further, the high-frequency power output applied to the susceptor 71 in this way is always measured by the detection device 83 (S304). The detection device 83 has a function of referring to the setting contents, that is, a function of referring to information stored in the storage unit 91. Therefore, when the self-bias voltage value measured in the plasma etching process being performed has an error exceeding the allowable range with respect to the previous (or immediately preceding) self-bias value (S305-Yes), The high frequency power supply output from the second power supply device 82 is set so that the self-bias voltage value of the second power supply device 82 becomes substantially the same as the self-bias voltage value before (or immediately before), that is, the self-bias value is stabilized. The control means 94 controls (S306). When the measured self-bias voltage value is within an allowable range with respect to the previous (or immediately preceding) self-bias value (S305-No), the high-frequency power supply to the susceptor 71 by the second power supply device 82. When the output application is continued (S307-Yes) and a preset etching process time has elapsed (when a desired etching shape is formed), it is not necessary to apply a high-frequency power output to the susceptor 71 (S307-No). ) The plasma etching process is terminated.
[0091]
Here, the self-bias voltage is controlled by alternately repeating the on-cycle in which the high-frequency power output is applied and the off-cycle in which the high-frequency power output is not applied, and controlling the duty (on cycle time / (on cycle time + off cycle time)). There is also a way to do it. At this time, the detection device detects only the peak when ON. Thereby, for example, the ratio (the etched amount of the base material / the etched amount of the resist layer) at a specific location of the base material can be controlled. Note that in order to generate the on / off cycle of the self-bias voltage, a special pulse power supply may be used, or the power on / off may be controlled by software.
[0092]
In this way, the shape drawn on the resist layer can be appropriately transferred to the desired shape on the substrate. Further, the etching selectivity is not limited to the ratio of the etching rate between the resist layer and the base material or the ratio of the depth to be etched, and is specified by the material of the resist layer and the base material. It is preferable.
[0093]
Further, the first dimension corresponds to a dimension of a target shape to be formed on the substrate, and the second dimension is a dimension obtained by multiplying the first dimension by the etching selectivity. . Furthermore, the second dimension is a depth of the resist layer processed by the shape processing step, and the first dimension is a depth in the shape of the matrix.
[0094]
(Shaping process)
(Electron beam drawing)
Here, in the present embodiment, the shape of the first dimension (for example, the groove depth of the groove 12a is a and the groove width is d) shown in FIG. 1B is formed on the substrate 12 by etching. Assuming this, the etching selectivity is set in advance. Then, based on the etching selection ratio, the second dimension of the shape shown in FIG. 1A (for example, the groove depth of the groove 13a is cb and the groove width is d) is the second dimension. The resist layer 13 is processed with the dimensions.
[0095]
Here, it is preferable to employ a drawing process using an electron beam drawing apparatus for this process.
[0096]
The “etching selection ratio” is an etching rate ratio when the base material 12 and the resist layer 13 are etched, and the value varies depending on the etching technique and the material of the base material 12 and the resist layer 13. It is desirable that the etching selection ratio is tabulated in advance and stored in the storage unit 91 for each of various conditions.
[0097]
That is, when the base material 12 and the resist layer 13 are formed of other various materials, a table of the above characteristics is stored in the storage means 91, and the combination of the material of the base material 12 and the resist layer 13 is set. Thus, the table used for the calculation may be selected. Here, as a material used for the resist layer, that is, the electron beam resist, for example, in addition to PMMA (polymethyl methacrylate), styrenic and acrylic organic polymer materials, and silica-based inorganic materials. The base material 12 may be a resin such as a polyolefin. Furthermore, when the base material 12 is silicon, it is preferable to form the first conductive type impurity member such as n-type silicon. This is because it is easy to apply optical film thickness evaluation after resist coating.
[0098]
In this manner, the electron beam drawing apparatus performs drawing so as to have the second dimension, thereby obtaining a resist shape that is the resist layer 13 having the groove 13a having the groove depth of the second dimension. be able to.
[0099]
When the plasma etching process based on the etching selectivity is performed on the base material 10 having the resist shape thus obtained by, for example, an inductively coupled plasma etching apparatus, as shown in FIG. The base material 14 is obtained. And the groove depth of the groove part 12a of the base material 12 of this base material 14 can be made into desired length.
[0100]
After the base material is dry-etched, a hard and surface-protective layer is formed on the surface of the base material such as a DLC (diamond-like carbon) layer or a WC layer. After forming such a layer, by forming an electroforming mold by forming a conductive film, the mold releasability is improved and the base material (matrix) can be used repeatedly. . The same effect as described above can be obtained when a substrate on which a layer having releasability and a layer having a surface protecting effect are directly used as a mold for an optical lens. Further, the same effect as described above can be obtained when the surface of the substrate is subjected to a treatment such as fluorination.
[0101]
FIG. 7A is a graph showing the relationship between the output of the conventional second power supply device and the self-bias voltage, and FIG. 7B shows the high-frequency power output of the second power supply device according to this embodiment. It is a graph which shows the relationship with a self-bias voltage.
[0102]
As shown in FIG. 7A, the high-frequency power output applied to the susceptor 71 (vertical axis in FIG. 7A) is set to a predetermined value (indicated by a circle) and output to the second power supply device 82. In this case, the relationship is stored in the storage means 91 as a table, and the second power supply 82 applies a predetermined high-frequency power output to the susceptor 71 with reference to the table, but the desired high-frequency power output is applied to the susceptor 71. Although the power value required to be applied to (a horizontal axis in FIG. 7A) is constant, the self-bias voltage varies. That is, FIG. 7A shows that the supplied power is constant, but the susceptor 71 fluctuates due to a current flowing due to a chemical reaction or the like of the etching process.
[0103]
On the other hand, the self-bias voltage change caused by the material to be etched, the type of etching gas, and the chemical reaction in the etching process is constantly monitored, and the power supply output value of the second power supply device 82 (specifically, the voltage value in detail) 7), the self-bias voltage value is kept substantially constant and variation in the self-bias voltage value is reduced, as shown in FIG. 7B. In this case, the power of the second power source 82 fluctuates in the horizontal axis direction because the self-bias voltage is made constant by controlling the high-frequency power source output.
[0104]
(About the configuration of the electron beam lithography system)
Next, an overall schematic configuration of the electron beam lithography apparatus itself, which is a precondition for achieving the function of forming the resist shape necessary for obtaining the desired groove depth shape as described above, will be described with reference to FIG. Will be described with reference to FIG. FIG. 8 is a diagram showing a schematic configuration of the electron beam drawing apparatus according to the present embodiment.
[0105]
As shown in FIG. 8, the electron beam drawing apparatus 1001 of the present embodiment forms a high-resolution electron beam probe with a large current to quickly draw a substrate 1002 (corresponding to the substrate 10 shown in FIG. 1). Scanning the top and drawing the resist layer on the substrate in three dimensions, forming a high resolution electron beam probe, generating an electron beam and irradiating the target with the beam An electron gun 1012 which is an electron beam generating means to be performed, a slit 1014 through which the electron beam from the electron gun 1012 passes, and an electron lens 1016 for controlling the focal position of the electron beam passing through the slit 1014 with respect to the substrate 2 An aperture 1018 disposed on the path from which the electron beam is emitted, a scanning position on the base material 1002 that is a target by deflecting the electron beam, and the like The deflector 1020 which controls, is configured to include a correction coil 1022 to correct the deflection, the. These parts are disposed in the lens barrel 1010 and maintained in a vacuum state when the electron beam is emitted.
[0106]
Furthermore, the electron beam drawing apparatus 1001 transports the base material 2 to the X, YZ stage 1030 which is a mounting table for mounting the base material 1002 to be drawn, and the mounting position on the X, YZ stage 1030. A loader 1040 that is a conveying means for measuring, a measuring device 1080 that is a measuring means for measuring the reference point of the surface of the base material 1002 on the X and YZ stage 1030, and an X and YZ stage 1030 for driving A stage driving unit 1050 as a driving unit, a loader driving device 1060 for driving the loader, and a vacuum exhausting apparatus that exhausts the interior of the lens barrel 1010 and the housing 1011 including the X and YZ stages 1030 so as to be evacuated. 1070 and a control circuit 1100 which is a control means for controlling these operations.
[0107]
The electronic lens 1016 is controlled by generating a plurality of electronic lenses according to the current values of the coils 1017a, 1017b, and 1017c, which are installed separately at a plurality of locations along the height direction. The focal position of the electron beam is controlled.
[0108]
The measuring apparatus 1080 includes a first laser length measuring device 1082 that measures the base material 1002 by irradiating the base material 1002 with a laser, and a laser beam (first light emitted by the first laser length measuring device 1082). The first laser light measurement unit 1084 reflects the base material 1002 and receives the reflected light, and the second laser length measurement is performed at a different irradiation angle from the first laser length measuring device 1082. And a second light receiving unit 1088 that receives the reflected light when the laser light (second irradiation light) emitted by the second laser length measuring device 1086 reflects off the base material 2. It consists of
[0109]
The stage driving means 1050 includes an X direction driving mechanism 1052 that drives the X and YZ stages 1030 in the X direction, a Y direction driving mechanism 1054 that drives the X and YZ stages 1030 in the Y direction, and the X and YZ stages 1030 in the Z direction. A Z-direction drive mechanism 56 that drives the X and YZ stages 1030 in the θ direction around the Z axis. In addition, an α direction drive mechanism that can be rotationally driven in the α direction around the Y axis, and a β direction drive mechanism that can be rotationally driven in the β direction around the X axis are provided to pitch, yaw, You may comprise so that rolling is possible. As a result, the X and YZ stages 1030 can be operated three-dimensionally and alignment can be performed.
[0110]
The control circuit 1100 includes an electron gun power supply unit 1102 for supplying power to the electron gun 1012, an electron gun control unit 1104 for adjusting and controlling current and voltage in the electron gun power supply unit 1102, and electron lenses 1016 (multiple A lens power supply unit 1106 for operating each of the electronic lenses), and a lens control unit 1108 for adjusting and controlling each current corresponding to each electronic lens in the lens power supply unit 1106. The
[0111]
Further, the control circuit 1100 includes a coil control unit 1110 for controlling the correction coil 1022, a shaping deflection unit 1112a for deflecting in the shaping direction by the deflector 1020, and a deflection in the sub-scanning direction by the deflector 1020. A sub-deflector 1112b for performing, a main deflector 1112c for deflecting in the main scanning direction by the deflector 20, and a high-speed D / D that converts and controls a digital signal to an analog signal to control the shaping deflector 1112a. A converter 1114a, a high-speed D / A converter 1114b that controls the conversion of a digital signal into an analog signal to control the sub-deflection unit 1112b, and a digital signal that is converted into an analog signal to control the main deflection unit 1112c And a high-precision D / A converter 1114c.
[0112]
Further, the control circuit 1100 corrects a position error in the deflector 1020, that is, supplies a position error correction signal or the like to each of the high-speed D / A converters 1114a and 1114b and the high-precision D / A converter 1114c. The position error correction circuit 1116 for correcting the position error by the correction coil 1022 by prompting the position error correction or supplying the signal to the coil control unit 1110, the position error correction circuit 1116, and each high-speed D / D An electric field control circuit 1118 which is an electric field control means for controlling the A converters 1114a and 1114b and the high-precision D / A converter 1114c to control the electric field of the electron beam, and a drawing pattern and the like are generated for the substrate 1002. And a pattern generation circuit 1120 for this purpose.
[0113]
Still further, the control circuit 1100 includes a first laser drive control circuit 1130 that controls the movement of the laser irradiation position and the angle of the laser irradiation angle by moving the first laser length measuring device 1082 up and down and left and right. A second laser drive control circuit 1132 for controlling the movement of the laser irradiation position and the angle of the laser irradiation angle by moving the second laser length measuring instrument 1086 up and down, left and right, and the first laser length measurement. The first laser output control circuit 1134 for adjusting and controlling the output (laser light intensity) of the laser irradiation light in the device 1082 and the output of the laser irradiation light in the second laser length measuring device 1086 are adjusted and controlled. A first laser output control circuit for calculating a measurement result based on the second laser output control circuit 1136 for receiving the light received by the first light receiving unit 1084 Configured a measurement calculation unit 1140, based on a light reception result of the second light receiving portion 1088, a second measurement calculation unit 1142 for calculating the measurement results, include.
[0114]
Furthermore, the control circuit 1100 includes a stage control circuit 1150 for controlling the stage driving means 1050, a loader control circuit 1152 for controlling the loader driving device 1060, and the first and second laser driving circuits 1130, 1132 described above. First and second laser output control circuits 1134 and 1136 First and second measurement calculation units 1140 and 1142 A stage control circuit 1150 A mechanism control circuit 1154 for controlling the loader control circuit 1152 and a vacuum exhaust apparatus 1070 An evacuation control circuit 1156 for controlling the evacuation of the gas, a measurement information input unit 1158 for inputting measurement information, a memory 1160 which is a storage means for storing inputted information and other plural information, A program memory 1162 storing a control program for performing various controls, and each of these And it is configured with a control unit 1170 which is formed by a CPU for example controls the, include.
[0115]
In the electron beam drawing apparatus 1001 having the above-described configuration, when the base material 1002 conveyed by the loader 1040 is placed on the X, YZ stage 1030, the inside of the lens barrel 1010 and the housing 1011 is evacuated by the vacuum exhaust device 1070. After the air and dust are exhausted, an electron beam is irradiated from the electron gun 1012.
[0116]
The electron beam emitted from the electron gun 1012 is deflected by the deflector 1020 via the electron lens 1016 and is deflected by the deflector 1020 (hereinafter, only with respect to the deflection-controlled electron beam after passing through the electron lens 1016). “Electron beam B” may be given a symbol), and drawing is performed by irradiating the drawing position on the surface of the base material 1002 on the X, YZ stage 1030, for example, a curved surface (curved surface). .
[0117]
At this time, the drawing position (at least the height position of the drawing positions) on the base material 1002 or the position of the reference point is measured by the measuring device 1080, and the control circuit 1100 determines the electronic lens 1016 based on the measurement result. The position of the focal depth of the electron beam B, that is, the focal position is controlled by adjusting and controlling each current value flowing through the coils 1017a, 1017b, 1017c, etc., and the movement is controlled so that the focal position becomes the drawing position. The
[0118]
Alternatively, based on the measurement result, the control circuit 1100 controls the stage driving unit 1050 to move the X and YZ stage 1030 so that the focal position of the electron beam B becomes the drawing position.
[0119]
In the present embodiment, either one of the control of the electron beam and the control of the X and YZ stages 1030 may be performed, or both may be used.
[0120]
Next, the measuring apparatus 1080 includes a first laser length measuring device 1082, a first light receiving portion 1084, a second laser length measuring device 1086, a second light receiving portion 1088, and the like.
[0121]
The first laser length measuring device 1082 irradiates the base material 1002 with the first light beam S1 from the direction intersecting the electron beam, and receives the first light beam S1 that passes through the base material 1002. Is detected.
[0122]
At this time, since the first light beam S1 is reflected at the bottom of the base material 1002, the (height) position on the flat portion of the base material 1002 is measured and calculated based on the first intensity distribution. It will be. However, in this case, the (height) position on the curved surface portion of the substrate 1002 cannot be measured.
[0123]
Therefore, in this embodiment, a second laser length measuring device 1086 is further provided. That is, the second laser length measuring instrument 1086 irradiates the base material 1002 with the second light beam S2 from a direction substantially orthogonal to the electron beam different from the first light beam S1, and transmits the base material 1002. The second light intensity distribution is detected by receiving the second light beam S2 through the pinhole included in the second light receiving unit 1088.
[0124]
In this case, the (height) position on the curved surface portion of the substrate can be measured and calculated based on the second intensity distribution. Then, using the height position of the base material as a drawing position, for example, the focal position of the electron beam is adjusted and drawing is performed.
[0125]
In the present embodiment, a processing program for performing various arithmetic processes, measurement processes, control processes, and the like as described above is stored in advance in a program memory (not shown) as a control program.
[0126]
As described above, the apparatus and method according to the present invention have been described according to some specific embodiments thereof, but those skilled in the art described the present invention without departing from the spirit and scope of the present invention. Various modifications can be made to the embodiment.
[0127]
For example, in each of the above-described embodiments, the surface of the base material is configured to be a flat surface or a convex curved surface. However, the present invention is not limited thereto, and may be, for example, a concave curved surface.
[0128]
In each of the above-described embodiments, the second dimension is calculated from the first dimension on the target substrate after the etching process by the etching selection ratio, and the electron beam lithography apparatus is previously set to the second dimension. By forming, it was set as the structure which obtains the desired shape of a 1st dimension after an etching. That is, the characteristics depending on the type of substrate are tabulated and stored in the storage means 91, and the high frequency power supply output of the inductively coupled plasma etching apparatus is controlled based on the etching selectivity so that the self-bias voltage is constant. Although a desired shape is obtained for the material, the present invention is not limited to this.
[0129]
In the above-described embodiment, the inductively coupled etching apparatus has been described as an example. However, the example of the apparatus is not limited to such a configuration. A plasma etching apparatus equipped with a plasma source such as a flat plate type plasma etching apparatus or a microwave type etching apparatus may be used.
[0130]
Further, in each of the above-described embodiments, the etching apparatus has been described as an example. However, another inductively coupled plasma processing apparatus having functions such as a film forming apparatus and an ashing apparatus may be used. . Further, the substrate is not limited to an optical element such as an optical lens and a semiconductor element, but the table may be mounted on an apparatus for processing an LCD glass substrate or a semiconductor wafer.
[0131]
Moreover, although the case where the base material which comprises a resist layer and a silicon layer as a resist layer was etched was demonstrated, when any layer of the base material which comprises multiple layers is etched, a base material and another layer structure The present invention can also be applied to a case where a substrate containing the material is etched.
[0132]
Furthermore, in each of the above-described embodiments, the optical lens such as an optical element is made of a resin material, and this is manufactured by injection molding. It is good also as a structure by which this is comprised with a glass material and this is manufactured with a mold.
[0133]
Therefore, in the above-described embodiment, a case has been described in which a mold for molding an optical lens such as an optical element is manufactured, and an optical lens is manufactured by injection molding based on this mold, but the present invention is not limited thereto. For example, an optical lens made of a glass material can be directly molded by transferring the shape of the optical lens after the etching process to a glass substrate, or a resin material or a glass material by injection molding or molding based on this glass mold. It is good also as a structure which manufactures the optical lens which consists of these.
[0134]
In addition, in the category of the idea of the present invention, those skilled in the art can conceive various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. .
[0135]
Furthermore, the above embodiment includes various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. That is, it goes without saying that examples include combinations of the above-described embodiments or any one of them and any of the respective modifications. In this case, even if not specifically described in the present embodiment, the operational effects obvious from the respective configurations disclosed in the respective embodiments and modifications can of course be exhibited in the present example as well. . Moreover, the structure by which some structural requirements were deleted from all the structural requirements shown by embodiment may be sufficient.
[0136]
The above description discloses only one example of the embodiment of the present invention, and can be appropriately modified and / or changed within a predetermined range. However, each embodiment is illustrative. , Not limiting.
[0137]
【The invention's effect】
As described above, according to the present invention, after fine drawing by an electron beam is performed on a resist layer, the inductively coupled plasma etching apparatus performs etching while maintaining the shape drawn on the resist layer. Since the plasma particles are appropriately guided with respect to the surface of the base material, it is possible to form an undulating three-dimensional optical element (particularly about 1 μm to 10 μm) that has been difficult to realize so far.
[0138]
Further, since the control device controls the second power supply device so that the self-bias voltage fluctuation is detected and the self-bias voltage is kept constant, the thickness of the sheath region generated on the substrate is constant. Thus, stable etching without variation is possible, and an appropriate optical element can be provided.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing the shape of a substrate to be etched by an etching apparatus according to the present invention.
FIG. 2 is an explanatory view showing an outline of a manufacturing process of a substrate in the present invention.
FIG. 3 is a cross-sectional view showing an embodiment showing the shape of a substrate to be etched by the etching apparatus according to the present invention.
FIG. 4 is a flowchart showing a processing procedure for manufacturing a substrate.
FIG. 5 is a block diagram showing an example of an embodiment of an etching apparatus according to the present invention.
FIG. 6 is a flowchart for explaining a plasma etching method in the present embodiment.
FIG. 7 is a graph showing the relationship between the output of the second power supply device and the self-bias voltage in the conventional and this embodiment.
FIG. 8 is a functional block diagram showing an example of the configuration of an electron beam drawing apparatus.
[Explanation of symbols]
1 Plasma etching equipment
12 Base material
12a Groove
13 resist layer
13a Groove
1001 Electron beam drawing apparatus

Claims (12)

A substrate holder for mounting a substrate on which a blazed resist layer is formed on the surface;
A first power supply device for etching the substrate by supplying electric power for turning the etching gas into plasma;
A bias output based on an etching selection ratio indicating a ratio between the height of the blaze shape formed on the surface of the resist layer and the height of the blaze shape to be formed on the surface of the base material is applied to the base material holder, and plasma is applied. A second power supply device for causing the particles to be incident on the base material while allowing the particles to enter the substrate.
A plasma etching apparatus comprising: a control device that controls the second power supply device so that a self-bias voltage generated between the bias output and the ground as a result of applying the bias output to the substrate holder is kept constant. . The control device includes a determination unit that detects the self-bias voltage and determines whether the self-bias voltage is stable over time within a predetermined range, and the second control unit is configured to determine whether the second bias is based on a result determined by the determination unit. The plasma etching apparatus according to claim 1, wherein the power supply device is controlled so that the bias voltage becomes constant. A shape processing step for processing the resist layer formed on the base material into a predetermined shape;
A plasma generation process for generating plasma particles;
Based on the etching selectivity, which is the ratio of the height of the resist layer shape formed by the shape processing step and the height of the desired shape to be formed on the substrate surface, the plasma particles are caused to travel straight with respect to the surface of the substrate. A bias output is applied to the substrate so as to be incident, and a self-bias voltage generated between the bias output and the ground as a result of applying the bias output to the substrate holder is detected, so that the self-bias voltage becomes constant. A method for producing a mother die used in an optical element molding die, comprising: a plasma control step for controlling the optical element. 5. The shape processing step includes a drawing step of drawing a predetermined shape on the resist layer by an electron beam and a developing step of developing the predetermined shape drawn by the drawing step. A method for producing a mother die used in the optical element molding die. 6. The method of manufacturing a mother die used for an optical element molding die according to claim 4, wherein the plasma generation step and the plasma control step are performed using an inductively coupled plasma etching apparatus. A mother die produced by the method for producing a mother die used for the optical element molding die according to any one of claims 4 to 6. 7. A method of manufacturing an optical element molding die based on a shape of a mother die, wherein the mother die is manufactured by a manufacturing method of a mother die used for an optical element molding die according to claim 4. A method for producing an optical element molding die, comprising a transfer step of obtaining an optical element molding die by transferring the shape of the optical element. 9. The method of manufacturing an optical element molding die according to claim 8, wherein in the transfer step, the shape of the mother die is transferred to the die by electroforming. 10. The method for producing a mold for molding an optical element according to claim 8, further comprising a step of forming a surface protective film on the surface of the substrate that has been dry-etched. An optical element molding die manufactured by the method for manufacturing an optical element molding die according to any one of claims 8 to 10. 11. An optical element manufacturing method, wherein an optical element is molded using the optical element molding mold manufactured by the optical element molding mold manufacturing method according to claim 8. An optical element manufactured by the optical element molding die according to claim 11.

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