JP4827127B2 - Inspection device - Google Patents

Description

  The present invention relates to an inspection apparatus for observing and inspecting an edge of a wafer, for example, a semiconductor wafer.

  2. Description of the Related Art Conventionally, wafer cracks in the semiconductor device manufacturing process due to micro cracks at the edge of the wafer, wafer cracks due to wafer edge deformation and chipping during the semiconductor process, and generation of foreign matter have become problems.

  Also, semiconductor devices caused by peeling or the like in subsequent processes due to deposits on the edge or front surface of the wafer, such as Cu, low-k film, ARC, CVD film, sputtered film, polymer residue after dry etching, etc. Yield reduction is becoming a problem.

  For this reason, as shown in Non-Patent Document 1, a polishing apparatus for removing the deposit and an inspection apparatus for inspecting the presence or absence of the deposit are used.

  For example, as described in paragraphs 0015 and 0022 of Patent Document 1 and FIG. 1, the center position of the wafer is positioned at the rotation center of the drive mechanism by the alignment mechanism, and at the outer periphery of the wafer mounted on the stage, There is known an observation apparatus in which a TV camera for observing from the front surface and the back surface of the wafer and a TV camera for observing from the side surface of the wafer are respectively arranged, and the peripheral portion, the side surface, and the lower portion of the wafer are observed with high accuracy by the camera. .

  As described in paragraph 0031 of Patent Document 2 and FIGS. 1 and 2, they correspond to the side surface, the upper surface, and the lower surface of the peripheral edge of the wafer, and are arranged with the imaging direction corresponding to each surface at a substantially right angle. There is known an inspection apparatus that includes a side imaging camera, a top imaging camera, and a bottom imaging camera, and performs edge inspection by observing the side, top, and bottom surfaces of the peripheral edge of the wafer with a camera.

  Similarly, in Patent Document 3, the edge inspection is performed by observing with a camera.

  Further, as shown in FIG. 7, page 7, left column, line 11 to page 31, column 31, line 31 of FIG. 9, an ultra-small electron microscope is placed on the upper side of the wafer so as to sandwich the wafer. In addition, there is known a pattern inspection apparatus which is arranged on each of the lower side and the lower side and observes the front and back of the wafer simultaneously.

Further, in order to observe in detail the defects detected by the inspection apparatus, for example, as shown in Patent Document 5, the stage is inclined by 60 degrees to enable observation from below the bevel to the apex and the wafer surface at 360 °. There has also been proposed an electron microscope apparatus (SEM) that observes the entire circumference of the edge of the wafer by endless rotational movement.
Electron Journal February 2006, pages 84-86 Japanese Patent Laid-Open No. 2001-221749 Japanese Patent No. 3629244 US Pat. No. 6,947,588 Japanese Patent No. 2810216 JP-A-11-162386

  However, in the electron microscope apparatus of Patent Document 4, since the stage is tilted by 60 degrees for observation, it is difficult to observe the side surface and back surface of the edge.

  Further, in Patent Documents 1, 2, and 3, since an imaging camera is used, it is impossible to find a fine defect on the wafer edge.

  Further, as in Patent Document 4, if the optical axes of a plurality of electron microscopes are provided close to both sides of the front and back of the wafer, charged particles such as secondary electrons and reflected electrons generated from the side surface, upper surface, and lower surface of the wafer edge are erroneous. In other words, it may be detected by a detector of another electron microscope, the signal may be confused, the image may be distorted, and a precise image may not be obtained.

  Therefore, an object of the present invention is to provide an inspection apparatus in which a plurality of electron microscopes are arranged so as to solve the above problems.

In order to solve the above problems, an invention according to claim 1 of the present application is directed to an inspection apparatus that inspects a wafer by arranging a plurality of electron microscope apparatuses or charged particle beam apparatuses and irradiating the wafer with charged particle beams. Electron microscope apparatus or charged particle beam apparatus are arranged spatially separated from each other on the front surface side, back surface side, and side surface side of the wafer, and the charged particle beams of at least two electron microscope apparatuses are pulsed, and the pulse interval Alternatively , the inspection apparatus is characterized in that the phases of the pulses are made different so that the signals obtained from the respective electron microscope apparatuses are subjected to synchronous detection for the pulses .

According to a second aspect of the present invention, there is provided an inspection apparatus for inspecting a wafer by irradiating the wafer with a charged particle beam by arranging a plurality of electron microscope apparatuses, and an optical axis of the electron microscope apparatus disposed on the front surface side of the wafer. The plurality of electron microscope apparatuses are arranged apart from each other in a form that does not coincide with the optical axis of the electron microscope apparatus arranged on the back surface side, and the charged particle beams of at least two electron microscope apparatuses are pulsed, The inspection apparatus is characterized in that the interval or the phase of the pulse is made different so that the signal obtained from each electron microscope apparatus is subjected to synchronous detection for the pulse .

According to a third aspect of the present invention, there is provided an inspection apparatus for inspecting a wafer by irradiating a wafer with a charged particle beam by arranging a plurality of electron microscope apparatuses, and an optical axis of the electron microscope apparatus disposed on the front surface side of the wafer. The optical axes of the electron microscope apparatuses arranged on the side surfaces are arranged spatially separated from each other, and the charged particle beams of at least two electron microscope apparatuses are made pulsed so that the pulse intervals or pulse phases are different. In addition , the inspection apparatus is characterized in that synchronous detection is performed on the pulse with respect to a signal obtained from each electron microscope apparatus .

According to a fourth aspect of the present invention, there is provided an inspection apparatus for inspecting a wafer by irradiating the wafer with a charged particle beam by arranging a plurality of electron microscope apparatuses, and an optical axis of the electron microscope apparatus disposed on the back side of the wafer. The optical axes of the electron microscope apparatuses arranged on the side surfaces are arranged spatially separated from each other, and the charged particle beams of at least two electron microscope apparatuses are made pulsed so that the pulse intervals or pulse phases are different. In addition , the inspection apparatus is characterized in that synchronous detection is performed on the pulse with respect to a signal obtained from each electron microscope apparatus .

The invention according to claim 5 is the inspection apparatus according to any one of claims 1, 2 , 3 , and 4, wherein at least one electron microscope apparatus has a magnetic field type lens, The electron microscope apparatus is an inspection apparatus having an electrostatic lens.

  According to a seventh aspect of the present invention, in the inspection apparatus described above, the electron microscope apparatus has an electrostatic lens.

  The invention according to claim 8 is the inspection apparatus according to the above-described inspection apparatus, wherein a secondary electron detector is arranged inside an electron microscope apparatus having an electrostatic lens.

  According to a ninth aspect of the present invention, in the inspection apparatus described above, an optical microscope for observing the edge upper surface of the wafer is used for alignment and high-speed inspection.

  According to a tenth aspect of the present invention, in the inspection apparatus described above, the inspection apparatus includes an optical microscope for observing the upper surface of the wafer edge, and has a zoom function or a function of switching at least two magnifications. .

  According to an eleventh aspect of the present invention, there is provided the inspection apparatus according to the above-described inspection apparatus, wherein the arrangement positions of the plurality of electron microscope apparatuses or charged particle beam apparatuses are variable.

The invention according to claim 11 has a function of inputting position coordinates of a defect detected using an optical wafer edge inspection apparatus and reviewing the position coordinates using a charged particle beam. Inspection equipment.

  In the inspection apparatus of the present invention, a plurality of electron microscope apparatuses are arranged spatially separated from each other so that charged particles do not interfere with each other on both sides of the wafer. Charged particles such as secondary electrons and reflected electrons generated from the laser beam are not erroneously detected by a detector of another electron microscope apparatus, and a good precision image can be obtained and the wafer edge can be observed and inspected.

  Embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a schematic explanatory view showing an inspection apparatus according to the present invention.

  FIG. 2 schematically shows the arrangement of the three small electron microscope apparatuses from above.

  1-2, three small electron microscope apparatuses are used, but the present invention is not limited to this, and two or four or more small electron microscope apparatuses may be arranged. Good.

  The wafer 1 to be inspected is, for example, a semiconductor wafer 1.

  The wafer 1 is placed on the turntable 2. The spindle of the rotary table 2 is placed on a fine movement XY stage (not shown). The turntable 2 can be moved in the XY directions and is configured to rotate by a drive mechanism (not shown).

  A camera 3 for alignment inspection, which is an optical microscope, is disposed on the upper side of the wafer 1. The center position of the wafer 1 is positioned and controlled to the rotation center of the drive mechanism described above by a control device not shown.

  The inspection apparatus shown in FIGS. 1 and 2 can be used for alignment and high-speed inspection, and has a zoom function and a switching function of at least two magnifications.

  Alignment is performed by detecting the position of the orientation flat or notch of the wafer 1. Since the center position of the wafer 1 is eccentric with respect to the turntable 2, the center of the spindle of the turntable 2 and the center position of the wafer 1 are made coincident with each other by a fine movement XY stage (not shown).

  Near the upper side of the wafer 1, a small electron microscope apparatus 4 (scanning electron microscope apparatus) for observing the edge upper surface for observing the edge upper surface of the wafer edge portion 1a is provided.

  Further, near the side surface of the wafer 1, a small electron microscope apparatus 5 (scanning electron microscope apparatus) for observing the edge side surface for observing the edge side surface (side) of the wafer edge portion 1a is provided.

  Further, a small electron microscope apparatus 6 (scanning electron microscope apparatus) for observing the edge back surface for observing the lower surface of the wafer edge portion 1 a is provided near the lower side of the wafer 1.

  As shown in FIG. 2, these small electron microscope apparatuses 4, 5 and 6 are spaced apart so that secondary electrons and reflected electrons detected by the secondary electron detector and reflected electron detector do not interfere with each other. The front and back surfaces of the wafer 1, particularly different portions of the edge portion 1 a (parts separated from each other) are observed and inspected. This is because the signals (secondary electrons, reflected electrons, etc.) obtained from the three electron microscope apparatuses 4, 5, 6 are separated.

  More specifically, the configuration in which all the electron microscope apparatuses 4, 5, 6 are arranged so as to be spatially separated from each other on both the front and back sides of the wafer 1 will be described. The electron beams of the respective electron microscope apparatuses 4, 5, 6 are The distance between the measurement points irradiated onto the edge portion 1a and inspected is 50 mm or more, and the respective electron microscope apparatuses 4, 5, and 6 are arranged.

  Specifically, the electron microscope apparatus 5 disposed on the edge side surface of the wafer 1 and the electron microscope apparatus 4 disposed on the upper surface of the wafer 1 are not a distance along the periphery of the wafer 1 but a linear distance of 50 mm or more. Place them apart. The electron microscope apparatus 4 arranged on the upper surface of the wafer 1 and the electron microscope apparatus 6 arranged on the lower surface of the wafer 1 are also arranged at a linear distance of 50 mm or more, not a distance along the periphery of the wafer 1.

  The arrangement of the electron microscope apparatuses 4, 5, and 6 shown in FIG. 2 is an example, and is not limited to this. The electron microscope apparatus 5 that is arranged on the edge side surface of the wafer 1 is arranged on the upper surface of the wafer 1. You may arrange | position between the electron microscope 4 and the electron microscope apparatus 6 arrange | positioned on the lower surface of the wafer 1, and the electron microscope apparatus 4 arrange | positioned on the upper surface of the wafer 1, and the electron arrange | positioned on the lower surface of the wafer 1. The arrangement position with the microscope device 6 may be changed.

  In addition, the optical axes of the electron microscope apparatuses 4, 5, and 6 do not coincide with each other and may be spaced away from each other, or the electron microscope apparatuses 4, 5, and 6 are spatially arranged apart from each other. May be.

  In the present application, “avoid interference of charged particles” means the following items. For example, signals (secondary electrons, reflected electrons, etc.) obtained from the edge 1a of the wafer 1 by the electron microscope apparatus 4 are only detected by the detectors (secondary electron detector, reflected electron detector, etc.) of the electron microscope apparatus 4. Detected and not detected by the detector (secondary electron detector, backscattered electron detector, etc.) of the electron microscope 5 arranged on the edge side surface (side) of the wafer 1, and the wafer 1 is detected by the electron microscope apparatus 5. Signals (secondary electrons, reflected electrons, etc.) obtained from the edge portion 1a of the wafer 1 are detected only by the detector of the electron microscope 5, and detected by the detector of the electron microscope 4 arranged on the upper surface of the edge 1a of the wafer 1. It will not be done. Similarly, signals (secondary electrons, reflected electrons, etc.) obtained from the edge 1a of the wafer 1 by the electron microscope apparatus 6 are detected by the detectors (secondary electron detector, reflected electron detector, etc.) of the electron microscope apparatus 6. The signal obtained from the edge portion 1a of the wafer 1 by the electron microscope apparatus 5 without being detected by the detector of the electron microscope 5 disposed on the edge side surface of the wafer 1 is It is detected only by the detector and is not detected by the detector of the electron microscope 6 disposed on the lower surface of the edge 1a of the wafer 1. Signals (secondary electrons, reflected electrons, etc.) generated by irradiating the edge 1a of the wafer 1 with the electron beams generated by the three electron microscope apparatuses 4, 5, 6 are detected by the detectors of the respective electron microscope apparatuses. It is detected only by (secondary electron detector, backscattered electron detector, etc.), and is not detected by a detector (secondary electron detector, backscattered electron detector, etc.) of another electron microscope apparatus.

  Also, for observing the edge side surface for observing the optical axis of the small electron microscope apparatus 4 for observing the edge upper surface of the edge portion (peripheral edge) of the wafer and the edge side surface (side) of the wafer edge portion. The optical axes of the small electron microscope apparatus 5 are arranged spatially separated from each other. For example, each optical axis is in a twisted position, for example, neither orthogonal nor parallel. More specifically, the electron microscope apparatus 5 disposed on the edge side surface of the wafer 1 and the electron microscope apparatus 4 disposed on the upper surface of the wafer 1 are not distances along the periphery of the wafer 1, Place them at a linear distance of 50 mm or more.

  Similarly, in the vicinity of the lower side of the wafer 1, in order to observe the optical axis of the small electron microscope apparatus 6 for observing the back surface of the edge for observing the lower surface of the wafer edge portion and the edge side surface (side) of the peripheral edge of the wafer. The optical axes of the small-sized electron microscope apparatus 5 for observing the edge side surface are arranged spatially separated from each other. That is, each optical axis is in a twisted position, for example, neither orthogonal nor parallel. More specifically, the electron microscope apparatus 4 disposed on the upper surface of the wafer 1 and the electron microscope apparatus 6 disposed on the lower surface of the wafer 1 are not distances along the periphery of the wafer 1 but are linear. The distance is preferably 50 mm or more.

  Further, the present invention is not limited to the three small electron microscope apparatuses 4, 5, and 6, and the present invention is an example in which a plurality of other small electron microscope apparatuses are arranged near the periphery of the edge portion (peripheral edge) 1 a of the wafer 1. including.

  Images obtained from these small electron microscope apparatuses 4, 5, 6 are displayed on a monitor (not shown), processed by an image processing apparatus (not shown), and displayed on a display (not shown). .

  Moreover, it is preferable that the charged particle beams of at least two electron microscope apparatuses among the three small electron microscope apparatuses 4, 5, 6 described above are pulsed so that the pulse intervals are different.

  The phase of the pulse may be different.

  It is preferable to perform synchronous detection on the pulse with respect to signals from secondary electron detectors, backscattered electron detectors and the like built in each of the small electron microscope apparatuses 4, 5, 6. This is because, by using a charged particle beam as a pulse wave, the beam can instantaneously reach a minute region such as a contact hole of the wafer 1 and observation and inspection can be performed in the minute region.

  Of the three small electron microscope devices 4, 5, and 6 described above, one electron microscope device has a magnetic lens (conventional electron microscope device), and the other two electron microscope devices are It may have an electrostatic lens. Manufacturing costs can be reduced by incorporating an electrostatic lens in a conventional electron microscope apparatus in which a magnetic lens is arranged.

  Further, all of the three small electron microscope apparatuses 4, 5, and 6 described above may have electrostatic lenses.

  A secondary electron detector is usually arranged inside the electron microscope apparatus having the electrostatic lens described above.

  The three small electron microscope apparatuses 4, 5, and 6 can be moved by an XYZθ actuator (not shown).

  Furthermore, in the inspection apparatus according to the present invention, for example, an optical wafer edge inspection apparatus such as an optical microscope is used to inspect the wafer, and position coordinates of detected defects, foreign matters, etc. are input to the inspection apparatus of the present invention. It is preferable to provide a function of finely inspecting and reviewing defects, foreign matters, and the like detected by an optical wafer edge inspection apparatus using a charged particle beam such as an electron beam. This makes it possible to quickly and finely identify the position of the detected defect, foreign matter, etc., and to inspect it finely using a charged particle beam such as an electron beam.

  As described above, when all the electron microscope apparatuses 4, 5, and 6 are preferably spatially separated from each other on both the front and back sides of the wafer 1, signals obtained from a plurality of electron microscope apparatuses (SEM) (SEM) Secondary electrons, reflected electrons, etc.) can be easily separated, and a fine and clear image can be obtained. Therefore, the yield of the wafer process due to microcracks in the edge portion 1a of the wafer 1 can be improved. As a result, fine foreign matters such as Cu, low-k, ARC, CVD, sputtered film, and polymer residue after dry etching, dust, etc. can be easily removed on the surface of the edge portion 1a of the wafer 1 or the back surface of the edge portion 1a. Can be found. Further, peeling or the like in the manufacturing process of the semiconductor wafer 1 can be eliminated.

  In the above embodiment, a plurality of small electron microscope apparatuses 4, 5, 6 are arranged around the edge 1 a of the wafer 1. However, the present invention is not limited to this, and a charged particle beam apparatus such as a small X-ray apparatus is used as the edge of the wafer 1. The inspection apparatus arrange | positioned on both sides of the front and back of the part 1a may be sufficient. In this case, an electron particle beam device may be disposed at each position of the small electron microscope devices 4, 5, and 6 illustrated in FIGS.

It is a schematic explanatory drawing which shows the inspection apparatus which concerns on this invention. The arrangement relationship of the three small electron microscope apparatuses shown in FIG. 1 is shown from above.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Wafer 2 Turntable 3 Camera 4 Small electron microscope apparatus for edge upper surface observation 5 Small electron microscope apparatus for edge side surface observation 6 Small electron microscope apparatus for edge back surface observation

Claims (11)

In an inspection apparatus for inspecting a wafer by irradiating a wafer with a charged particle beam by arranging a plurality of electron microscope apparatuses or charged particle beam apparatuses,
A plurality of electron microscope devices or charged particle beam devices are arranged spatially separated from each other on the front surface side, back surface side, and side surface side of the wafer ,
The charged particle beams of at least two electron microscope apparatuses are made pulsed, the pulse intervals or pulse phases are made different, and the signals obtained from the respective electron microscope apparatuses are synchronously detected with respect to the pulses. Inspection apparatus characterized by that. In an inspection apparatus in which a plurality of electron microscope apparatuses are arranged and a wafer is irradiated with a charged particle beam to inspect the wafer,
A plurality of electron microscope devices are arranged apart from each other in a form in which the optical axis of the electron microscope device arranged on the front surface side of the wafer does not coincide with the optical axis of the electron microscope device arranged on the back surface side ,
The charged particle beams of at least two electron microscope apparatuses are made pulsed, the pulse intervals or pulse phases are made different, and the signals obtained from the respective electron microscope apparatuses are synchronously detected with respect to the pulses. Inspection apparatus characterized by that. In an inspection apparatus in which a plurality of electron microscope apparatuses are arranged and a wafer is irradiated with a charged particle beam to inspect the wafer,
The optical axis of the electron microscope apparatus arranged on the front surface side of the wafer and the optical axis of the electron microscope apparatus arranged on the side surface side are arranged spatially separated from each other ,
The charged particle beams of at least two electron microscope apparatuses are made pulsed, the pulse intervals or pulse phases are made different, and the signals obtained from the respective electron microscope apparatuses are synchronously detected with respect to the pulses. Inspection apparatus characterized by that. In an inspection apparatus in which a plurality of electron microscope apparatuses are arranged and a wafer is irradiated with a charged particle beam to inspect the wafer,
The optical axis of the electron microscope device arranged on the back side of the wafer and the optical axis of the electron microscope device arranged on the side surface are arranged spatially separated from each other ,
The charged particle beams of at least two electron microscope apparatuses are made pulsed, the pulse intervals or pulse phases are made different, and the signals obtained from the respective electron microscope apparatuses are synchronously detected with respect to the pulses. Inspection apparatus characterized by that. In the inspection apparatus according to any one of claims 1, 2 , 3 , and 4,
At least one electron microscope apparatus has a magnetic lens, and the other electron microscope apparatus has an electrostatic lens. In the inspection apparatus according to any one of claims 1, 2, 3, and 4,
An inspection apparatus characterized in that the electron microscope apparatus has an electrostatic lens. In the inspection apparatus according to any one of claims 1, 2, 3, and 4,
An inspection apparatus, wherein a secondary electron detector is disposed inside an electron microscope apparatus having an electrostatic lens. In the inspection apparatus according to any one of claims 1, 2, 3, 4, 5, 6, and 7,
An inspection apparatus, wherein an optical microscope for observing the upper surface of a wafer edge is used for alignment and high-speed inspection. In the inspection apparatus according to any one of claims 1, 2, 3, 4, 5, 6, and 7,
An inspection apparatus, wherein an optical microscope for observing an upper surface of a wafer has a zoom function or a switching function of at least two magnifications. The inspection apparatus according to any one of claims 1, 2, 3, 4, 5, 6, and 8 , wherein the arrangement positions of the plurality of electron microscope apparatuses or charged particle beam apparatuses are variable. Inspection device. Enter the position coordinates of the detected defect using an optical wafer edge inspection apparatus, in any one of claims 1 to 9, characterized in that it has a function to review the position coordinates using a charged particle beam The inspection device described.

Images