Wafer detection athermalization objective lens and method

Abstract

The invention provides an athermalization objective lens and method for wafer detection, and relates to the technical field of semiconductor detection.The objective lens comprises a thermal tolerance lens set, a zoom lens set, a lens barrel, a radiator, a radial flexible unit, an axial flexible unit, a memory metal ring and a wedge block. The advantages of simple passive thermal control structure and large-stroke focusing of active control are achieved, thermal deformation of the first optical lens can be effectively reduced through the arrangement of the radial flexible unit and the axial flexible unit in the thermal tolerance lens group, the imaging quality of the objective lens can be ensured within a large temperature range, and the imaging quality of the objective lens is improved. Through the radiator, the effects of outward conduction of internal temperature by the objective lens and isolation of external temperature are achieved, the influence of temperature change on the focal length of the objective lens is reduced, high-precision imaging quality is achieved, and the problems that an existing passive athermalization scheme is limited in precision, and an active athermalization scheme is complex in system and high in cost are solved.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor detection technology, and in particular to a wafer detection athermalization objective lens and method. Background Art

[0002] Wafer inspection is a crucial link in the semiconductor manufacturing process, and its accuracy directly affects chip yield and performance. As the feature size of integrated circuits continues to shrink and Moore's Law continues to advance, higher requirements are placed on the resolution and accuracy of wafer inspection equipment. High numerical aperture (NA) objective lenses are key components for achieving high-resolution imaging, and their focal stability is crucial to imaging quality. Any slight focal drift will cause blurred imaging, thus affecting defect identification and detection.

[0003] However, there are many thermal factors in the wafer inspection process, which pose challenges to the focal stability of the objective lens: ambient temperature fluctuations, wafer heating, light source radiation, and internal heating of the objective lens will cause the temperature of the objective lens to change, causing thermal expansion or contraction, and ultimately leading to focal drift, optical axis tilt, and increased aberrations, seriously affecting inspection accuracy and efficiency.

[0004] At present, there are two main solutions to solve the problem of thermal drift of objective lenses: passive and active. The passive solution reduces the impact of temperature changes through thermal insulation design, low expansion coefficient materials and athermal mechanical structure design. The cost is relatively low, but the compensation accuracy is limited. The active solution uses temperature sensors and actuators (such as PZT, VCM, etc.) to form a closed-loop control system to monitor and compensate for focal drift in real time. The compensation accuracy is high, but the system is complex, costly, and has power consumption and heat generation problems. Summary of the invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defects in the prior art, thereby providing a wafer inspection athermal objective lens and method.

[0006] A wafer inspection athermal objective lens comprises: an optical lens group and a heat dissipation outer lens shell, wherein the optical lens group is arranged in the heat dissipation outer lens shell, the optical lens group comprises a thermal tolerance lens group and a zoom lens group arranged in sequence from bottom to top, the heat dissipation outer lens shell comprises a lens barrel and a radiator arranged in sequence from inside to outside, the thermal tolerance lens group comprises a first lens seat, a second lens seat and a third lens seat arranged in sequence from outside to inside, a plurality of radial flexible units are evenly distributed between the first lens seat and the second lens seat, a plurality of axial flexible units are evenly distributed between the second lens seat and the third lens seat, the first lens seat is connected to the inner wall of the lens barrel, a first optical lens is arranged on the third lens seat, the zoom lens group comprises a connecting lens seat, a limiting lens seat and a zoom lens seat arranged in sequence from outside to inside, the connecting lens seat is connected to the inner wall of the lens barrel, a plurality of wedge blocks are slidably arranged on the limiting lens seat, a memory metal ring is connected through the wedge blocks, the wedge blocks are slidably connected to the zoom lens seat, and a second optical lens is arranged on the zoom lens seat.

[0007] Furthermore, a glue injection hole is provided on the third lens holder, and a flexible glue layer is formed by injecting glue into the glue injection hole, and the first optical lens is bonded to the flexible glue layer.

[0008] Furthermore, the wafer inspection athermal objective lens also includes a reset spring, a limit groove corresponding to the reset spring is opened on the limit lens seat, a limit ring is arranged on the zoom lens seat, one end of the reset spring is arranged in the limit groove, and the other end of the reset spring is arranged on the limit ring.

[0009] Furthermore, a limiting pressure ring is provided on the limiting ring, and the limiting pressure ring is connected to the second optical lens.

[0010] Furthermore, the wafer inspection athermal objective lens also includes a flow guide cover, which is arranged on the outer wall of the lens barrel, and a heat-insulating glass is arranged on the end surface of the flow guide cover close to the thermal tolerance lens group.

[0011] Furthermore, heat dissipation silicone grease is filled between the lens barrel and the radiator.

[0012] Furthermore, a plurality of strip-shaped grooves are evenly arranged on the heat sink.

[0013] Furthermore, the outer surface of the air deflector is sprayed with a heat reflective coating.

[0014] Furthermore, a heat insulation coating is sprayed on a surface of the heat insulation glass away from the thermal tolerance lens assembly.

[0015] The present invention also includes a method for athermalizing wafer inspection, which is implemented based on an athermalizing wafer inspection objective lens as described in any of the above items. When the temperature rises, the heat inside the objective lens is discharged through a heat sink, and the radial flexible unit and the axial flexible unit allow the first optical lens to be displaced to compensate for the focal length change caused by thermal expansion due to the temperature increase. At the same time, the memory metal ring contracts, driving the wedge block to move in a direction close to the second optical lens, so that the zoom lens mount moves in the axial direction to actively compensate for the focal length drift caused by temperature change.

[0016] The technical solution of the present invention has the following advantages: The technical solution provided by the present invention avoids the disadvantages of traditional active control and passive control, inherits the advantages of active control and passive control, and realizes the advantages of simple passive thermal control structure and large-stroke focusing of active control by introducing passive control of memory metal ring. The setting of radial flexible unit and axial flexible unit in thermal tolerance lens group can effectively reduce the thermal deformation of the first optical lens, so that the imaging quality of the objective lens can be guaranteed within a larger temperature range. The heat sink can realize the outward conduction of the internal temperature of the objective lens and the insulation effect of the external temperature, reduce the influence of temperature change on the focal length of the objective lens, and achieve high-precision imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a schematic diagram of the structure of the thermal tolerance lens assembly and the zoom lens assembly of the present invention; Figure 2 It is a schematic diagram of the structure of the heat-insulating glass, the air guide cover and the radiator of the present invention; Figure 3 It is a schematic diagram of the structure of the thermal tolerance mirror assembly of the present invention; Figure 4 It is a schematic diagram of the structure of the zoom lens assembly of the present invention.

[0019] Description of reference numerals: 1-optical lens group; 1-1-thermal tolerance lens group; 1-1-1-first lens seat; 1-1-2-second lens seat; 1-1-3-third lens seat; 1-1-4-flexible glue layer; 1-1-5-radial flexible unit; 1-1-6-axial flexible unit; 1-1-7-glue injection hole; 1-1-8-lightweight slot; 1-2-zoom lens group; 1-2-1-connecting lens seat; 1-2-2-limiting lens seat; 1-2-2-1-limiting slot; 1-2-2-2-limiting End face; 1-2-3-zoom lens mount; 1-2-3-1-first inclined plane; 1-2-3-2-limiting ring; 1-2-4-memory metal ring; 1-2-5-wedge block; 1-2-5-1-second inclined plane; 1-2-6-reset spring; 2-insulating glass; 2-1-insulating coating; 3-air guide cover; 3-1-heat reflective coating; 4-lens barrel; 4-1-heat dissipating silicone grease; 5-heat sink; 5-1-strip groove; 6-first optical lens; 7-second optical lens. DETAILED DESCRIPTION

[0020] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] like Figure 1~Figure 4 A wafer inspection athermal objective lens shown in the figure comprises: an optical lens group 1 and a heat dissipation outer lens shell, the optical lens group 1 is arranged in the heat dissipation outer lens shell, the optical lens group 1 comprises a thermal tolerance lens group 1-1 and a zoom lens group 1-2 arranged in sequence from bottom to top, the heat dissipation outer lens shell comprises a lens barrel 4 and a heat sink 5 arranged in sequence from inside to outside along a radial direction, the heat sink 5 is mounted on the outer wall surface of the lens barrel 4, the thermal tolerance lens group 1-1 comprises a first lens seat 1-1-1, a second lens seat 1-1-2 and a third lens seat 1-1-3 arranged in sequence from outside to inside along a radial direction, a plurality of radial flexible units 1-1-5 are evenly distributed between the first lens seat 1-1-1 and the second lens seat 1-1-2, a plurality of axial flexible units 1-1-6 are evenly distributed between the second lens seat 1-1-2 and the third lens seat 1-1-3, the number of the radial flexible units 1-1-5 and the number of the axial flexible units 1-1-6 are both three, and the radial flexible units 1-1-5 and the axial flexible units 1-1-6 are The thickness of the flexible units 1-1-6 is 0.5 mm, the width is 2 mm, and the length is 5 mm. The radial flexible units 1-1-5 and the axial flexible units 1-1-6 are arranged alternately. The first lens seat 1-1-1 is connected to the inner wall of the lens barrel 4. The third lens seat 1-1-3 is provided with a first optical lens 6. The zoom lens group 1-2 includes a connecting lens seat 1-2-1, a limiting lens seat 1-2-2 and a zoom lens seat 1-2-3 which are arranged in sequence from the outside to the inside in the radial direction. -2-3, the connecting lens seat 1-2-1 is connected to the inner wall of the lens barrel 4, a plurality of wedge blocks 1-2-5 are slidably arranged on the position-limiting lens seat 1-2-2, a memory metal ring 1-2-4 is penetrated and connected to the wedge block 1-2-5, the wedge block 1-2-5 is slidably connected to the zoom lens seat 1-2-3, a second optical lens 7 is arranged on the zoom lens seat 1-2-3, and a lightweight groove 1-1-8 is also provided on the first lens seat 1-1-1, which helps to reduce the weight of the objective lens; The design of the heat dissipation outer lens shell is intended to minimize the influence of the ambient temperature change on the internal temperature of the objective lens. In addition to the thermal tolerance lens group 1-1 and the zoom lens group 1-2, the optical lens group 1 may also include multiple thermal tolerance lens groups 1-1. The thermal tolerance lens group 1-1 and the zoom lens group 1-2 are stacked and assembled inside the lens barrel 4 in an axial order. The first lens seat 1-1-1, the second lens seat 1-1-2 and the third lens seat 1-1-3 together form a flexible lens seat. The lens barrel 4 is made of 6061 aluminum alloy material, the inner diameter of the lens barrel 4 is 50 mm, the length of the lens barrel 4 is 100 mm, and the wall thickness of the lens barrel 4 is 5 mm. The higher thermal conductivity of the lens barrel 4 helps to conduct the internal heat to the radiator 5, and the radiator 5 is made of 7075 aluminum alloy material; The design of the thermal tolerance lens group 1-1 is to compensate for the expansion or contraction of the lens caused by temperature changes. The first optical lens 6 is made of fused quartz material, which has a low thermal expansion coefficient. The flexible lens holder is made of Kovar 4J29 material, which has a thermal expansion coefficient similar to that of quartz. The Kovar 4J29 material is used in conjunction with the first optical lens 6 in the anti-thermal expansion optical system. The design of the zoom lens group 1-2 is intended to actively compensate for the focal length drift caused by temperature changes through the deformation of the memory metal ring 1-2-4. The connecting lens seat 1-2-1, the limit lens seat 1-2-2 and the zoom lens seat 1-2-3 are all made of aluminum alloy. The memory metal ring 1-2-4 is made of nickel-titanium alloy (Nitinol). The wire diameter of the memory metal ring 1-2-4 is 1mm. The phase change temperature of the memory metal ring 1-2-4 is set at about 40°C, and the specific temperature depends on the focal length change amplitude. The wedge block 1-2-5 is made of 316 stainless steel. The cone angle coefficients of the second bevel 1-2-5-1 on the wedge block 1-2-5 and the first bevel 1-2-3-1 on the zoom lens seat 1-2-3 are both 0.1. The design of the wedge block 1-2-5 converts radial displacement into axial displacement, realizing the advantages of simple passive thermal control structure and large-stroke focusing with active control.

[0025] The above-mentioned athermal objective lens for wafer inspection avoids the shortcomings of traditional active control and passive control, inherits the advantages of active control and passive control, and realizes the advantages of simple passive thermal control structure and large-stroke focusing of active control by introducing passive control of memory metal ring 1-2-4. The arrangement of radial flexible unit 1-1-5 and axial flexible unit 1-1-6 in thermal tolerance lens group 1-1 can effectively reduce thermal deformation of first optical lens 6, so that imaging quality of objective lens can be guaranteed within a larger temperature range. Through radiator 5, the objective lens can conduct internal temperature outward and isolate from external temperature, thereby reducing the influence of temperature change on focal length of objective lens and achieving high-precision imaging quality.

[0026] like Figure 3 As shown, in this embodiment, a glue injection hole 1-1-7 is provided on the third lens holder 1-1-3, and glue is injected into the glue injection hole 1-1-7. After the glue solidifies, a flexible glue layer 1-1-4 is formed, and the first optical lens 6 is bonded to the flexible glue layer 1-1-4; the flexible glue layer 1-1-4 is specifically methyl vinyl silicone rubber, and the thickness of the flexible glue layer 1-1-4 is 0.2 mm. The methyl vinyl silicone rubber has certain flexibility and low thermal expansion coefficient, which can effectively reduce the thermal deformation of the first optical lens 6, so that the objective lens can ensure the imaging quality within a larger temperature range.

[0027] like Figure 4As shown, in the present embodiment, the athermal objective lens for wafer inspection further includes a reset spring 1-2-6, a limit groove 1-2-2-1 corresponding to the reset spring 1-2-6 is provided on the limit mirror seat 1-2-2, a limit ring 1-2-3-2 is provided on the zoom lens seat 1-2-3, one end of the reset spring 1-2-6 is arranged in the limit groove 1-2-2-1, the depth of the limit groove 1-2-2-1 is 2 mm, and the other end of the reset spring 1-2-6 is arranged on the limit ring 1-2-3-2; the reset spring 1-2-6 is made of chrome-vanadium steel material, which is suitable for use in environments with large temperature changes. The spring stiffness is 1 N / mm, which provides a reset force to ensure that the zoom lens seat 1-2-3 returns to its initial position when the temperature drops.

[0028] like Figure 4 As shown, in the present embodiment, a limiting pressure ring is provided on the limiting ring 1-2-3-2, and the limiting pressure ring is connected to the second optical lens 7; the limiting pressure ring plays a role of limiting and fixing the second optical lens 7, and the end face where the upper limit groove 1-2-2-1 of the limiting lens seat 1-2-2 is located is the limiting end face 1-2-2-2, and the spacing distance between the limiting end face 1-2-2-2 and the upper end face of the limiting pressure ring is 1mm, which limits the axial movement distance of the second optical lens 7 to 1mm, thereby ensuring the imaging quality. The outer ring of the zoom lens seat 1-2-3 is also provided with a limiting ring 1-2-3-2, which is used to limit the displacement of the zoom lens seat 1-2-3 during movement, thereby also ensuring the imaging quality.

[0029] like Figure 1 and Figure 2 As shown, in this embodiment, the wafer inspection athermal objective lens also includes a guide cover 3, which is arranged on the outer wall of the lens barrel 4, and the guide cover 3 is assembled on the front end face of the entire objective optical system, and a heat-insulating glass 2 is arranged on the end face of the guide cover 3 close to the thermal tolerance lens group 1-1; the wafer or the wafer stage carries heat, which increases the temperature of the surrounding air, and the hot air flow rises to the front end of the objective lens, affecting the imaging quality of the objective lens, and the guide cover 3 placed on the front end face of the objective lens can guide this part of the heat flow to the periphery of the objective lens, thereby reducing the influence of the hot air flow on the imaging quality of the objective lens; the guide cover 3 is made of 7075 aluminum alloy material, and the outer surface conical surface of the guide cover 3 is sprayed with a heat-reflecting coating 3 -1; the heat-reflective coating 3-1 is a silver-plated coating with a heat reflectivity greater than 95%. The surface of the heat-reflective coating 3-1 is roughened to avoid light pollution to the wafer under test. The heat-reflective coating 3-1 can effectively reduce the impact of environmental thermal radiation on the objective optical system; the thickness of the heat-insulating glass 2 is 0.5 mm. The heat-insulating glass 2 is made of fused quartz material. The heat-insulating glass 2 has high light transmittance and good heat-insulating performance. The heat-insulating coating 2-1 is sprayed on one side of the heat-insulating glass 2 away from the thermal tolerance lens group 1-1; the heat-insulating coating 2-1 is an indium tin oxide film with a thickness of 100 nm, which further blocks external heat from entering the interior of the objective while maintaining a high light transmittance.

[0030] like Figure 2 As shown, in this embodiment, heat dissipation silicone grease 4-1 is filled between the lens barrel 4 and the heat sink 5; the heat dissipation silicone grease 4-1 is evenly and densely distributed, the thickness of the heat dissipation silicone grease 4-1 is 1 mm, and the heat dissipation silicone grease 4-1 is specifically graphene composite high thermal conductivity silicone grease, which is used to fill the air gap and improve the heat conduction efficiency.

[0031] like Figure 2 As shown, in this embodiment, a plurality of strip grooves 5-1 are evenly arranged on the heat sink 5; the depth of the strip grooves 5-1 is 2 mm, the width of the strip grooves 5-1 is 1 mm, and the spacing between the strip grooves 5-1 is 1 mm. The heat dissipation fins formed by the strip grooves 5-1 increase the heat dissipation area and improve the heat dissipation efficiency.

[0032] like Figure 2~Figure 4 As shown, the present invention also includes a method for athermalizing wafer inspection, which is implemented based on a wafer athermalizing objective lens as described in any one of the above items. When the temperature rises, the heat inside the objective lens is extracted through the heat sink 5, and the radial flexible unit 1-1-5 and the axial flexible unit 1-1-6 allow the first optical lens 6 to be displaced to compensate for the focal length change caused by thermal expansion due to the temperature increase. At the same time, the memory metal ring 1-2-4 contracts, driving the wedge block 1-2-5 to move in a direction close to the second optical lens 7, so that the zoom lens holder 1-2-3 moves in the axial direction to actively compensate for the focal length drift caused by the temperature change. Specifically, the objective lens can effectively conduct the heat inside the objective lens through the design of the radiator 5 and the guide cover 3, and reduce the influence of external heat. The heat dissipation fins formed by the strip grooves 5-1 increase the heat dissipation area, improve the heat dissipation efficiency, and also improve the heat conduction efficiency; the heat reflective coating 3-1 can effectively reduce the influence of environmental thermal radiation on the system, the insulating glass 2 with the heat insulation coating 2-1 further blocks the external heat from entering the objective lens optical system, the heat dissipation silicone grease 4-1 enhances heat conduction and reduces the internal temperature change, the Kovar alloy 4J29 material has a similar thermal expansion coefficient to quartz, and can be used in conjunction with the first optical lens 6 in the anti-thermal expansion optical system to effectively reduce the focal length offset caused by temperature changes. The radial flexible unit 1-1-5 and the axial flexible unit 1-1-6 allow the first optical lens 6 to be displaced to compensate for the focal length change caused by thermal expansion due to temperature increase, and the radial The flexible unit 1-1-5 and the axial flexible unit 1-1-6 are of precisely designed size and shape to ensure that within a certain temperature range, the lens group can automatically compensate for focal length changes. When the temperature rises, the memory metal ring 1-2-4 contracts, driving the wedge block 1-2-5 to move toward the second optical lens 7, so that the zoom lens holder 1-2-3 moves in the axial direction to actively compensate for focal length drift caused by temperature changes. At this time, the reset spring 1-2-6 is compressed and stored, and the phase change temperature of the memory metal ring 1-2-4 can be adjusted according to actual needs to ensure that the focal length can be accurately compensated at the actual working temperature. When the temperature drops, the memory metal ring 1-2-4 is released, driving the wedge block 1-2-5 to move away from the second optical lens 7. At this time, the reset spring 1-2-6 releases the pressure, the zoom lens holder 1-2-3 returns to its original position, and the objective lens system returns to the original focal length position; In addition, the air guide cover 3, the lens barrel 4 and the heat sink 5 can have any form of connection method and connection configuration when their relative positions are constant. The graphene composite high thermal conductivity silicone grease material in the heat dissipating silicone grease 4-1 can be replaced by other types of silicone grease materials, and the methyl vinyl silicone rubber in the flexible adhesive layer 1-1-4 can be replaced by heat-resistant silicone grease with the same function.

[0033] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A wafer inspection athermal objective lens, comprising: An optical lens group (1) and a heat dissipation outer mirror housing, characterized in that the optical lens group (1) is arranged in the heat dissipation outer mirror housing, the optical lens group (1) comprises a heat tolerance lens group (1-1) and a zoom lens group (1-2) arranged in sequence from bottom to top, the heat dissipation outer mirror housing comprises a lens barrel (4) and a heat sink (5) arranged in sequence from inside to outside, the heat tolerance lens group (1-1) comprises a first lens seat (1-1-1), a second lens seat (1-1-2) and a third lens seat (1-1-3) arranged in sequence from outside to inside, a plurality of radial flexible units (1-1-5) are evenly distributed between the first lens seat (1-1-1) and the second lens seat (1-1-2), and a plurality of axial flexible units (1-1-5) are evenly distributed between the second lens seat (1-1-2) and the third lens seat (1-1-3). The invention relates to a zoom lens assembly (1-2), wherein the first lens seat (1-1-1) is connected to the inner wall of the lens barrel (4), the third lens seat (1-1-3) is provided with a first optical lens (6), the zoom lens assembly (1-2) comprises a connecting lens seat (1-2-1), a limiting lens seat (1-2-2) and a zoom lens seat (1-2-3) which are arranged in sequence from the outside to the inside, the connecting lens seat (1-2-1) is connected to the inner wall of the lens barrel (4), a plurality of wedge blocks (1-2-5) are slidably arranged on the limiting lens seat (1-2-2), a memory metal ring (1-2-4) is penetrated and connected to the wedge blocks (1-2-5), the wedge blocks (1-2-5) are slidably connected to the zoom lens seat (1-2-3), and a second optical lens (7) is arranged on the zoom lens seat (1-2-3).

2. The athermal objective lens for wafer inspection according to claim 1, characterized in that: The third lens seat (1-1-3) is provided with a glue injection hole (1-1-7), and a flexible glue layer (1-1-4) is formed by injecting glue into the glue injection hole (1-1-7), and the first optical lens (6) is bonded to the flexible glue layer (1-1-4).

3. The athermal objective lens for wafer inspection according to claim 1, characterized in that: The wafer detection athermal objective lens also includes a reset spring (1-2-6); a limit groove (1-2-2-1) corresponding to the reset spring (1-2-6) is provided on the limit lens seat (1-2-2); a limit ring (1-2-3-2) is provided on the zoom lens seat (1-2-3); one end of the reset spring (1-2-6) is arranged in the limit groove (1-2-2-1), and the other end of the reset spring (1-2-6) is arranged on the limit ring (1-2-3-2).

4. The athermal objective lens for wafer inspection according to claim 3, characterized in that: The limiting ring (1-2-3-2) is provided with a limiting pressure ring, which is connected to the second optical lens (7).

5. The athermal objective lens for wafer inspection according to claim 1, characterized in that: The wafer inspection athermal objective lens further comprises a flow guide cover (3), the flow guide cover (3) being arranged on the outer wall of the lens barrel (4), and a heat insulating glass (2) being arranged on the end surface of the flow guide cover (3) close to the thermal tolerance lens group (1-1).

6. The athermal objective lens for wafer inspection according to claim 1, characterized in that: Heat dissipation silicone grease (4-1) is filled between the lens barrel (4) and the heat sink (5).

7. The athermal objective lens for wafer inspection according to claim 1, characterized in that: The heat sink (5) is evenly provided with a plurality of strip-shaped grooves (5-1).

8. The athermal objective lens for wafer inspection according to claim 5, characterized in that: The outer surface of the air guide cover (3) is sprayed with a heat reflective coating (3-1).

9. The athermal objective lens for wafer inspection according to claim 5, characterized in that: A heat insulation coating (2-1) is sprayed on a side of the heat insulation glass (2) away from the thermal tolerance lens group (1-1).

10. A method for athermalizing wafer inspection, the method being implemented based on the athermalizing wafer inspection objective lens according to any one of claims 1 to 9, characterized in that: When the temperature rises, the heat inside the objective lens is discharged through the heat sink (5), and the radial flexible unit (1-1-5) and the axial flexible unit (1-1-6) allow the first optical lens (6) to generate displacement, thereby compensating for the focal length change caused by thermal expansion due to the temperature rise. At the same time, the memory metal ring (1-2-4) contracts, driving the wedge block (1-2-5) to move in a direction close to the second optical lens (7), so that the zoom lens holder (1-2-3) moves in the axial direction to actively compensate for the focal length drift caused by the temperature change.

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