KR101720595B1 - Method and apparatus for producing raster image useable in exposure apparatus based on dmd and recording medium for recording program for executing the method - Google Patents

Abstract

A method for generating a raster image usable in a DMD-based exposure apparatus according to an embodiment of the present invention includes: a step of superposing a plurality of virtual pixel arrays to generate a superposed pixel array; a step of mapping the superimposed pixel array onto a virtual vector image; a step of generating a superimposed raster image by determining on/off of all pixels in the superimposed pixel array mapped onto the vector image; and a step of converting the superimposed raster image into one raster image.

Description

TECHNICAL FIELD [0001] The present invention relates to a raster image generating method and apparatus usable in a DMD-based exposure apparatus, and a recording medium on which a program for executing a raster image generating method is recorded. FOR EXECUTING THE METHOD}

The present invention relates to a raster image generating method and apparatus, and a recording medium. More particularly, the present invention relates to a method and apparatus for generating raster images using a DMD-based exposure apparatus capable of generating a plurality of exposure patterns using a DMD including a plurality of micromirrors A raster image generating method and apparatus, and a recording medium on which a program for executing a raster image generating method is recorded.

In recent years, demand trends in domestic and overseas tend to create demand mainly for high value added products with high technical difficulty. The rapid paradigm shift of digital electronic devices and smart phones led to the rapid conversion of most of the PCB products used in this way to the multi-product small-volume production method and the rapid life cycle (Fast Life Cycle). .

In order to positively cope with this phenomenon from the technical point of view, there has been a need for a new exposure technique and system that is different from the existing method for realizing the micro-circuit line width on the PCB.

New exposure methods suited to the needs of the market have been developed mainly in the overseas market, and non-mask or maskless Direct Imaging exposure methods are emerging as the most representative technologies .

In recent years, domestic PCB industry has become a multi-layer product group including MLB, Embedded PCB, Build-up PCB, RF PCB and Optical PCB, although the main types of flexible PCB products in Korea are single-side and double- . Reflecting recent trends in the PCB market, we are aggressively replacing PCBs with high-value products related to rigid and flexible PCBs, which require micro-circuit patterns with a circuit line width of 30 μm or less. It is expected to proceed.

In order to solve the situation and trend of the domestic market, there is a need to develop a technology for securing the core technology for exposing the microcircuit linewidth. For this purpose, a direct imaging technique to overcome the limitations of the conventional masking technique, It is required to develop a new exposure methodology suitable for a PCB manufacturing process.

A DMD (Digital Mirror Device) -based exposure apparatus uses a UV light source on a digital mask to implement a fine pattern without using a pattern mask for exposure pattern in an exposure process Direct Imaging method is used.

DMD-based exposure apparatuses include optical illumination optics, DMD, and optical projection optics. The light irradiation optical system is an optical system for inputting a beam generated from a UV light source to the DMD in a state of uniform illumination, the DMD is an element for modulating the beam of the condensed light source into a desired light source shape, It is an optical system that makes the exposure pattern reflected by the DMD to a desired magnification so as to expose the surface of the PCB (or substrate).

In order to perform an exposure process using a DMD-based exposure apparatus, an original image that is actually desired on the surface of the PCB is required. The original image is usually a raster image, which is an image implemented on a pixel-by-pixel basis.

A raster image is a rasterized image from a vector image. A vector image is an image that is based on mathematical equations and is implemented using objects such as points, straight lines, curves, and polygons.

The DMD included in the DMD-based exposure apparatus is an optical modulation element having a pixel array structure, and is an element that receives data of a raster image as an input and exposes it.

In order to expose a more precise image using the DMD's limited pixel pitch (10.8 um), a suitable arrangement of the DMD, the illumination system, the stage, and the controller is used to fit the newly superimposed / A raster image is required.

In addition, the rasterization method which is conventionally well-known can switch the vector image vi to the raster image ri at a very high speed, but there is a problem of difficulty in roughness control. Specifically, since the DMD included in the DMD-based exposure apparatus receives the raster image as an input to perform the exposure, the roughness of the patterned line on the exposure surface causes an aperture array (aperture array, it is difficult to adjust the roughness.

It is an object of the present invention to provide a raster image generating method and apparatus capable of providing a raster image so that a DMD-based exposure apparatus can expose a more precise image using a DMD limited pixel pitch (10.8 um) A recording medium on which a program for executing a raster image generating method is recorded.

It is another object of the present invention to provide a raster image generating method and apparatus capable of adjusting the roughness of a line patterned on an exposure surface, and a recording medium on which a program for executing a raster image generating method is recorded.

According to another aspect of the present invention, there is provided a method of generating a raster image that can be used in a DMD-based exposure apparatus, the method comprising: superposing a plurality of virtual pixel arrays to generate an overlapped pixel array; Mapping the superimposed pixel array onto a virtual vector image; Generating a superimposed raster image by determining on / off of all pixels in the superimposed pixel array mapped onto the vector image; And a converting step of converting the nested raster image into one raster image.

Here, in the overlapping step, the number of overlapping virtual pixel arrays may be determined according to a k factor value.

Here, in the generating step, pixels having a ratio of overlapping with the vector image among all the pixels may be determined to be on, and pixels less than the threshold ratio may be determined to be off.

Here, in the converting step, all the pixels of the superimposed raster image may be rearranged in order according to their positions to generate the one raster image.

An apparatus for generating a raster image that can be used in a DMD-based exposure apparatus according to an embodiment of the present invention includes: an overlapping unit that overlaps a plurality of virtual pixel arrays to generate an overlapped pixel array; A mapping unit for mapping the superimposed pixel array onto a virtual vector image; Generating a superimposed raster image by determining on / off of all pixels in the superimposed pixel array mapped onto the vector image; And a conversion unit converting the superimposed raster image into one raster image.

Here, the overlapping unit may determine the number of the virtual pixel arrays to be overlapped according to a k factor value.

Here, the generating unit may determine that pixels having a ratio of overlapping with the vector image among all the pixels are equal to or greater than a predetermined threshold ratio, and may determine that pixels less than the threshold ratio are off.

Here, the converting unit may generate the one raster image by rearranging all the pixels of the overlapped raster image in order according to their positions.

When the raster image generated according to the above-described configuration of the present invention is provided to a DMD-based exposure apparatus, there is an advantage that a more precise image can be exposed using a limited pixel pitch (10.8 um) of the DMD.

Further, there is an advantage that the roughness of the line patterned on the exposure surface can be adjusted.

1 is a block diagram of a DMD-based exposure apparatus according to the present invention.
2 is a conceptual diagram for explaining a method for rasterizing a vector image according to an embodiment of the present invention to generate a raster image.
3 is a flowchart illustrating a method of generating a raster image according to an embodiment of the present invention.
4 is a conceptual diagram for explaining a raster image generating method according to an embodiment of the present invention shown in FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals refer to like elements, and the size and thickness of each element may be exaggerated for clarity of explanation.

Before describing a method of generating a raster image according to an embodiment of the present invention, an example of a DMD-based exposure apparatus in which a raster image of the present invention can be used will be described first.

1 is a block diagram of a DMD-based exposure apparatus according to the present invention.

1, a DMD-based exposure apparatus according to the present invention includes a light source 1, a first optical system 2, a DMD (Digital Micro-mirror Device) 3, a second optical system 4, (5), a stage (6), and a controller (7).

An exposed workpiece 5 is provided on the stage 6 and the exposed workpiece 5 is movable in the x, y and z directions together with the stage 6 in a state of being mounted on the stage 6 .

An alignment mark may be formed on one side of the panel on which the pinhole 5 is mounted, and an alignment mark (not shown) serves to align the relative position between the panel and the DMD 3.

The light source 1 provides a beam for exposure, and the beam is irradiated to the object 5. The beam from the light source 1 can also be used for alignment of the DMD 3 with the panel.

The beam from the light source 1 is transmitted to the DMD 3 through the first optical system 2.

The first optical system 2 is an optical system that transmits a beam between the light source 1 and the DMD 3 and allows the beam to be used for exposure.

The first optical system 2 may include a condensing lens and may include a guide member such as a mirror or a prism for controlling the path of the beam.

The DMD 3 selectively reflects the beam provided from the first optical system 2 to irradiate the object 5 in a desired pattern form, and includes a plurality of micromirrors. The DMD 3 continuously changes the pattern for selectively reflecting the beam in each micromirror so that the DMD 3 moves from one side to the other and forms a desired pattern at each position of the object 5. [ The beam selectively reflected by the DMD 3 is transmitted to the second optical system 4.

The DMD 3 may be mounted parallel to the surface of the object 5, or may be mounted to be tilted at a predetermined angle.

The second optical system 4 causes the beam to be irradiated onto the object 5 placed on the stage 6 and more precisely to cause the beam to be accurately focused on the object 5. Of course, the second optical system 4 may be provided with a guide member for adjusting the path of the beam 51. The second optical system 4 may include a projection lens that performs at least a function of causing the beam to be accurately focused on the object 5.

The beam exited through the second optical system 4 is irradiated to the exposed object 5 to perform exposure and the exposed object 5 and the DMD 3 are provided between the second optical system 4 and the exposed object 5. [ An alignment device (beam splitter) may be provided for performing alignment of the light beam.

1, assuming that one of the micromirrors of the DMD 3 is one pixel, the number of pixels of the DMD 3 is fixed, and each pixel of the DMD 3 The existing mirrors are arranged at fixed pitch intervals (approximately 10.8 um) with neighboring mirrors. Therefore, in order to generate a high-precision, high-resolution fine circuit pattern using a fixed pixel pitch, a tilted DMD 3 and an aperture array attached to an optical projection optical system can be used.

2 is a conceptual diagram for explaining a method for rasterizing a vector image according to an embodiment of the present invention to generate a raster image.

The vector image (vi image) shown in FIG. 2 refers to an image based on mathematical equations and implemented using an object such as a point, a straight line, a curve, or a polygon. In Fig. 2, the vector image vi is in a cross shape and its interior is filled with a predetermined color.

Rasterization refers to the transformation of the vector image vi shown in FIG. 2 into a raster image ri and each point of the converted raster image ri contains information such as color and depth.

The rasterization method shown in Fig. 2, that is, the raster image generation method, generates a nested raster image corresponding to the vector image (vi), and converts the nested raster image into one raster image.

The superimposed raster image is a virtual image, in which the pixel arrays (a) of the same shape are not completely overlapped with each other but overlapped by a predetermined interval.

Each pixel of one raster image contains color information, and one raster image can be stored in memory as one bit of bitmap data. A raster image stored in the memory is provided to the DMD-based exposure apparatus shown in FIG. 1, and the DMD-based exposure apparatus shown in FIG. 1 draws the provided raster image on the exposure surface.

The raster image generating method shown in Fig. 2 will be described in more detail with reference to Figs. 3 to 4. Fig.

FIG. 3 is a flowchart illustrating a method of generating a raster image according to an embodiment of the present invention, and FIG. 4 is a conceptual diagram illustrating a method of generating a raster image according to an embodiment of the present invention shown in FIG.

Referring to FIG. 3, a method of generating a raster image according to an exemplary embodiment of the present invention includes a step 310 of overlapping virtual pixel arrays, a mapping step 320 of mapping virtual pixel images superimposed on a vector image, A generating step 330 for generating a superimposed raster image and a transforming step 340 for converting the superimposed raster image into a single raster image.

Each of the above steps will be described in detail with reference to FIG.

The overlapping step 310 is a step of overlapping a plurality of virtual pixel arrays (a). A pixel array superimposed on Figure 4 (A) is shown. The overlapped pixel array is a plurality of virtual pixel arrays (a) superposed according to predetermined conditions. In Fig. 4 (A), two pixel arrays (a) are superimposed. One pixel array (a) has a plurality of rows and a plurality of apertures arranged in a plurality of rows. One pixel array (a) may correspond to one aperture array mounted inside the DMD-based exposure apparatus shown in FIG. Thus, each of the openings in one pixel array (a) may be an aperture through which light from the DMD 3 is emitted.

The overlap of the virtual pixel arrays (a) can be determined according to a k factor. If the K factor is set to 3, then three virtual pixel arrays per unit distance can be overlapped. Here, the unit distance means a distance between two adjacent apertures in one pixel array (a).

The mapping step 320 is a step of mapping the superimposed virtual pixel array in the superposition step 310 onto the vector image vi. Here, the vector image is an image in which the DMD-based exposure apparatus shown in FIG. 1 is aimed at the exposure surface.

The generating step 330 is a step of generating a superimposed raster image from the overlapped pixel arrays mapped onto the vector image. A superimposed raster image is shown in Figure 4 (D). The on / off of each of the pixels in each pixel array (a) mapped onto the vector image can be determined to generate a superimposed raster image. For example, for each pixel array (a), on / off of the pixels can be determined based on a ratio of overlapping with the vector image. That is, pixels having a ratio of overlapping with a vector image among all the pixels may be determined to be ON, and pixels having a ratio lower than a threshold ratio may be determined to be OFF. The threshold ratio can be determined by the user. For example, the threshold ratio may be set to 70% or 100%.

The conversion step 340 is a step of converting the superimposed raster image into one raster image. The raster image superimposed on (D) in Fig. 4 is a state in which a plurality of pixel arrays are superimposed, and thus can not be stored in the memory as one bit bitmap data in this state. Therefore, if the nested raster image is converted into one virtual raster image, the converted raster image can be stored in the memory as 1-bit bitmap data.

One way to convert a nested raster image into a raster image is to rearrange the entire pixels of the nested raster image in order, rather than in the order of the pixel arrays. One raster image converted into (E) of Fig. 4 is shown. For example, if it is assumed that three pixel arrays (a) are overlapped and 1 * 1 (1 row 1 row) pixels of the first pixel array are 1 * 1 pixels of one raster image, The 1 * 2 pixel of the pixel array is not 1 * 2 pixel of one raster image but the 1 * 4 pixel of the first pixel array becomes 1 * 2 pixel of one raster image. The 1 * 1 pixel of the second pixel array and the 1 * 1 pixel of the third pixel array are located between the 1 * 1 pixel and the 1 * 2 pixel of the first pixel array, 1 is 1 * 2 pixels of one raster image, and 1 * 1 pixel of the third pixel array is 1 * 3 pixel of one raster image.

One raster image converted through the conversion step 340 may be stored in the memory as one bit of bitmap data.

If the raster image generated using the raster image generating method shown in FIGS. 3 to 4 is provided to the DMD-based exposure apparatus, it is possible to use the DMD of the exposure apparatus with a finer pixel pitch (10.8 um) The image can be exposed.

Further, there is an advantage that the roughness of the patterned line exposed by the exposure apparatus can be adjusted. Specifically, there is an advantage in that the number of overlapping pixel arrays in the overlapping step 310 may be adjusted or the roughness may be adjusted by controlling the threshold ratio for determining on / off of each pixel in the generating step 330. [

Further, even if the line patterned on the exposure surface includes an oblique line, a curved line, or a circular component, there is an advantage that such oblique line, curved line, or circular pattern can be precisely patterned.

Meanwhile, the raster image generating method according to the embodiment of the present invention illustrated in FIGS. 2 to 4 may be implemented in the form of program instructions that can be executed through various computer components and recorded in a computer-readable recording medium . The computer-readable recording medium may include program commands, data files, data structures, and the like, alone or in combination.

The program instructions recorded on the computer-readable recording medium may be those specially designed and constructed for the present invention or may be those known to those skilled in the art of computer software.

Examples of the computer-readable recording medium include magnetic media such as a hard disk, a floppy disk and a magnetic tape, optical recording media such as CD-ROM and DVD, magneto-optical media such as a floptical disk, optical media), and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language code such as those generated by a compiler, as well as high-level language code that can be executed by a computer using an interpreter or the like. The hardware device may be configured to operate as one or more software modules for performing the process according to the present invention, and vice versa.

In addition, the raster image generating method according to the embodiment of the present invention described in Figs. 2 to 4 can be performed in any one of the raster image generating apparatuses. The raster image generating apparatus includes a superimposing unit 310 performing the superimposing step 310 of FIG. 3, a mapping unit 320 performing the mapping step 320 of FIG. 3, a generating unit 330 performing the generating step 330 of FIG. 3, And a conversion unit 340 for performing the conversion step 340 of FIG. Alternatively, the raster image generating apparatus may be implemented as one raster image generating unit and included in a DMD-based exposure apparatus.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, As will be understood by those skilled in the art.

1: Light source
2: first optical system
3: DMD (Digital Micro-mirror Device)
4: Second optical system
5: Pine mineral
6: stage
7: Controller

Claims (9)

A raster image generating method usable in a DMD-based exposure apparatus,
Superimposing a plurality of virtual pixel arrays to generate an overlapped pixel array;
Mapping the superimposed pixel array onto a virtual vector image;
Generating a superimposed raster image by determining on / off of all pixels in the superimposed pixel array mapped onto the vector image; And
A conversion step of converting the nested raster image into one raster image;
/ RTI >
The method according to claim 1, wherein, in the overlapping step,
The number of the virtual pixel arrays to be overlapped is determined according to a k factor value,
Wherein the K factor is a number of the plurality of virtual pixel arrays overlapping per unit distance and the unit distance is a distance between two adjacent apertures in one virtual pixel array.
2. The method according to claim 1,
Wherein a pixel having a ratio of overlapping with the vector image of all the pixels is greater than a predetermined threshold ratio is determined to be on and a pixel having the threshold ratio is determined to be off.
2. The method according to claim 1,
And rearranging all the pixels of the nested raster image in order according to their positions to generate the one raster image.
A recording medium on which a program for executing the raster image generating method according to any one of claims 1 to 4 is recorded.
A raster image generating apparatus usable in a DMD-based exposure apparatus,
Superposing a plurality of virtual pixel arrays to generate a superposed pixel array;
A mapping unit for mapping the superimposed pixel array onto a virtual vector image;
Generating a superimposed raster image by determining on / off of all pixels in the superimposed pixel array mapped onto the vector image; And
A converter for converting the superimposed raster image into a raster image;
The raster image generating apparatus comprising:
7. The apparatus of claim 6,
Determining a number of the virtual pixel arrays to be overlapped according to a k factor value,
Wherein the K factor is the number of the plurality of virtual pixel arrays overlapping per unit distance and the unit distance is a distance between two adjacent apertures in one virtual pixel array.
7. The apparatus according to claim 6,
And determines that pixels having a ratio of overlapping with the vector image among all the pixels overlap with a predetermined threshold ratio are turned on and pixels having less than the threshold ratio are determined to be turned off.
7. The image processing apparatus according to claim 6,
And rearranges all the pixels of the nested raster image in order according to their positions to generate the one raster image.

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