JP2009151257A - Inclined exposure lithography system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inclined exposure lithography system capable of obtaining a required solid inclination pattern for a photoresist layer. <P>SOLUTION: This inclined exposure lithography system includes mainly a base material, a photoresist layer, a photomask, and a polarization part. The photoresist layer is placed on the base material, the photomask is placed on the photoresist layer, and an interval is provided to a space to the photoresist layer. The polarization part is placed on the photomask, and refractively emits a ray emitted from a light source, and generates the deviation of a specific angle. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a tilt exposure lithographic system. In particular, the present invention relates to a tilt exposure lithographic system that uses a polarizing component to change the direction of incident light and to perform a tilt exposure manufacturing process that corresponds to diffraction.

  The lithographic technology plays a very important role in the micromachine manufacturing process and the semiconductor manufacturing process. In the known lithographic manufacturing process, the light beam is simultaneously vertical in the photomask and the photosensitive polymer material, and is a planar (2D) or 2.5 dimensional (2.5D) structure pattern depending on the photomask pattern and size. With nano-scale structure size and precision manufacturing capability.

  However, in order to realize a 3D structure, this technology needs to support special photomasks (grayscale photomasks, etc.), distribute the light beam intensity, perform exposure lithography, and three-dimensionalize the photosensitive polymer material. is there. Alternatively, it is necessary to carry out a post-treatment (such as a heat flow method) and heat-dissolve the 2.5D photosensitive polymer material by surface tension to form a semi-spherical shape, or to manufacture by a non-isotropic etching method using a special lattice surface. . In these techniques, it is difficult to control the slope roughness and the slope angle of the former both, the cost is high, and only one or two special tilt angles can be obtained by the non-isotropic etching method.

  Traditional ultra-precision machining uses a specific diamond cutter angle to cut the substrate being processed, achieving nano-level machining accuracy and controlling the structure forming angle. However, since it belongs to a top-down cutting process, it is difficult to control the absolute height of the substrate surface and the structure vertex. At the same time, there are problems such as base material processing (such as electroless plating metallized surface treatment), processing time, processing waste, and cost required for larger area processing.

  Patent Document 1 shows a microstructure having 2.5D and a manufacturing method thereof. As shown in FIG. 1, first, a light transmission substrate 11 having a surface 111 is provided. In addition, the surface 111 includes a light-impermeable area 112 and a lens 113. The lens 113 produces an effect of focusing after passing the light beam. Subsequently, a photoresist layer 12 is formed on the surface 111. When the light source 13 passes through the light transmitting substrate 11 and irradiates the photoresist layer 12, the light beam is focused after passing through the lens 113. Therefore, by removing a part of the photoresist layer 12, the inclined surface 122 having the inclination angle θ can be manufactured. The slope angle of this type is determined by the focusing ability (curvature radius, etc.) of the lens, but the distribution of light energy is not uniform, and in addition, the refraction position such as the side angle forms an arc shape due to diffraction.

  Patent Document 2 posts an infiltration type tilt exposure module. As shown in FIG. 2A, the base material 21 on which the photoresist layer 22 and the photomask 23 are to be placed is immersed in a liquid medium 24 and subsequently irradiated with light rays 20. When the light beam 20 passes through the photomask 23 from the liquid medium 24 and irradiates the photoresist layer 22, the light beam 20 performs an inclined lithograph on the photoresist layer 22 (see FIG. 2B). Since the intensity of light is equal to the power of illuminance and time, the square of light illuminance and distance are inversely proportional. Therefore, this type of inclined exposure cannot make the entire exposure energy uniform, and if the lithographic area increases, it becomes more difficult to make the light intensity uniform. Moreover, it is disadvantageous for manufacturing a large area due to the limitation of the tilt angle of the machine. In addition, the liquid-mediated removal on the substrate in the subsequent manufacturing process is also a challenge.

  In general non-gap exposure, if the light source is vertical exposure, the structure formed is only a vertical column and the angle on both sides is close to 90 ° (see FIG. 3). If there is a gap, the optical diffraction problem will be caused, the line width will increase, and the structural slope will become increasingly flat (see FIG. 4). Or it also causes problems such as poor arc-shaped analysis (see FIGS. 5 and 6). Therefore, in the technical implementation, the existence of a gap between the photomask and the photoresist must be avoided as much as possible.

  A method in which a prism is simply used and a light beam is deflected and exposed is limited by a material refractive index. Since the refractive index of general materials is 1.5 ± 0.2, the maximum deflection angle is only around 30 degrees. Achieving large angle modifications is very difficult and the maximum exposure angle is too small, reducing its value in practical applications (see FIG. 7). There is also a method of expanding the angle change during etching by adding an inclined substrate, but this makes the light energy distribution relatively non-uniform, and the manufactured structure is only an inclined columnar structure.

  In addition, when diffraction is simply used, it is generally not possible to have a gap between the photomask and the photoresist. This is because a small gap of several tens of microns causes an increase in line width and becomes a slope. However, since the angle is small (8 °), it is generally only an electroforming mold removal angle. If the gap is further enlarged, the angle can be enlarged, but the diffraction becomes severe and the structure becomes an arc shape. Therefore, it can be applied only to non-planar surfaces.

  Therefore, the present inventor has developed a tilt exposure lithographic system that is easy to control the angle, has a clear folding, and can be manufactured by existing mechanical equipment.

Taiwan Patent No. 1278903 Specification US Pat. No. US7012,762

  The problem to be solved by the present invention is to provide a tilt exposure lithography system that establishes a polarizing component between a photoresist layer and a light source, modifies the light incident direction, supports gap diffraction, and achieves the purpose of tilt exposure lithography It is to be.

In order to solve the above problems, the present invention provides the following tilt exposure lithographic system.
Including substrate, photoresist layer, photomask, polarizing components,
The photoresist layer is placed on the substrate;
The photomask is disposed on the photoresist layer, and has a gap between the photoresist layer;
The polarizing component is placed on the photomask, reflects the light emitted from the light source, and generates a specific angle shift.

The invention of claim 1 includes a substrate, a photoresist layer, a photomask, a polarizing component,
The photoresist layer is placed on the substrate;
The photomask is disposed on the photoresist layer, and has a gap between the photoresist layer;
The polarizing component is installed on the photomask, and the tilted exposure lithographic system is characterized in that a light beam emitted from a light source is reflected to cause a specific angle shift.
According to a second aspect of the present invention, there is provided the tilted exposure lithographic system according to the first aspect, wherein the polarizing component is a prism.
According to a third aspect of the invention, there is provided the tilted exposure lithographic system according to the second aspect, wherein the prism is a polygonal prism.
According to a fourth aspect of the present invention, there is provided the tilted exposure lithographic system according to the second aspect, wherein a light transmission medium is applied on the prism.
According to a fifth aspect of the present invention, there is provided the tilted exposure lithographic system according to the first aspect, wherein the gap is not less than 5 μm and not more than 150 μm.
According to a sixth aspect of the present invention, there is provided the tilted exposure lithographic system according to the first aspect, wherein the light source includes a light guiding optical module.
The invention according to claim 7 provides the tilted exposure lithographic system according to claim 1, wherein the polarizing component is a triangular prism.
The invention according to claim 8 provides the tilted exposure lithographic system according to claim 1, wherein the polarizing component has a raster microstructure.
According to a ninth aspect of the present invention, there is provided the tilted exposure lithographic system according to the eighth aspect, wherein a light passage difference of light passing through a narrow gap between the raster microstructures is an integral multiple of the light wavelength.
According to a tenth aspect of the present invention, there is provided the tilted exposure lithographic system according to the first aspect, wherein the substrate is a silicon wafer, glass, or acrylic.
An eleventh aspect of the present invention is the tilted exposure lithographic system according to the first aspect, wherein the light source is ultraviolet light.
According to a twelfth aspect of the present invention, there is provided the inclined exposure lithographic system according to the first aspect, wherein the photoresist layer is a positive photoresist or a negative photoresist.
The invention of claim 13 is the tilt exposure lithographic system according to claim 1, wherein the material of the polarizing component is selected from the group consisting of glass, quartz, plastic, and polymer.
According to a fourteenth aspect of the present invention, there is provided the tilted exposure lithographic system according to the first aspect, wherein the specific angle is not less than 0 degrees and not more than 180 degrees.
The invention of claim 15 is characterized in that the substrate, the photoresist layer, the photomask, and the polarizing component are further immersed in a liquid, and the refractive index of the polarizing component is different from the refractive index of the liquid. An inclined exposure lithographic system according to claim 1.

  As described above, in the present invention, the polarizing component is installed, the incident angle of the incident light and the final emission angle are changed from 0 degree to 180 degrees, and the photoresist layer is subjected to the tilt exposure lithograph, which is necessary. A three-dimensional inclination pattern can be obtained.

  FIG. 8 is a schematic view of the tilted exposure lithographic system of the present invention. The inclined exposure lithographic system 3 includes a substrate 31, a photoresist layer 32, a photomask 33, a polarizing component 34, and a light source 35. The photoresist layer 32 is applied on the substrate 31, and the substrate 31 is a silicon wafer, glass, acrylic, or the like. After the application of the photoresist layer 32 is completed, it is hardened by soft baking. Thereafter, a photomask 33 having a pattern designed in advance is placed on the photoresist layer 32. Using a light source 35 (ultraviolet light or the like), the photoresist layer 32 is exposed to obtain a necessary three-dimensional pattern. If necessary, a positive photoresist or a negative photoresist can be used to form the photoresist layer 32.

The advantage over the known technique of the present invention is that a polarizing component 34 is installed between the photomask 33 and the light source 35 to change the direction of the light beam emitted by the light source 35. At the same time, a gap G is maintained between the photomask 33 and the photoresist layer 32. In FIG. 8, the polarizing component 34 is a prism. Based on Snell's law, the incident angle θ _{1 of the} light beam and the inclination angle α of the polarizing component 34 are adjusted, and the materials of the polarizing component 34 and the photoresist layer 32 are selected (ie, the polarizing component 34 and the photoresist layer). The final exposure exit angle θ ₅ of the light beam can be controlled simply by controlling the diffraction rate of 32 and controlling the diffraction effect using the size of the gap G at the same time.

If the photoresist layer 32 is a positive photoresist, the unmasked portion is removed by the photomask 33 after exposure. Thus, a necessary pattern is obtained.
If the photoresist layer 32 is a negative photoresist, the unmasked portion is strengthened by the photomask 33 after exposure, and a structure that is difficult to dissolve in lithographic liquid is formed. Thereafter, the unexposed photoresist layer 32 is further removed with a lithographic solution to obtain a necessary pattern.

  Therefore, as shown in FIG. 9, the necessary tilted exposure molded photoresist layer 32 remains on the substrate 31 after exposure lithography. Thereafter, steps such as hard baking, lithographic inspection, etching, photoresist removal, and final inspection in the lithographic manufacturing process are continued. The three-dimensional structure thus obtained undergoes a sputtering seed layer, electroplating, and demolding stamper molding. Next, the stamper is covered on a roller and further rolled onto an optical substrate by a hot rolling method. However, since the above manufacturing process is common sense in this area, it will not be described in detail here.

  In the present invention, in addition to the prism, the polarizing component 34 can be a triangular prism (see FIG. 10) or a raster microstructure (see FIG. 11), and a prism is a polygonal prism (see FIG. 12). can do. The polarizing component can be selected according to the needs of the user as long as the traveling direction of the light beam can be modified and can be used in the tilt exposure lithographic process.

  In addition, light transmission media having different refractive indexes of one layer or several layers can be applied on the polarizing component, whereby the angle of incident light can be changed. Alternatively, the substrate 31, the photoresist layer 32, the photomask 33, and the polarizing component 34 are immersed in the liquid 36, and the refractive index of the liquid 36 and the refractive index of the polarizing component 34 are different from each other. The direction can be further corrected (see FIG. 13).

  As shown in FIG. 14, which is a schematic raster diagram of the tilt exposure lithography system of the present invention, for convenience of explanation, the raster S is illustrated as three narrow gaps. When the monochromatic plane light L is incident on the raster S, it is diffracted just by the diffraction angle Φ of the raster S, and then the secondary level light wave L ′ emitted from the first gap, the second gap, and the third gap. The passage differences AA ′ = λ, BB ′ = 2λ, and CC ′ = 3λ. Of these, λ is the monochromatic light wavelength. Thus, the raster S can turn monochromatic light and has a function equivalent to that of a prism.

  As shown in FIG. 15, which is a schematic diagram in which the tilt exposure lithographic system of the present invention is associated with a light guide optical module, the light guide optical module 70 is used as a light source, which includes a light emitting unit 701, reflecting mirrors 702 and 703, and tilt exposure. A lithographic system 71 is included. The light emitting unit 71 generates parallel light, the reflecting mirror 702 has a mirror surface of 45 degrees and folds the parallel light, and the reflecting mirror 703 has a mirror surface of non-45 degrees and deflects the parallel light. The parallel light after the deflection is further incident on an inclined exposure lithographic system 71 to perform exposure lithographic.

  Therefore, in the present invention, in addition to exposure using a prism, exposure can be performed by adding diffraction. A gap of about 5 to 150 microns (μ) is retained between the photomask and the photoresist layer. The originally exposed photoresist changes from a columnar shape to a trapezoidal shape, and a prism is added to the outside, so that the light beam is obliquely exposed. To do. In this way, not only can the slope angle be expanded, but also a micro trapezoidal structure can be manufactured, which is very suitable for application to optical filters such as a light guide plate.

  16 to 19 are schematic diagrams of molding patterns of the tilt exposure lithography system of the present invention. FIG. 16 illustrates that a tilted exposure lithographic system of the present invention can be applied to perform exposure + diffraction to produce a large angle pattern. In FIG. 17, a triangular pattern (V-Cut) is manufactured by using two times of exposure + diffraction. In FIG. 18, a trapezoid pattern is produced using exposure + diffraction, and the most necessary trapezoidal structure can be produced by using the coupling of these two methods, and the flat surface angle of the slope is 60 degrees or more. To reach. As shown in FIG. 19A, which is a three-dimensional view of FIG. 18, the flatness of the slope of the manufactured pattern is very good. As shown in FIG. 19B, which is a top view of FIG. 19A, and FIG. 19C, which is an enlarged view of FIG. 19B, the slope surface of the manufactured pattern is smooth and carrier, the folding position is very clear, and the arcuate shape is There is no problem.

  As described above, the purpose of installing the polarizing component in the present invention is to cause the incident angle and the final emission angle of the incident light to be modified from 0 degrees to 180 degrees, and perform an oblique exposure lithograph on the photoresist layer, It is to obtain a necessary three-dimensional inclination pattern.

Therefore, the tilted exposure lithographic system of the present invention has the following advantages as compared with known techniques.
(1) Since a large area base material can be manufactured, productivity is high.
(2) The angle of the tilt pattern is determined by the installation angle and refractive index of the polarizing component, and it can be used easily and diversify exposure by using existing production machines. (3) Lithographic technology is limited to vertical structures Thus, a structure such as a three-dimensional triangle, trapezoid, or parallelogram corresponding to different exposure angles can be manufactured, and the original 2D structure can be changed to a 3D structure.
(4) In order to combine the two types of exposure methods (prism + diffraction) into one, the prism exposure slope is flat and does not have an arc shape by simply selecting a prism material with an appropriate distance. Also, it has the advantage that a large area material for diffractive exposure can be manufactured, and there is no need to tilt the substrate. In addition, a continuous trapezoid (one side is vertical and one side is inclined) can be manufactured, and this type of shape is very suitable for application to manufacture of a light guide plate.

It is step schematic of the well-known inclination exposure lithographic shaping | molding method. It is the schematic of another kind of well-known inclination exposure lithographic shaping | molding method, and the side view of the inclination structure manufactured by this inclination exposure lithographic shaping | molding method. It is a shaping | molding pattern schematic of the well-known inclination exposure lithographic shaping | molding method. It is a shaping | molding pattern schematic of the well-known inclination exposure lithographic shaping | molding method. It is a shaping | molding pattern schematic of the well-known inclination exposure lithographic shaping | molding method. It is a shaping | molding pattern schematic of the well-known inclination exposure lithographic shaping | molding method. It is a shaping | molding pattern schematic of the well-known inclination exposure lithographic shaping | molding method. 1 is a schematic diagram of a tilted exposure lithographic system of the present invention. It is a side view of the inclination structure manufactured by this invention inclination exposure lithography system. FIG. 6 is a schematic diagram of a modified example of the tilted exposure lithography system of the present invention. FIG. 6 is a schematic diagram of another variation of the tilted exposure lithographic system of the present invention. FIG. 7 is a schematic diagram of still another variation of the tilted exposure lithographic system of the present invention. FIG. 6 is a schematic diagram of still another variation of the tilted exposure lithographic system of the present invention. 1 is a raster schematic diagram of a tilt exposure lithographic system of the present invention. FIG. It is the schematic which makes this invention inclination exposure lithography system correspond to a light guide optical module. It is the shaping | molding pattern schematic diagram of this invention inclination exposure lithography system. It is the shaping | molding pattern schematic diagram of this invention inclination exposure lithography system. It is the shaping | molding pattern schematic diagram of this invention inclination exposure lithography system. It is the shaping | molding pattern schematic diagram of this invention inclination exposure lithography system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Light transmissive substrate 111 Surface 112 Light impervious zone 113 Lens 12 Photoresist layer 122 Slope 13 Light source 20 Light beam 21 Base material 22 Photoresist layer 23 Photomask 24 Liquid medium 3 Inclination exposure lithographic system 31 Base material 32 Photoresist layer 33 Photo Mask 34 Polarizing component 35 Light source 36 Liquid 70 Light guide optical module 71 Inclined exposure lithographic system 701 Light emitting unit 702 Reflecting mirror 703 Reflecting mirror G Gap L Monochromatic light L ′ Monochromatic light S Raster θ Tilt angle θ ₁ Incident angle θ ₂ Emission angle θ ₃ Incident angle θ ₄ Output angle θ ₅ Output angle α Tilt angle Φ Diffraction angle

Claims (15)

Including substrate, photoresist layer, photomask, polarizing components,
The photoresist layer is placed on the substrate;
The photomask is disposed on the photoresist layer, and has a gap between the photoresist layer;
An inclined exposure lithographic system, wherein the polarizing component is placed on the photomask and reflects a light beam emitted from a light source to cause a shift of a specific angle.   2. The tilt exposure lithographic system according to claim 1, wherein the polarizing component is a prism.   3. The tilt exposure lithographic system according to claim 2, wherein the prism is a polygonal prism.   3. The tilt exposure lithographic system according to claim 2, wherein a light transmission medium is applied on the prism.   2. The tilt exposure lithographic system according to claim 1, wherein the gap is not less than 5 [mu] m and not more than 150 [mu] m.   2. The tilt exposure lithographic system according to claim 1, wherein the light source includes a light guide optical module.   2. The tilted exposure lithographic system according to claim 1, wherein the polarizing component is a triangular prism.   2. The tilted exposure lithographic system according to claim 1, wherein the polarizing component has a raster microstructure.   9. The tilt exposure lithographic system according to claim 8, wherein a light passage difference of light passing through a narrow gap between each raster microstructure is an integral multiple of the light wavelength.   2. The tilt exposure lithography system according to claim 1, wherein the substrate is a silicon wafer, glass, or acrylic.   2. The tilt exposure lithography system according to claim 1, wherein the light source is ultraviolet light.   2. The tilt exposure lithography system according to claim 1, wherein the photoresist layer is a positive photoresist or a negative photoresist.   2. The tilt exposure lithographic system according to claim 1, wherein the material of the polarizing component is selected from the group consisting of glass, quartz, plastic, and polymer.   2. The tilt exposure lithographic system according to claim 1, wherein the specific angle is not less than 0 degrees and not more than 180 degrees.   2. The tilt exposure according to claim 1, wherein the substrate, the photoresist layer, the photomask, and the polarizing component are further immersed in a liquid, and the refractive index of the polarizing component is different from the refractive index of the liquid. Lithographic system.