JPH10300441A - Semiconductor inspecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To take the image of an intended wide ranged area on an object with a high resolution only by a lighting means to the object by providing the image of a semiconductor chip of the object by use of a lens, and switching the object visual field by an optical axis deflection switching means. SOLUTION: In the measurement of a semiconductor chip 1 in one field of view, X, Y-directional galvano-mirrors 15a, 15b are driven and positioned so that the optical axes are coincident to a reference position. An image is formed on an X-directional CCD line sensor 16a through an objective lens 17, the galvano-mirrors 15a, 15b, a half mirror 22, an imaging lens 18, and an optical axis branching mirror group 23. In case of an X-axially long image, the galvano-mirror Y15b is driven without using a Y-directional line sensor 16b to form a two-dimensional image data in an image processing unit 25. In the measurement of the chip in the other field of view, the galvano-mirrors 15a, 15b are driven and positioned to form the image on the Y-directional line sensor 16b. In case of a Y-axially long image, the galvano-mirror X15a is driven without using the X-directional line sensor 16a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor inspection apparatus for inspecting the appearance of a wire bonded to a pad of a semiconductor chip and a lead of a lead frame.

[0002]

2. Description of the Related Art In recent semiconductor device manufacturing technologies,
Along with the integration of elements, the size and the fine pitch of the leads are rapidly progressing, and along with this, the unmanned operation by introducing automated equipment into the manufacturing process is progressing.

[0003] On the other hand, as for the inspection process which is a post-process,
At last, the transition from visual inspection to automation has been attempted.

FIG. 10 is a configuration diagram of a conventional wire bonding inspection apparatus described in, for example, Japanese Patent Application Laid-Open No. 7-63528. In the figure, 1 is a semiconductor chip to be inspected, 3 is oblique illumination for illuminating the semiconductor chip 1, 4 is epi-illumination for illuminating the semiconductor chip 1,
5 is imaging means for capturing an image of the semiconductor chip 1,
Reference numeral 6 denotes an oblique illumination 3, an epi-illumination 4, and an optical head in which the imaging unit 5 is assembled. Reference numeral 2 denotes an XYZ stage for positioning the imaging unit 5 (optical head 6) with respect to the semiconductor chip 1. An illumination control unit for adjusting the light quantity of the epi-illumination 4 and switching the illumination; an image processing unit 8 for analyzing image data taken in by the imaging means 5; a stage control unit 9 for driving and controlling the XYZ stage 2; Is an overall control unit that performs the above control.

FIG. 6 is a schematic view of a semiconductor chip 1 to be inspected by the present apparatus. 11 denotes a ball, 12 denotes a wire, 13 denotes a stitch, and 14 denotes a lead.

The semiconductor chip 1 as an object is
The image pickup means 5 is moved to the position where the first ball portion exists using the YZ stage 2, and the image of the ball 11 is captured after focusing. The image at this time is as shown in FIG. 7, for example, and a plurality of balls 11 are captured in one screen.

Thereafter, in order to measure all the balls in the semiconductor chip 1, every time the ball is inspected, the number of times of the stage (the total number of balls in the chip / the number of balls that can be captured in one screen) is determined. The movement in the XY directions is repeated.

[0008] Further, similarly to the ball, the wire and the stitch are moved to the first target item position and focused, and then, (the total number of wires in the chip / the number of wires that can be taken in one screen) The stage is moved in the X and Y directions several times (the total number of stitches in the chip / the number of stitches that can be captured in one screen), and the image of each item is captured. In these images, a plurality of wires 12 and stitches 13 are captured in one screen as in the case of the ball 11, as shown in FIG. 8 for wires and FIG. 9 for stitches. The inspection time by this method is, for example, 200
In the case of a pin semiconductor chip, it takes about 2 minutes per chip to inspect all items.

As another method, a ball 11, a wire 12, a stitch 1
If all 3 or any two of the three items are taken, the number of movements of the XYZ stage 2 in the XY directions is reduced, but the number of movements of focusing in each inspection item, that is, the number of movements in the Z-axis direction is reduced. To increase.

[0010]

As described above, the size of semiconductor chips and the fine pitch of leads are rapidly increasing due to integration, and the precision of fine inspection and the area to be inspected are wide. In order to inspect the whole area of each item of the semiconductor chip by the above-described procedure, a high-speed stage movement is required. Further, for high-precision inspection, high-resolution imaging means may be used to increase the imaging magnification. However, with this, the number of inspection portions that can be captured on one screen decreases, and the number of times the XYZ stage 2 moves increases. . However, the optical head 6 assembled with the oblique illumination 3, the epi-illumination 4, and the imaging means 5 is large and heavy in terms of structure, so that the XYZ stage 2 is used to move the optical head 6 at high speed and frequently. Is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and has as its object to provide a semiconductor inspection apparatus capable of capturing an image of a wide area at a high resolution and at a high speed.

[0012]

A semiconductor inspection apparatus according to a first configuration of the present invention is an object in a semiconductor inspection apparatus for performing an appearance inspection of a wire bonded to a pad of a semiconductor chip and a lead of a lead frame. Lens means for obtaining an optical image of an object on a semiconductor chip, optical axis deflection switching means for switching a field of view of an object, illumination means for the object, and imaging for imaging an optical image obtained from the lens means Means.

The semiconductor inspection apparatus according to the second configuration of the present invention uses a galvanomirror as the optical axis deflection switching means.

Further, the semiconductor inspection apparatus according to the third configuration of the present invention uses a CCD line sensor as the imaging means.

In a fourth aspect of the present invention, a semiconductor inspection apparatus according to a fourth aspect of the present invention provides a driving system for the optical axis deflection switching means, which synchronizes with a video fetch timing of the image pickup means and which corresponds to the licensor element size for each video fetch. A two-dimensional image is formed by giving a moving speed corresponding to the imaging size for one minute.

In a semiconductor inspection apparatus according to a fifth aspect of the present invention, a driving point of the optical axis deflection switching means is limited, so that an image of a rectangular area of only a necessary portion is taken into the imaging means. .

Further, in a semiconductor inspection apparatus according to a sixth configuration of the present invention, two sets of the optical axis deflection switching means and the imaging means are arranged for scanning in the X and Y axis directions.

In the semiconductor inspection apparatus according to a seventh aspect of the present invention, the imaging unit is connected to the driving unit, and the licensing device is connected to the driving unit every time the image is captured while synchronizing with the video capturing timing of the imaging unit. By giving a moving speed corresponding to the imaging size corresponding to the size, the imaging means itself is driven to form a two-dimensional image.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be specifically described with reference to the drawings showing the embodiments. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a semiconductor inspection apparatus according to a first embodiment of the present invention. More specifically, FIG. 1 shows a configuration of a semiconductor inspection apparatus that performs an appearance inspection of a wire bonded to a pad of a semiconductor chip and a lead of a lead frame. Is shown. In the figure, reference numeral 1 denotes a semiconductor chip to be inspected, which is positioned on an inspection table (not shown). Reference numerals 15a and 15b denote X-axis deflection galvanometer mirrors (hereinafter, X-direction galvanometer mirrors) and Y-axis deflection galvanometer mirrors (hereinafter, Y-direction galvanometer mirrors) which are optical axis deflection switching means, respectively, and 16a and 16b denote imaging means, respectively. A certain CCD line sensor for taking in the X-axis direction (hereinafter referred to as X-direction CCD line sensor), a CCD line sensor for taking in the Y-axis direction (hereinafter referred to as Y-direction CCD line sensor), and 17 and 18 are objective lenses as lens means, respectively. It is an image lens. 19 is a galvanomirror 15
The entire area of the semiconductor chip 1 to be inspected is a galvanomirror 15a in the X and Y directions.
15b. Reference numeral 20 denotes oblique illumination as illumination means, which is provided between the semiconductor chip 1 and the objective lens 17. 21 is an epi-illumination which is also a lighting means,
The X- and Y-direction galvanometer mirrors 15 a and 15 b are installed so as to be incident from between the imaging lens 18. 22, 2
Reference numeral 3 denotes an optical axis branching mirror group. Reference numeral 24 denotes a galvano control unit for driving and controlling the X and Y direction galvanometer mirrors 15a and 15b; 25, an image processing unit for analyzing image data taken from the X, Y direction CCD line sensors 16a, 16b; , Epi-illumination 2
An illumination control unit 27 for controlling light amount adjustment and illumination switching 1 is an overall control unit for controlling the entire system.

Next, a measuring method will be described with reference to FIGS. FIG. 2 is a schematic view of a semiconductor chip for explaining the effect of the image capturing method according to the first embodiment of the present invention, and FIG. 3 is a diagram for explaining the effect of the image capturing method according to the first embodiment of the present invention. FIG. 4 is an enlarged view of a ball portion, and FIG. 4 is a principle diagram of an optical system for explaining an image capturing method according to the first embodiment of the present invention. When the semiconductor chip 1 is positioned on an inspection table (not shown), the irradiation state of the oblique illumination 20 and the epi-illumination 21 is set so as to realize the optimal imaging state of the target inspection item, and X, Y
The direction galvanometer mirrors 15a and 15b are driven so that the optical axis is aligned with the reference position of the part to be the first inspection item. For example, as shown in FIG. 2, when measuring the ball 11 included in the area 29a, the optical axis is set to the reference position 28a.
X, Y direction galvanometer mirrors 15a, 15b to match
Drive and position. The image of the portion of the region 29a of the semiconductor chip 1 includes the objective lens 19, the X and Y direction galvanometer mirrors 15a and 15b, the half mirror 22, the imaging lens 18,
An image is formed on the X-direction CCD line sensor 16a through the optical axis branching mirror group 23. Note that when capturing an image in which the X direction is horizontally long as in the area 29a, the Y direction CCD
The line sensor 16b is not used.

Here, the X-direction line sensor 16a receives image data of one line in the X-axis direction passing on the reference position 28a. Therefore, in order to capture the image data of the rectangular area indicated by 29a, as shown in FIG. 4, the X-direction line sensor 1
6a corresponding to the size of one element (a /
The galvanomirror Y15b is driven by the distance n).
In other words, the galvanomirror Y15b is driven by the number of lines required to measure the ball 11 while synchronizing with the X-direction line sensor 16a taking in the image data at the speed v obtained from the following formula, Two-dimensional image data of the rectangular area 29a is formed in the image processing unit 25. v = (a / n) / t (1)

FIG. 3 shows an example of the image area 30 of the ball 11 taken in by the above procedure. Here, for example, X
When the element of the direction line sensor 16a is composed of 5000 pixels per line and captures at a resolution of about 2 μm per pixel, an image having a size of about 10 mm in the line direction (X direction) can be captured, and the required number of lines in the Y direction can be obtained. Only, for example, if you need 0.3mm in the Y direction, only 150 lines,
What is necessary is just to set so that the Y-direction galvanometer mirror 15b may be driven. In this way, it is possible to capture an image of only a rectangular area required for inspection in a wide field of view such as 10 mm × 0.3 mm in one image capturing operation at high speed and with high resolution.

By the way, with the same resolution as the above CCD line sensor, a general CCD area sensor (5
When an image is captured at about 00 × 500 pixels), a single capturing operation causes the area 31 shown in FIG.
An image having a size of about 1 mm is to be captured. To capture an area having the same size as the area 30 captured by the above-described CCD line sensor, it is necessary to capture about 10 times in the X direction. In addition, in the Y direction, an area other than the ball 11 that is unnecessary for the inspection is unnecessarily taken in. In this example, about three times waste occurs.

Similarly, when the stitch 13 in the area 29b is measured as shown in FIG. 2, the oblique illumination 20 and the oblique illumination 20 are used so as to realize the optimum imaging state for the stitch 13 as in the case of the ball 11 measurement. The irradiation state of the epi-illumination 21 is set, and the X and Y direction galvanometer mirrors 15a and 15b are driven and positioned so that the optical axis is aligned with the reference position 28b.
The image of the portion 9b is formed on the Y-direction line sensor 16b through the objective lens 19, the X and Y direction galvanometer mirrors 15a and 15b, the half mirror 22, the imaging lens 18, and the optical axis branching mirror group 23. Note that the X direction line sensor 16a is not used when capturing an image in which the Y direction is horizontally long as in the area 29b.

Then, similarly to the measurement of the ball 11 in the area 29a, while the galvanomirror X15a is being driven, image data for one line is fetched one by one by the CCD line sensor Y16b. Is formed.

The inspection time by the above method is, for example, about 40 seconds per chip for inspecting all items on a 200-pin semiconductor chip.

In the first embodiment, the epi-illumination 21 is controlled by the X- and Y-direction galvanometer mirrors 15 via the optical axis branching mirror 22.
It has been described that the optical axis branching mirror 22 is installed between the imaging lens 18 and the optical axis branching mirror 23, and the imaging lens 18 is installed. And from the space between the optical axis branching mirror 23,
A similar effect can be obtained in lighting.

Embodiment 2 In the above embodiment, when the rectangular area of the image data is horizontally long in the X direction and horizontally long in the Y direction, the X and Y direction galvanometer mirrors 15a and 15b and the X and Y direction line sensors 16 are respectively provided.
a and 16b are used properly. For example, while taking an X-direction landscape image such as 29a and analyzing the image data of 29a, taking a Y-direction landscape image such as 29b is performed. Parallel processing of image capture and image data analysis is possible with the configuration of the present invention. By performing the two types of processing in parallel in this manner, the inspection time can be further reduced.

Embodiment 3 In the first embodiment, when an image of a rectangular area horizontally long in the X-axis direction, such as when inspecting the ball 11 in the area 29a, is taken into the X-direction CCD line sensor 16a, the Y-direction galvanometer mirror 15b is driven. However, as shown in FIG. 5, the X-direction line sensor 16a itself is moved to the Y direction orthogonal to the sensor array direction by using the sensor driving unit 32 as shown in FIG.
The galvanomirror is used only to align the optical axis with the reference position 28a, and the X-direction line sensor 15a itself is driven at the speed shown in FIG. Then, the rectangular area 29a can be captured. If the Y-direction line sensor 16b can be driven in the X direction orthogonal to its own sensor array, it can be applied to image capture of a rectangular area horizontally long in the Y-axis direction such as the area 29b. That is, the X- and Y-direction line sensors 16a and 16b, which are imaging means, have the optical axis deflection switching function.

Embodiment 4 In the first embodiment, the semiconductor chip 1 that requires a horizontally long inspection area in both the X and Y directions, such as the areas 29a and 29b, has been described.
The present invention can also be applied to a semiconductor chip 1 that requires only a horizontally long inspection area in only one direction of X or Y, such as a dual in-line type chip. For example, when only an inspection area that is horizontally long in the X direction is required, in FIG.
b becomes unnecessary.

[0031]

Since the present invention is configured as described above, it has the following effects.

According to the semiconductor inspection apparatus of the first configuration of the present invention, in the semiconductor inspection apparatus for inspecting the appearance of the wire bonded to the pad of the semiconductor chip and the lead of the lead frame, the inspection of the semiconductor chip as the object is performed. By controlling the optical axis deflection switching means for switching the field of view of the object, the lens means and the illumination means for obtaining an optical image of the object, and the illumination means for the object only, the target area of the target on the object is The image can be taken into the image pickup means for picking up an optical image obtained from the lens means, and it is not necessary to separately provide a drive means on the lens means or the object mounting table.

Further, according to the semiconductor inspection apparatus of the second configuration of the present invention, high-speed positioning can be performed by using the galvanomirror for the optical axis deflection switching means, and the target image data on the object can be obtained. It is possible to take in the image pickup means.

Further, according to the semiconductor inspection apparatus of the third configuration of the present invention, by using a CCD line sensor for the image pickup means, it is possible to capture image data of a wide field of view and high resolution into the image pickup means. It becomes possible.

Further, according to the semiconductor inspection apparatus of the fourth configuration of the present invention, the licensor element is connected to the drive system of the optical axis deflection switching means for each image capture while synchronizing with the image capture timing of the imaging means. High-speed positioning can be performed by giving a moving speed corresponding to the imaging size corresponding to the size, and target image data on an object is taken into the imaging means and developed into a wide-field, high-resolution two-dimensional image. Becomes possible.

Further, according to the semiconductor inspection apparatus of the fifth configuration of the present invention, by limiting the driving points of the optical axis deflection switching means, the image data of the rectangular area of only the necessary portions can be taken into the imaging means. Can be performed, and imaging processing of a portion unnecessary for measurement is eliminated, and high-speed image capturing is enabled.

According to the semiconductor inspection apparatus of the sixth configuration of the present invention, two sets of the optical axis deflection switching means and the imaging means are arranged for scanning in the X and Y axis directions, respectively. Efficient image capture according to the shape of the object can be performed.

Further, according to the semiconductor inspection apparatus having the seventh configuration of the present invention, the imaging means is connected to the driving means, and the driving means is synchronized with the video capturing timing of the imaging means every time the video is captured. By providing the speed of moving by the imaging size corresponding to the licensor element size and driving the imaging unit itself, the imaging unit itself has the optical axis deflection switching function, and the same as when using the optical axis deflection switching unit In addition, it becomes possible to capture the target image data on the object into the imaging means and develop it into a two-dimensional image with a wide field of view and high resolution.

[Brief description of the drawings]

FIG. 1 is a configuration diagram illustrating a semiconductor inspection device according to a first embodiment of the present invention;

FIG. 2 is a schematic diagram of a semiconductor chip for describing an image capturing method according to the first embodiment of the present invention.

FIG. 3 is an enlarged view of a ball portion for describing an effect of the image capturing method according to the first embodiment of the present invention.

FIG. 4 is a principle diagram of an optical system for explaining an image capturing method according to the first embodiment of the present invention.

FIG. 5 is a supplementary configuration diagram showing an additional portion of the configuration diagram of the semiconductor inspection device according to the second embodiment of the present invention;

FIG. 6 is a schematic view of a semiconductor chip as an object of the present invention.

FIG. 7 is an enlarged view of a ball portion.

FIG. 8 is an enlarged view of a wire portion.

FIG. 9 is an enlarged view of a stitch portion.

FIG. 10 is a configuration diagram showing a conventional semiconductor inspection device.

[Explanation of symbols]

1 semiconductor chip, 11 balls, 12 wires, 13
Stitch 14 Lead, 15 Galvano mirror (optical axis deflection switching means), 16 CCD line sensor (imaging means), 17 Objective lens (lens means), 18 Imaging lens (lens means), 19 Optical axis, 20 Oblique illumination ( Illumination means), 21 epi-illumination (illumination means), 24 galvano control unit, 25 image processing unit, 26
Lighting control unit, 27 overall control unit.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masahiko Sakamoto 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Masahiko Uno 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 3 (72) Inventor Shoji Yoshida 2-3-2 Marunouchi, Chiyoda-ku, Tokyo

Claims (7)

[Claims] 1. A semiconductor inspection apparatus for inspecting the appearance of a wire bonded to a pad of a semiconductor chip and a lead of a lead frame, wherein a lens means for obtaining an optical image of a semiconductor chip as an object, and a field of view of the object. A semiconductor inspection apparatus, comprising: an optical axis deflection switching unit for switching; an illumination unit for an object; and an imaging unit for imaging an optical image obtained from the lens unit. 2. The semiconductor inspection apparatus according to claim 1, wherein said optical axis deflection switching means is a galvanomirror. 3. The semiconductor inspection apparatus according to claim 1, wherein said imaging means is a line sensor. 4. A method of synchronizing with the image capturing timing of the image capturing unit and giving the drive system of the optical axis deflection switching unit a speed of moving by an image size corresponding to the licensor element size for each image capturing, 2
4. The semiconductor inspection apparatus according to claim 3, wherein a three-dimensional image is formed. 5. The semiconductor inspection apparatus according to claim 3, wherein an image of a rectangular area of only a necessary portion is taken into said imaging means by limiting a driving range of said optical axis deflection switching means. 6. The apparatus according to claim 1, wherein two sets of the optical axis deflection switching means and the imaging means are arranged for scanning in the X and Y axis directions. Semiconductor inspection equipment. 7. A speed at which the imaging unit is connected to a driving unit, and the imaging unit moves to the driving unit by an imaging size corresponding to the size of the licensor element every time a video is captured, while synchronizing with a video capturing timing of the imaging unit. 4. The semiconductor inspection apparatus according to claim 3, wherein the two-dimensional image is formed by driving the image pickup means by applying the control signal.