JPH02272306A - Image detector - Google Patents

Abstract

PURPOSE:To simplify a device and to improve detection accuracy by condensing plural images on the same optical axis by means of an optical system and switching them through a shutter, thereby detecting them at one image pickup position. CONSTITUTION:The image on an optical axis (a) is condensed by an objective lens 7 and conducted to the optical axis of an image-formation lens 10 through a reflection mirror 8. The image on an optical axis (b) is condensed by an objective lens 15 through a reflection mirror 14, enters a beam splitter 9 through a reflection mirror 16 and is conducted to the optical axis of the image- formation lens 10. The shutter 30 selectively conducts the image on the optical axis (a) and the image on the optical axis (b) to the beam splitter 9. Image- pickup is performed to the light passing through the beam splitter 9 by a CCD camera 11 through the image-formation lens 10. A 1st optical system 12 and a 2nd optical system 17 are laterally moved by a belt 22.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image detection device, and in particular, an image detection device suitable for highly accurate alignment such as alignment of packaged semiconductor elements. Regarding equipment.

(Prior Art) As semiconductor devices have become more highly integrated in recent years, semiconductor manufacturing equipment is also required to have a mechanism that can perform high-precision processing.
For example, in an inspection process for inspecting various electrical characteristics of a packaged semiconductor element, it is essential to perform highly accurate alignment in order to perform highly accurate inspection.

Conventionally, such a semiconductor inspection apparatus has a tray with a large number of element housing parts, for example, in a grid pattern, and packaged semiconductor elements such as QFP, SOP, etc. are placed in the element housing parts.
etc., and take out the semiconductor devices one by one from the tray, and test each semiconductor device on the tray by sequentially contacting the test terminals such as probe needles provided on the test head of the C-type driver. There is something configured like this.

By the way, as semiconductor devices become more highly integrated, the number of terminals and narrower pitches of semiconductor devices on package legs is increasing. In this case, highly accurate positioning is required, and in order to improve the throughput of the apparatus, this highly accurate positioning must be performed at high speed.

As a conventional alignment mechanism, there is one that uses an image detection mechanism that performs image recognition of a predetermined part of a semiconductor element and performs alignment based on this image information.The optical system of such an image detection mechanism is It consists of an irradiation light source, a condensing lens, a detection camera such as a COD camera, etc.

(Problem to be Solved by the Invention) By the way, when performing position detection using such an image detection mechanism, in order to improve accuracy, images are taken of multiple locations, for example, two locations on the object to be measured, and based on the image information of these position measurement is performed.

Furthermore, in order to perform image detection with higher precision, optical systems have been increased in magnification.

However, with the conventional image detection mechanism described above, when performing JPI determination on multiple locations on the object to be measured, these measurement locations may not be within the same field of view, and in such cases, the optical system must be moved or It is necessary to move the API object to sequentially bring all the measurement parts into the field of view and perform the 71-1 measurement, which has the problem of complicating the work and slowing down the detection speed.

Furthermore, if the distance between the 1iPJ constant parts of the object to be measured differs, it is necessary to change the optical system and the amount of movement of the object to be measured during measurement, and this will prevent changes in the shape of the object. Another problem was that it was difficult to respond flexibly.

In addition, in order to deal with this problem, if you try to lower the magnification of the optical system to widen the field of view and include all the measurement parts in one field of view, there is a problem that the decrease in magnification causes a deterioration in DI determination accuracy. Ta.

Particularly in the semiconductor field, with the recent increase in the integration of semiconductor elements, the number of electrode terminals has increased and the pitch has become narrower, and there is a demand for the development of an image detection device with an optical system that can perform high-precision image detection at high speed. It had been.

The present invention has been made to solve the above-mentioned conventional problems, and has a simple structure, can perform high-precision image detection at high speed, and can easily cope with changes in the object to be measured. The object of the present invention is to provide an image detection device that can perform the following functions.

[Structure of the Invention] (Means for Solving the Problems) An image detection device of the present invention is an image detection device that captures images of a plurality of predetermined imaging locations of a subject. a plurality of detection optical systems that respectively capture images; a condensing optical system that condenses light from these detection optical systems onto the same optical path; and a light selection mechanism for selecting only light on a predetermined optical axis from among the light guided along these optical axes, and by switching the light selection mechanism, the plurality of detection optical systems Among them, only the light from a predetermined detection optical system is configured to enter the condensing optical system.

The present invention also provides an image detection device for detecting images of two measurement points on an object to be measured, including two detection optical systems that respectively detect images of each measurement point of the object to be measured;
The present invention is characterized in that it includes an optical axis moving mechanism (left) that moves the optical axes of these detection optical systems mirror-symmetrically.

Furthermore, the present invention is characterized in that the condensing optical system includes a variable magnification mechanism.

(Function) The present invention achieves simplification of the device configuration,
It is possible to improve detection accuracy and detection speed, and to improve detection accuracy and speed. IP
Even if the shape of a constant object changes, it becomes possible to easily cope with the change.

(Example) Hereinafter, an example in which the present invention is applied to a detection mechanism for detecting the position of a flat package type semiconductor element (hereinafter referred to as a chip) will be described with reference to the drawings.

On the examination table 1, which is movable in the x-y-z-θ direction, there is a
P1 A fixed chip 2, for example, a square-shaped Fura-Soto package IC is mounted.

Diagonally above the edge of this chip 2, there is a light-emitting source, for example, an 8-watt halogen lamp 3 housed in a holding casing 4.
, 5 are arranged. This holding housing 4 has a divided structure so that a plurality of rows of chips 2, for example, three sides of the chip, can be irradiated independently, and each independent holding housing 4 has a plurality of, for example, two, 10-gen lamps 3. are accommodated respectively.

Furthermore, a semi-transparent member such as a ground glass 6 is provided in the light path of the light output opening of the holding housing 4 in order to equalize the amount of light emitted from the rotary gen lamp 3.

A first objective lens 7 is disposed above the lead row on one side of the chip 2 to convert the reflected light from the chip into a parallel beam of light, and further above the optical axis of this first objective lens 7 is a A first reflecting mirror 8 is provided to reflect the parallel light beam from the first objective lens 7 in a predetermined direction, for example, 90 degrees to the left in the figure.

A beam splitter 9, an imaging lens 10, and an image detection mechanism, such as a CCD camera 11, are arranged in this order on the optical axis of the first reflecting mirror 8 in the direction of light reflection so as to be on the same optical axis. . The first objective lens 7 and the first reflecting mirror 8 constitute a first detection optical system 12, and the beam splitter 9 and the imaging lens 10 constitute a condensing optical system 13.

On the other hand, above the lead row on the side opposite to the lead row of the chip 2, there is a second reflection mirror 14 for reflecting the reflected light from the chip 2 in the same direction as the reflection direction of the first reflection mirror 8. is provided, and this second reflecting mirror 14
On the optical axis in the reflection direction, a second objective lens 15 equivalent to the first objective lens 7 for converting the reflected light into a parallel beam, and a third reflecting mirror 16 are placed on the same optical axis in order. It is arranged. The third reflecting mirror 16 has its reflecting surface positioned so that the parallel light beam transmitted through the second objective lens 15 is reflected toward the beam splitter 9 at an angle of, for example, 90 degrees. The optical path is configured such that the light beam from the CCD camera 16 is reflected by the beam splitter 9 toward the imaging lens 10 and then enters the CCD camera 11 . The second reflecting mirror 14, the second
A second detection optical system 17 is composed of the objective lens 15 and the third reflection mirror 16.

Further, the first objective lens 7 and the first reflecting mirror 8 are supported by a first support plate 18 that is movable in the horizontal direction, and a second
The reflecting mirror 14 and the second objective lens 15 are each fixed to a second supporting plate 19 that is movable in the horizontal direction.
First and second rods 20.21 are horizontally provided on the side surfaces of the first and second support plates 18.19 facing the imaging lens, respectively.

That is, these first and second rods 20, 21 are in parallel relationship with each other.

In the gap between the first and second rods 20 and 21, a pair of rollers 23 on which a drive transmission belt 22 is stretched is provided, and one side of the belt 22 of this roller 23, for example the upper side, The first rod 20 and the other side, for example, the lower side of the belt 22, are attached to the second rod 21 with a fixing jig 24.
25, and the rotation of the roller 23 causes the first
The support plate 18 and the second support plate 19 are configured to move in opposite directions at equal pitches. Also, a part of the belt 22 is provided with a belt 22 that maintains the tension of the belt 22 at a constant level. , a spring mechanism 26 is inserted to reduce movement errors of the belt 22.

On the upper surface of the first support plate 18, there is provided a mechanism for moving the first support plate 18 and the second support plate 19 at equal pitches in opposite directions by moving the first support plate 18 in the horizontal direction. A support plate moving mechanism such as a ball screw mechanism 27 is provided, and a first support plate 18 is provided on the side surface of the first support plate 18.
A tightening rod 28 is provided parallel to the opening/end 20.

The clamping rod 28 and the second rod 20 are each provided with a clamping mechanism, such as a clamping mechanism 29, 30, for limiting the movement of these rods 20, 28 as required.

Optical axis a between first objective lens 7 and beam splitter 9 (
Hereinafter, the optical axis of the first detection optical system is referred to as the first optical axis), and the optical axis b between the second reflection mirror 14 and the beam splitter 9 (hereinafter, the optical axis of the second detection optical system is referred to as the first optical axis). A shutter mechanism 30 is disposed above the first optical axis a and the second optical axis as necessary.
It is configured so that either one of the reflected light on the optical axis a and the reflected light on the second optical axis is made to enter the condensing optical system 13 as necessary.

The operation of the image detection optical system having such a configuration will be described below.

First, the shutter mechanism 30 is operated to select a desired optical axis side of the first optical axis a or the second optical axis, for example, the first optical axis a.
One side is open, and the other optical axis, for example, the second optical axis, is closed. That is, in this state, only the reflected light from the first detection optical system 12 is incident on the CCD camera 11.

The reflected light from the light source 5 reflected at a predetermined part of the chip 2, for example, a lead row, is diffused and passes through the first objective lens 7.
incident on .

The reflected light that entered the first objective lens 7 is focused into parallel light and enters the first reflection mirror 8, where it is reflected 90 degrees, passes through the shutter mechanism 30, and enters the beam splitter 9. do.

The reflected light that has entered the beam splitter 9 travels straight and enters the imaging lens 10 , where it is condensed and then enters the CCD camera 11 .

An image recognition mechanism (not shown) is connected to the CCD camera 11, and detects the position of the chip 2 from the reflected light incident thereon. At this time, the reflected light that has passed through the second detection optical system 17 is blocked by the shutter mechanism 30.

In this way, after the image of the lead row on one side of the chip 2 is detected, the image of the lead row 0 on the other side of the chip 2 is detected.

First, the shutter mechanism 30 is operated to close the first optical axis a, open the second optical axis, and open the second detection optical system 17.
Only the reflected light that has passed through the CCD camera is made to enter the CCD camera.

The reflected light from the chip 2 is reflected at 90 degrees by the second reflection mirror 14 while being diffused, and enters the second objective lens 15 .

The reflected light that has entered the second objective lens 15 is focused into parallel light and enters the third reflection mirror 16, where it is reflected by 90 degrees and then enters the beam splitter 9.

The reflected light incident on the beam splitter 9 is 90
The light is reflected repeatedly and enters the imaging lens 10, where it is condensed and enters the CCD camera 11.

Thereafter, the position of the chip is detected by an image recognition mechanism (not shown) similar to the first detection optical system 12 described above.

In this way, by providing detection optical systems corresponding to the number of measurement sites on the chip 2, image detection of each measurement site can be performed simply by switching the shutter mechanism 30, and it is possible to detect images within the field of view of the optical system, unlike conventional methods. There is no need to move the chip 2 or the optical system, and the detection operation can be performed at high speed.

Furthermore, since measurement is possible without moving the optical system at all, it is possible to prevent a decrease in detection accuracy due to blurring of the optical system.

Furthermore, a halogen lamp 3 is used as a light source 4 for chip irradiation.
Since the irradiation light is transmitted through a semi-transparent member such as frosted glass, the amount of irradiation light is uniform and a good image can be obtained.

Further, since the condensing optical system 13 is configured to be used in common with the first and second detection optical systems, the apparatus can be simplified and an increase in apparatus cost can be suppressed.

In the above-mentioned embodiment, the case where there are two detection optical systems has been described, but it is also possible to use a plurality of detection optical systems.

Next, if the pitch between the d-no fixed parts of chip 2 changes, for example, use a larger chip 71! The adjustment operation of the optical system in the case of setting II will be described below.

When measuring a lead array of a chip larger than the chip of the above embodiment, it is necessary to widen the pitch between the first optical axis a and the second optical axis.

In such a case, first, the ball screw mechanism 27 is operated manually or automatically to move the first support plate 18 in a predetermined direction, for example, rightward in the figure.

The first objective lens 7 and the first reflecting mirror 8
Since it moves together with the support plate 18, the first optical axis a also moves to the right in the figure.

At this time, the movement of the first rod 20 is also transmitted to the second rod 21 via the belt 22 and roller 23,
The second support plate 19 moves by the same amount in the opposite direction to the first support plate 18, that is, to the left in the figure.

Since the second reflecting mirror 14 and the second objective lens 15 move together with the second support plate 19, the second optical axis also moves to the left in the figure by the same amount as the first optical axis a. do. That is, by operating the ball screw mechanism 27, the first optical axis a
The second optical axis and the second optical axis move mirror-symmetrically with respect to the center thereof.

After adjusting the optical axis pitch interval, the first support plate 18 is tightened by tightening the rod 28 and the rod 20 of the second support plate 19 by the clamp mechanisms 29 and 30, respectively.
．． Fix 19.

In this way, the pitch between the first and second optical axes a and b can be changed only by operating the ball screw mechanism 27, and can also be moved mirror-symmetrically, so that the shape of the chip 2 can be changed. Even in such cases, the optical system can be easily adjusted, and measurements of various chip shapes can be easily performed.

By the way, as mentioned above, when moving the optical axes a and b, the first and second objective lenses 7.15 and the imaging lens 10
There is a possibility that the magnification of the optical system will change due to the change in the distance from the
Since the first and second objective lenses 7.15 are configured with lenses that turn the diffused incident light into parallel light, the magnification of the optical system is The magnification is determined only by the ratio of the focal length ill L + of ill L + and the focal length ri of the imaging lens 10, and even if the distances L2 and J22 between the first and second objective lenses 7.15 and the imaging lens change, the magnification will not change. will never change.

Further, as an application example of the above embodiment, it is also possible to make the magnification of the optical system variable.

FIG. 3 is a diagram showing an example in which the optical system of the above-mentioned embodiment is made into a variable magnification type, in which the beam splitter 9 allows the incident light from the first optical system to travel straight and reflects it upward, and It is configured to reflect the incident light from the detection optical system toward the imaging lens 10 and make it travel straight upward.

Above this beam splitter 9 is a fourth reflecting mirror 3.
1 is provided, and the reflected light reflected by this fourth reflecting mirror 31 is passed through a beam adjustment lens 3 such as a beam expander that narrows down or expands the beam width of the incident light.
2 and enters the imaging lens 10 via a fifth reflecting mirror 33 and a beam splitter 34.

Also, on the optical axis C between the beam splitter 9 and the fourth reflecting mirror 31, and on the optical axis C between the beam splitter 9 and the beam splitter 3
A shutter mechanism 35 is provided on the optical axis d between the two optical axes b1C and 4 for blocking either one of the optical axes b1C as necessary.

In such an image detection device equipped with a variable magnification mechanism,
By opening the optical axis C side and closing the optical axis d side by the shutter mechanism 35, the reflected light from the first and second detection optical systems 12.17 enters the luminous flux and the g6 lens 32, where After the beam width has changed at , the beam enters the imaging lens 10, so the magnification changes according to the changed beam width. Therefore, by frequently replacing the light flux adjustment lens 32, it is possible to obtain an optical system with a desired magnification.

As a semiconductor inspection apparatus to which such an image detection apparatus is applied, there is one shown in FIG.

The device main body 41 includes a tray 43 containing a large number of chips 42.
Tray loader system 44 for loading and unloading
And the chips 42 taken out one by one from this tray 43
and an inspection stage system 45 for mounting the test piece on an inspection table and transporting it to the inspection section. In addition, the tray loader mentioned above
A chip transfer mechanism 46 for holding the chips 42 and transferring the chips between the tray loader system 44 and the inspection stage system 45 is provided at the prefecture-side boundary of the inspection stage system 44.

The tray loader system 44 includes a sender mechanism 47 that can be raised and lowered to store a large number of trays 43, a tray buffer mechanism 48 for temporarily storing empty trays, and a tray 43 that stores a large number of trays 43 containing chips 42 that have been inspected. The receiver mechanisms 49, which can be raised and lowered, are connected to the chip transfer mechanism 46, respectively.
are arranged in parallel along the Hereinafter, this juxtaposition direction will be referred to as the Y direction, and the direction perpendicular to this will be referred to as the X direction.

The chip transfer mechanism 46 has a structure in which each FJal structure for chip transfer is developed around a base 50 placed at the boundary between the tray loader system 44 and the inspection stage system 45. A tray transfer mechanism 51 that is movable in the Y-Z direction is disposed on the side surface of the tray loader system 44 of 50 . The tray 43 is sucked and held by the holding portion 51a of the tray transfer mechanism 51.

Also, perpendicular to the end of the base 50 on the sender mechanism 47 side,
A chip loading mechanism 52 is provided to transport the chips 42 on the tray 43 of the sender mechanism 47 to the inspection stage system 45. On the other hand, a chip loading mechanism 52 is provided to transport the chips 42 on the tray 43 of the sender mechanism 47 to the inspection stage system 45. Chip 4 that has been inspected
A chip unloading mechanism 53 is provided for transporting the chips onto the tray 43 of the receiver mechanism 49.

The chip loading mechanism 52 and the chip loading mechanism 53 each include an X-Z stage 55 for moving the carrying arm 54 protruding in the Y direction in the It is composed of a chip holding section 56 that is movably provided.

A chip 42 is mounted on the side surface of the base 50 on the inspection stage system 45 side.
A pair of holding parts 57a and 57b are provided at a predetermined interval to hold the chip 42 by suction, and one holding part 57a holds the chip 42 transported to the inspection stage system 45 by the chip carrying mechanism 52 for inspection on the inspection stage system 45. At the same time as transferring onto the table 58, the double transfer mechanism 57 transfers the inspected chip 42 on the inspection table 58 to the delivery table 59 to the chip carry-out mechanism 53 using the other holding part 57b. It is arranged to be movable in the Z direction.

The inspection stage system 45 includes an inspection table 5 on which the chip 42 is placed.
8, an inspection table stage 60 that moves this inspection table 58 in the x-y-z-θ direction, and an inspection table stage 60 that is arranged on the movement trajectory of the inspection table 58 and captures an image of the chip 42 on the inspection table 58, and The fine alignment mechanism 61 provides positioning information during alignment to the drive control mechanism of the inspection table stage 60.

The fine alignment mechanism 61 includes the image detection device of the embodiment shown in FIG. 1 and an image recognition mechanism (not shown).

The fine alignment operation of the chip 42 in the semiconductor inspection apparatus having such a configuration is performed by moving the inspection table 58 on which the chip 42 is mounted to the inspection section 63 in which the test head 62 and the like are disposed.
This is performed after stopping once below the fine alignment mechanism 61 during the movement.

The fine alignment mechanism 61 of this embodiment is configured to perform the alignment using an image recognition mechanism. 1. Second detection optical system 12.17
The shutter mechanism 30 alternately switches to take an image, and the position of the chip 42 is detected from the information obtained from this image.

Then, the detected chip position information is compared with the chip position information of the predetermined base (2) to determine the positional deviation,
Based on the information on the amount of positional deviation, the inspection table 58 is moved and aligned so that the chip 42 is in the correct position.

After completing the fine alignment of the chip 42 in this way, the inspection table 58 is moved below the test head 62, the inspection table 58 is raised, and the lead terminals of the chip 42 are connected to the lower surface of the test head 62 (not shown). Test by touching the probe needle.

In this way, by applying the image detection device of the present invention,
By simply switching the shutter mechanism 30, two of the chips 42 can be used.
The measurement site can be easily imaged, and there is no need to move the inspection table 58 to bring the measurement site of the chip into the field of view of the optical system as in the conventional method, and the inspection speed can be improved.

After the inspection is completed, the inspection table 58 is moved to the transfer position again, and one of the chip holding parts 57b of the double transfer mechanism 57 is used to remove the inspected chips 42 on the inspection table 58.
is held and transferred onto the chip delivery table 59, and the next test chip is transferred onto the test table 58 using the other chip holding section 57a. Then, the chips 42 on the chip delivery table 59 are transferred onto the tray 43 of the receiver mechanism 49 by the chip unloading mechanism 53. At this time, chips determined to be defective by the inspection are dropped into a defective product storage box 64 arranged below the movement track of the transport arm 54 .

By the way, the image detection device of the present invention can be applied to technical fields other than the semiconductor manufacturing field, and will be even more effective if applied to fields where high-precision image detection needs to be performed at high speed.

[Effects of the Invention] As explained above, according to the present invention, with a simple structure,
It is possible to obtain an image detection device that can perform highly accurate image detection at high speed, and can also easily cope with changes in the fixed object.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an image detection device according to an embodiment of the present invention, FIG. 2 is a diagram showing the lens system of FIG. 1, and FIG. 3 is a diagram showing an embodiment in which the optical system is equipped with a variable magnification mechanism. Figure shown, 4th
The figure is a plan view showing the configuration of a semiconductor inspection apparatus to which the embodiment of FIG. 1 is applied. 2... Chip, 3... Halogen lamp, 5... Light source, 6... Ground glass, 7
...First objective lens, 8...First reflection mirror 9...Beam splitter, 10.
...Imaging lens, 11...CCD camera, 12...First detection optical system, 13...
・Condensing optical system, 14...Second reflection mirror 1
5...Second objective lens, 16...Third reflection mirror 17...Second detection optical system,
18...Inspection table, 20.21...Rod, 22...Bell l-123...Roller, 27...Ball screw 30・・・・・・
... Shutter mechanism, 32 ... Luminous flux width adjustment lens, 35 ... Shutter mechanism, 61 ... Fine alignment mechanism.

Claims (3)

[Claims] (1) An image detection device that captures images of a plurality of predetermined imaging locations of a subject, including a plurality of detection optical systems that capture images of each of the above-mentioned imaging locations of the subject, and light from these detection optical systems. A condensing optical system that condenses the light onto the same optical path, and a condensing optical system that is provided on the optical axis between the plurality of detection optical systems and the condensing optical system, and a predetermined light among the lights that are guided along these optical axes. and a light selection mechanism for selecting only on-axis light, and by switching this light selection mechanism, only the light from a predetermined detection optical system among the plurality of detection optical systems enters the condensing optical system. An image detection device characterized in that it is configured to. (2) In an image detection device that detects images of two measurement points on an object to be measured, there are two detection optical systems that detect images of each measurement point of the object, and optical axes of these detection optical systems. An image detection device comprising: an optical axis moving mechanism that moves the optical axis mirror-symmetrically. (3) The image detection device according to claim 1 or 2, wherein the condensing optical system includes a variable magnification mechanism.