JP3864612B2 - Method and apparatus for manufacturing microstructure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing method and a manufacturing apparatus for a minute gear and a minute optical component manufactured by an additive manufacturing method, or a microstructure such as a mold for molding these, and in particular, can improve yield and cross-sectional shape accuracy. The present invention relates to a method and an apparatus for manufacturing a microstructure that can be formed.
[0002]
[Prior art]
The additive manufacturing method is rapidly spreading in recent years as a method of modeling a three-dimensional object having a complicated shape designed by a computer with a short delivery time. A three-dimensional object modeled by the additive manufacturing method is used as a model (prototype) of parts of various devices in order to examine the operation and shape of parts. Many of the parts to which this method is applied are relatively large parts of several centimeters or more, but in recent years, this method has also been applied to minute parts formed by precision machining, such as minute gears and minute optical parts. There is a need to do it. For example, Japanese Patent Application Laid-Open No. 10-305488 discloses a conventional microstructure manufacturing method and apparatus that meet such needs.
[0003]
FIG. 8 shows a laminating apparatus according to this conventional microstructure manufacturing method and apparatus. The laminating apparatus 3 includes a vacuum chamber 300 in which a laminating process is performed. A substrate holder 301 on which the substrate 400 is placed and a thin film formed on the substrate 400 are transferred to the inside of the vacuum chamber 300. 302, a mark detection unit 306 such as a microscope that is attached to the stage 302 and detects an alignment mark on the substrate 400, an X-axis table 310 that moves the stage 302 in the x-axis direction, and a stage 302 that moves in the Y-axis direction A Z-axis table 330 that moves the substrate holder 301 in the Z-axis direction, and a θ table 340 that rotates the substrate holder 301 around the Z-axis.
[0004]
9A to 9C show the manufacturing process. As shown in FIG. 2A, the microstructure is manufactured by depositing a thin film 402 of aluminum or the like on a substrate 400 via a release layer 401 such as polyimide by vacuum deposition or the like. As shown in FIGS. 2B and 2C, the thin film 402 is patterned by photolithography to form a plurality of thin films 402a corresponding to each cross-sectional shape of the microstructure at a predetermined pitch. Simultaneously formed at predetermined positions. Next, the substrate (pattern substrate) 400 on which the plurality of thin films 402 a are formed is placed on the substrate holder 301 in the vacuum chamber 300 shown in FIG. 8, and the alignment mark 403 is observed using the mark detection unit 306. Then, positioning is performed by the X-axis table 310, the Y-axis table 320, and the θ table 340 so that the alignment mark 403 reaches the origin position. Next, the stage 302 is determined in advance from the origin position by the X-axis table 310 and the Y-axis table 320 so that the stage 302 is positioned on the first layer of thin film (thin film having the largest diameter in the example in the figure) 402a. Move the distance. After the substrate holder 301 is raised and bonded to the counter substrate (not shown) on the stage 302, the substrate holder 301 is lowered, and the thin film 402a is peeled off from the substrate 400 and transferred to the stage 302 side. When joining the second and subsequent thin films (thin film having the second largest diameter in the example in the figure) 402a, the X-axis table 310 and the Y-axis are set so that the stage 302 is positioned on the second thin film 402a. The stage 302 is moved by a predetermined pitch by the table 320, and the second thin film 402a is similarly transferred onto the first thin film 402a. By repeating this, a plurality of films are formed on the counter substrate as shown in FIG. A microstructure 410 in which the thin film 402a is stacked is formed. According to this manufacturing method, since a plurality of thin films can be formed by using a deposition method such as a sputtering method with good film thickness controllability and excellent film thickness uniformity over the entire substrate, the resolution in the stacking direction is very small. A structure can be manufactured.
[0005]
[Problems to be solved by the invention]
However, according to the conventional microstructure manufacturing method and apparatus, the pattern substrate is warped due to the initial shape of the substrate, the release layer and the internal stress of the thin film, so that the thin film contacts the entire surface of the counter substrate during thin film transfer. This makes it difficult to transfer the thin film onto the counter substrate. Also, if the substrate is warped in a concave shape with respect to the counter substrate, the counter substrate will come in contact with the edge portion of the substrate during thin film transfer, and as a result, the edge portion of the substrate is chipped and particles are generated. Sometimes. Therefore, there is a problem that the yield is lowered.
On the other hand, the initial shape of the substrate and the internal stress of the release layer and thin film are measured in advance, and then the direction and amount of warpage of the substrate when the release layer and thin film are formed on the substrate are obtained, and the obtained warpage Based on the direction and amount of warpage, determine the material and formation conditions of the warpage control layer that relaxes the warpage of the substrate when formed on the substrate, and apply the warpage control layer to the substrate based on the determined material and formation conditions. The present applicant has proposed a manufacturing method of a microstructure that reduces the warpage of the substrate and improves the yield by forming, but according to this method, many steps are required to manufacture the pattern substrate. Thus, there is a problem that the manufacturing time of the pattern substrate increases.
[0006]
Also, according to the conventional microstructure manufacturing method and apparatus, the substrate may move when the thin film and the counter substrate are joined and then separated from each other. In this case, the position of each thin film is shifted, As a result, there exists a problem that cross-sectional shape accuracy falls.
[0007]
Accordingly, an object of the present invention is to provide a method and an apparatus for manufacturing a microstructure capable of improving yield and cross-sectional shape accuracy.
[0008]
[Means for Solving the Problems]
In order to achieve the above-mentioned object, the present invention provides a microstructure in which a plurality of thin films formed on a pattern substrate are pressed onto the counter substrate in a predetermined order to stack the plurality of thin films on the counter substrate. In the method of manufacturing the microstructure for manufacturing the surface, the surface arithmetic on the back surface is formed on a flat surface of 1 μm or less having a surface arithmetic average roughness of 250 nm or less before the plurality of thin films are pressed onto the counter substrate. by adsorbing the patterned substrate in which the average roughness 10nm or less from the back surface side, there is provided a method of manufacturing a microstructure, characterized in that the surface of the patterned substrate to the following flatness 1μm .
[0009]
Further, in order to achieve the above-mentioned object, the present invention is configured by laminating the plurality of thin films on the counter substrate by pressing the plurality of thin films formed on the pattern substrate on the counter substrate in a predetermined order. In the microstructure manufacturing apparatus for manufacturing a structure, the pattern substrate is formed by a plane having a flatness of 1 μm or less and having a surface arithmetic average roughness of 250 nm or less , and the surface arithmetic average roughness of the back surface is 10 nm or less the adsorbed from the back side, there is provided a manufacturing system for a microstructure, characterized in that the surface of the patterned substrate with a flatness setting means for following flatness 1 [mu] m.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a method and apparatus for manufacturing a microstructure according to the present invention will be described in detail with reference to the accompanying drawings.
[0011]
FIG. 1 shows a laminating apparatus according to a first embodiment of the present invention. The laminating apparatus 1 has a vacuum chamber 2, and an xy-θ stage 4 that moves in the x-axis direction, the y-axis direction, and the θ-direction around the z-axis, respectively, inside the vacuum chamber 2, and x- An electrostatic chuck 5 provided on the y-θ stage 4 and attracting and fixing the pattern substrate 3 formed by forming a plurality of thin films on the substrate to the attracting surface 5a by electrostatic force, and a counter substrate 6 on the surface 7a First, the z stage 7 that is formed and moves in the z-axis direction, and the particle beam 8 is irradiated to each of the xy-θ stage 4 side and the z stage 7 side to perform FAB (Fast Atom Beam) processing. The particle beam emitting end 9A and the second particle beam emitting end 9B, the vacuum gauge 10 for detecting the degree of vacuum in the vacuum chamber 2, and the z stage 7 facing the xy-θ stage 4, are provided on the pattern substrate. By detecting the position mark formed in 3 For example a microscope such mark detecting unit for detecting an alignment state of the turn substrate 3 are disposed (not shown). The “FAB treatment” means that, for example, an argon atom beam is accelerated as a particle beam 8 at a voltage of about 1 kV and irradiated on the surface of the material to remove the oxide film, impurities, etc. on the surface of the material, thereby forming a clean surface. The process to do. In this embodiment, the FAB irradiation conditions are changed in the range of an acceleration voltage of 1 to 1.5 kV and an irradiation time of 1 to 10 minutes according to the material to be processed.
[0012]
The xy-θ stage 4 can be used in a vacuum, and an x stage 40 and a y stage 41 that move the pattern substrate 3 in the x-axis direction and the y-axis direction, respectively, and θ that rotates around the z-axis. Stage 42.
[0013]
The z stage 7 is made of metal such as stainless steel or aluminum alloy, for example. The counter substrate 6 has a 10 mm square, and is formed in advance on the surface 7 a of the z stage 7 so that a microstructure formed of a plurality of thin films stacked on the z stage 7 can be easily taken out from the z stage 7. The
[0014]
FIG. 2 shows a control system of the laminating apparatus 1. The laminating apparatus 1 has a control unit 11 that controls the entire apparatus 1, and various information including a program of the control unit 11 (such as movement pitch information of the xy-θ stage 4) is included in the control unit 11. , A vacuum pump 13 that evacuates the vacuum chamber 2, a first FAB processing unit 14A that irradiates the particle beam 8 from the first and second particle beam emitting ends 9A and 9B, and a second one, respectively. FAB processing unit 14B, electrostatic chuck driving unit 17 for applying a predetermined voltage (for example, 500V) to the electrostatic chuck 5, x-axis motor 40a and x-axis position detecting unit 40b constituting the x stage 40, y stage 41, the y-axis motor 41a and the y-axis position detector 41b, the θ motor 42a and the θ position detector 42b that constitute the θ stage 42, the z axis motor 7b and the z axis that constitute the z stage 7.置検 out portion 7c, and the mark detecting unit 18, and the vacuum gauge 10 respectively connected. For example, an encoder, a laser interferometer, a glass scale, or the like can be used for the x-axis position detection unit 40b, the y-axis position detection unit 41b, the θ position detection unit 42b, and the z-axis position detection unit 7c. By using these, sub-μm movement accuracy can be realized.
[0015]
The first and second FAB processing units 14A and 14B apply an acceleration voltage of 1 to 15 kV to the corresponding first and second particle beam emitting ends 9A and 9B.
[0016]
The control unit 11 moves the xy-θ stage 4 on which the pattern substrate 3 is placed at a predetermined pitch based on the program stored in the memory 12 and the movement pitch information of the xy-θ stage 4. Each part of the laminating apparatus 1 is controlled so as to form a microstructure by sequentially laminating and joining the surface 7a of the z stage 7 via the counter substrate 6.
[0017]
FIG. 3 shows the configuration of the electrostatic chuck 5. The electrostatic chuck 5 includes a power source 51 that applies a predetermined voltage (for example, 500 V) between an electrode plate 52 to be described later and the ground, and an electrode plate 52 that is connected to the positive electrode of the power source 51 and is electrostatically made positive. The dielectric plate 53 is integrally provided on the electrode plate 52 and is electrostatically made positive by the electrode plate 52, and is electrostatically made negative by the attracting surface 5a which is the surface of the dielectric plate 53. The patterned substrate 3 is attracted by electrostatic force. It is also possible to reverse the polarity of the power source 51 so that the dielectric plate 53 is electrostatically negative, and the pattern substrate 3 that is electrostatically positive is attracted by electrostatic force.
[0018]
The dielectric plate 53 is configured by forming the surface on which the attracting surface 5a is formed with a flatness of 1 μm or less so that even if the pattern substrate 3 is warped, it is straightened and fixed when adsorbed. It has become. Examples of the material constituting the dielectric plate 53 include a ceramic system made of alumina or the like, and a polymer system made of silicone rubber or the like, but a ceramic system with extremely high planar accuracy is preferable. Further, the adsorption surface 5a has a surface arithmetic average roughness of 250 nm or less, more preferably 50 nm or less, and the pattern substrate 3 is firmly fixed to prevent displacement of the pattern substrate 3 during thin film transfer. ing. For the same reason, the back surface of the pattern substrate 3 has a surface arithmetic average roughness of 10 nm or less, more preferably 1 nm or less.
[0019]
Next, a method for manufacturing a microstructure using the laminating apparatus 1 according to the first embodiment will be described.
[0020]
4 (a) to (c), FIG. 5 (a), (b), FIG. 6 (a), (b), and FIG. 7 show the manufacturing process.
[0021]
(1) Film deposition First, as shown in FIG. 4A, a Si wafer having both surfaces polished is prepared as a substrate 31, and polyimide (Hitachi Chemical Polyimide PIX3400) is applied onto the substrate 31 by a spin coating method. It is applied and baked at a maximum temperature of 350 ° C. to form a release layer 32. At this time, the substrate 31 had a concave shape with the peripheral portion warped by about 30 μm with respect to the central portion due to the stress of the polyimide. The arithmetic average roughness of the back surface of the substrate 31 was 1 nm.
[0022]
Next, as shown in FIG. 4B, an A1 thin film 33 is deposited on the release layer 32 by a sputtering method to a thickness of 0.5 μm. Note that high purity A1 is used as the target, the sputtering pressure is 0.5 Pa, and the temperature of the substrate 31 is room temperature. During film formation, the film thickness is constantly monitored by a crystal oscillator type film thickness meter, and the film formation is terminated when the film thickness reaches 0.5 μm. As a result, the film thickness distribution of the A1 thin film 33 on the substrate 31 was 0.5 ± 0.02 μm or less. In addition, since the stress of the Al thin film 33 was small, the substrate shape was not affected.
[0023]
(2) Patterning Next, as shown in FIG. 4 (c), a photoresist (not shown) is applied to the surface of the substrate 31, and the A1 thin film 33 is etched by a normal photolithography method. The pattern substrate 3 is formed by forming a plurality of pattern thin films 34 by patterning into the cross-sectional shape of the microstructure. A positive type photoresist was used, and the resist was exposed using a photomask (not shown). After the A1 thin film 33 is etched, the photoresist is removed with a stripping solution. When patterning the cross-sectional shape, at the same time, an alignment mark (not shown) for performing relative alignment in the xy plane of the substrate 31 and the z stage 7 is formed at a predetermined position. The substrate shape did not change after patterning.
[0024]
(3) Introduction of the pattern substrate 3 into the vacuum chamber 2 Next, as shown in FIG. 5A, the pattern substrate 3 on which the plurality of pattern thin films 34 are formed is replaced with xy-θ in the vacuum chamber 2. Set and fix to the electrostatic chuck 5 on the stage 4. That is, the electrostatic chuck driving unit 17 is controlled by the control unit 11 and a voltage is applied between the electrode plate 52 of the electrostatic chuck 5 and the ground by the power source 51 to make the dielectric plate 52 electrostatically positive. The pattern substrate 3 electrostatically made negative by the suction surface 5a is sucked and fixed by electrostatic force. In the present embodiment, an alumina dielectric plate 52 having a flatness of the adsorption surface 5a of 1 μm or less and an arithmetic average roughness of 100 nm is used, and the applied voltage of the power source 51 is set to 500V. With this fixing, the amount of warpage of the pattern substrate 3 became 1 μm or less, and the pattern substrate 3 became flat.
[0025]
(4) Alignment adjustment (positioning)
The operator measures the alignment state of the pattern substrate 3, that is, the relative positional relationship between the counter substrate 6 and the pattern substrate 3, by detecting the position mark formed on the pattern substrate 3 while magnifying and observing the pattern substrate 3 with the mark detector 18. The xy-θ stage 4 is adjusted so that the first pattern thin film 34 is positioned directly under the counter substrate 6.
[0026]
(5) When the exhaust operator in the vacuum chamber 2 depresses an exhaust switch (not shown) of the stacking apparatus 1, the control unit 11 controls the vacuum pump 13 based on the detection value of the vacuum gauge 10 to move the interior of the vacuum chamber 2. The vacuum chamber 2 is evacuated to a level of 10 ⁻⁶ Pa and the inside of the vacuum chamber 2 is brought into a high vacuum state or an ultrahigh vacuum state.
[0027]
(6) The FAB processing control unit 11 controls the first and second FAB processing units 14A and 14B to irradiate the surface of the counter substrate 6 with an argon atom beam as the particle beam 8 from the first particle beam emitting end 9B. Then, the surface of the pattern thin film 34 is irradiated with the same argon atom beam as the particle beam 8 from the second particle beam emitting end 9A to perform the FAB process. In this embodiment mode, an argon atom beam is irradiated at a voltage of 1.5 kV and a current of 15 mA for 10 minutes.
[0028]
(7) As shown in FIG. 5 (b), the thin film transfer control unit 11 controls the z axis motor 7b based on the detection signal of the z axis position detection unit 7c to lower the z stage 7, and the first layer The surface of the clean counter substrate 6 is brought into contact with the surface of the pattern thin film 34 and the surface of the first pattern thin film 34 are brought into contact with each other, and a predetermined load (for example, 50 kgf / cm ² ) is applied for a predetermined time (for example, 5 minutes) ) When pressed, the counter substrate 6 and the first pattern thin film 34 are firmly bonded. The bonding strength was evaluated by a tensile test and found to be 50 to 100 MPa.
Next, as shown in FIG. 6 (a), when the z stage 7 is raised and returned to the original position, the first pattern thin film 34 on the pattern substrate 31 and the release layer 32 therebelow are adhered. Since the bonding force between the counter substrate 6 and the first pattern thin film 34 is greater than the force, the first pattern thin film 34 is transferred from the pattern substrate 31 to the counter substrate 6 side. At this time, since the surface roughness of the attracting surface 5a of the electrostatic chuck 5 and the back surface of the pattern substrate 3 was good, the pattern substrate 3 did not move on the electrostatic chuck 5.
[0030]
Next, as shown in FIG. 6B, the control unit 11 sets the xy-θ stage 4 to a predetermined value based on the program stored in the memory 12 and the movement pitch information of the xy-θ stage 4. Move the pitch. As a result, the second pattern thin film 34 is positioned directly below the counter substrate 6.
[0031]
Thereafter, in the same manner as described above, positioning, FAB irradiation, and transfer are performed, so that the second pattern thin film 34 is laminated on the first pattern thin film 34 as shown in FIG. The only difference from the first step is that in the FAB processing step, the second time, the surface of the counter substrate 6 on the z stage 7 is not irradiated with an argon atom beam, but the back surface of the first pattern thin film 34. It is to irradiate and clean the surface (the surface that has been in contact with the substrate 31 through the release layer 32 until then). Thereafter, the miniaturized structure is completed on the counter substrate 6 by repeating the steps of positioning, FAB irradiation, and transfer. Thereafter, the counter substrate 6 is removed to obtain a microstructure.
[0032]
According to the first embodiment described above, the following effects can be obtained.
(1) When the pattern substrate 3 is fixed on the electrostatic chuck 5, the pattern substrate 3 has a flatness of 1 μm or less following the shape of the suction surface 5a having a flatness of 1 μm or less. The pattern thin film 34 can be reliably transferred to the counter substrate 6 in contact. Further, the counter substrate 6 does not come into contact with the edge portion of the pattern substrate 3, and the generation of particles can be prevented. As a result, the yield can be improved.
(2) Since the arithmetic average roughness of the adsorption surface 5a of the electrostatic chuck 5 is 250 nm or less and the arithmetic average roughness of the back surface of the substrate 31 is 10 nm or less, the contact area between the two increases, and the adsorption The pattern substrate 3 can be firmly fixed to the surface 5a. For this reason, when the counter substrate 6 is separated from the pattern substrate 3 during thin film transfer, the pattern substrate 3 can be prevented from moving and being displaced, and as a result, the cross-sectional shape accuracy of the microstructure can be improved. .
[0033]
【The invention's effect】
As described above, according to the microstructure manufacturing method and apparatus of the present invention, before pressing a plurality of thin films onto a counter substrate, a pattern is formed on a plane having a predetermined flatness with a predetermined surface arithmetic average roughness. Since the substrate is adsorbed to make the pattern substrate have a predetermined flatness, the yield and the accuracy of the cross-sectional shape of the microstructure can be improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a stacking apparatus according to a first embodiment of the invention.
FIG. 2 is a block diagram showing a control system of the stacking apparatus according to the first embodiment.
FIG. 3 is an explanatory view showing an electrostatic chuck of the laminating apparatus according to the first embodiment.
FIG. 4 is a sectional view showing a film forming process and a patterning process according to the first embodiment.
FIG. 5 is an explanatory diagram showing a transfer process according to the first embodiment.
FIG. 6 is an explanatory diagram showing a transfer process according to the first embodiment.
FIG. 7 is an explanatory diagram showing a transfer process according to the first embodiment.
FIG. 8 is an explanatory view showing a stacking apparatus according to a conventional microstructure manufacturing method.
FIG. 9 is an explanatory view showing a conventional film forming process and a patterning process.
FIG. 10 is a perspective view showing a microstructure completed by a conventional manufacturing method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Stacking apparatus 2 Vacuum chamber 3 Pattern substrate 4 xy-theta stage 5 Electrostatic chuck 5a Suction surface 6 Opposite substrate 7 z stage 7a Surface of z stage 7b z-axis motor 7c z-axis position detection part 8 Particle beam 9A 1st Particle beam emitting end 9B Second particle beam emitting end 10 Vacuum gauge 11 Control unit 12 Memory 13 Vacuum pump 14A First FAB processing unit 14B Second FAB processing unit 17 Electrostatic chuck driving unit 18 Mark detection unit 31 Substrate 32 the release layer 33 thin film <br/> 34 patterned film 40 x stage 40a x-axis motor 40b x-axis position detector 41 y stage 41a y-axis motor 41b y-axis position detector 42 theta stage 42a theta motor 42b theta position detection Part 51 Power supply 52 Electrode plate 53 Dielectric plate

Claims (6)

In a method for manufacturing a microstructure, a plurality of thin films formed on a pattern substrate are pressed onto a counter substrate in a predetermined order to laminate the plurality of thin films on the counter substrate to manufacture a micro structure.
Prior to press-contacting the plurality of thin films onto the counter substrate, the patterned substrate having a surface arithmetic average roughness of a back surface of 10 μm or less on a flat surface having a flatness of 1 μm or less having a surface arithmetic average roughness of 250 nm or less the adsorbed from the back side, the manufacturing method for a microstructure characterized by the surface of the patterned substrate to the following flatness 1 [mu] m. The adsorption of the pattern substrate to the flat surface is such that a dielectric plate integrated with an electrode plate electrostatically having a predetermined polarity as the flat surface has the predetermined polarity, and the pattern substrate is electrostatically The method for manufacturing a microstructure according to claim 1, wherein the method is performed by setting the polarity opposite to the predetermined polarity. The method for manufacturing a microstructure according to claim 2 , wherein the dielectric plate uses ceramics. In the microstructure manufacturing apparatus for manufacturing a microstructure by stacking the plurality of thin films on the counter substrate by pressing the plurality of thin films formed on the pattern substrate on the counter substrate in a predetermined order,
Formed by the following surface arithmetic mean roughness 1μm or less flatness of a plane having a 250 nm, the patterned substrate was 10nm or less surface arithmetic mean roughness of the rear surface by suction from the back side, of the patterned substrate An apparatus for manufacturing a microstructure, comprising flatness setting means for making the surface flatness of 1 μm or less . It said flatness setting means, chromatic an electrostatically predetermined polarity to the electrodes plate, a dielectric plate before SL having a 1μm following flatness that is a predetermined polarity is integral with the electrode plate 5. The microstructure manufacturing apparatus according to claim 4 , wherein the pattern substrate is electrostatically made to have a polarity opposite to the predetermined polarity and is attracted to the dielectric plate . 6. The microstructure manufacturing apparatus according to claim 5 , wherein the dielectric plate is ceramic.

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