JP2006300705A - Apparatus for inspecting foreign matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for inspecting a foreign matter, capable of inspecting existence of the foreign matter without being affected by the size of a substrate. <P>SOLUTION: The apparatus has a frame 3 for fixing relative positions of a light source 1 and a CCD type solid-state image sensing device (CCD) 2, scans a surface to be inspected W<SB>S</SB>of the substrate W while fixing the relative positions by using the frame 3, and inspects the existence of the foreign matter on the substrate W. Since the relative positions are fixed, attenuation of light is constant regardless of the size of the substrate W being an object to be inspected. Consequently, no detection error caused by the attenuation occurs, whereby the existence of the foreign matter can be inspected without being affected by the size of the substrate W. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a foreign matter inspection apparatus for inspecting the presence or absence of foreign matter adhering to the inspection surface of a semiconductor substrate, a glass substrate for a liquid crystal display, a glass substrate for a photomask, and a substrate for an optical disk (hereinafter simply referred to as “substrate”). In particular, the present invention relates to a technique for inspecting the presence or absence of foreign matter by irradiating light and detecting light scattered by the foreign matter.

  In recent years, with the high integration of integrated circuits, there is a demand for miniaturization of pattern circuits formed on a substrate. Along with miniaturization, the function of the integrated circuit is deteriorated due to foreign matters adhering to the substrate. Therefore, there is a foreign substance inspection apparatus that inspects the presence or absence of foreign matter by irradiating the inspection surface of the substrate with spot light and detecting light scattered by the foreign matter with the surface on which the foreign matter is attached as an inspection surface (for example, patents) Reference 1).

In the case of the above-described Patent Document 1, spot light is irradiated from an oblique direction with respect to the inspection surface of the substrate. Therefore, the inspectable region is narrow, and it is difficult to recognize a pattern formed on the substrate and a foreign substance. Therefore, a transparent plate-like member is arranged in parallel to the inspection surface of the substrate, spot light is irradiated substantially in parallel to the gap between the plate-like member and the inspection surface of the substrate, and total reflection is repeated in the gap. While detecting the presence or absence of foreign matter, or detecting the presence or absence of foreign matter by irradiating spot light substantially in parallel, a foreign matter inspection apparatus that widens the inspectable area and facilitates recognition of patterns and foreign matters (For example, refer to Patent Document 2).
JP-A-8-15169 (page 2-3, FIG. 9) JP-A-9-89793 (page 2-3, FIGS. 1 and 2)

  However, even when the spot light is irradiated substantially parallel to the inspection surface of the substrate as described above, the attenuation of the light differs depending on the size of the substrate to be inspected, and a detection error occurs due to the attenuation.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a foreign matter inspection apparatus capable of inspecting the presence or absence of foreign matter without being affected by the size of the substrate.

In order to achieve such an object, the present invention has the following configuration.
That is, the invention according to claim 1 includes a light irradiation means for irradiating the substrate with light substantially parallel to the inspection surface of the substrate, and a light detection means for detecting light scattered from the inspection surface of the substrate, A foreign matter inspection apparatus that inspects the presence or absence of foreign matter by irradiating light from the light irradiating means onto the inspection surface of the substrate and detecting the light scattered by the foreign matter on the substrate by the light detecting means. A fixing means for fixing the relative position of the means and the light detection means, and scanning the inspection surface of the substrate while fixing the relative position by the fixing means to inspect for the presence of foreign matter on the substrate. It is characterized by doing.

  [Operation / Effect] According to the invention described in claim 1, the light irradiating means irradiates the substrate with light substantially parallel to the inspection surface of the substrate. Recognition other than that becomes possible. Further, a fixing means for fixing the relative position between the light irradiation means and the light detection means is provided, and the inspection surface of the substrate is scanned while the relative position is fixed by the fixing means. Since the presence or absence of foreign matter is inspected, the attenuation of light is constant regardless of the size of the substrate to be inspected. Therefore, it is possible to inspect the presence or absence of foreign matter without being affected by the size of the substrate without causing a detection error due to attenuation. Note that “substantially parallel” in this specification indicates a range in which the angle formed between the inspection surface of the substrate and the irradiated optical axis is 0 ° to 10 °.

  An example of the invention described above includes a calculation processing unit that calculates foreign substance identification information indicating information on the presence or absence of a foreign substance by calculation processing, and the calculation processing unit calculates foreign substance identification information based on light detected by the light detection unit, Inspecting the presence or absence of foreign matter (the invention according to claim 2). By providing such arithmetic processing means, it is possible to easily check for the presence of foreign matter.

  In each invention, it is preferable that a plurality of light detection means are provided, and the foreign matter inspection is performed in parallel by detecting light in parallel with these light detection means (the invention according to claim 3). By performing in parallel, the time required for the foreign substance inspection can be reduced.

  In each invention, the first foreign matter removing means for removing the foreign matter by irradiating light is provided, and when the presence or absence of the foreign matter is inspected based on the light detection by the light detecting means, the first foreign matter removing means removes the foreign matter. It is preferable (the invention according to claim 4). By providing the first foreign matter inspection means, foreign matters can be removed in addition to the inspection, and the number of substrates that have been inspected due to the presence of foreign matters can be reduced after the inspection.

  In addition, when the first foreign matter inspection means is provided, it is provided with an illumination field setting means for setting the size of the illumination field of the light irradiated by the first foreign matter removal means, and based on detection of light by the light detection means. The illumination field setting means preferably changes and sets the illumination field size according to the size of the inspected foreign matter (the invention according to claim 5). The size of the field of view is set according to the size of the foreign object, so that it is possible to prevent the foreign object from being damaged even if the foreign object is small or not being removed even though the foreign object is large. Therefore, the foreign matter can be appropriately removed.

  Further, when the first foreign matter inspecting means is provided, the second foreign matter removing means for supplying the pressurized gas to remove the foreign matter is provided, and both the first foreign matter removing means and the second foreign matter removing means are used. It is preferable to remove foreign matter (the invention according to claim 6). The foreign matter can be removed more reliably by removing the foreign matter by irradiating with light and supplying the pressurized gas to remove the foreign matter.

  According to the foreign matter inspection apparatus according to the present invention, the inspection device has a fixing means for fixing a relative position between the light irradiation means and the light detection means, and the inspection surface of the substrate while fixing the relative position by the fixing means. Since the top is scanned to check for the presence of foreign matter on the substrate, the presence or absence of foreign matter can be inspected without being affected by the size of the substrate.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic diagram of a foreign matter inspection apparatus according to an embodiment, FIG. 2 is a block diagram illustrating a schematic configuration of the foreign matter inspection apparatus according to the embodiment, and FIG. 3 is a diagram illustrating a plurality of CCD solid-state imaging devices. It is the top view which showed an example of parallel scanning. 1A is a schematic plan view, and FIG. 1B is a schematic side view.

As shown in FIG. 1B, the foreign matter inspection apparatus according to the embodiment includes a stage S that supports the back surface opposite to the inspection surface (front surface) W _S of the substrate W, and movement that is not illustrated. By moving the stage S in the horizontal plane (XY plane in FIGS. 1 and 3) by the mechanism, the substrate W supported by the stage S is moved in the horizontal plane.

Above the stage S, together we are disposed light source 1 for irradiating a spot light O to the substrate W substantially parallel to the test surface W _S of the substrate W, in the vertical direction from the test surface W _S of the substrate W A CCD (Charge Coupled Device) type solid-state imaging device (hereinafter abbreviated as “CCD”) 2 for detecting scattered light O _S (see FIG. 2) is provided. In this embodiment, as shown in FIG. 1A, a plurality of light sources 1 are provided in the Y direction and a plurality of CCDs 2 are provided in the same direction so that foreign matter inspection can be performed in parallel when scanning in a horizontal plane. Prepare. In this specification, “substantially parallel” indicates a range in which the angle formed between the inspection surface W _S of the substrate W and the irradiated optical axis A _X (see FIG. 2) is 0 ° to 10 °. In the present embodiment, the range from 5 ° to 10 ° is set in consideration of interference between the inspection surface W _S and the light source 1 or the CCD 2. Of course, it is more preferable to make the angle smaller and parallel, so if there is no interference as described above, it may be less than 5 ° if it exceeds 0 °. The light source 1 corresponds to the light irradiation means in this invention, and the CCD 2 corresponds to the light detection means in this invention.

In this embodiment, a discharge lamp (metal halide lamp) that emits light by excitation of a metal vapor and a halide product is employed as the light source 1. Note that the substance to be excited is not particularly limited, other than the halide, such as a He—Ne laser. The light source 1 is not limited to the metal halide lamp of the present embodiment, and is not particularly limited as long as it is a normal light irradiation means used for inspecting foreign matters. The CCD 2 detects the light O _S scattered from the inspection surface W _S of the substrate W by receiving the incident light, capturing an optical image and converting it into an electrical signal. The light detection means is not limited to the CCD 2 of the present embodiment, and is not particularly limited as long as it is a normal light detection means used for inspecting foreign matter.

From the light source 1 is irradiated with the spot light O to the test surface W _S of the substrate W, a light O _S scattered by foreign matter on the substrate W CCD 2 is inspected for its foreign substance by detecting. The substrate W which is supported by the stage S is moved in a horizontal plane, the light source 1 and CCD2 are relatively scanned over inspection surface W _S of the substrate W, to inspect the presence or absence of foreign matter on the substrate W. When the substrate W moves in the horizontal plane, the light source 1 and the CCD 2 may be fixed, or the light source and the CCD 2 may be moved in the horizontal plane in the direction opposite to the movement direction of the substrate W in the horizontal plane. Good. Further, when the substrate W is fixed, the light source 1 and the CCD 2 may be moved in the horizontal plane. That is, scans the inspection surface W _S of the substrate W, in order to inspect the presence or absence of foreign matter on the substrate W, at least one of the light source 1 and CCD2 or substrate W may be moved.

In this embodiment, the CCD 2 is arranged so as to detect the light O _S scattered in the vertical direction from the inspection surface W _S of the substrate W. However, the light O _S scattered by the foreign matter is not only in the vertical direction, and therefore in the oblique direction. A CCD 2 may be provided.

In this embodiment, a frame 3 is provided in addition to the light source 1 and the CCD 2 described above. The frame 3, FIG. 1 (b), the are bent into "U-shaped", as shown in FIG. 2, with disposing the bar B _R on one of the lower end which is bent, is bent A bar _BL is also provided at the other lower end. Both the bars B _R and B _L are configured to extend in the Y direction as shown in FIG. 1A. Each light source 1 is supported by the bar B _R and each bar B _L is supported by each bar B _L. Each CCD 2 is supported. As shown in FIG. 1A, two bent frames 3 are arranged. By forming in this way, the frame 3 fixes the relative position between the light source 1 and the CCD 2. The frame 3 corresponds to the fixing means in this invention.

  In this embodiment, in addition to the light source 1, CCD 2, and frame 3 described above, a microscope 5 having a laser 4 and a supply nozzle 6 (see FIG. 1B) that supplies pressurized gas are provided. ing. A collimator 7 that sets the size of the irradiation field of the laser beam L (see FIG. 2) from the laser 4 is disposed in the irradiated portion of the laser 4. The laser 4 irradiates the laser beam L to remove foreign matters, and the supply nozzle 6 ejects pressurized gas and supplies it to remove foreign matters. In the present embodiment, the laser 4 and the supply nozzle 6 move together as the light source 1 and the CCD 2 fixed by the frame 3 move. The laser 4 corresponds to the first foreign matter removing means in the present invention, the supply nozzle 6 corresponds to the second foreign matter removing means in the present invention, and the collimator 7 corresponds to the irradiation field setting means in the present invention.

  In this embodiment, a YAG laser having a wavelength of 532 nm to 355 nm is employed as the laser 4. However, the wavelength of the laser and the type of laser are not limited to this. As the gas, an inert gas that does not cause a chemical reaction with respect to the substrate W is preferable, and a nitrogen gas or a rare gas typified by helium (He) or argon (Ar) is preferable.

  In this embodiment, the foreign matter is removed using both the laser 4 and the supply nozzle 6. When removing the foreign matter, the laser 4 may be irradiated with the laser beam L while jetting the gas from the supply nozzle 6, or the gas may be jetted from the supply nozzle 6 before and after the laser beam L is irradiated from the laser 4. May be.

  In addition, in this embodiment, an arithmetic processing circuit 11 and a control circuit 12 are provided. The arithmetic processing circuit 11 and the control circuit 12 are composed of a central processing unit (CPU) and the like. Based on the light detected by the CCD 2, the arithmetic processing circuit 11 obtains foreign substance identification information indicating information on the presence or absence of a foreign substance by an arithmetic process, and checks the presence or absence of the foreign substance. The arithmetic processing circuit 11 corresponds to the arithmetic processing means in this invention.

To be more specific, the setting foreign identification information that foreign matter is present when having a preset predetermined value or more electrical signals, the light O _S scattered by the foreign matter when the foreign matter is present CCD2 is Photoelectric conversion to electrical signals. Therefore, foreign matter that when the foreign object is not present, the scattered light O _S CCD2 does not detect, or electrical signals weak scattered light CCD2 is to photoelectric conversion detection because it is smaller than the predetermined value, there is no foreign matter Identification information is obtained. Conversely, if the foreign object is present, since the photoelectrically converted into an electric signal the light O _S scattered by foreign matter detected by CCD 2, converted electrical signal as it more than a predetermined value, that the foreign matter is present Foreign matter identification information is obtained.

  In the present embodiment, eight CCDs 2 are provided and two arithmetic processing circuits 11 are provided. Accordingly, each arithmetic processing circuit 11 performs arithmetic processing on the light detected by the four CCDs 2. In addition, it is not limited to the form of CCD2 and the arithmetic processing circuit 11 like a present Example, According to the number of CCD2 and the capability of the arithmetic processing circuit 11, a form can be changed suitably. Therefore, one arithmetic processing circuit 11 may perform arithmetic processing on the light detected by the plurality of CCDs 2, or each arithmetic operation is performed on the light detected by each CCD 2 with the CCD 2 and the arithmetic processing circuit 11 corresponding one-to-one. The processing circuit 11 may perform arithmetic processing.

The control circuit 12 comprehensively controls each part constituting the apparatus of this embodiment. In addition, in this embodiment, the control circuit 12, by moving the substrate W supported on the stage S in a horizontal plane, and controls the scanning on the test surface W _S of the substrate W, the above-mentioned arithmetic processing circuit The foreign matter removal control is performed on the basis of the foreign matter identification information obtained by 11. When the control circuit 12 receives foreign substance identification information from the arithmetic processing circuit 11 that a foreign substance exists, the laser beam L is irradiated by operating the laser 4 to remove the foreign substance, and the supply nozzle 6 is operated. Foreign matter is removed by blowing gas. In addition, when the foreign object identification information is distinguished, for example, by changing the value of the electric signal according to the size of the foreign object, the collimator 7 changes the irradiation field of the laser light L according to the size of the foreign object. The control circuit 12 may operate the collimator 7 so as to change and set the size.

As described above, when a plurality of CCDs 2 are provided in the Y direction, in this embodiment, scanning in the direction shown in FIG. It should be noted that the parallel scanning in FIG. 3 is a relative scanning and is a movement of at least one of the light source 1, the CCD 2, and the substrate W. In the case of FIG. 3, first, the CCDs 2 are simultaneously scanned in the (positive) X direction. After scanning to the edge of the substrate W, each CCD 2 is slightly scanned in the Y direction, and each CCD is simultaneously scanned in the (negative) X direction. During scanning, it scans the inspection surface W _S of the substrate W while fixing the relative position of the light source 1 and CCD2 by the frame 3. In the scanning of FIG. 3, the scanning may be realized by moving the stage S supporting the substrate W in the X and Y directions, or the frame 3 or the substrate W supporting the light source 1 or the CCD 2 is supported. Scanning may be realized by moving one of the stages S in the X direction and moving the other in the Y direction. Further, scanning may be realized by moving the frame 3 in the X and Y directions.

The whole test surface W _S of the substrate W after the scanning, when inspecting the presence or absence of foreign matter on the basis of the detection of light by the CCD 2, the foreign matter laser 4 and the supply nozzle 6 are both removed. Also during this removal, it scans the inspection surface W _S of the substrate W laser 4 and the supply nozzle 6. Also in the case of scanning for removing the foreign matter, at least one of the laser 4, the supply nozzle 6, and the substrate W may be moved.

  Further, the foreign matter removal by the laser 4 and the supply nozzle 6 may be performed in parallel with the scanning for the foreign matter inspection. As shown in FIG. 1, the location detected by the CCD 2 is different from the location where foreign matter is removed by the laser 4 and the supply nozzle 6, so foreign matter is removed when the laser 4 and the supply nozzle 6 scan the location detected by the CCD 2. do it.

According to the present embodiment apparatus constructed as above, the light source 1, the spot light O substantially parallel to the test surface W _S of the substrate W so that irradiates the substrate W, to widen the inspectable area Thus, it is possible to recognize foreign substances and the others (for example, the pattern of the substrate W). Also, a frame 3 for fixing the relative position between the light source 1 and the CCD 2, and scans the inspection surface W _S of the substrate W while fixing the relative position described above by the frame 3, on the substrate W Therefore, the attenuation of light is constant regardless of the size of the substrate W to be inspected. Therefore, it is possible to inspect the presence or absence of foreign matter without being affected by the size of the substrate W without causing a detection error due to attenuation.

  In this embodiment, an arithmetic processing circuit 11 that obtains foreign matter identification information indicating information on the presence or absence of foreign matter is provided by arithmetic processing, and the arithmetic processing circuit 11 obtains foreign matter identification information based on the light detected by the CCD 2 to detect foreign matter identification information. Check for presence. By providing such an arithmetic processing circuit 11, it is possible to easily check for the presence of foreign matter.

  In this embodiment, a plurality of CCDs 2 are provided, and these CCDs 2 detect light in parallel, so that foreign matter inspection is performed in parallel. By performing in parallel, the time required for the foreign substance inspection can be reduced.

  In the present embodiment, a laser 4 that removes the foreign matter by irradiating the laser beam L is provided, and when the presence or absence of the foreign matter is inspected based on detection of light by the CCD 2, the laser 4 removes the foreign matter. By providing such a laser 4, foreign matters can be removed in addition to the inspection, and the number of substrates W that have been inspected as being present due to the presence of foreign matters can be reduced after the inspection. Furthermore, in the present embodiment, a supply nozzle 6 that supplies pressurized gas to remove foreign matters is provided, and foreign matters are removed using both the laser 4 and the supply nozzle 6. By irradiating the laser beam L to remove the foreign matter and supplying the pressurized gas to remove the foreign matter, the foreign matter can be more reliably removed.

  Further, when the collimator 7 changes the size of the irradiation field of the laser beam L according to the size of the foreign matter, the foreign matter (for example, the pattern of the substrate W) is damaged even though the foreign matter is small. In addition, it is possible to prevent the foreign matter from being completely removed although the foreign matter is large, and the foreign matter can be appropriately removed.

  The present invention is not limited to the above-described embodiment, and can be modified as follows.

  (1) In the above-described embodiment, the laser 4 and the supply nozzle 6 are provided to remove foreign matters in addition to the inspection, but it is not always necessary to provide them. You may apply to the apparatus which performs only an inspection.

  (2) In the embodiment described above, both the laser 4 and the supply nozzle 6 are used to remove the foreign matter. However, the foreign matter may be removed only by the laser 4.

  (3) In the above-described embodiment, a plurality of CCDs 2 are provided, and the foreign matter inspection is performed in parallel by detecting light in parallel with these CCDs. However, only one CCD 2 may be provided. An example of parallel scanning when one CCD 2 is provided is shown in FIG. In the case of FIG. 4 as well, as in FIG. 3 of the embodiment, at least one of the light source 1, the CCD 2, and the substrate W may be moved.

  (4) The fixing means in the present invention is not limited to the frame 3 of the embodiment, and may fix the relative position of the light irradiation means represented by the light source 1 and the light detection means represented by the CCD 2. That's fine. For example, the relative positions of the light source 1 and the CCD 2 may be fixed by housing the light source 1 and the CCD 2 in a housing having an opening below. In this case, the housing corresponds to the fixing means in the present invention.

  (5) In the embodiment described above, the spot light O emitted from the light source 1 has a small energy and is suitable for inspecting foreign matter, and the laser light L emitted from the laser 4 has energy higher than that of the spot light. Suitable for removing large foreign matter. Therefore, in general, the light irradiated for the foreign substance inspection and the light irradiated for the foreign substance removal are different from each other, but the energy is smaller than the laser light L and the energy is smaller than the spot light O. It is also possible to employ light having a large current and use the light for both foreign matter inspection and foreign matter removal. Then, after the foreign matter inspection and the removal of the foreign matter using the light, the removal of the foreign matter may be performed again by irradiating light having a large energy such as the laser beam L.

(A) is a schematic top view of the foreign material inspection apparatus which concerns on an Example, (b) is the side view. It is a block diagram which shows schematic structure of the foreign material inspection apparatus which concerns on an Example. It is the top view which showed an example of the parallel scanning by a some CCD type solid-state image sensor. It is the top view which showed an example of the parallel scanning by one CCD type solid-state image sensor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Light source 2 ... CCD type solid-state image sensor (CCD)
3 ... Frame 4 ... laser 6 ... supply nozzle 7 ... collimator 11 ... processing circuit W ... substrate W _S ... inspection surface O ... spotlight O _S ... scattered light L ... laser light

Claims (6)

  A light irradiation means for irradiating the substrate with light substantially parallel to the inspection surface of the substrate; and a light detection means for detecting light scattered from the inspection surface of the substrate. Is a foreign matter inspection apparatus for inspecting the presence or absence of foreign matter by detecting the light scattered by the foreign matter on the substrate, the relative position of the light irradiation means and the light detection means A foreign matter inspection apparatus comprising: a fixing means for fixing the substrate, and scanning the inspection surface of the substrate while fixing the relative position by the fixing means to inspect for the presence of foreign matter on the substrate.   2. The foreign matter inspection apparatus according to claim 1, further comprising arithmetic processing means for obtaining foreign matter identification information indicating information on the presence or absence of the foreign matter by arithmetic processing, wherein the arithmetic processing means is based on the light detected by the light detecting means. A foreign matter inspection apparatus for obtaining the foreign matter identification information and inspecting for the presence or absence of foreign matter.   The foreign matter inspection apparatus according to claim 1 or 2, wherein a plurality of the light detection means are provided, and the foreign matter inspection is performed in parallel by detecting light in parallel. Foreign matter inspection device.   4. The foreign matter inspection apparatus according to claim 1, further comprising: a first foreign matter removing unit that irradiates light to remove the foreign matter, and the presence or absence of foreign matter based on detection of light by the light detecting unit. The foreign matter inspection apparatus, wherein the foreign matter is removed by the first foreign matter removing means when the product is inspected.   5. The foreign matter inspection apparatus according to claim 4, further comprising an illumination field setting unit that sets a size of an illumination field of light irradiated by the first foreign matter removal unit, and is inspected based on detection of light by the light detection unit. The foreign matter inspection apparatus, wherein the illumination field setting means changes and sets the size of the illumination field according to the size of the foreign matter. 6. The foreign matter inspection apparatus according to claim 4 or 5, further comprising: a second foreign matter removing unit that supplies pressurized gas to remove the foreign matter, wherein the first foreign matter removing unit and the second foreign matter removing unit are provided. A foreign matter inspection apparatus characterized by using both together to remove foreign matter.

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