A low-stress narrow-band UV lens for photolithography

Abstract

The invention relates to the technical field of lens design, manufacturing and adjustment for ultraviolet lithography machines, and specifically to a low-stress narrow-band ultraviolet lens for lithography machines. The design comprises a front lens group, an intermediate lens group, a light bar group, an eccentric adjustment mechanism group and a rear lens group. The eccentric cylindrical surface of the intermediate lens group frame cooperates with the rear lens group frame, and the outer eccentric lens frame cooperates with the rear lens group frame to form a double eccentric structure. The positional relationship between the intermediate lens group frame and the outer eccentric lens frame is adjusted to ensure that the optical axis of the double eccentric adjustment mechanism group coincides with the optical axis of the intermediate lens group. The edge of the eccentric mechanism pressure ring is fixed on the rear lens group frame, and the inner eccentric lens frame and the outer eccentric lens frame are fixed in the rear lens group frame. All lens working surfaces of the lens are not subjected to mechanical stress, so the imaging quality of the lens can be well guaranteed, the distortion can be reduced, and the coaxiality of the lens can be conveniently adjusted.

Description

Technical Field

[0001] The invention relates to the technical field of lens design, manufacturing and adjustment for ultraviolet lithography machines, and in particular to a low-stress narrow-band ultraviolet lens for lithography machines. Background Art

[0002] The working principle of the photolithography machine is that ultraviolet light is emitted by a plasma light source, which is collected by a collection system and then irradiated onto a mask plate by a transmission system. The ultraviolet spectrum pattern on the mask plate is accurately reduced by a UV lens at a certain proportion onto a silicon wafer coated with photoresist. After being processed by relevant subsequent processes, the required micro-image or circuit structure is left behind. The precision of the circuit structure mainly depends on the UV lens, which naturally becomes a key component of the photolithography machine.

[0003] The ultraviolet lenses currently used in the market are composed of a lens group composed of multiple lenses assembled through a lens barrel according to a certain spacing size. Although they can basically realize the lithography function, the mechanical parts and lenses are fastened by the roller edge method, that is, after the lens is installed in the frame, the edge of the frame is squeezed and bent on a precision lathe with a special tool so that it tightly wraps the lens along the chamfered slope of the lens corner. Under this fastening method, the lens magnification and edge distortion are large, the imaging quality of the lens group is poor, and ultimately the prepared circuit is difficult to meet the system requirements.

[0004] The document with the publication number CN207232486U discloses a UV lens for a photolithography machine, which adopts a technical solution of sequentially coaxially installing the first lens, the second lens, the third lens, and the fourth lens in the outer lens barrel through a pressure ring, a large spacer, and a screw; coaxially installing the fifth lens, the sixth lens, the seventh lens, and the eighth lens through a pressure ring and a small spacer to form a center group; the center group is then coaxially installed with the first lens, the second lens, the third lens, and the fourth lens in the outer lens barrel; finally, the ninth lens and the tenth lens are coaxially installed on one side of the outer lens barrel through a small spacer and a pressure ring. Although the scheme uses the pressure ring method instead of the roller edge method to fix the lens to avoid stress concentration on the lens working surface to produce large distortion, it is difficult to keep each lens in the precise coaxiality of the design through the assembly structure of fixed center and fixed spacing, and it is difficult to adjust the lens magnification error after the UV lens is installed. Summary of the invention

[0005] The main technical problem solved by the present invention is to provide a low-stress narrow-band ultraviolet lens optical machine device for a photolithography machine, which can solve the problems of low lens imaging quality, large distortion, low yield, etc. caused by lens stress.

[0006] In order to solve the above technical problems, a technical solution adopted by the present invention is: a low-stress narrow-band ultraviolet lens for a photolithography machine, the design includes a front lens group, a middle lens group, a light barrier group, an eccentric adjustment mechanism group and a rear lens group, wherein:

[0007] The front lens group consists of a front lens group frame and a first lens, and the first lens is arranged in the head of the front lens group frame.

[0008] The middle lens group is composed of a middle lens group frame, a second lens, a third lens and a fourth lens. The second lens, the third lens and the fourth lens are arranged in sequence in the middle lens group frame. The outer surface of the middle lens group frame adopts an eccentric cylindrical surface.

[0009] The light bar group is composed of a light bar group frame, a light bar and a light bar pressing ring, and the light bar head is fixed in the light bar group frame by the light bar pressing ring;

[0010] The eccentric adjustment mechanism group is composed of an inner eccentric frame, an outer eccentric frame, a fifth lens, a sixth lens and a seventh lens. The inner eccentric frame and the outer eccentric frame are rotatably connected, and the inner surface of the outer eccentric frame is set as an eccentric cylindrical surface; the fifth lens, the sixth lens and the seventh lens are sequentially arranged backward in the inner eccentric frame;

[0011] The rear mirror group consists of a rear mirror group frame, an eighth lens and a rear mirror group pressure ring. The front mirror group frame is connected to the rear mirror group frame by bolts. The middle mirror group frame, the light barrier group frame and the outer eccentric frame are sequentially arranged in the rearward direction in the rear mirror group frame. The eccentric cylindrical surface of the middle mirror group frame cooperates with the rear mirror group frame, and the outer eccentric frame cooperates with the rear mirror group frame to form a double eccentric structure. The positional relationship between the middle mirror group frame and the outer eccentric frame is adjusted to meet the coincidence of the optical axis of the double eccentric adjustment mechanism group and the optical axis of the middle mirror group. The edge of the eccentric mechanism pressure ring is fixed on the rear mirror group frame, and the inner eccentric frame and the outer eccentric frame are fixed in the rear mirror group frame. The eighth lens is arranged in the tail of the rear mirror group frame and is fixed by the rear mirror group pressure ring.

[0012] The middle lens group frame is provided with positioning screw holes, which are arranged on the circumference of the second lens, the third lens and the fourth lens. The coaxiality of the lens can be adjusted by adjusting bolts in the positioning screw holes.

[0013] The first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens are bonded to the gaps between the lens frames by using a two-component optical soft adhesive.

[0014] Furthermore, a glue injection groove is arranged in the lens frame of the front lens group, the width of the glue injection groove is 2mm, and the interval between the glue injection groove and the cylindrical surface of the first lens is 0.1mm~0.5mm; a glue injection groove is arranged in the inner eccentric lens frame, the width of the glue injection groove is 2mm, and the interval between the glue injection groove and the cylindrical surfaces of the fifth lens, the sixth lens and the seventh lens is 0.75mm; glue dots holes are evenly distributed in the glue injection groove, and the glue dots holes are arranged to be 8, and the diameter of the glue dots holes is 2mm. The glue dots holes pass through the front lens frame or the inner eccentric lens frame to facilitate glue injection in the glue injection groove.

[0015] A balancing hole is arranged on the middle lens group frame. The balancing hole has a diameter of 2 mm and runs through the middle lens group frame. The balancing hole is used to balance the internal air pressure of the narrow-band ultraviolet lens and reduce the lens distortion caused by the air pressure.

[0016] The ultraviolet lens also includes an adjustment ring, which is arranged on the head of the front lens group and is threadedly connected to the lens frame of the front lens group, used to connect the ultraviolet lens to the photolithography machine, and can be moved along the axial direction of the lens to adjust the object working distance of the lens;

[0017] An adjusting gasket is arranged at the connection between the front lens group and the middle lens group, and the lens magnification can be further fine-tuned according to the adjusting gasket to compensate for the magnification error caused by processing and assembly and improve the yield rate.

[0018] The beneficial effects of the present invention are as follows: in the narrow-band ultraviolet lens described in the present invention, all lens working surfaces are not subjected to mechanical stress, which can well ensure the imaging quality of the lens and reduce distortion. At the same time, a double eccentric structure is provided, which can conveniently adjust the coaxiality of the lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention.

[0020] Among them, the front lens group 1, the middle lens group 2, the light bar group 3, the eccentricity adjustment mechanism group 4, the rear lens group 5, the front lens group frame 1-1, the first lens 1-2, the adjustment ring 1-3, the adjustment gasket 1-4, the middle lens group frame 2-1, the second lens 2-2, the third lens 2-3, the fourth lens 2-4, the light bar group frame 3-1, the light bar 3-2, the light bar pressure ring 3-3, the inner eccentric lens frame 4-1, the outer eccentric lens frame 4-2, the fifth lens 4-3, the sixth lens 4-4, the seventh lens 4-5, the rear lens group frame 5-1, the eighth lens 5-2, and the rear lens group pressure ring 5-3. DETAILED DESCRIPTION

[0021] Embodiment 1: The preferred embodiment of the present invention is described in detail below in conjunction with the accompanying drawings. A low-stress narrow-band ultraviolet lens for a photolithography machine includes a front lens group, a middle lens group, a light barrier group, a double eccentric mechanism group and a rear lens group.

[0022] The front lens group consists of a front lens group frame and a first lens. The first lens is arranged inside the head of the front lens group frame. An adjustment ring is arranged outside the head of the front lens group, and the adjustment ring is threadedly connected to the front lens group frame.

[0023] The middle lens group is composed of a middle lens group frame, a second lens, a third lens and a fourth lens. The second lens, the third lens and the fourth lens are sequentially arranged backwards in the middle lens group frame, and the outer surface of the middle lens group frame adopts an eccentric cylindrical surface.

[0024] The light bar group is composed of a light bar group frame, a light bar and a light bar pressure ring. The light bar head is fixed in the light bar group frame by the light bar pressure ring. The size and position of the light bar are fixed through precise processing and assembly.

[0025] The eccentric adjustment mechanism group consists of an inner eccentric frame, an outer eccentric frame, a fifth lens, a sixth lens and a seventh lens. The inner eccentric frame and the outer eccentric frame are rotatably connected, and the inner surface of the outer eccentric frame is set as an eccentric cylindrical surface; the fifth lens, the sixth lens and the seventh lens are sequentially arranged backwards in the inner eccentric frame, and during assembly, the positional relationship between the inner eccentric frame and the outer eccentric frame is adjusted to ensure that the optical axis of the eccentric adjustment mechanism group coincides with the optical axis of the intermediate lens group.

[0026] The rear mirror group consists of a rear mirror group frame, an eighth lens and a rear mirror group pressure ring. The front mirror group frame is connected to the rear mirror group frame by bolts. The middle mirror group frame, the light barrier group frame and the outer eccentric frame are sequentially arranged in the rear mirror group frame. The edge of the eccentric mechanism pressure ring is fixed on the rear mirror group frame, and the inner eccentric frame and the outer eccentric frame are fixed in the rear mirror group frame. The eighth lens is arranged in the tail of the rear mirror group frame and fixed by the rear mirror group pressure ring.

[0027] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A low stress narrow band UV lens for a photolithography machine, characterized in that The invention comprises a front lens group, a middle lens group, a light bar group, an eccentric adjustment mechanism group and a rear lens group, wherein: the front lens group is composed of a front lens group frame and a first lens, the first lens is arranged in the head of the front lens group frame, the middle lens group is composed of a middle lens group frame, a second lens, a third lens and a fourth lens, the second lens, the third lens and the fourth lens are arranged in the middle lens group frame in sequence, and the outer surface of the middle lens group frame adopts an eccentric cylindrical surface; the light bar group is composed of a light bar group frame, a light bar and a light bar pressure ring, and the head of the light bar is fixed in the light bar group frame by the light bar pressure ring; the eccentric adjustment mechanism group is composed of an inner eccentric lens frame, an outer eccentric lens frame, a fifth lens, a sixth lens and a seventh lens, the inner eccentric lens frame and the outer eccentric lens frame are rotatably connected, and the inner surface of the outer eccentric lens frame is arranged as an eccentric cylindrical surface; the inner eccentric lens frame is arranged according to the inner eccentric lens frame. A fifth lens, a sixth lens and a seventh lens are arranged backwards; the rear lens group consists of a rear lens group frame, an eighth lens and a rear lens group pressure ring, the front lens group frame is connected to the rear lens group frame by bolts, and the middle lens group frame, the light bar group frame and the outer eccentric lens frame are arranged backwards in the rear lens group frame in sequence; the eccentric cylindrical surface of the middle lens group frame cooperates with the rear lens group frame, and the outer eccentric lens frame cooperates with the rear lens group frame to form a double eccentric structure, the edge of the eccentric mechanism pressure ring is fixed on the rear lens group frame, and the inner eccentric lens frame and the outer eccentric lens frame are fixed in the rear lens group frame; the eighth lens is arranged in the tail of the rear lens group frame and is fixed by the rear lens group pressure ring; the low stress narrow-band ultraviolet lens also includes an adjustment ring, which is arranged at the head of the front lens group and is threadedly connected to the front lens group frame; an adjustment gasket is arranged at the connection between the front lens group and the middle lens group.

2. A low stress narrow band UV lens for a photolithography machine as claimed in claim 1, characterized in that The lens frame of the middle lens group is provided with positioning screw holes, and the positioning screw holes are arranged on the circumference of the second lens, the third lens and the fourth lens.

3. A low stress narrow band UV lens for a photolithography machine as claimed in claim 1, characterized in that The gaps between the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens and each lens frame are bonded with a two-component optical soft adhesive.

4. A low stress narrow band UV lens for a photolithography machine as claimed in claim 3, characterized in that A glue injection groove is set in the frame of the front lens group. The width of the glue injection groove is 2mm, and the interval between the first lens cylindrical surface is 0.1mm~0.5mm. A glue injection groove is set in the inner eccentric frame. The width of the glue injection groove is 2mm, and the interval between the fifth lens, the sixth lens and the seventh lens cylindrical surface is 0.75mm. Glue holes are evenly distributed in the glue injection groove, and the number of glue holes is 8. The diameter of the glue holes is 2mm.

5. A low stress narrow band UV lens for a photolithography machine as claimed in claim 1, characterized in that A balancing hole is arranged on the lens frame of the middle lens group, wherein the diameter of the balancing hole is 2 mm and the balancing hole passes through the lens frame of the middle lens group.

Images