JPH11197865A - Positioning device and laser processing device - Google Patents

Abstract

(57) [Problem] To provide a positioning device capable of performing autofocusing accurately and at high speed even if the film thickness varies, and a laser processing device equipped with the positioning device. SOLUTION: Semiconductor device 12 as "object"
A vertical incidence type position detection system 17 for irradiating the semiconductor device 12 with measurement light from the vertical direction to detect position information of the semiconductor device 12 in the vertical direction, and irradiating the measurement light from the oblique direction to the surface of the semiconductor device 12 And an oblique incidence type position detection system 18 for detecting position information of the semiconductor device 12 in the vertical direction, and for the position information of the semiconductor device 12 detected by the vertical incidence type position detection system 17, The present invention is characterized in that the positioning apparatus is provided with a correction amount detection system 26 for detecting a deviation of position information of the semiconductor device 12 detected by the oblique incidence type position detection system 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning device for positioning another device or the like with respect to an object, and a laser processing device equipped with the positioning device.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 3 and 4, for example, a laser processing apparatus equipped with this kind of positioning apparatus is known.

That is, in this laser processing apparatus, a Z stage 1 movable in the Z direction is provided on an XY stage (not shown) movable in the XY directions. "Is held by the semiconductor device 2.

A processing laser light source 3 for emitting a processing laser is arranged on the semiconductor device 2, and a processing laser emitted from the processing laser light source 3 is supplied to a half mirror 4.
The light is reflected by the objective lens 5 and is condensed by the objective lens 5 to irradiate the fuse 2 a as a “target portion” of the semiconductor device 2.

The laser processing apparatus is provided with an oblique incidence type position detection system 6 for detecting position information of the semiconductor device 2 in the vertical direction (vertical direction) as a "positioning apparatus". This oblique incidence position detection system 6
Is provided with an oblique incidence AF beam irradiation system 7 for projecting the oblique incident beam for measurement onto the semiconductor device 2 from an oblique direction, and reflects the reflected light of the projected focused slit image of the oblique incident beam via a focus offset mechanism 8. Receiving system 9 for receiving light
Is provided.

Then, reflected light of the oblique incident beam for measurement applied to the fuse 2a of the semiconductor device 2 from the oblique incident AF beam irradiation system 7 is incident on a predetermined position of the light receiving system 9 via the focus offset mechanism 8. To Z stage 1
By performing the position adjustment by adjusting the position, the auto focus is performed, and the fuse 2a of the semiconductor device 2 and the focal plane of the objective lens 5 substantially coincide with each other.

However, as shown in FIG. 4, the semiconductor device 2 may have a thin film 2b formed on the surface thereof except for the fuse 2a. Is incident on the fuse 2 a of the semiconductor device 2, the light is blocked by the thin film 2 b and irradiated on the surface of the thin film 2 b. Therefore, when the autofocus is to be performed by the above-described method, the position of the fuse 2a is defocused by the thickness T of the thin film 2b.

Therefore, the focus offset mechanism 8 is
The focal plane of the objective lens 5 is adjusted in advance by an amount corresponding to the film thickness T of the thin film 2b determined by the design.
a.

[0009]

However, even when the focus offset mechanism 8 is adjusted in advance by an amount corresponding to the film thickness T of the thin film 2b, when the film thickness T of the thin film 2b varies, There is a problem that defocus is caused by the variation.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a positioning apparatus capable of performing autofocusing accurately and at high speed even if the film thickness varies, and a laser processing apparatus equipped with the positioning apparatus.

[0011]

In view of such a problem, the invention described in claim 1 irradiates a measuring beam to a target object from a vertical direction to obtain position information of the target object in the vertical direction. A vertical incidence type position detection system for detecting, and an oblique incidence type position detection system for irradiating measurement light from an oblique direction to the surface of the object to detect position information in the vertical direction of the object. A correction amount detection system for detecting a deviation of the position information of the object detected by the oblique incidence position detection system with respect to the position information of the object detected by the vertical incidence position detection system. Characterized in that it is a positioning device.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, a laser which emits a processing laser from a processing laser light source and irradiates a target portion of the object through an objective lens to perform processing. A laser processing apparatus, wherein the positioning apparatus according to claim 1 is used, and laser light configured to irradiate a target portion of the target object with the measurement light of the vertical incidence type position detection system via the objective lens. The device is characterized in that:

According to a third aspect of the present invention, in addition to the configuration of the second aspect, the object has a thin film formed on a surface thereof, and a surface of the object and a focal plane of the objective lens are aligned. The object and the focal plane are relatively moved along the optical axis of the objective lens based on an output of the oblique incidence type position detection system and the detected deviation so as to substantially coincide with each other. I do.

According to a fourth aspect of the present invention, in addition to the configuration of the first or second aspect, the object portion of the object is a fuse of a semiconductor device.

[0015]

Embodiments of the present invention will be described below.

FIG. 1 and FIG. 2 are diagrams showing an embodiment of the present invention.

First, the configuration of the laser processing apparatus will be described. In this laser processing apparatus, a Z stage 11 movable in the Z direction is provided on an XY stage (not shown) movable in the XY directions. The semiconductor device 12 as an "object" is gripped.

A processing laser light source 13 for emitting a processing laser is arranged on the semiconductor device 12. The processing laser light emitted from the processing laser light source 13 is reflected by a half mirror 14 and condensed by an objective lens 15. 12 as a “target part” of the semiconductor device 12
a.

On the other hand, this laser processing apparatus is equipped with a positioning device. The positioning device uses a vertical incident beam for measurement as “measuring light” from the vertical direction with respect to the fuse 12 a of the semiconductor device 2. And a vertical incidence type position detecting system 17 for detecting position information of the fuse 12a in the vertical direction by applying a measurement oblique incident beam as “measuring light” from an oblique direction to the surface of the semiconductor device 2. And an oblique incidence type position detecting system 18 for detecting position information in the vertical direction.

The vertical incidence type position detecting system 17 reflects the vertical incidence beam for measurement emitted from the illumination light source 27 on the half mirror 28 and irradiates the fuse 12a via the objective lens 15 from the vertical direction. This fuse 1
The image of 2a is photographed by the camera 19 through the objective lens 15, and the degree of focus is calculated by the image processing device 20, so that the position information of the fuse 12a in the vertical direction is detected. Based on this position information, the Z stage 11 is positioned at the position where the degree of focus is highest.

The oblique incidence type position detection system 18 is provided with an oblique incidence AF beam irradiation system 22 for projecting the oblique incidence beam for measurement onto the semiconductor device 12 from an oblique direction, and focuses the projected oblique incidence beam. A light receiving system 24 that receives the reflected light of the slit image via the focus offset mechanism 23 is provided.

The oblique incidence AF beam irradiation system 22 irradiates the surface of the semiconductor device 12 (the surface of the thin film 12b when the thin film 12b is formed, and the surface of the fuse 12a when the thin film 12b is not formed). The reflected light of the oblique incident beam for measurement is received by the light receiving system 24 via the focus offset mechanism 23, so that the position information of the surface in the vertical direction is detected.

The position information of the surface of the semiconductor device 12 detected by the oblique incidence type position detection system 18 is compared with the position information of the fuse 12 a of the semiconductor device 12 detected by the vertical incidence type position detection system 17. The deviation is detected by the correction amount detection system 26.

In addition, based on the output of the oblique incidence type position detecting system 18 and the deviation detected by the correction amount detecting system 26, the surface of the fuse 12a and the focal plane of the objective lens 15 substantially coincide with each other. Thus, the fuse 12a and the focal plane are relatively moved along the optical axis of the objective lens 15. Here, the Z stage 11 is relatively moved by moving up and down.

Next, the operation will be described.

In order to process (cut) the fuse 12 a of the semiconductor device 12, first, the Z stage 11 is driven so that the fuse 12 a substantially coincides with the focal plane of the objective lens 15.

That is, the fuse 12a of the semiconductor device 12 is irradiated with a vertical incident beam for measurement from the vertical direction, and an image of the fuse 12a is photographed by the camera 19 through the objective lens 15, and the image processing device 20
By calculating the degree of focus at the fuse 12a
Position information in the vertical direction is detected. Based on this position information, the Z stage 11 is positioned at a position where the degree of focus of the vertical incidence type position detection system 17 is the highest.

In this state, the oblique incidence AF beam irradiation system 22 of the oblique incidence type position detecting system 18 projects a measurement oblique incident beam onto the semiconductor device 12 from an oblique direction. Since the thin film 12b is provided on the surface of the semiconductor device 12, this oblique incident beam is not projected on the fuse 12a, but is projected on the surface of the thin film 12b. This reflected light is received by the light receiving system 24 via the focus offset mechanism 23. Then, the focus offset mechanism 23 is adjusted such that the focus signal is output from the oblique incidence type position detection system 18 at the Z position focused by the vertical incidence type position detection system 17.

In the processing of the remaining semiconductor devices 12 of the same lot, autofocusing is performed by focusing only by the oblique incidence type position detection system 18 without using the vertical incidence type position detection system 17. , Semiconductor device 1
Processing is performed by irradiating the second fuse 12a with a processing laser.

As described above, the processing of the semiconductor device 12 is performed as follows.
For example, in the first semiconductor device 12 of one lot, the focus offset mechanism 23 is adjusted based on the deviation of the position information of the oblique incidence type position detection system 18 with respect to the position information of the vertical incidence type position detection system 17, and then In the remaining semiconductor devices 12 of the same lot, autofocusing can be performed at high speed by focusing only by the oblique incidence type position detection system 18 and the fuse 1
2a can be processed accurately.

By performing such an operation for each lot, for example, even if the film thickness of the thin film 12b varies for each lot, the focal plane of the objective lens 15 can be made to coincide with the fuse 12a of the semiconductor device 12 and accurate. Alignment and, consequently, accurate processing can be performed.

On the other hand, by using this positioning device, the film thickness T of the thin film 12b can be measured. That is, as shown in FIG. 2, in a state where the thin film 12b is not formed, focusing is performed between the vertical incidence position detection system 17 and the oblique incidence position detection system 18, and then the thin film 12b is formed. In this case, by adjusting the focus offset mechanism 23 of the oblique incidence type position detection system 18 by the above-described method, this adjustment amount is converted into the height of the Z stage 11, so that the thickness T of the thin film 12b is reduced. It is possible to measure.

In the above embodiment, the description has been given of the case where the positioning device is provided in the laser processing device. However, the present invention is not limited to this, and the positioning device may be used alone or in a device other than the laser processing device. Also, the target portion of the target object is not limited to the fuse of the semiconductor device.

Further, in the above embodiment, the oblique incident beam is shifted by using the focus offset mechanism 23, so that even when the oblique incident beam for measurement is applied to the surface of the thin film 12b, the surface of the fuse 12a and the objective lens In a state where the focal planes coincide with each other, the focused state can be detected by the oblique incidence type position detection system 18. However, without being limited to this, instead of shifting the obliquely incident beam by the focus offset mechanism 23, for example, the light receiving system 2
An electrical offset corresponding to the deviation of the position information of the oblique incidence type position detection system 18 from the position information of the vertical incidence type position detection system 17 can also be given to the output of 4.

[0035]

As described above, according to the invention described in each of the claims, the oblique incidence type position detection system for the position information of the object detected by the vertical incidence type position detection system. By providing a correction amount detection system for detecting a deviation of the position information of the detected object, oblique incidence having a rapidity through the correction amount detection system based on the position information of the vertical incidence type position detection system having accuracy. By correcting the position information of the position detecting system, a positioning operation having accuracy and speed can be performed.

According to the second aspect of the present invention, by applying the positioning device to the laser processing device, the target portion of the target can be quickly and accurately positioned with respect to the objective lens. As a result, the target portion can be laser-processed quickly and accurately.

According to the third aspect of the present invention, it is possible to effectively and quickly laser-process a target portion particularly when a thin film is formed on the surface of the target object.

According to the fourth aspect of the present invention, laser processing of a fuse of a semiconductor device can be performed quickly and accurately.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a laser processing apparatus equipped with a positioning device according to an embodiment of the present invention.

FIG. 2 is a schematic view of a laser processing apparatus equipped with the alignment device according to the embodiment, showing a state where laser processing is performed on a semiconductor device on which a thin film is not formed.

FIG. 3 is a schematic view corresponding to FIG. 2 of a laser processing apparatus showing a conventional example.

FIG. 4 is a schematic view corresponding to FIG. 1 of a laser processing apparatus showing the conventional example.

[Explanation of symbols]

 12 Semiconductor device (target object) 12a Fuse (target part) 12b Thin film 13 Processing laser light source 15 Objective lens 17 Vertical incidence position detection system 18 Oblique incidence position detection system 19 Camera 20 Image processing device 22 Oblique incidence AF beam irradiation system 23 Focus offset mechanism 24 Light receiving system 26 Correction amount detection system

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01S 3/00 H01L 21/82 F

Claims (4)

[Claims] 1. A vertical incidence type position detection system for irradiating an object with measurement light from the vertical direction to detect position information in the vertical direction of the object, and a direction oblique to the surface of the object. And an oblique incidence type position detection system for detecting position information of the object in the vertical direction by irradiating measurement light from the object, and for the position information of the object detected by the vertical incidence type position detection system. And a correction amount detection system for detecting a deviation of position information of the object detected by the oblique incidence type position detection system. 2. A laser processing apparatus for performing processing by emitting a processing laser from a processing laser light source and irradiating a target portion of the object through an objective lens, wherein the positioning apparatus according to claim 1 is used, A laser processing apparatus characterized in that measurement light of a vertical incidence type position detection system is applied to a target portion of the target object via the objective lens. 3. The output of the oblique incidence type position detection system and the detection so that a thin film is formed on the surface of the object, and the surface of the object substantially coincides with the focal plane of the objective lens. The laser processing apparatus according to claim 2, wherein the object and the focal plane are relatively moved along the optical axis of the objective lens based on the obtained deviation. 4. The laser processing apparatus according to claim 2, wherein the target portion of the target is a fuse of a semiconductor device.