JP2013235202A - Hybrid laser scanning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive and compact laser scanning device that includes both of a maskless high definition laser direct drawing function to a base material and a laser confocal microscope function by detection of laser reflection light.SOLUTION: A hybrid laser scanning device comprises: a first laser light source for a laser direct drawing; a second laser light source for inspection of a base material surface; collimating lenses that are provided to correspond to respective laser light sources; a light guide optical system that sends out two laser light to a deflector as the same light path; an fθ lens that images the laser light reflected by the deflector on a base material surface; and a detection element that detects a light amount of reflection light from the base material surface via the fθ lens, the deflector, a second beam splitter provided in the light guide optical system, a lens, and a pin hole arranged at a position (imaging point of a confocal) optically conjugate to a focus position of the base material with respect to the lens. A direct drawing to the base material is performed by the first laser light source and the inspection of the base material surface is performed by the second laser light source, and thereby one device is provided with functions of a laser direct drawing device and a laser confocal microscope.

Description

  The present invention provides maskless digital data direct drawing (direct drawing) of an offset printing plate, direct drawing on a dry film in circuit formation of a printed circuit board, and a fine pattern on a thin film resist coated on a silicon wafer or a precision glass substrate. A hybrid laser that can perform direct drawing, etc., and can also detect defects such as minute scratches and diggs existing in these offset printing plates, dry films, silicon wafers, thin film resists coated on precision glass substrates, etc. The present invention relates to a scanning device.

  For example, in Patent Documents 1 and 2, digital data drawing on an offset printing plate, drawing on a dry film in circuit formation of a printed circuit board, formation of a fine pattern on a thin film resist coated on a silicon wafer or a precision glass substrate, etc. Such a laser direct drawing (direct drawing) apparatus is used.

  The laser direct drawing apparatus disclosed in Patent Documents 1 and 2 reflects light emitted from a light source such as a laser that is turned ON / OFF by digital data by a polygon mirror that rotates at high speed, and passes through the fθ lens. A desired pattern or image is directly drawn by scanning the thin film resist coated on the offset printing plate, printed board, silicon wafer or precision glass substrate.

  Among these, the fine scratches on the base plate surface of the offset printing plate and the printed board are not covered with the resist layer on the upper surface, so that there has been no serious problem in the subsequent process. However, recently, the use of such a laser direct drawing apparatus to directly draw a fine pattern on a thin film resist coated on a silicon wafer or a precision glass substrate has increased. In this case, defects such as minute scratches and digs on the substrate often cause defective pattern formation after exposure and development because of the thin film resist.

  For this reason, for example, when forming a fine pattern on a silicon wafer, it is common to first use a laser confocal microscope as shown in Patent Document 3 to perform surface defect inspection at the blank wafer stage. The apparatus disclosed in Patent Document 3 reflects light emitted from a light source such as a laser beam by a polygon mirror that rotates at high speed via a collimator lens and a beam splitter, and then reflects the light on a document via a scanning lens and a reflection mirror. Contrary to now, the light reflected from the material is returned to the reflecting mirror, scanning lens, polygon mirror, beam splitter and finally detected by a photoelectric device such as a photomultiplier to inspect the defect. It is.

JP 2009-128499 A JP 2005-128313 A JP 2011-76024 A

  Recently, however, domestic companies have increased the production of high-value-added, multi-product small lots, and such inspections have become commonplace for inspection of all products. Therefore, a company needs to have both a defect inspection apparatus and a laser direct drawing apparatus using such a laser confocal microscope, and each of them is expensive and thus requires a large cost and requires a wide installation place.

  In terms of the process, pattern inspection and development are performed with a laser direct drawing apparatus installed separately after defect inspection at the above-mentioned substrate stage (blank wafer). In addition to performing precise defect inspection with a focus microscope and the like, it is necessary to repeat the installation and movement of the base material, and it is difficult to maintain the reproducibility of the inspection because different apparatuses are used.

  Therefore, in the present invention, the main optical system parts are used in common, and a direct drawing function on a base material such as an offset printing plate, a printed circuit board, a silicon wafer or a precision glass, and a minute scratch existing in these base materials, It is an object to provide a hybrid laser scanning device having both functions of a laser confocal microscope function for inspecting defects such as diggs.

In order to solve the above problems, the present invention
A first laser light source for performing direct drawing on a laser direct drawing base material, and a first laser light source for inspecting the surface of the base material including the laser direct drawing base material or the base material surface for observation. The second laser light source, a collimating lens provided in correspondence with each of the laser light sources to convert the laser light into parallel light, and a second light source for sending the paralleled two laser lights to the same optical path and sending them to the deflector. A light guide optical system including one beam splitter, an fθ lens that forms an image on the surface of the base material using the laser light reflected by the deflector as scanning light, and the amount of reflected light reflected from the surface of the base material. , Fθ lens, deflector, second beam splitter provided in the light guide optical system, lens, and a position optically conjugate with the focus position of the substrate with respect to the lens (confocal imaging) Position) A detection element for detecting via a pinhole,
The first laser light source is used for direct drawing on the laser direct drawing base material, and the second laser light source is used for inspection of the surface of the substrate including the laser direct drawing base material or for observation. It is characterized by being performed by.

  As described above, the hybrid laser scanning apparatus according to the present invention has both functions of a laser direct drawing apparatus and a laser confocal microscope. Therefore, it is necessary to separately provide a laser direct drawing apparatus and a laser confocal microscope as in the past. Therefore, the system can be formed at a low cost, and the installation space can be set up with only one space. In addition, since the lasers used for the laser direct drawing and the laser confocal microscope are different from each other, a resist coating or a laminate coating is used as a second laser light source for functioning as a substrate defect inspection apparatus (that is, a laser confocal microscope). It is possible to select a laser light source having a wavelength that is not exposed to light even when inspected in this state. Therefore, it is possible to inspect not only the state of the raw substrate before coating the resist, but also the state after laser direct drawing / development, and any state can be inspected. This makes it possible to maintain the reproducibility of the inspection as compared with the case where the substrate is re-installed with the laser direct drawing apparatus and the laser confocal microscope.

  The present invention also includes a moving mechanism in a direction orthogonal to the scanning direction (X direction) and the direction orthogonal to the scanning direction (Y direction) of the laser light that is placed on the substrate and deflected by the deflector to scan the substrate. By having a stage having a moving mechanism in a direction (Z direction) perpendicular to the plane formed by the X direction and the Y direction, the entire surface of the substrate can be automatically directly drawn by a laser. It is also possible to perform two-dimensional and three-dimensional inspections including material shape measurement.

  As described above, the hybrid laser scanning device according to the present invention can form a system at low cost and can be installed with only one installation space, which can greatly reduce the cost. In addition, the substrate defect inspection system can inspect with resist or laminate coating, so it is not necessary to remove the substrate and inspect it with a laser confocal microscope. A defect inspection can be carried out simultaneously with the operation, so that a very speedy process can be performed in the process, and the reproducibility of the inspection can be maintained.

  In combination with a mechanism that allows movement in the X and Y directions, two-dimensional and three-dimensional inspections including automatic direct drawing of the entire surface of the substrate and measurement of the shape of the substrate It is possible to do so, and it brings about a great effect.

It is a figure for demonstrating the basic composition outline of this invention. A moving mechanism in a scanning direction (X direction) of the laser beam and a direction (Y direction) perpendicular to the scanning direction, and a moving mechanism in a direction (Z direction) perpendicular to a plane formed by the X direction and the Y direction; It is a figure for demonstrating the stage which has.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Absent.

  FIG. 1 is a diagram for explaining an outline of a basic configuration of an embodiment of a hybrid laser scanning device according to the present invention. In the figure, reference numeral 1 denotes a first laser light source for operating as a laser direct drawing apparatus. For example, a laser having a wavelength within a spectral sensitivity wavelength range optimum for photosensitive or processing of a photosensitive material or workpiece in a range of 350 to 1064 nm. Is used.

  The laser light emitted from the first laser light source 1 is collimated by the collimator lens 2 and passes through a light guide optical system including a beam splitter 203, a beam splitter 3, and a corner mirror 4 which will be described in detail later. Then, it is sent to a deflector 5 such as a polygon mirror rotating at high speed. Then, it is reflected while being deflected by each reflecting surface of the deflector 5, condensed by the fθ lens 6, and exposed on the substrate 8 while performing linear scanning with a scanning width such as 7-1 to 7-3. go.

  The light from the first laser light source 1 is ON / OFF controlled by data for drawing a pattern sent to the laser driver 103. Data for drawing the pattern is stored in the personal computer 101 as a control device. Thus, the vector data is converted into raster data such as a bitmap, stored in the memory unit 102 and sent to the laser driver 103.

  For example, a liquid resist is applied or a dry film is laminated on the exposure surface on the substrate 8, and the configuration shown in FIG. 1 is combined with stages as shown in FIG. It can function as a laser direct drawing apparatus for pattern drawing in three dimensions.

  On the other hand, when inspecting minute defects on the substrate 8, first, the surface to be measured of the substrate 8 is placed at the same position as the laser exposure focus surface described above. Then, the second laser light source 201, the collimating lens 202, and the laser light from the first laser light source 1 having different wavelengths from the first laser light source 1 are transmitted, and the wavelength from the second laser light source 202 is transmitted. A beam splitter 203 that reflects the laser beam and a laser driver 204 that drives the second laser light source 201 are used.

  When inspecting the defect of the base material 8, the defect inspection data is given from the personal computer 101 to the laser driver 204 to drive the second laser light source 201. The laser light emitted from the second laser light source 201 is converted into a parallel light beam by the collimator lens 202 and reflected by the beam splitter 203, and the beam splitter 3 and the corner mirror 4 are passed through similarly to the laser light from the first laser light source 1. Then, it is sent to a deflector 5 such as a polygon mirror. Then, the light is condensed by the fθ lens 6 while being deflected by each reflecting surface of the deflector 5 and irradiated on the base material 8 while performing linear scanning with a scanning width such as 7-1 to 7-3.

  Then, the light reflected from the surface to be measured of the substrate 8 is transmitted through the beam splitter 3 via the fθ lens 6, the deflector 5 such as a polygon mirror, and the corner mirror 4, and from the first laser light source 1. Then, the light passes through a filter 12 that blocks only the reflected laser light and allows only the reflected laser light from the second laser light source 201 to pass through, and is focused on the pinhole 10 by the lens 9. The pinhole 10 is disposed at a position optically conjugate with the focus position of the substrate 8 (confocal imaging position). Therefore, the amount of light passing through the pinhole 10 is maximized when the surface to be measured of the substrate 8 is at the focus position of the fθ lens 6, and if the focus is shifted, the focused beam diameter becomes large at the position of the pinhole 10. The amount of light per unit area is reduced, and the amount of light passing through the pinhole 10 is also reduced.

  Therefore, if the surface to be measured has irregularities, the amount of light is maximized when light reflected from the focus position on the surface to be measured passes through the pinhole 10. On the other hand, the light (scattered light) reflected from the position deviated from the focus position due to the reflected light from the surface that is not in focus, foreign matter, or a defect (scattered light) increases the diameter of the condensed beam by the lens 9 and the light quantity per unit area. And the amount of light passing through the pinhole 10 is also reduced.

  In order to continuously detect the amount of light passing through the pinhole 10, a photoelectric conversion element 11 such as a photodiode or CCD is provided behind the pinhole 10, and the analog output signal of the photoelectric conversion element 11 is A / D. It is converted into a digital signal by a conversion element (analog / digital conversion board) 104 and taken into the personal computer 101. The personal computer 101 incorporates software for visualizing the output of the A / D conversion element 104 as a grayscale image on the surface of the base material 8 on the monitor 105 screen, and the reflected light from the defective portion and the foreign matter portion is reduced as described above. Therefore, it is displayed as a dark part image compared with a smooth part (bright part).

  Therefore, if there is a defect or foreign matter on the base material 8, the monitor 105 can silently detect the defect or foreign matter by configuring the software so as to notify the outside of the existence of the dark part. Moreover, it can be made to function as a two-dimensional or three-dimensional laser confocal microscope by combining with stages as shown in FIG. 2 described later.

  As described above, the first embodiment of the present invention has the functions of both the laser direct drawing device and the laser confocal microscope while commonly using the main parts of the deflector 5 and the fθ lens optical system 6 in the laser scanning optical system. Thus, a hybrid laser scanning device can be provided. Therefore, since it is not necessary to separately provide a laser direct drawing apparatus and a laser confocal microscope as in the prior art, the system can be formed at low cost, and installation can be performed with only one installation space.

  Of course, the deflector 5 may be a galvanometer mirror as well as the polygon mirror among the components described above. When performing defect inspection simultaneously with the laser direct drawing operation, in the configuration shown in FIG. 1, the reflected light from both the first laser light source 1 and the second laser light source 201 from the base material 8 passes through the beam splitter 3. It will pass through and reach the photoelectric conversion element 11, and there may be a case where the correct amount of light cannot be measured. Therefore, a filter that blocks the reflected light from the first laser light source 1 and passes only the reflected light from the second laser light source 201 between the beam splitter 3 and the lens 9 or between the lens 9 and the pinhole 10. You may install.

  FIG. 2 is orthogonal to the scanning direction (X direction) of the laser beam on which the substrate 8 in FIG. 1 described above is placed and deflected by the deflector 5 to scan the substrate 8. It is an example of a stage configuration for moving in a direction (referred to as Y direction) and a direction perpendicular to this XY plane (referred to as Z direction).

  In the figure, 101 is a personal computer as the same control device as FIG. 1, 301 is an optical unit showing optical systems such as optical systems 1 to 6 and optical systems 201 to 203 in FIG. 1 as a unit, and 302 is the X direction described above. , 303 is a Y stage for moving the base material 8 in the X direction, 304 is a Z stage for moving the base material 8 in the Z direction, 305 is a data control including laser drivers indicated by 103 and 204 in FIG. A housing 306 is a stage control housing that controls the Y stage 303 and the Z stage 304.

  Among these, the Y stage 303 and the Z stage 304 are configured such that, for example, a pulse motor or a servo motor and a reduction gear or a ball screw are combined so that the stage on which the substrate is placed can be moved with slight variation. .

  In such a stage configuration, for example, when the configuration of FIG. 1 is operated as a laser direct drawing apparatus, raster data is sent from the personal computer 101 to the data control housing 305 including the memory unit 102 and the laser driver 103 shown in FIG. . Then, as described above, the first laser light source 1 is turned on / off by the raster data, and the laser light is deflected at high speed via the collimating lens 2, the beam splitter 3, and the corner mirror 4. Sent to vessel 5. Then, the laser light is reflected while being deflected by each reflecting surface of the deflector 5, collected by the fθ lens 6, and subjected to linear scanning such as a laser scanning line 302 to expose the surface of the substrate.

  When one laser scanning line 302 is scanned, a command is sent from the personal computer 101 to the stage control housing 306 to move the Y stage 303 in the Y direction by one line, and the Y stage 303 moves in the Y direction by one line. Moving. Similarly, the next scanning line is exposed and moved in the Y direction by one line over the entire surface of the substrate 8, and laser direct drawing is performed. The movement in the Y direction may be performed continuously for one line during the scanning time of one line, not every time scanning of one line is completed.

  On the other hand, when the configuration of FIG. 1 is operated as a laser confocal microscope, a light emission instruction of the second laser light source 201 is sent from the personal computer 101 to the laser driver 204, and the stage control housing 306 of FIG. Is sent a movement instruction in the Y direction for one line.

  Then, as described in the description of FIG. 1, the light intensity of the reflected light from the base material 8 detected by the photoelectric conversion element 11 and converted into a digital signal by the A / D conversion element 104 is taken into the personal computer 101, and the defect is detected. And the foreign matter portion are displayed on the monitor 105 as an image that is darker than the smooth portion (bright portion), and the defective portion and the foreign matter portion are inspected.

  When data such as the height in the Z direction of the defective part and the foreign part is necessary, first, the PC 101 issues an instruction to move in the Y direction to the stage control housing 306 so that the defective part and the foreign part are scanned with the laser beam. When the dark part of the defective part and the foreign part is displayed on the monitor 105, the PC 101 issues a Z direction movement instruction to the stage control housing 306 to move the stage in the Z direction so that the dark part becomes a bright part. At this time, if the defective part and the foreign object part are displayed darker without being brightened, the moving direction is reversed because the moving direction is reversed, and the difference between the position of maximum brightness and the position before moving in the Z direction, That is, when the movement distance is obtained, it becomes the height in the Z direction of the defective part and the foreign substance part.

  By doing so, it becomes possible to systematically construct a laser confocal microscope detection function including two-dimensional and three-dimensional laser direct drawing and shape measurement.

  The hybrid laser scanning device according to the present invention has the functions of both a laser direct drawing device and a laser confocal microscope, can form a system at low cost, and can be installed in only one space. Significant cost reduction is possible. In addition, the substrate defect inspection system can inspect with resist or laminate coating, so it is not necessary to remove the substrate and inspect it with a laser confocal microscope. A defect inspection can be carried out simultaneously with the operation, so that a very speedy process can be performed in the process, and the reproducibility of the inspection can be maintained.

DESCRIPTION OF SYMBOLS 1 1st laser light source 2 Collimating lens 3 Beam splitter 4 Corner mirror 5 Deflector 6 f (theta) lens 7-1 to 7-3 Laser scanning light 8 Base material 9 Lens 10 Pinhole 11 Photoelectric conversion element 12 Filter 101 Personal computer 102 Memory part 103 Laser Driver 104 A / D Conversion Element 105 Monitor 201 Second Laser Light Source 202 Collimating Lens 203 Beam Splitter 204 Laser Driver 301 Optical Unit 302 Laser Scan Line 303 Y Stage 304 Z Stage 305 Data Control Case 306 Stage Control Case

Claims (2)

A first laser light source for performing direct drawing on a substrate for direct laser drawing;
A second laser light source for inspecting the surface of the substrate including the substrate for direct laser drawing or for inspecting the substrate surface for observation;
A collimating lens that is provided corresponding to each of the laser light sources and converts the laser light into parallel light;
A light guide optical system including a first beam splitter for setting the two paralleled laser beams in the same optical path and sending them to a deflector;
An fθ lens that forms an image on the surface of the base material as a scanning light beam reflected by the deflector;
The amount of reflected light reflected from the surface of the base material is determined based on the focus position of the base material with respect to the fθ lens, the deflector, the second beam splitter provided in the light guide optical system, the lens, and the lens. And a detection element for detecting via a pinhole arranged at a position optically conjugate (confocal imaging position),
The first laser light source is used for direct drawing on the laser direct drawing base material, and the second laser light source is used for inspection of the surface of the substrate including the laser direct drawing base material or for observation. A hybrid laser scanning device characterized by the above.   A moving mechanism in a scanning direction (X direction) and a direction perpendicular to the scanning direction (Y direction) of the laser light that is placed on the base material and is deflected by the deflector to scan the base material, and the X direction and the Y direction The hybrid laser scanning device according to claim 1, further comprising a stage having a moving mechanism in a direction (Z direction) perpendicular to a plane formed by the direction.

Images