CN221260828U - Optical detection device - Google Patents

Abstract

An optical detection device disclosed in an embodiment of the present utility model includes: the laser device is located on the light inlet side of the front-end variable-magnification laser beam expanding system, the rear-end optical shaping system is located on the light outlet side of the front-end variable-magnification laser beam expanding system, the front-end variable-magnification laser beam expanding system comprises a zoom lens group, a compensation lens group and a fixed lens group, the zoom lens group and the compensation lens group are movably arranged on the optical axis of the front-end variable-magnification laser beam expanding system, the fixed lens group is fixedly arranged on the optical axis, and the compensation lens group is located between the zoom lens group and the fixed lens group. The embodiment of the utility model can perform variable-magnification shaping on the laser spot, thereby ensuring the uniformity of the obtained laser linear spot and effectively reducing the damage threshold of the laser.

Description

Optical detection device

Technical Field

The utility model relates to the technical field of optical detection, in particular to optical detection equipment.

Background

The laser light source used in the optical detection process is a coherent light source, and has the characteristics of high single color, high brightness and the like, so that the laser light source is widely used in the field of semiconductor detection. However, since the energy distribution of the laser light source used for optical detection is gaussian, there are problems such as uneven energy distribution and high damage threshold, and the element and the surface of the object to be measured are easily damaged during optical detection. Along with the development of optical technology, methods such as a diffraction element (DIFFRACTIVE OPTICAL ELEMENTS, DOE for short), a micro-lens array, a prism and the like are presented, so that the linear light spot flat top uniform shaping of laser beams is realized, and the bottleneck problem in the application is solved to a certain extent. However, in the field of wafer defect detection in the field of semiconductor detection, the requirements for flat-top uniform shaping of line light spots are strict, and the laser light spots emitted by the laser commonly used in the field have a size error of +/-5%, and the shaping methods such as a diffraction element, a micro lens array, a prism and the like are sensitive to the laser light spot size error, so that the uniqueness of the flat-top uniform shaping result of the line light spots is lower, and further the stability and the repeatability of the detection result are lower.

Disclosure of utility model

In view of the above, according to the optical detection device provided by the embodiment of the utility model, the front-end variable-magnification laser beam expansion system formed by the zoom lens group, the compensation lens group and the fixed lens group is introduced to perform variable-magnification expansion on the laser beam and then output the laser beam to the rear-end optical shaping system, so that uniformity of the obtained laser linear light spot can be ensured, and meanwhile, the damage threshold of laser can be effectively reduced.

Specifically, an optical detection device provided by an embodiment of the present utility model includes: the laser device is located on the light inlet side of the front-end variable-magnification laser beam expanding system, the rear-end optical shaping system is located on the light outlet side of the front-end variable-magnification laser beam expanding system, the front-end variable-magnification laser beam expanding system comprises a zoom lens group, a compensation lens group and a fixed lens group, the zoom lens group and the compensation lens group are movably arranged on the optical axis of the front-end variable-magnification laser beam expanding system, the fixed lens group is fixedly arranged on the optical axis, and the compensation lens group is located between the zoom lens group and the fixed lens group.

In one embodiment of the utility model, the focal power of the variable focal length lens is greater than 0, the focal power of the compensation lens is less than 0, and the focal power of the fixed lens is greater than 0.

In one embodiment of the utility model, the distance between the zoom lens group and the compensation lens group on the optical axis is 15mm-25mm; the distance between the compensation lens group and the fixed lens group on the optical axis is 3mm-65mm.

In one embodiment of the present utility model, the zoom lens group includes a first lenticular lens having a radius of curvature of an incident surface ranging from 35mm to 37mm and an exit surface ranging from 35mm to 37mm; the compensating lens group comprises a biconcave lens, wherein the radius of curvature of an incident surface of the biconcave lens ranges from 8mm to 10mm, and the radius of curvature of an emergent surface of the biconcave lens ranges from 8mm to 10mm; the fixed lens group comprises a second biconvex lens, the radius of curvature of the incident surface of the second biconvex lens ranges from 75mm to 80mm, and the radius of curvature of the emergent surface of the second biconvex lens ranges from 75mm to 80mm.

In one embodiment of the present utility model, the diameter of the first biconvex lens is equal to the diameter of the biconcave lens, and the diameter of the second biconvex lens is 2 times the diameter of the first biconvex lens.

In one embodiment of the present utility model, the thickness of the first lenticular lens on the optical axis ranges from 9mm to 10mm; the thickness of the first biconvex lens on the optical axis ranges from 9mm to 10mm; the thickness of the second biconcave lens on the optical axis ranges from 9mm to 10mm.

In one embodiment of the present utility model, the thickness of the biconcave lens on the optical axis is smaller than the thickness of the first biconvex lens on the optical axis, which is smaller than the thickness of the second biconvex lens on the optical axis.

In one embodiment of the present utility model, the front-end variable magnification laser beam expansion system has a magnification range of 1.2 times to 2 times.

In one embodiment of the utility model, the back-end optical shaping system comprises a diffractive element located on the light exit side of the front-end variable magnification laser beam expansion system.

In one embodiment of the utility model, the light intensity of the laser spot emitted by the laser is Gaussian, the wavelength of the laser is 266nm, the size of the laser spot is 3mm, and the size error of the laser spot is +/-5%.

One or more of the above technical solutions may have one or more of the following advantages: according to the embodiment of the utility model, the front-end variable-magnification laser beam expanding system is arranged in the optical detection equipment, and comprises the zoom lens group, the compensation lens group and the fixed lens group which are movably arranged, and the relative positions among the zoom lens group, the compensation lens group and the fixed lens group can be correspondingly adjusted, so that the laser beam entering the front-end variable-magnification laser beam expanding system is expanded and is output to the rear-end optical shaping system for shaping after the expansion is completed, the uniformity of a line light spot obtained after the laser shaping can be ensured, and the damage threshold of the laser can be effectively reduced.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present utility model, the drawings required for the description of the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.

Fig. 1 is a schematic structural diagram of an optical detection device according to an embodiment of the present utility model.

Fig. 2 is a schematic structural diagram of a front-end variable magnification laser beam expanding system according to an embodiment of the present utility model.

Fig. 3 is a zoom schematic diagram of the front-end variable magnification laser beam expansion system shown in fig. 2.

Fig. 4 is a schematic structural diagram of a zoom lens group of the front-end variable magnification laser beam expansion system shown in fig. 2.

Fig. 5 is a schematic structural diagram of a compensating lens group of the front-end variable magnification laser beam expansion system shown in fig. 2.

Fig. 6 is a schematic structural diagram of a fixed mirror group of the front-end variable magnification laser beam expansion system shown in fig. 2.

Fig. 7 is a schematic structural diagram of another optical detection device according to an embodiment of the present utility model.

Fig. 8 is a spot diagram of the laser after beam expansion by the front-end variable magnification laser beam expansion system.

Fig. 9 is a wavefront view of the laser after being expanded by the front-end variable magnification laser beam expansion system.

Fig. 10 is a spot diagram of the laser beam after being expanded by the front-end variable magnification laser beam expansion system.

Fig. 11 is a spot diagram of the laser after being shaped by the optical detection device.

Detailed Description

In order that the above objects, features and advantages of the utility model will be readily understood, a more particular description of the utility model will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model. The present utility model may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the utility model, whereby the utility model is not limited to the specific embodiments disclosed below.

In the description of the embodiments of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the embodiments of the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and therefore should not be construed as limiting the present utility model.

Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present utility model, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present utility model, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present utility model, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used herein for illustrative purposes only and are not meant to be the only embodiment.

Referring to fig. 1 and 2, the present embodiment provides an optical detection apparatus, for example, including a laser 3, a front-end variable magnification laser beam expanding system 1, and a back-end optical shaping system 2. The laser 3 is located at the light incident side of the front-end variable-magnification laser beam expansion system 1, and the rear-end optical shaping system 2 is located at the light emergent side of the front-end variable-magnification laser beam expansion system 1. The front-end variable power laser beam expanding system 1 includes, for example, a zoom lens group 10, a compensation lens group 20 and a fixed lens group 30, where the zoom lens group 10 and the compensation lens group 20 are movably disposed on an optical axis of the front-end variable power laser beam expanding system 1, the fixed lens group 30 is fixedly disposed on the optical axis, the compensation lens group 20 is disposed between the zoom lens group 10 and the fixed lens group 30, and a laser beam emitted by the laser 3 may be incident into the zoom lens group 10 from an incident side of the front-end variable power laser beam expanding system 1 along the optical axis, sequentially passes through the zoom lens group 10, the compensation lens group 20 and the fixed lens group 30, and is emitted from an emergent side of the front-end variable power laser beam expanding system 1, and enters the rear-end optical shaping system 2 to shape the expanded laser beam. The zoom lens group 10 is, for example, a first biconvex lens, the compensation lens group 20 is, for example, a biconcave lens, the fixed lens group 30 is, for example, a first biconvex lens, the focal power of the zoom lens group is greater than 0, the focal power of the compensation lens group is less than 0, and the focal power of the fixed lens group is greater than 0, so as to specifically realize beam expansion of the laser beam entering the front-end variable magnification laser beam expansion system 1.

Wherein, as shown in fig. 4, 5 and 6, the thickness T1 of the first biconvex lens 11 on the optical axis ranges from 9mm to 10mm; the thickness T2 of the biconcave lens 21 on the optical axis is in the range of 9mm to 10mm. The thickness T3 of the second biconvex lens 31 on the optical axis ranges from 9mm to 10mm. The diameter of the first biconvex lens is equal to the diameter of the biconcave lens, the diameter of the second biconvex lens is 2 times the diameter of the first biconvex lens, specifically, the diameter D1 of the first biconvex lens 11 is, for example, 12.7mm, and the diameter D2 of the second biconvex lens 21 is, for example, 25.4mm; the diameter D3 of the biconcave lens 31 is, for example, 12.7mm. The first biconvex lens 11 is a spherical mirror, the radius of curvature of the incident surface 111 of the first biconvex lens 11 ranges from 35mm to 37mm, and the radius of curvature of the emergent surface 112 of the first biconvex lens 11 ranges from 35mm to 37mm; the second biconvex lens 21 is a spherical mirror, the radius of curvature of the incident surface 211 of the second biconvex lens 21 ranges from 75mm to 80mm, and the radius of curvature of the exit surface 212 of the second biconvex lens 21 ranges from 75mm to 80mm; the biconcave lens 31 is a spherical mirror, the radius of curvature of the incident surface 311 of the biconcave lens 31 ranges from 8mm to 10mm, and the radius of curvature of the exit surface 312 of the biconcave lens 31 ranges from 8mm to 10mm, so that the laser beam with any wavelength and size is expanded, and the laser beam after being expanded is injected into the rear-end optical shaping system 2 for shaping, so that the uniformity of the linear light spot of the laser obtained after the shaping of the rear-end optical shaping system 2 is ensured, the damage threshold of the laser is effectively reduced, and when the laser is used for detecting wafer defects, for example, elements contacting the laser end and wafers to be detected are protected. In one embodiment of the present utility model, it is preferable that the thickness T1 of the first biconvex lens 11 is 9.8mm, the thickness T2 of the biconcave lens 21 is 9.5mm, and the thickness T3 of the second biconvex lens 31 is 10mm.

In one embodiment of the present utility model, as shown in fig. 3, the distance between the zoom lens group 10 and the compensation lens group 20 on the optical axis is 15mm-25mm, the distance between the compensation lens group 20 and the fixed lens group 30 on the optical axis is 3mm-65mm, the zoom lens group 10 can move along the optical axis within a certain range, so as to adjust the distance between the zoom lens group 10 and the compensation lens group 20, and meanwhile, the compensation lens group 20 can also move along the optical axis within a certain range, so as to adjust the distance between the compensation lens group 20 and the fixed lens group 30, and the front end variable power laser beam expansion system 1 can realize the expansion of different multiplying powers on the laser by adjusting the relative positions of the zoom lens group 10 and the compensation lens group 20. In one embodiment of the present utility model, the front-end variable magnification laser beam expansion system 1 has a magnification range of 1.2 times to 2 times. In other implementations of the embodiments of the present utility model, the front-end variable magnification laser beam expansion system 1 may be adapted for higher (low) magnification, wider (narrow) range of expansion magnification.

In one embodiment of the present utility model, as shown in fig. 1 and 7, the rear-end optical shaping system 2 includes, for example, a diffraction element 40 (DIFFRACTIVE OPTICAL ELEMENTS, abbreviated as DOE), where the diffraction element 40 is located, for example, on the light-emitting side of the front-end variable-magnification laser beam expanding system 1. The laser 3 may emit laser light along an optical axis, for example, and the light intensity of a laser spot emitted by the laser 3 may be in gaussian distribution, for example, that is, the laser light emitted by the laser 3 is a gaussian beam. In one embodiment of the present utility model, the wavelength of the laser light emitted by the laser 3 is 266nm, the laser spot size is 3mm, and the error of the laser spot size is ±5%. Further, after the laser enters the front-end variable-magnification laser beam expansion system 1 from the light entrance side along the optical axis, the laser is emitted from the front-end variable-magnification laser beam expansion system 1 along the optical axis and enters the light entrance side of the diffraction element 40 after being subjected to variable-magnification expansion, and then the laser is shaped by the diffraction element 40, at this time, the light spots of the laser after being shaped by the diffraction element 40 are linear light spots, under different magnifications, the root mean square size of the light spots of the emitted laser is smaller than Yu Aili spot size (shown in fig. 8), the wavefront difference (shown in fig. 9) is smaller than a quarter wavelength, at this time, the gaussian beam is in the range of the light spot size error, the linear light spot length of the shaped gaussian beam is about 14mm, the uniformity is >90%, the line width is <15um, the damage threshold of the gaussian beam can be reduced by 4 times (shown in fig. 10 and 11).

In one embodiment of the present utility model, the rear-end optical shaping system 2 further includes a micro lens array and a prism, and the micro lens array, the prism and the like cooperate with the diffraction element 40 to compensate the effect caused by the size error of the laser spot, so as to ensure the uniformity of the linear light spot of the output laser, and at the same time, further compress the line width of the narrow linear light spot to a certain extent, and improve the utilization rate of the laser.

In summary, in the embodiment of the present utility model, for example, the front-end variable-magnification laser beam expansion system is set in the optical detection device, where the front-end variable-magnification laser beam expansion system is composed of a zoom lens group, a compensation lens group and a fixed lens group, which are sequentially set, where the zoom lens group and the fixed lens group are biconvex lenses, the compensation lens group is biconcave lenses, the thickness ranges of the zoom lens group, the compensation lens group and the fixed lens group are all 9mm-10mm, and the relative positions among the zoom lens group, the compensation lens group and the fixed lens group can be correspondingly adjusted, so that the laser beam incident into the front-end variable-magnification laser beam expansion system is expanded, and after the laser beam is expanded, the laser beam is shaped by the diffraction element, thereby ensuring uniformity of line spots obtained after laser shaping, and effectively reducing the damage threshold of the laser beam; the root mean square size of the linear light spot of the shaped laser is smaller than Yu Aili spot diameter, the wavefront difference is less than 1/4 wavelength, the optical detection device achieves the diffraction limit, and the performance is in the optimal state

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for the sake of brevity, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above embodiments only represent a few embodiments of the present utility model, which are described in more detail and are not to be construed as limiting the scope of the present application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the utility model, which are all within the scope of the utility model. Accordingly, the scope of the utility model should be assessed as that of the appended claims.

Claims (7)

1. An optical inspection apparatus, comprising: the system comprises a laser, a front-end variable-magnification laser beam expanding system and a rear-end optical shaping system, wherein the laser is positioned at the light inlet side of the front-end variable-magnification laser beam expanding system, the rear-end optical shaping system is positioned at the light outlet side of the front-end variable-magnification laser beam expanding system, the front-end variable-magnification laser beam expanding system comprises a zoom lens group, a compensation lens group and a fixed lens group, the zoom lens group and the compensation lens group are movably arranged on the optical axis of the front-end variable-magnification laser beam expanding system, the fixed lens group is fixedly arranged on the optical axis, and the compensation lens group is positioned between the zoom lens group and the fixed lens group;

The rear-end optical shaping system comprises a diffraction element, wherein the diffraction element is positioned on the light-emitting side of the front-end variable-magnification laser beam expanding system;

The focal power of the zooming lens group is larger than 0, the focal power of the compensating lens group is smaller than 0, and the focal power of the fixed lens group is larger than 0; the distance between the zoom lens group and the compensation lens group on the optical axis is 15mm-25mm; the distance between the compensation lens group and the fixed lens group on the optical axis is 3mm-65mm.

2. The optical detection apparatus according to claim 1, wherein the zoom lens group includes a first lenticular lens having a radius of curvature of an incident surface ranging from 35mm to 37mm and an exit surface having a radius of curvature ranging from 35mm to 37mm;

The compensating lens group comprises a biconcave lens, wherein the radius of curvature of an incident surface of the biconcave lens ranges from 8mm to 10mm, and the radius of curvature of an emergent surface of the biconcave lens ranges from 8mm to 10mm;

The fixed lens group comprises a second biconvex lens, the radius of curvature of the incident surface of the second biconvex lens ranges from 75mm to 80mm, and the radius of curvature of the emergent surface of the second biconvex lens ranges from 75mm to 80mm.

3. The optical detection apparatus according to claim 2, wherein the diameter of the first biconvex lens is equal to the diameter of the biconcave lens, and the diameter of the second biconvex lens is 2 times the diameter of the first biconvex lens.

4. The optical detection apparatus according to claim 2, wherein a thickness of the first lenticular lens on the optical axis ranges from 9mm to 10mm;

The thickness of the second biconvex lens on the optical axis ranges from 9mm to 10mm;

the thickness of the biconcave lens on the optical axis ranges from 9mm to 10mm.

5. The optical detection apparatus according to claim 4, wherein a thickness of the biconcave lens on the optical axis is smaller than a thickness of the first biconvex lens on the optical axis, which is smaller than a thickness of the second biconvex lens on the optical axis.

6. The optical detection apparatus of claim 1, wherein the front-end variable magnification laser beam expansion system has a magnification range of 1.2-2.

7. The optical detection device according to claim 1, wherein the light intensity of the laser spot emitted by the laser is gaussian, the wavelength of the laser is 266nm, the laser spot size is 3mm, and the size error of the laser spot is ±5%.