A thermal-free objective lens for wafer inspection and method

Abstract

The present invention provides athermal objective lens and method for wafer detection, which relates to the technical field of semiconductor detection. The objective lens includes a heat capacity difference lens group, a zoom lens group, a lens barrel, a radiator, a radial flexible unit, an axial flexible unit, a shape memory alloy ring and a wedge block. By introducing passive control of the shape memory alloy ring, the advantages of a simple passive thermal control structure and large-stroke focusing of active control are achieved. Through the setting of the radial flexible unit and the axial flexible unit in the heat capacity difference lens group, the thermal deformation of the first optical lens can be effectively reduced, so that the objective lens can ensure the imaging quality within a large temperature range. Through the radiator, the objective lens can conduct the internal temperature outwards and isolate the external temperature, reduce the influence of temperature change on the focal length of the objective lens, and achieve high-precision imaging quality, solving the problems of limited accuracy of the existing passive athermalization scheme and complex system and high cost of the active athermalization scheme.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor detection, and particularly relates to an athermal objective lens for wafer detection and a method thereof. Background Art

[0002] Wafer detection is a crucial link in the semiconductor manufacturing process, and its accuracy directly affects the chip yield and performance. With the continuous reduction of the feature size of integrated circuits and the continuous advancement of Moore's law, higher requirements are put forward for the resolution and accuracy of wafer detection equipment. High numerical aperture (NA) objective lenses are key components for achieving high-resolution imaging, and the stability of their focal length is crucial for imaging quality. Any slight focal length drift will result in blurred imaging, thus affecting the identification and detection of defects.

[0003] However, there are many thermal factors in the wafer detection process, which pose challenges to the focal length stability of the objective lens: environmental temperature fluctuations, self-heating of the wafer, light source radiation, and internal heating of the objective lens, etc. will all cause temperature changes of the objective lens, resulting in thermal expansion or contraction, and ultimately leading to focal length drift, optical axis tilt, and increased aberration, seriously affecting the detection accuracy and efficiency.

[0004] Currently, there are mainly two solutions to solve the problem of thermal drift of the objective lens: passive and active solutions. The passive solution reduces the influence of temperature changes through thermal insulation design, materials with low expansion coefficients, and athermal mechanical structure design. The cost is relatively low, but the compensation accuracy is limited. The active solution constitutes a closed-loop control system through temperature sensors and actuators (such as PZT, VCM, etc.), and monitors and compensates for focal length drift in real time. The compensation accuracy is high, but the system is complex, the cost is high, and there are problems of power consumption and heating. 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, so as to provide an athermal objective lens for wafer detection and a method thereof.

[0006] A thermal-free objective lens for wafer detection, comprising: an optical lens group and a heat dissipation outer lens housing. The optical lens group is disposed in the heat dissipation outer lens housing. The optical lens group includes a heat capacity difference lens group and a zoom lens group arranged in sequence from bottom to top. The heat dissipation outer lens housing includes a lens barrel and a radiator arranged in sequence from inside to outside. The heat capacity difference lens group includes a first lens mount, a second lens mount, and a third lens mount arranged in sequence from outside to inside. A plurality of radial flexible units are evenly distributed between the first lens mount and the second lens mount, and a plurality of axial flexible units are evenly distributed between the second lens mount and the third lens mount. The first lens mount is connected to the inner wall of the lens barrel, and a first optical lens is disposed on the third lens mount. The zoom lens group includes a connecting lens mount, a limiting lens mount, and a zoom lens mount arranged in sequence from outside to inside. The connecting lens mount is connected to the inner wall of the lens barrel. A plurality of wedge-shaped blocks are slidably disposed on the limiting lens mount. A memory metal ring is penetrated through the wedge-shaped blocks. The wedge-shaped blocks are slidably connected to the zoom lens mount, and a second optical lens is disposed on the zoom lens mount.

[0007] Further, a glue injection hole is provided on the third lens mount. 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] Further, the thermal-free objective lens for wafer detection further includes a return spring. A limiting groove corresponding to the return spring is provided on the limiting lens mount, and a limiting ring is disposed on the zoom lens mount. One end of the return spring is disposed in the limiting groove, and the other end of the return spring is disposed on the limiting ring.

[0009] Further, a limiting retaining ring is disposed on the limiting ring, and the limiting retaining ring is connected to the second optical lens.

[0010] Further, the thermal-free objective lens for wafer detection further includes a flow guide cover. The flow guide cover is disposed on the outer wall of the lens barrel, and a heat insulating glass is disposed on the end face of the flow guide cover close to the heat capacity difference lens group.

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

[0012] Further, a plurality of strip-shaped grooves are evenly provided on the radiator.

[0013] Further, a heat reflection coating is sprayed on the outer surface of the flow guide cover.

[0014] Further, a heat insulation coating is sprayed on the side of the heat insulating glass away from the heat capacity difference lens group.

[0015] The present invention also includes a method for athermalizing wafer inspection, which is implemented based on an athermalizing objective lens for wafer inspection as described in any of the above items. When the temperature rises, the heat inside the objective lens is dissipated through a radiator, 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 toward the second optical lens, so that the zoom lens mount moves in the axial direction to zoom and actively compensate for the focal length drift caused by temperature change.

[0016] The technical solution of the present invention has the following advantages:

[0017] The technical solution provided by the present invention avoids the shortcomings of traditional active control and passive control, inherits the advantages of active control and passive control, and achieves the advantages of simple passive thermal control structure and large-stroke focusing of active control by introducing memory metal ring passive control. The provision of radial flexible units and axial flexible units in the 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 large temperature range. The heat sink realizes the outward conduction of the internal temperature of the objective lens and the insulation effect of the external temperature, thereby reducing the influence of temperature changes on the focal length of the objective lens and achieving high-precision imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 Schematic diagram of the structure of the thermal tolerance lens assembly and the zoom lens assembly of the present invention;

[0020] Figure 2 This is a schematic structural diagram of the heat-insulating glass, air guide cover and radiator of the present invention;

[0021] Figure 3 Schematic diagram of the thermal tolerance mirror assembly structure of the present invention;

[0022] Figure 4 Schematic diagram of the structure of the zoom lens assembly of the present invention.

[0023] Description of reference numerals:

[0024] 1 - Optical lens group; 1 - 1 - Heat capacity difference lens group; 1 - 1 - 1 - First lens holder; 1 - 1 - 2 - Second lens holder; 1 - 1 - 3 - Third lens holder; 1 - 1 - 4 - Flexible adhesive layer; 1 - 1 - 5 - Radial flexible unit; 1 - 1 - 6 - Axial flexible unit; 1 - 1 - 7 - Glue injection hole; 1 - 1 - 8 - Lightweight groove; 1 - 2 - Zoom lens group; 1 - 2 - 1 - Connecting lens holder; 1 - 2 - 2 - Limiting lens holder; 1 - 2 - 2 - 1 - Limiting groove; 1 - 2 - 2 - 2 - Limiting end face; 1 - 2 - 3 - Zoom lens holder; 1 - 2 - 3 - 1 - First inclined surface; 1 - 2 - 3 - 2 - Limiting ring; 1 - 2 - 4 - Memory metal ring; 1 - 2 - 5 - Wedge block; 1 - 2 - 5 - 1 - Second inclined surface; 1 - 2 - 6 - Return spring; 2 - Heat insulation glass; 2 - 1 - Heat insulation coating; 3 - Diverter; 3 - 1 - Heat reflection coating; 4 - Lens barrel; 4 - 1 - Heat dissipation silicone grease; 5 - Radiator; 5 - 1 - Strip-shaped groove; 6 - First optical lens; 7 - Second optical lens. Detailed implementation mode

[0025] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of them. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is 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 should not be construed as a limitation of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0027] In the description of the present invention, it should be noted that unless otherwise clearly specified and limited, the terms "installation", "connection", "connection" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0028] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] As shown in Figures 1 to 4 a thermal-free objective lens for wafer detection, comprising: an optical lens group 1 and a heat dissipation outer lens housing. The optical lens group 1 is arranged in the heat dissipation outer lens housing. The optical lens group 1 includes a heat capacity difference lens group 1-1 and a zoom lens group 1-2 arranged in sequence from bottom to top. The heat dissipation outer lens housing includes a lens barrel 4 and a radiator 5 arranged in sequence from inside to outside in the radial direction. The radiator 5 is installed on the outer wall surface of the lens barrel 4. The heat capacity difference lens group 1-1 includes 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 in the 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 both the radial flexible units 1-1-5 and the axial flexible units 1-1-6 is three. The thickness of both the radial flexible units 1-1-5 and the axial 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 in an alternating and spaced manner. The first lens seat 1-1-1 is connected to the inner wall of the lens barrel 4. A first optical lens 6 is arranged on the third lens seat 1-1-3. 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 arranged in sequence from outside to inside in the radial direction. The connecting lens seat 1-2-1 is connected to the inner wall of the lens barrel 4. A plurality of wedge-shaped 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-shaped blocks 1-2-5. The wedge-shaped blocks 1-2-5 are 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. A lightweight groove 1-1-8 is also opened on the first lens seat 1-1-1, which helps to reduce the weight of the objective lens;

[0030] The design of the heat dissipation outer lens housing aims to minimize the influence of environmental temperature changes on the internal temperature of the objective lens. In addition to the heat capacity difference lens group 1-1 and the zoom lens group 1-2, the optical lens group 1 may also include a plurality of heat capacity difference lens groups 1-1. The heat capacity difference lens groups 1-1 and the zoom lens group 1-2 are stacked and assembled inside the lens barrel 4 in the axial order. The first lens seat 1-1-1, the second lens seat 1-1-2, and the third lens seat 1-1-3 jointly 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 relatively high thermal conductivity of the lens barrel 4 helps to conduct the internal heat to the radiator 5. The radiator 5 is made of 7075 aluminum alloy material;

[0031] The design of the heat capacity difference lens group 1-1 aims 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 coefficient of thermal expansion. The flexible lens mount is made of Kovar alloy 4J29 material, and the coefficient of thermal expansion of Kovar alloy 4J29 material is similar to that of quartz, so it is used in combination with the first optical lens 6 in the anti-thermal expansion optical system;

[0032] The design of the zoom lens group 1-2 aims to actively compensate for the focal length drift caused by temperature changes through the deformation of the shape memory metal ring 1-2-4. The connecting lens mount 1-2-1, the limiting lens mount 1-2-2, and the zoom lens mount 1-2-3 are all made of aluminum alloy material. The shape memory metal ring 1-2-4 is made of nickel-titanium alloy (Nitinol) material. The wire diameter of the shape memory metal ring 1-2-4 is 1 mm, and the phase transition temperature of the shape memory metal ring 1-2-4 is set near 40 °C, and the specific temperature depends on the range of focal length change. The wedge block 1-2-5 is made of 316 stainless steel material. The taper coefficients of the second inclined surface 1-2-5-1 on the wedge block 1-2-5 and the first inclined surface 1-2-3-1 on the zoom lens mount 1-2-3 are both 0.1. The design of the wedge block 1-2-5 converts the radial displacement into axial displacement, realizing the advantages of a simple passive thermal control structure and a large-stroke focusing of active control.

[0033] The above-mentioned wafer inspection athermal objective lens avoids the disadvantages of traditional active control and passive control, inherits the advantages of active control and passive control, realizes the advantages of a simple passive thermal control structure and a large-stroke focusing of active control through the introduction of passive control of the shape memory metal ring 1-2-4. Through the setting of the radial flexible unit 1-1-5 and the axial flexible unit 1-1-6 in the heat capacity difference lens group 1-1, the thermal deformation of the first optical lens 6 can be effectively reduced, so that the objective lens can ensure the imaging quality within a large temperature range. Through the radiator 5, the objective lens can conduct the internal temperature outwards and isolate the external temperature, reduce the influence of temperature changes on the focal length of the objective lens, and achieve high-precision imaging quality.

[0034] As Figure 3 shown, in this embodiment, a glue injection hole 1-1-7 is provided on the third lens mount 1-1-3. By injecting glue into the glue injection hole 1-1-7, a flexible glue layer 1-1-4 is formed after the glue solidifies, 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. Methyl vinyl silicone rubber has certain flexibility and a low coefficient of thermal expansion, 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 large temperature range.

[0035] As Figure 4As shown, in this embodiment, the athermalized objective lens for wafer detection 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 lens holder 1-2-2. A limit ring 1-2-3-2 is provided on the zoom lens holder 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. 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, providing a reset force to ensure that the zoom lens holder 1-2-3 returns to the initial position when the temperature decreases.

[0036] As Figure 4 shown, in this embodiment, a limit retaining ring is provided on the limit ring 1-2-3-2, and the limit retaining ring is connected to the second optical lens 7. The limit retaining ring plays a role in limiting and fixing the second optical lens 7. The end face where the limit groove 1-2-2-1 is located on the limit lens holder 1-2-2 is the limit end face 1-2-2-2. The spacing distance between the limit end face 1-2-2-2 and the upper end face of the limit retaining ring is 1 mm, restricting the axial movement distance of the second optical lens 7 to 1 mm to ensure the imaging quality. An outer ring of the zoom lens holder 1-2-3 is also sleeved with a limit ring 1-2-3-2 to limit the displacement during the movement of the zoom lens holder 1-2-3 and also ensure the imaging quality.

[0037] As Figure 1 and Figure 2 shown, in this embodiment, the athermalized objective lens for wafer detection further includes a flow guide cover 3. The flow guide cover 3 is arranged on the outer wall of the lens barrel 4, and the flow guide cover 3 is assembled on the front end face of the entire objective lens optical system. An insulating glass 2 is provided on the end face of the flow guide cover 3 close to the heat capacity difference lens group 1-1. The wafer or the wafer stage has heat, causing the temperature of the surrounding air to increase. The hot air flow rises to the front end of the objective lens and affects the imaging quality of the objective lens. The flow guide cover 3 placed on the front end face of the objective lens can divert this part of the heat flow to the periphery of the objective lens, reducing the influence of the hot air flow on the imaging quality of the objective lens. The flow guide cover 3 is made of 7075 aluminum alloy material. A heat reflection coating 3-1 is sprayed on the outer surface conical surface of the flow guide cover 3. The heat reflection coating 3-1 is a silver-plated coating, and the heat reflectivity is greater than 95%. The surface of the heat reflection coating 3-1 is roughened to avoid light pollution to the measured wafer. The heat reflection coating 3-1 can effectively reduce the influence of environmental thermal radiation on the objective lens optical system. The thickness of the insulating glass 2 is 0.5 mm. The insulating glass 2 is made of fused quartz material. The insulating glass 2 has high light transmittance and good heat insulation performance. An insulating coating 2-1 is sprayed on the side of the insulating glass 2 away from the heat capacity difference lens group 1-1. The insulating coating 2-1 is an indium tin oxide film, and the thickness of the insulating coating 2-1 is 100 nm, further blocking external heat from entering the objective lens interior while maintaining a high light transmittance.

[0038] As Figure 2 shown, in this embodiment, heat-conducting silicone grease 4-1 is filled between the lens barrel 4 and the radiator 5; the heat-conducting silicone grease 4-1 is evenly and densely distributed, the thickness of the heat-conducting silicone grease 4-1 is 1 mm, and the heat-conducting silicone grease 4-1 is specifically graphene composite highly heat-conductive silicone grease, which is used to fill the air gap and improve the heat conduction efficiency.

[0039] As Figure 2 shown, in this embodiment, a plurality of strip-shaped grooves 5-1 are evenly formed in the radiator 5; the groove depth of the strip-shaped groove 5-1 is 2 mm, the groove width of the strip-shaped groove 5-1 is 1 mm, and the spacing of the strip-shaped groove 5-1 is 1 mm. The heat dissipation fins formed by the strip-shaped grooves 5-1 increase the heat dissipation area and improve the heat dissipation efficiency.

[0040] As Figures 2 to 4 shown, the present invention further includes a method for anastigmatic wafer detection, which is realized based on any one of the above-described anastigmatic objective lenses for wafer detection. When the temperature rises, the heat inside the objective lens is exported through the radiator 5. The radial flexible unit 1-1-5 and the axial flexible unit 1-1-6 allow the first optical lens 6 to generate displacement so as to compensate 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 towards the second optical lens 7, so that the zoom lens holder 1-2-3 moves axially to actively compensate for the focal length drift caused by the temperature change;

[0041] Specifically, through the designs of the radiator 5 and the baffle 3, the heat inside the objective lens is effectively conducted out, and the influence of external heat is reduced. The heat dissipation fins formed by the strip-shaped grooves 5-1 increase the heat dissipation area, improve the heat dissipation efficiency, and also improve the heat conduction efficiency. The heat reflection coating 3-1 can effectively reduce the influence of environmental heat radiation on the system. The heat insulation 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 coefficient of thermal expansion to quartz. When used in combination with the first optical lens 6 in the anti-thermal expansion optical system, it can effectively reduce the focal length shift 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 displace, thereby compensating for the focal length change caused by thermal expansion due to temperature rise. The radial flexible unit 1-1-5 and the axial flexible unit 1-1-6 adopt precisely designed sizes and shapes to ensure that within a certain temperature range, the lens group can automatically compensate for the focal length change. When the temperature rises, the shape memory alloy ring 1-2-4 contracts, driving the wedge block 1-2-5 to move towards the second optical lens 7, causing the zoom lens mount 1-2-3 to move axially to actively compensate for the focal length drift caused by temperature changes. At this time, the return spring 1-2-6 is compressed and stores energy. The phase change temperature of the shape memory alloy ring 1-2-4 can be adjusted according to actual requirements to ensure accurate compensation of the focal length at the actual working temperature. When the temperature drops, the shape memory alloy ring 1-2-4 releases, driving the wedge block 1-2-5 to move away from the second optical lens 7. At this time, the return spring 1-2-6 releases the pressure, and the zoom lens mount 1-2-3 returns to its original position, and the objective lens system returns to the original focal length position;

[0042] In addition, when the relative positions of the baffle 3, the lens barrel 4, and the radiator 5 are fixed, they can be connected in any form and connection configuration. The graphene composite high thermal conductivity silicone grease material in the heat dissipation silicone grease 4-1 can be replaced with other types of silicone grease materials, and the methyl vinyl silicone rubber in the flexible adhesive layer 1-1-4 can be replaced with a heat-resistant silicone grease adhesive with the same function.

[0043] Obviously, the above embodiments are merely examples for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A wafer inspection athermal objective lens, comprising: Optical lens group (1) and heat dissipation outer lens housing, characterized in that the optical lens group (1) is arranged in the heat dissipation outer lens housing, the optical lens group (1) includes a heat capacity difference lens group (1-1) and a zoom lens group (1-2) arranged in sequence from bottom to top, the heat dissipation outer lens housing includes a lens barrel (4) and a radiator (5) arranged in sequence from inside to outside, the heat capacity difference lens group (1-1) includes 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), 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 first lens seat (1-1-1) is connected to the inner wall of the lens barrel (4), a first optical lens (6) is arranged on the third lens seat (1-1-3), 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) arranged in sequence from outside to inside, the connecting lens seat (1-2-1) is connected to the inner wall of the lens barrel (4), a plurality of wedge-shaped blocks (1-2-5) are slidably arranged on the limiting lens seat (1-2-2), a memory metal ring (1-2-4) is connected through the wedge-shaped blocks (1-2-5), the wedge-shaped 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); The wafer detection athermalized objective lens further includes a return spring (1-2-6), a limiting groove (1-2-2-1) corresponding to the return spring (1-2-6) is opened on the limiting lens seat (1-2-2), a limiting ring (1-2-3-2) is arranged on the zoom lens seat (1-2-3), one end of the return spring (1-2-6) is arranged in the limiting groove (1-2-2-1), and the other end of the return spring (1-2-6) is arranged on the limiting ring (1-2-3-2).

2. The athermalized objective lens for wafer detection according to claim 1, wherein, A glue injection hole (1-1-7) is arranged on the third lens seat (1-1-3), 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. Athermal objective lens for wafer inspection according to claim 1, characterized in that, A limiting retaining ring is arranged on the limiting ring (1-2-3-2), and the limiting retaining ring is connected to the second optical lens (7).

4. Athermal objective lens for wafer inspection according to claim 1, characterized in that, The wafer detection athermalized objective lens further includes a diversion cover (3), the diversion cover (3) is arranged on the outer wall of the lens barrel (4), and a heat-insulating glass (2) is arranged on the end face of the diversion cover (3) close to the heat capacity difference lens group (1-1).

5. The athermalized objective lens for wafer detection according to claim 1, wherein A heat dissipation silicone grease (4-1) is filled between the lens barrel (4) and the radiator (5).

6. The athermal objective lens for wafer detection according to claim 1, wherein A plurality of strip-shaped grooves (5-1) are evenly opened on the radiator (5).

7. The athermal objective lens for wafer detection according to claim 4, characterized in that, A heat reflection coating (3-1) is sprayed on the outer surface of the diversion cover (3).

8. Athermal objective lens for wafer inspection according to claim 4, characterized in that, A heat-insulating coating (2-1) is sprayed on the side of the heat-insulating glass (2) away from the heat capacity difference lens group (1-1).

9. Athermalization method for wafer detection, which is implemented based on the athermalized objective lens for wafer detection according to any one of claims 1 to 8, characterized in that, When the temperature rises, the heat inside the objective lens is dissipated through the radiator (5). The radial flexible unit (1-1-5) and the axial flexible unit (1-1-6) allow the first optical lens (6) to generate displacement to compensate for the focal length change caused by thermal expansion due to the temperature rise. At the same time, the shape memory alloy ring (1-2-4) contracts, driving the wedge block (1-2-5) to move towards the second optical lens (7), causing the zoom lens mount (1-2-3) to move axially to actively compensate for the focal length drift caused by temperature changes.

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