JP2008089489A - Profile measuring device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a profile measuring device with simple arrangement and adjustment of light sources and an optical system. <P>SOLUTION: This profile measuring device 10 which measures the profile of an object 100 made of a semiconductor material containing silicon has the light source 15 which emits visible light 17 with a wavelength of 400-800 nm, the light source 18 which emits near-infrared light 18 with a wavelength of 900-1200 nm, the optical system 14 in which first and second light beams are entered onto the object along one optical axis 19 in the same direction, and an image pickup element 22 which has sensitivity to two light beams 17, 18 and receives the reflection light of the light beams 17, 18. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method and apparatus for measuring the shape of an object. In particular, the present invention relates to an apparatus and method that can be suitably used for optically measuring the shape of an object or device having partially different thicknesses, or an object or device having a thinned portion.

Conventionally, as an apparatus for measuring the shape of an object, there is an apparatus described in Patent Document 1 (semiconductor component inspection apparatus). In this apparatus, the reflected light of the light (white light) illuminated on the surface of the semiconductor component and the transmitted light of the light (red light) illuminated on the other back surface of the semiconductor component are arranged on the surface side of the semiconductor component. This is detected by a CCD sensor, and glass breakage or silicon breakage of a semiconductor component is detected from an image detected by the CCD sensor.
Japanese Patent No. 3506170

  However, in the apparatus disclosed in Patent Document 1, the light source that emits two lights and the optical system thereof are arranged above and below the semiconductor component, which causes a problem that the design of the entire apparatus becomes complicated. is there. Moreover, when adjusting an optical system, the optical system respectively arrange | positioned at the upper and lower sides of a semiconductor component must be adjusted, and there exists a problem that adjustment work becomes complicated. Furthermore, when a metal film that does not transmit red light is present on the back surface of the semiconductor component, there is a problem that a shape including a crack cannot be detected correctly.

  In order to solve such a problem, the present invention provides a shape measuring device for measuring the shape of an object made of a semiconductor material containing silicon, and a first light source that emits first light having a wavelength of 400 nm to 800 nm. , A second light source that emits second light having a wavelength of 900 nm to 1200 nm, and an optical system in which the first light and the second light are incident on the object from the same direction along one optical axis. And a light receiving portion that is sensitive to the first light and the second light and receives reflected light from the object of the first light and the second light.

  According to the shape measuring apparatus having such a configuration, since the two lights are incident on the surface of the object from the same direction, the arrangement and adjustment of the light source and the optical system are simple. Even if there is a metal film that does not transmit light on the back surface of the object (the surface opposite to the surface on which light is incident), the shape of the portion covered with the metal film can be measured correctly.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. In the following description, the terms “up”, “down”, “left”, “right” and other terms including specific terms are used as necessary to indicate a specific direction. These terms are intended to facilitate understanding of the referenced invention and do not limit the technical scope of the invention.

Embodiment 1

  FIG. 1 shows a schematic configuration of a shape measuring apparatus according to the present invention. An object of shape measurement by the shape measuring apparatus 10 is not limited, but in the first embodiment and other embodiments described later, a semiconductor device having a thin portion is handled as an object. Specifically, FIG. 1 shows a pressure sensor 100 having a thin-walled diaphragm that can be deformed according to pressure as an object. As shown in FIG. 2, the sensor 100 includes a cylindrical portion 102 that surrounds the central axis 101 and a thin diaphragm 103 that closes one end of the cylindrical portion 102. The thickness of the diaphragm 103 is determined so that the direction of the central axis 101 can be deformed in accordance with the pressure difference between the inside and the outside of the cylindrical portion 102. The cylindrical portion 102 and the diaphragm 103 are made of a base material made of silicon, for example, a single substrate selected from a single crystal silicon substrate, a polycrystalline silicon substrate, and an SOI (silicon-on-insulator) substrate. It is formed by etching. As shown in FIG. 2, electrical wiring (trace wiring) 104 is formed on the upper surface of the sensor 100. As the material of the wiring 104, for example, an aluminum conductive metal is used.

  Referring again to FIG. 1, the shape measuring apparatus 10 includes a base 11 that supports the sensor 100 with the central axis 101 directed in the vertical direction, as illustrated. A drive mechanism 12 that adjusts the position of the sensor 100 in two directions (X and Y directions) orthogonal to the horizontal plane and in the vertical direction (Z direction) may be connected to the base 11.

  The shape measuring apparatus 10 includes a light source unit 13 and an optical system 14 disposed above the base 11 in order to illuminate the sensor 100 supported by the base 11. The light source unit 13 includes a first light source 15 and a second light source 16. The first light source 15 emits first visible light 17 having a wavelength of about 400 nm to about 800 nm. The second light source 16 emits near-infrared light 18 of the second light having a wavelength of about 900 nm to about 1200 nm. The first light source 15 and the second light source 16 are adjusted so that the visible light 17 and the near-infrared light 18 emitted from the respective light sources move along the same optical axis 19. In FIG. 1, the visible light 17 and the near-infrared light 18 are shown offset from the optical axis 19 so that they can be distinguished and recognized. In the first embodiment, the optical system 14 includes a beam splitter 20. The beam splitter 20 changes the traveling direction of the visible light 17 and the near-infrared light 18 emitted from the light sources 15 and 16, that is, a sensor supported by the base 11 as shown in the figure by changing the optical axis 19 vertically downward. It arrange | positions so that 100 may be illuminated from the upper direction. The optical system 14 according to the embodiment includes a lens 21 disposed between the beam splitter 20 and the base 11. The lens 21 may be composed of a single lens or a combined lens in which a plurality of lenses are combined.

  The shape measuring apparatus 10 also has an image sensor 22 formed of a charge image sensor (CCD) above the beam splitter 20. In the embodiment, the image sensor 22 is connected to an image processing device 23 that analyzes an image captured by the image sensor 22. The image processing device 23 is connected to an image display device 24 such as a liquid crystal display device.

  The operation of the shape measuring apparatus 10 having the above configuration will be described. The sensor 100, which is an object for shape measurement, is installed on the base 11 with the central axis 101 directed in the vertical direction and the diaphragm 103 positioned at the top. At this time, it is preferable to make the central axis 101 of the sensor 100 substantially coincide with the optical axis 19 of the shape measuring apparatus 10 so that the entire sensor 100 is illuminated.

  In this state, the light sources 15 and 16 of the light source unit 13 are activated to emit visible light 17 and near infrared light 18. Visible light 17 and near infrared light 18 emitted from the light sources 15 and 16 enter the beam splitter 20 along the optical axis 19. The beam splitter 20 deflects the optical axes of the visible light 17 and the near-infrared light 18 in the vertical direction and enters the sensor 100 through the lens 21.

  As shown in FIG. 2, the visible light 17 incident on the sensor 100 does not pass through the sensor 100 but is reflected by the sensor upper surface (boundary surface with the atmosphere) 105, and the reflected light 17 ′ moves up the optical axis 19. Proceed toward. On the other hand, part of the near infrared light 18 incident on the sensor 100 is reflected by the sensor upper surface 105 to become reflected light 18 ′, and the rest enters the inside of the sensor 100. A part of the near-infrared light 18 entering the inside of the sensor 100 is reflected by the sensor inner surface (diaphragm inner surface) 106 (boundary surface with the atmosphere) to be reflected light 18 ″, and travels upward. The remaining near-infrared light 18 ′ ″ that has passed through the sensor inner surface 106 passes through the sensor 100. The visible light 17 ′ reflected by the upper surface 105 of the sensor 100, the near-infrared light 18 ′ reflected by the upper surface 105 of the sensor 100, and the near-infrared light 18 ″ reflected by the sensor inner surface 106 are reflected on the optical axis 19. Along the lens 21 and the beam splitter 20 in order, and is received by the image sensor 22. The near-infrared light 18 that has entered the tube portion 102 may partially be reflected by the lower surface of the sensor (bottom surface of the tube portion) and return to the upper side of the sensor, but the thickness (height in the vertical direction) of the tube portion 102 is Since it is considerably larger than the diaphragm 103, it is attenuated while traveling inside the cylinder portion 102, and even if some near infrared light 18 passes through the sensor upper surface 105 and returns upward, the imaging is performed. The amount of light received by the element 22 is considered to be considerably small.

  Returning to FIG. 1, the image sensor 22 transmits an image obtained by combining the visible light 17 and the near-infrared light 18 to the image processing device 23. The image processing device 23 processes an image using a built-in image processing program, outputs the processed image to the image display device 24 as necessary, and displays the image on the image display device 24. An example of an image displayed on the image display device 24 is shown in FIG. If the image displayed on the image display device 24 is unclear, the drive mechanism 12 can be operated to make the displayed image clear.

  In the image 200 shown in FIG. 3, a low-density square area 201 that appears in the center indicates the planar shape of the diaphragm 103, and a high-density peripheral area 202 that appears around the square area 201 indicates the cylindrical portion 102. In addition, the light and dark mixed region 203 appearing in the peripheral region 202 shows the electric wiring 104 formed on the sensor upper surface 105. As shown in this figure, on the image 200, the cylinder portion 102, the diaphragm 103, and the electrical wiring 104 of the sensor 100 are displayed with clearly different densities. One reason for this is that, as described above, all or most of the visible light 17 is reflected by the sensor upper surface 105, and part of the near infrared light 18 is the upper surface 105 and the inner surface 106 of the sensor 100. Depending on the thickness of the sensor portion through which the near-infrared light that has entered the inside of the sensor 100 is transmitted. It is considered that the light is attenuated, and as a result, the light amount of the diaphragm image and the cylindrical portion image received by the image sensor 22 is different. Further, since the metal wiring 104 cannot transmit not only the visible light 17 but also the near-infrared light 18, the metal wiring 104 is displayed with a density different from that of the diaphragm 103 and the cylindrical portion 102.

  Therefore, by evaluating the image shown in FIG. 3, it can be determined whether the diaphragm 103 and the electrical wiring 104 in the sensor 100 have an appropriate shape. In addition, by displaying the density (reference density) of the image captured when the diaphragm 103 has the target thickness on the image display device 24, the reference density and the density of the actually captured diaphragm image are compared. It is also possible to determine whether or not the diaphragm 103 has a target thickness.

  Infrared light includes near-infrared light, mid-infrared light, and thermal infrared light. When mid-infrared light or thermal infrared light is used, information on the temperature of the measurement object is captured. In the present invention, the use of mid-infrared light or thermal infrared light is not included in the image received by the element, and the imaging device has no sensitivity in the wavelength band of these mid-infrared light and thermal infrared light. It is considered inappropriate.

  Further, the sensor 100 is not limited to the form shown in FIG. 1. For example, as shown in FIG. 4, the sensor 110 having a form in which the thickness of the cylindrical part 102 gradually increases downward, or the cylindrical part 102. A sensor 120 having a metal film 107 formed on the lower surface is also included in the measurement target of the shape measuring apparatus of the present invention.

  As described above, in the conventional shape measuring apparatus, since the light source and the optical system are respectively arranged above and below the measurement target, there is a problem that the configuration of the entire apparatus becomes large and complicated. In the apparatus, since the light source and the optical system can be arranged only on one side (upper side) of the measurement object, the apparatus can be easily and miniaturized. In addition, in the conventional shape measuring apparatus, red light is used as transmitted light. For example, when the object is made of silicon, the red light cannot be transmitted unless the thin part is considerably thin, and imaging is therefore performed. The shape cannot be accurately recognized from the captured image. On the other hand, since the shape measuring apparatus described above uses near-infrared light that passes through silicon, the shape of the thin portion is clearly different from the shape of other portions even if the thin portion is not considerably thin. Images displayed in different modes can be obtained.

Embodiment 2

  FIG. 6 shows a shape measuring apparatus 10 ′ according to the second embodiment. As illustrated, the shape measuring apparatus 10 ′ according to the second embodiment includes a filter unit 30 in the light source unit 13 and the beam splitter 20. The filter unit 30 includes a first filter 31 that adjusts the amount of visible light 17 that is first light, a second filter 32 that adjusts the amount of near-infrared light 18 that is second light, and these It has a filter holder 33 that detachably holds the first filter 31 and the second filter 32 at a position where they cross the optical axis 19 (position shown in the figure).

  According to the shape measuring apparatus 10 'of the second embodiment having such a configuration, the intensities of the visible light 17 and the near-infrared light 18 are separately controlled, and a thin part and a thick part (for example, the diaphragm 103 and the cylinder) Difference in the amount of reflected light obtained from the portion 102, or a defective portion and a non-defective portion, or a groove portion and other portions), and as a result, the thin portion and the thick portion displayed on the image display device 24 Images can be displayed with clearly different densities.

  The performance required for the filter differs depending on the object to be measured. For example, in the case of the illustrated sensor with a diaphragm, the diaphragm has a thickness of about 10 μm and an aluminum electrode (wiring) is formed on the upper surface of the diaphragm. The ratio of the light intensity of visible light and near infrared light that passes through the filter and enters the sensor (near infrared light intensity / visible light intensity) is about 0.8 to 0.9. Each filter is selected.

  In the second embodiment, the filter unit 30 is disposed between the light source unit 13 and the beam splitter 20, but between the beam splitter 20 and the lens 21, between the lens 21 and the base 11, or the beam splitter 20 It can be arranged at any position between the image sensors 22. In the second embodiment, the filter unit 30 includes the two filters 31 and 32, but the first filter unit that houses the first filter 31 and the second filter unit that houses the second filter 32. May be installed in different places.

  In the second embodiment, the filter unit 30 is shown as a unit independent of the light source unit 13, but may be integrated into the light source unit 13.

Embodiment 3

  FIG. 7 shows a shape measuring apparatus 10 ″ according to the third embodiment. As illustrated, in the shape measuring apparatus 10 '' of the third embodiment, a sheet-like light absorbing member 40 made of a material that absorbs the near-infrared light 18 of the second light is disposed on the surface of the base 11. The object to be measured is supported on it. As a material that absorbs the near-infrared light 18, for example, a sheet or a plate having a surface coated with carbon black can be used.

  According to the shape measuring apparatus 10 '' of the third embodiment configured as described above, the near-infrared light 18 transmitted through the measurement object is absorbed by the light absorbing member 40, and the reflected light becomes reflected light on the imaging device 22. Since it is not detected, there is a large difference in the amount of reflected light obtained from the thin portion and the thick portion (for example, the diaphragm 103 and the cylindrical portion 102, or the defective portion and the non-defective portion, or the groove portion and other portions). As a result, the thin portion and thick portion images displayed on the image display device 24 can be displayed with clearly different densities.

  In the above-described embodiments, the lens 21 is provided between the beam splitter 20 and the base 11, but the lens 21 is not always necessary. However, when observing the shape of a partial region of the object in detail, the lens is effective for converging light in that region.

The figure which shows the structure of the shape measuring apparatus which concerns on this invention. Sectional drawing of the pressure sensor which measures a shape with the shape measuring apparatus of this invention. The figure which shows the image of the result of having measured the shape of the pressure sensor with the shape measuring apparatus of this invention. Sectional drawing which shows the other form of a measuring object. Sectional drawing which shows the other form of a measuring object. The figure which shows the structure of the shape measuring apparatus which concerns on Embodiment 2. FIG. FIG. 6 is a diagram illustrating a configuration of a shape measuring apparatus according to a third embodiment.

Explanation of symbols

10, 10 ', 10' ': shape measuring device, 11: base, 12: drive mechanism, 13: light source unit, 14: optical system, 15: first light source, 16: second light source, 17: visible Light (first light), 18: Near infrared light (second light), 19: Optical axis, 20: Beam splitter, 21: Lens, 22: Image sensor, 23: Image processing device, 24: Image display Device: 30: Filter unit, 31: First filter, 32: Second filter, 40: Light absorbing member, 100: Pressure sensor, 101: Center axis, 102: Tube portion, 103: Diaphragm, 104: Electric wiring , 105: sensor upper surface, 106: sensor inner surface, 200: image.

Claims (6)

A shape measuring device for measuring the shape of an object made of a semiconductor material containing silicon,
A first light source that emits first light having a wavelength of 400 nm to 800 nm;
A second light source that emits second light having a wavelength of 900 nm to 1200 nm;
An optical system in which the first light and the second light are incident on the object from the same direction along one optical axis;
A shape measuring apparatus comprising a light receiving section that has sensitivity to the first light and the second light and receives reflected light from the object of the first light and the second light.   A first light intensity adjusting unit arranged on an optical path through which the first light passes and adjusts an intensity of the first light; arranged on an optical path through which the second light passes; The shape measuring apparatus according to claim 1, further comprising at least one of a second light intensity adjusting unit that adjusts light intensity.   A light absorbing member that absorbs the second light is disposed opposite to the object surface portion on the opposite side of the object surface portion on which the first light and the second light are incident. The shape measuring apparatus according to claim 1 or 2. A shape measuring method for measuring the shape of an object made of a semiconductor material containing silicon,
Emitting a first light having a wavelength of 400 nm to 800 nm;
Emitting second light having a wavelength of 900 nm to 1200 nm;
The first light and the second light are incident on the object from the same direction along one optical axis,
A shape measuring method, wherein a light receiving unit having sensitivity to the first light and the second light receives reflected light from the object of the first light and the second light. A shape measuring device for measuring the shape of an object,
A first light source that emits first light having a first wavelength that is opaque to the object;
A second light source that emits second light having a second wavelength different from the first wavelength and having transparency to the object;
An optical system that makes the first light and the second light emitted from the first light source and the second light source incident on the object from the same direction;
A light receiving portion having sensitivity to the first light and the second light and receiving the first reflected light and the second reflected light reflected at the boundary between the object and the atmosphere is provided. Shape measuring device. A shape measuring method for measuring the shape of an object,
Emitting first light of a first wavelength that is impervious to the object,
A second light having a second wavelength different from the first wavelength and having transparency to the object;
The first light and the second light are incident on the object from the same direction,
A shape measuring method, wherein the first reflected light and the second reflected light reflected at the boundary between the object and the atmosphere are received.

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