TWI405948B - Non-contacting aligning method for planes in three-dimensional environment - Google Patents

Abstract

A non-contacting aligning method for planes in a three-dimensional environment is disclosed. The method includes: projecting a light beam in a predetermined incident angle onto a transparent first object and an opaque second object that are facing each other; and calculating a distance between the first and second objects basing on the tangent trigonometric function of the incident angle of the light beam.

Description

Non-contact 3D full plane position alignment

The invention relates to a method and a device for measuring the stacking error of two objects, and more particularly, a non-contact measuring method for monitoring the XY axis error of two object pairs and monitoring the two object stacks The vertical relative distance (Z axis) and parallelism of the time.

In the lithography process, transferring the reticle pattern to a circuit substrate and transferring the defined pattern on the reticle to the wafer surface process involves measuring and correcting the error of the object stacking error To ensure that the pattern can be transferred accurately. Therefore, the XY-axis positioning of the two-piece object, the Z-axis positioning of the vertical relative distance, and the parallel positioning are very important in the lithography process. In addition to the lithography process, when the sensor head of a SQUID Microscope is installed, the relative distance and parallelism of the sensor head to the sample have a direct influence on the sensitivity of the interferometer.

Take the lithography process as an example to illustrate how traditional techniques can solve the problem of XYZ triaxial positioning of stacked objects.

It is known to use an image capture device set on the Z-axis to monitor the overlapping of the XY-axis mark points of the stack of objects. One of the Z-axis monitoring methods is to use a moving lens to monitor the focal plane image of the object. In the process of moving monitoring, if the focal plane produces a focus change, it means that there is a tilt between the two stacks of objects. angle. However, this method is difficult to interpret when the image resolution is insufficient, and the tilt angle cannot be known exactly.

The second method of Z-axis monitoring is to use at least two image capturing devices to shoot from different angles and compare the images at different angles to obtain the distance in the Z-axis direction, but it requires complicated calculation and it is very difficult to operate the alignment. It is also impossible to accurately measure the tilt angle between the objects.

The purpose of this case is to provide a non-contact method for monitoring the vertical relative distance and parallelism of the objects of the two stacks, and the X-Y axis plane monitoring to achieve the 3D full plane position alignment.

The non-contact method described above mainly projects the obliquely incident stripe light onto the stacked object, and uses the stripe light incident angle and the incident angle tangent trigonometric function to calculate the vertical relative distance of the two stacks of the object. The parallelism of the two is determined by observing whether the projected stripe lights are parallel to each other from the plane of the X-Y axis of the object. When a tilt angle occurs between the two pairs of objects, an angle is formed between adjacent two stripe lights, and the angle between the two stacks is calculated by using the angle and the trigonometric relationship. A known adjustment means can use the above-mentioned measurement results to adjust one of the pairs of objects to achieve the purpose of overlapping the object X-Y-Z triaxial positioning and determining that the overlapping objects remain parallel.

The apparatus for implementing the above non-contact means includes an image capturing device, a stripe light generating device and a computing device. The image capturing device is configured to set a Z-axis of the first object and the second object, the stripe light generating device generates a stripe light that is projected at a predetermined angle on the first object and the second object, The stripe light reflected by the two objects is projected on the first object, and the stripe light image projected on the first object and the second object is captured by the image capturing device, and the computing device measures the first object. The distance between the two stripe lights is used and the relative vertical distance of the first object and the second object is calculated by the incident angle tangent trigonometric function using the known incident angle of the stripe light. In addition, whether the first and second objects are parallel may be determined by the parallelism of the stripe light on the second object with the stripe light on the first object. The angle of inclination of the first object relative to the second object may also be calculated by the angle of the stripe light on the first object and the second object and a trigonometric relationship. In order to facilitate the adjustment of the first object by a known adjustment means, the first object is made parallel to the second object. In the above case, the image capturing device can capture the X-Y axis plane images of the first and second objects, and determine whether the overlapping pairs of the two points are aligned. According to this, the non-contact method of this case can achieve the purpose of 3D full-plane position alignment.

As a first figure, a method of calculating the vertical relative distance Z of a first object 10 and a second object 20 of a parallel stack is described. The obliquely incident stripe light 30 is projected at a predetermined angle (θ) on the first object 10 that is permeable to light and the second object 20 that reflects light, and the stripe light reflected by the second object 20 is projected on the first object 10. Therefore, the first object 10 has an incident stripe light 31 and a reflective stripe light 32, and the second object 20 has an incident stripe light 33. Assuming that the distance between the two stripe lights 31, 32 of the incident stripe light 31 and the reflected stripe light 32 of the first object 10 is 2X, the vertical relative distance Z of the first object 10 and the second object 20 can be calculated by Equation 1.

As shown in the second and third figures, the three stripe lights 31, 32, 33 are presented in the first object 10 and the second object 20, and the first object 10 and the second object 20 are depicted in a front view. When the vertical relative distance Z changes, the relative distance between the incident stripe light 31 and the reflected stripe light 32 present in the first object 10 also changes. When the vertical relative distance Z is large, the difference in the relative distance between the incident stripe light 31 and the reflected stripe light 32 is large, and conversely, it is small.

As shown in the fourth and fifth figures, the change of the three stripe lights 31, 32, 33 is described as if the first object 10 is tilted relative to the second object 20 in a front view. When the first object 10 and the second object 20 have an oblique angle φ, the incident stripe light 31 and the reflected stripe light 32 present in the first object 10 and the incident stripe light 33 present in the second object 20 There is an angle ψ, and the inclination angle φ can be calculated by the formula 2.

A known adjustment means can adjust the vertical distance of the first object 10 relative to the second object 20 by a vertical relative distance Z to achieve a target value. The first object 10 can also be adjusted to be parallel with the second object 20 by using the calculated tilt angle φ.

Apparatus for implementing the above method, including an image capture device 40, a stripe light generating device 50, and a computing device 60 coupled to the image capture device 40, are depicted as in the sixth and seventh figures. The image capturing device 40 is disposed on the Z-axis of the first object 10 and the second object 20, and the stripe light generating device 50 can generate the stripe light 30, the incident stripe light 31 projected on the first object 10, and The image of the reflected stripe light 32 and the incident stripe light 33 of the second object 20 is captured by the image capturing device 40. The computing device 60 can measure the incident stripe light of the first object 10 by the captured image. 31 and the relative distance of the reflected stripe light 32, and using the known stripe light incident angle θ, the relative vertical distance Z of the first object 10 and the second object 20 is calculated by Equation 1. Whether the first and second objects are parallel is determined by the parallelism of the stripe light on the second object 20 and the stripe light on the first object 10. When there is an oblique angle between the first and second objects, the computing device 60 calculates the tilt angle φ of the first object 10 by Equation 2.

The above-mentioned stripe light generating device 50 mainly includes: a light source 51, an angle adjuster 52 for mounting the light source 51 and adjusting the incident angle of the light source, and an auxiliary device for causing the light source 51 to have a stripe shape with a predetermined width (about 500 μm). 53. The light source 51 can be an LED. The auxiliary device 53 has a configuration with a slit 54. The LED light source is focused through the slit 54 and then focused by a convex lens 55 to be present in the first object 10 and the second stripe light. Object 20. The stripe light has a width of about 500 μm. The light source 51 can also be laser light, and the auxiliary device 53 is a cylindrical lens, and the stripe light having a width of about 60 μm can be generated on the first object 10 and the second object 20.

In the embodiment of the present invention, since the first object 10 that is permeable to light is mostly composed of glass with high light transmittance, in order to make the stripe light clearly appear on the first object 10 (glass) that can transmit light, The surface of the first article 10 is ground using an aluminum oxide powder to produce a developing surface which has a reduced light transmittance after surface treatment and has a partial reflection effect to cause the incident stripe light 31 and the reflection stripe Light 32 can be clearly presented on the development surface.

In another embodiment of the present invention, a developing surface having a partial reflective effect can be formed on the surface of the first object 10 by coating, so that the incident stripe light 31 and the reflected stripe light 32 can be clearly presented on the developing surface. .

As shown in the eighth figure, the image capturing device 40 can also capture the X-Y plane image of the first object 10 and the second object 20 to determine whether the marking points 15 of the two are aligned. According to the above device, the above device can monitor the X-Y-Z triaxial full plane position.

Although the present case is illustrated by a preferred embodiment, those skilled in the art can make various forms of changes without departing from the spirit and scope of the present invention. The above embodiments are only used to illustrate the present case and are not intended to limit the scope of the present invention. All kinds of modifications or changes that are not in violation of the spirit of the case are the scope of patent application in this case.

10‧‧‧First object

15‧‧‧ points

20‧‧‧Second objects

30‧‧‧Striped light

31‧‧‧ incident streak light

32‧‧‧ Reflection stripe light

33‧‧‧ incident stripe light

40‧‧‧Image capture device

50‧‧‧Striped light generating device

51‧‧‧Light source

52‧‧‧ Angle adjuster

53‧‧‧Assistor

54‧‧‧slit

55‧‧‧ convex lens

60‧‧‧ Computing device

The first figure is a side view depicting the calculation of the vertical relative distance of the parallel stack of objects.

The second figure depicts a situation in which stripe light is present in a stack of objects in a top view.

The third figure describes the case where the stripe light changes when the relative distance between the objects is changed in a front view.

The fourth figure depicts a tilt angle between the stacked objects in a side view.

The fifth figure depicts a situation in which the stripe light changes when there is an oblique angle between the objects in a front view.

The sixth figure is one of the schematic diagrams of the device of the present invention.

The seventh picture is the second schematic of the device in this case.

The eighth figure depicts the stacked object X-Y axis plane with a pair of markers in a top view.

10‧‧‧First object

20‧‧‧Second objects

30‧‧‧Striped light

40‧‧‧Image capture device

50‧‧‧Striped light generating device

51‧‧‧Light source

52‧‧‧ Angle adjuster

53‧‧‧Assistor

54‧‧‧slit

55‧‧‧ convex lens

60‧‧‧ Computing device

Claims (6)

A non-contact 3D full-plane position alignment method includes: projecting a stripe light at a predetermined incident angle to a pair of permeable first objects and a opaque second object; and using the stripe light The tangent trigonometric function of the incident angle calculates the vertical relative distance between the first object and the second object, and calculates the angle between the stripe light of the first object and the stripe light of the second object on a plane. An angle of inclination between the first object and the second object. The non-contact 3D full-plane position alignment method according to claim 1, wherein the approximation of the inclination angle is calculated by the following relationship, wherein the inclination angle is an inclination between the first object and the second object. The angle is the angle between the stripe light of the first object and the stripe light of the second object on a plane: The non-contact 3D full-plane position alignment method according to claim 1, wherein the true value of the tilt angle is calculated by the following relationship, wherein the tilt angle is between the first object and the second object. The angle of inclination is an angle between the stripe light of the first object and the stripe light of the second object on a plane: The non-contact 3D full-surface alignment method according to claim 1, wherein the surface of the first object that is permeable to light is provided with a developing surface having a partial reflectivity. The non-contact 3D full planar alignment method according to claim 4, wherein the surface of the first object is ground with an aluminum oxide powder to form the developing surface. The non-contact 3D full-plane position alignment method according to claim 4, wherein the first object surface coating method produces a developing surface having a partial reflectance.