JP2003203883A - Microscope and observing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a microscope, and its observing method, in which the surface and rear surface of a semiconductor, e.g. a silicon wafer, or a work, e.g. an electronic component material, can be observed readily without requiring exchange of a microscope for picking up the surface image and a microscope for picking up the rear surface image. <P>SOLUTION: A CCD camera 12E for white light picking up a white light image and a CCD camera 12F for IR picking up an infrared light image are built in a microscope 12 for observing a work W so that a white light image and an infrared light image can be picked up simultaneously or individually through electrical switching without. replacing the microscope or the CCD camera. Consequently, the surface and rear surface of a work W, e.g. a silicon wafer, can be observed extremely easily. In the dicing process of a semiconductor wafer, surface and rear surface images of the work are displayed simultaneously on one monitor screen so that chipping occurring at the edge part of a cut groove on the surface side of the wafer and chipping on the rear surface side can be observed comparatively and machining quality can be evaluated readily. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microscope for observing a work and a work observing method using the microscope.
In particular, the present invention relates to a microscope for observing the front surface and the back surface of a work, which is used in a dicing device or the like for grooving or cutting a work such as a semiconductor or electronic component material, and an observation method thereof.

[0002]

2. Description of the Related Art A workpiece such as a semiconductor or electronic component material is subjected to groove processing and cutting processing by a dicing device. In a dicing device, a thin grindstone called a blade that rotates at high speed is used to process a workpiece while applying grinding water. This dicing device is provided with a microscope for observing a workpiece to be processed, and the microscope has a CCD for picking up a microscope image.
A camera is built in. Workpiece alignment is performed using this microscope prior to processing. The alignment is performed by taking a microscopic image of the circuit pattern formed on the surface of the work with the CCD camera. A normal white light CCD camera is used to capture the surface image of the work.

Among semiconductor works, for example, CCD
When cutting a workpiece such as a wafer that extremely dislikes dirt on the surface, place it on the work table with the surface side of the workpiece facing down so that the grinding powder during grinding does not adhere to the workpiece surface. Grooves are grinded from the back side. In this case, the alignment of the work must capture an image of the circuit pattern on the front side of the work from the back side of the work, which cannot be captured by a normal CCD camera for white light. In such a case, Inf
CCD camera for rare ray (hereinafter CCD for IR
Take a picture with a camera.

Further, since a work such as a semiconductor is a highly brittle material, chipping is likely to occur at the edge of the cutting groove. Therefore, it is necessary to observe the processing state of the work after cutting. In this case, the edge chipping of the groove on the surface side of the work is observed by imaging with a normal CCD camera for white light. In addition, for chipping on the back surface side, infrared light is emitted from the front surface side of the work, transmitted through the work, reflected by the back surface of the work, and returning light is imaged by an IR CCD camera.

[0005]

However, the microscope used in this conventional dicing apparatus is a microscope in which a CCD camera for normal white light is incorporated and a microscope in which a CCD camera for IR is incorporated. And were separate and independent microscopes. For this reason, a microscope in which a CCD camera for white light is incorporated and a CC for IR are used for imaging the front surface of the work and the back surface of the work.
I had to replace the microscope with the D camera built in. For this reason, every time the microscope is exchanged, the posture and position of the microscope must be adjusted, which requires a lot of man-hours for observing the work. Further, when it is desired to display the front surface image and the back surface image of the work on one screen at the same time, a very complicated operation is required, and when observing various parts of the work, it is practically impossible. .

The present invention has been made in view of such circumstances, and when observing the front and back surfaces of a workpiece such as a semiconductor such as a silicon wafer or an electronic component material, a microscope for front surface imaging and a back surface imaging are used. An object of the present invention is to provide a microscope capable of easily observing the front surface and the back surface without requiring replacement with the microscope, and an observation method thereof.

[0007]

In order to achieve the above object, the present invention is a microscope for observing a work, wherein the microscope includes a CCD camera for capturing a white light image and an infrared light image. It is characterized in that it has a built-in IR CCD camera. According to the microscope of the present invention, the white light image and the infrared light image can be taken simultaneously or separately by electrically switching them without replacing the microscope or the CCD camera. Therefore, the front and back surfaces of a work such as a silicon wafer can be observed very easily.

Further, in the present invention, in the method of observing the front surface and the back surface of a work by using the microscope, the step of focusing the microscope on the surface of the work and the step of focusing the microscope on the back surface of the work. And CC for capturing the white light image on the surface of the work from the front side of the work.
D camera, a step of picking up the back surface of the work from the front side of the work by an IR CCD camera for picking up the infrared light image, a step of storing the picked-up image, the white light image And a step of simultaneously displaying on the same monitor screen a front surface image of the work captured by a CCD camera that captures the image and a back surface image of the work captured by the IR CCD camera that captures the infrared light image. It features a method of observing the front and back surfaces of.

According to the observation method of the present invention, the front surface image of the work and the back surface image of the work can be simultaneously displayed on one monitor screen. Therefore, for example, in a dicing step of a semiconductor wafer, a cutting groove on the front surface side of the wafer is formed. The chipping generated on the edge and the chipping on the back surface side can be compared and observed, and the processing quality can be easily evaluated. Further, by memorizing the position where the surface of the microscope is focused on the front surface and the position where the surface of the microscope is focused on the rear surface of the workpiece, it is possible to automatically create an observation image of the front surface and the rear surface of the same type of workpiece.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of a microscope according to the present invention will be described in detail below with reference to the accompanying drawings, and a method of observing a work when the microscope is provided in a dicing device will be described as an example. In each figure, the same members are given the same numbers.

FIG. 1 is a conceptual diagram showing the structure of a microscope according to the present invention. The microscope 12 is a stereoscopic microscope for observing the work W placed on the work table 25, and includes an objective lens 12A, eyepieces 12B and 12C, as shown in FIG.
Half mirrors 12D, 12J, CCD camera 1 for white light
2E, an IR CCD camera 12F, a filter 12G, a converging lens 12H, a light source 12I, and the like.

The half mirror 12D splits the optical path into a straight optical path and an optical path perpendicular to the straight optical path. Eyepiece 12
The image pickup surfaces of the white light CCD camera 12E and the IR CCD camera 12F are located at the focal positions of B and 12C, respectively. A filter 12G that transmits only infrared light is inserted between the eyepiece lens 12C and the IR CCD camera 12F. Further, the light source 1 for illuminating the work W through the converging lens 12H and the half mirror 12J.
2I is incorporated. CCD camera 12E for white light,
And the IR CCD camera 12F are the image processing devices 17 respectively.
To the monitor television 13. Further, the microscope 12 is moved in the vertical direction by the microscope vertical drive means 16.

Next, the operation of the microscope 12 constructed as above will be described. As shown in FIG. 1, the observed work W is placed on the work table 25 with its front surface facing up and its back surface facing down. The illuminating light emitted from the light source 12I is supplied to the microscope 12 by the converging lens 12H.
Converged to illuminate the focal position of the half mirror 1
The optical path is vertically changed downward by 2J to illuminate the work W. The image of the workpiece W observed is the objective lens 1
After passing through 2A, it is bent at a right angle by the half mirror 12D and the white light CCD camera 1 by the eyepiece lens 12B.
An image is formed by focusing on the imaging surface of 2E. The white light CCD camera 12E captures the formed image and outputs it as digital data to the image processing device 17. On the other hand, the light traveling straight through the half mirror 12D is converged by the eyepiece lens 12C,
CC for IR as an infrared image transmitted through the filter 12G
An image is formed on the imaging surface of the D camera 12F. This infrared light imaging screen is imaged by the IR CCD camera 12F and is also output to the image processing device 17 as digital data.

As described above, since the microscope 12 of the present invention incorporates the white light CCD camera 12E and the IR CCD camera 12F, the image of the work W is picked up as a white light image or electrically. It is possible to pick up an infrared light image by switching to, and it is also possible to pick up a white light image and an infrared light image at the same time.

FIG. 2 shows a dicing apparatus equipped with the microscope 12 of the present invention for cutting a workpiece such as a semiconductor or electronic component material into individual chips. The dicing device 10 is
The work W is processed by the processing unit 20 covered with the mist cover 40. In the processing unit 20, a rotary blade (not shown) that performs groove processing and cutting processing of the work W is attached to the air bearing spindle incorporated in the high frequency motor, and 30,000 r
It is rotated at a high speed of pm to 60,000 rpm, and is index-fed in the arrow Y direction in the figure by a feed mechanism (not shown). This rotating blade is a thin disk,
An electrodeposition blade in which diamond abrasive grains or CBN abrasive grains are electrodeposited with nickel, or a resin blade bonded with resin is used. The work W to be processed is sucked and fixed on the upper surface of the work table 25 and is fed by grinding in the direction of arrow X in the figure.

A microscope 12 for observing the surface of the work W is provided outside the processing section 20, and the image is taken by the CCD camera 1.
It can be observed on the screen of the monitor TV 13 via 2E and 12F. The operation / display unit 11 is provided with switches and display means for operating each unit of the dicing device 10. The controller 15 is a part that controls each operation of the dicing device 10, and includes a microprocessor,
It is composed of a memory, an input / output circuit, and the like, and is stored inside the pedestal of the dicing device 10. The indicator lamp 14 displays the dicing apparatus 10 in operation, processing completion, standby, alarm, etc., and is provided at a high position so that it can be seen from a distance.

The work W placed on the work table 25
Is observed with the microscope 12 for alignment before processing or for examining the size of chipping generated at the edge of the grinding groove after processing. In the case of the alignment of the work W, since the normal work W is placed on the work table 25 with the surface side on which the alignment pattern is formed facing up, the white light CCD camera 12E images the alignment pattern. To do. When the work W is a light receiving element, a CCD, or a light emitting element, in order to prevent the grinding powder from adhering to the surface during dicing, the work may be placed with the pattern surface facing down and dicing from the back surface side. In such a case, the alignment is performed by using the infrared light passing through the work W and capturing the infrared light image with the IR CCD camera 12F. When checking the size of chipping generated at the edge of the grind groove after processing, CC for white light
White light image of the surface by D camera 12E and IR CC
This is performed using an infrared light image of the back surface obtained by the D camera 12F.

The microscope 12 of the present invention includes a CCD for white light.
Since both the camera 12E and the IR CCD camera 12F are incorporated, it is not necessary to replace the microscope or the CCD camera in the observation of the front surface and the back surface of the work W, and the conventional imaging method is performed each time. Compared with other equipment, man-hours are greatly reduced.

FIG. 3 is a flow chart showing an example of an embodiment of the method for observing the front surface and the back surface of a work according to the present invention. As shown in FIG. 1, the observed work W is placed on the work table 25 with the front surface facing up and the back surface facing down. When observing the front surface and the back surface of the work W, as shown in FIG. 3, the operation of focusing the microscope 12 on the front surface of the work W to be observed first is performed. It is confirmed whether or not the position of the in-focus microscope is previously stored as position data (step S11). If the data is stored, the microscope drive means 16 is driven based on the stored position data, and the focus is automatically adjusted (step S14). If the position data is not stored, the microscope driving means 16 is manually operated for focusing (step S12). The position data focused by this manual operation is stored (step S13). When the automatic or manual focusing of the microscope 12 on the surface of the work W is completed, the surface image of the work W is captured by the white light CCD camera 12E (step S15), and the image data is stored in the image processing device 17 as digital data. Is performed (step S16).

Next, the operation of focusing the microscope 12 on the back surface of the work W will be described. Also here, it is confirmed whether or not the position data of the microscope on which the microscope 12 is focused is stored on the back surface of the work W (step S17). If the data is stored, the microscope driving means 16 is driven based on the stored position data, and the focus is automatically adjusted (step S120). If the position data is not stored, the microscope driving means 16 is manually operated for focusing (step S18). Position data focused on the back surface of the work W by this manual operation is also stored (step S19). When the focus of the microscope 12 on the back surface of the work W is completed automatically or manually, the back surface image of the work W is captured by the IR CCD camera 12F (step S21), and the image data is stored in the image processing device 17 as digital data. (Step S22). Next, the image data of the front surface and the back surface of the work W that is picked up and stored is processed by the image processing device 17, the front surface image and the back surface image of the work W are combined into one screen, and the monitor of the monitor TV 13 is displayed. It is displayed on the screen (step S23).

FIG. 4 shows a monitor screen of the monitor television 13 created by the above method. The small screen in the center of the screen represents the backside monitor image 13B of the work W,
The screen of the peripheral portion represents the surface monitor image 13A of the work W. In both cases, the grinding groove formed in the work W and the state of chipping generated at the edge thereof are observed. From this screen, it is observed that the chipping generated on the back surface of the work W is smaller than the chipping on the front surface. In this way, the processing statuses of the front surface and the back surface can be simultaneously displayed on one screen on the composite screen, so that the processing quality can be easily evaluated.

In the present embodiment, the microscope 12 is provided with the half mirror 12D and branched into the optical path entering the white light CCD camera 12E and the optical path entering the IR CCD camera 12F. However, the present invention is not limited to this. , Half mirror 12D
Instead of the above, a movable total reflection mirror is provided, and the optical path is made incident on the CCD camera 12E for white light and the CCD for IR.
You may make it switch to the case where it injects into the camera 12F. Further, although the illumination light source is the common light source for white light and infrared light, the infrared light source may be provided separately and switched according to the purpose. Further, although the illumination is configured as coaxial illumination, it may be oblique illumination, or both coaxial illumination and oblique illumination may be provided and used properly according to the purpose.

[0023]

As described above, according to the present invention, the microscope is equipped with a CCD camera for capturing a white light image and an IR CCD camera for capturing an infrared light image. The white light image and the infrared light image can be simultaneously or electrically switched and individually captured without replacing the CCD camera. Therefore, the front and back surfaces of a work such as a silicon wafer can be observed very easily. Further, since it is not necessary to replace the microscope and it is not necessary to prepare two kinds of microscopes, it is possible to reduce the equipment cost and the downtime of the device due to the microscope replacement.

Further, since the front surface image of the work and the back surface image of the work can be simultaneously displayed on one monitor screen, for example, in the dicing process of a semiconductor wafer, chipping that occurs at the edge of the cutting groove on the front surface side of the wafer and The chipping on the back surface side can be easily compared and observed, and the processing quality can be accurately evaluated. Furthermore, by storing the position where the surface of the microscope is focused on the front surface and the position where the surface of the microscope is focused on the rear surface of the microscope, it is possible to automatically create an observation image of the front surface and the rear surface of the same type of workpiece.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing a configuration of a microscope according to an embodiment of the present invention.

FIG. 2 is a perspective view of a dicing device equipped with the microscope of the present invention.

FIG. 3 is a flowchart illustrating an observation method according to an embodiment of the present invention.

FIG. 4 is a conceptual diagram showing a monitor screen according to the observation method of the present invention.

[Explanation of symbols]

W ... Work, 10 ... Dicing device, 12 ... Microscope, 1
2A ... Objective lens, 12B, 12C ... Eyepiece lens, 12
D, 12J ... Half mirror, 12E ... White light CCD camera, 12F ... IR CCD camera, 12H ... Converging lens, 12I ... Light source, 13 ... Monitor TV,
25 ... Work table

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuya Fukuoka             9-7 Shimorenjaku, Mitaka City, Tokyo Stocks             Company Tokyo Seimitsu F term (reference) 2H052 AA11 AB25 AC13 AC14 AD02                       AF21 AF25

Claims (2)

[Claims] 1. A microscope for observing a work, wherein the microscope includes a CCD camera for capturing a white light image and an IR CCD camera for capturing an infrared light image. A microscope to do. 2. A method for observing a front surface and a back surface of a work by using the microscope according to claim 1, wherein the step of focusing the microscope on the front surface of the work and the focus of the microscope on the back surface of the work. And a step of capturing the surface of the work from the front side of the work with a CCD camera that captures the white light image, and a CCD camera for IR that captures the back surface of the work from the infrared light image of the back side of the work And a step of storing the captured image, a surface image of the work captured by a CCD camera that captures the white light image, and an IR CC that captures the infrared light image.
A method of observing the front surface and the back surface of a work, which includes a step of simultaneously displaying a back surface image of the work captured by a D camera on one monitor screen.