CN108037640A - Separated near-field micro-nano photoetching method and device based on white light interference gap detection and ultra-precise alignment overlay technology - Google Patents

Abstract

The invention discloses a separated near-field micro-nano lithography method and device based on white light interference gap detection and ultra-precise alignment overlay technology. The method can realize large-area separated exposure and ultra-precise alignment overlay. The device includes an ultra-precision environmental control system, an active vibration isolation platform, a support frame, an ultraviolet exposure light source, a lithography lens module, a gap detection system, an alignment module, a film holder module and a control system. The device can realize nanoscale online gap detection and leveling through white light interference spectrum measurement technology, so as to realize separate exposure; through the alignment module and control system, it can realize ultra-precision alignment overlay technology.

Description

A separation method based on white light interference gap detection and ultra-precise alignment overlay technology Near-field micro-nano lithography method and device

technical field

The present invention relates to the field of near-field micro-nano lithography processing technology, more specifically, to a separate near-field micro-nano lithography method and device based on white light interference precision gap detection and ultra-precision alignment overlay technology, which can realize separation super-resolution micro-nano lithography.

Background technique

With the rapid development of the IC industry, the miniaturization and storage density of electronic product integrated circuits are getting higher and higher, so it is urgent to develop processing technologies and equipment with high efficiency, low cost, large area and good controllability. At present, in the traditional microfabrication technology route, micron-scale processing equipment represented by laser direct writing, near-contact ultraviolet lithography, and reactive ion beam etching have been widely used in research units. Writing and focusing ion beam equipment has also entered the processing platform system of scientific research units. Due to the complex and expensive light source system and high numerical aperture projection objective lens system, the high price of traditional nanoscale resolution lithography equipment is the main reason hindering its entry into the laboratory. Therefore, to meet the processing needs of hundreds of nanometers to tens of nanometers, researchers have to rely on electron beam direct writing and focused ion beam direct writing equipment. Although both have high-resolution processing capabilities, the processing efficiency is extremely low and the processing cost is extremely high.

Surface Plasmon (SP) resonance interference lithography is a large-area, low-cost, and widely used micro-nano processing method developed in recent years to break through the diffraction limit and improve lithographic resolution. However, as a near-field lithography mode, this technology has the disadvantage of a short working distance. During exposure, blowing, pressurization and vacuum suction are usually required to ensure the working distance. Moreover, this process mode is very easy to contaminate the substrate, destroy the mask pattern, and even damage the mask, which limits the reuse of the mask, thereby seriously affecting the exposure quality and efficiency, and increasing the exposure cost. The off-axis SP excitation lighting method can increase the lithography working distance to the order of hundreds of nanometers, but how to accurately detect and control the gap and ensure the stability and reliability of the lithography effect has become a new technical problem. At present, optical interferometry is one of the most effective methods for measuring the gap between two plates. It has the characteristics of fast detection speed, high sensitivity and precision, and can be used for gap detection in nanometer and micrometer scales.

The invention is a near-field micro-nano lithography method and device. The device can realize nanoscale online gap detection and leveling through white light interference spectrum measurement technology, so as to realize separate exposure and effectively protect the reticle and substrate; through dual-frequency laser interferometer, precision displacement stage, nano Feedback control of the translation stage, alignment module and gap detection module realizes ultra-precise overlay alignment and step-by-step lithography functions.

Contents of the invention

The technical problem to be solved in the present invention is to overcome the short service life of the reticle, large lateral displacement after contact between the reticle and the substrate, and low alignment accuracy in the existing near-field lithography method in the contact exposure mode. For the deficiencies, a separate near-field micro-nano lithography method and device based on white light interference gap detection and ultra-precision alignment overlay technology are provided. The closed-loop feedback control of the gap detection system and the alignment module realizes the functions of separate exposure and ultra-precise alignment overlay.

The technical scheme that the present invention solves its technical problem adopts is:

A separate near-field micro-nano lithography device based on white light interference gap detection and ultra-precision alignment overlay technology, the device includes an ultra-precision environmental control system, active vibration isolation platform, marble plate, support frame, main substrate, ultraviolet Exposure light source, lithography lens module, gap detection system, alignment module, film carrier module and control system, active vibration isolation platform, marble plate, support frame, main substrate, UV exposure light source, lithography lens module, gap detection system , the alignment module and the film holder module are installed in the ultra-precision environmental control system housing, the active vibration isolation platform is installed on the vibration damping foundation, the marble plate is installed on the active vibration isolation platform, the support frame and the film holder module are installed on the On the marble slab, the main substrate is installed on the support frame, the ultraviolet exposure light source, lithography lens module, gap detection system, and alignment module are installed on the main substrate, and the control system is installed outside the casing of the ultra-precision environmental control system; the lithography lens The module is installed in the central sinking groove of the main substrate, and a mask plate is installed in the photolithography lens module, and the photolithography pattern area, the alignment pattern area and the gap detection window area are processed on the mask plate, wherein the photolithography pattern area is located in the mask plate on a boss of height h.

Further, the gap detection system includes three sets of the same gap detection module, each gap detection module includes a fiber optic probe, a collimator, a halogen light source, and a spectrometer, wherein the fiber optic probe has 3 ends, which are the light input end and the light output end And the probe end, wherein, the light input end is connected to the halogen light source, the light output end is connected to the spectrometer, the probe end and the mask plate are installed in the central sinker of the main substrate at 90°, the collimator is installed at the front end of the probe end, the halogen light source and the The spectrometer is installed in the chassis of the control system.

Further, the alignment module includes a left alignment module and a right alignment module, which are mounted symmetrically on both sides of the lithography lens module on the main substrate, and are used for real-time monitoring of the state of the alignment pattern area.

Further, the wafer stage module includes a dual-frequency laser interferometer, a six-axis precision translation stage, a six-axis nanometer translation stage, a wafer stage, and a substrate, wherein the dual-frequency laser interferometer and the six-axis precision translation stage are installed on a marble plate In the above, the six-axis nano-translation stage is installed on the six-axis precision translation stage, the wafer stage is installed on the six-axis nano-transition stage, and the substrate is adsorbed on the wafer stage.

Further, the separated near-field lithography with a single field of 10mm×10mm can be realized. Among them, the cleanliness of the ultra-precision environmental control system is required to reach 100; the active vibration isolation platform is required to meet the VC-F standard; the mask plate and base The PV value of the one-sided type reaches λ/20, where λ is the wavelength of the ultraviolet exposure light source; the height of the boss on the reticle is required to be h=(10～80)μm±20nm; the cleanliness of the reticle and the substrate is required to be tested and Particle removal; it is required to control the gap between the mask plate and the substrate at 200-300nm.

Further, the gap control between the reticle and the substrate requires that a chromium (Cr) film with a thickness of 5-10 nm be plated on the gap detection window area on the reticle; the detection accuracy of the gap detection system is required to reach 10 nm; the wafer stage module is required The leveling accuracy reaches 20nm.

Further, tens of nanometer precision alignment overlay technology can be realized, in which the detection accuracy of the alignment module is required to reach the nanometer level, and the positioning accuracy of the six-axis nano-shift stage is required to reach the nanometer level.

A separate near-field micro-nano lithography method based on white light interference gap detection and ultra-precise alignment overlay technology. engraving device, this method can realize large-area separated exposure and ultra-precise alignment overlay, and through white light interference spectroscopy measurement technology, it can realize online gap detection and leveling at the nanometer level, thereby realizing separated exposure; through moiré fringes Alignment technology, which can realize ultra-precise alignment and overlay technology.

Compared with the existing contact-type near-field micro-nano lithography method and device, the present invention has the following advantages:

1. The device adopts an ultra-precise environmental control system to ensure a good lithography environment.

2. The device adopts an active vibration isolation platform and a marble plate to ensure the stability and reliability of separate exposure and ultra-precise alignment overlay.

3. The device adopts white light interference spectrum measurement technology and moiré fringe alignment technology, which can realize online gap detection and ultra-precise alignment overlay of nanometer level.

4. The device provides feedback data through the dual-frequency laser interferometer and the gap detection system, adjusts the six-axis precision translation stage and the six-axis nano-translation stage, and can realize active leveling and alignment overlay with nanometer precision, so that the gap and lateral The displacement is stable and controllable, finally realizing split exposure and ultra-precise alignment overlay.

5. The device can realize separate photolithography, which can effectively protect the reticle and increase its service life; it can effectively reduce the lateral displacement between the reticle and the substrate, and improve the accuracy of alignment overlay.

Description of drawings

1 is a schematic diagram of the overall structure of a separate near-field micro-nano lithography device based on white light interference gap detection and ultra-precision alignment overlay technology according to the present invention;

Figure 2 is a schematic structural diagram of the lithography lens module, gap detection system and alignment module of a separate near-field micro-nano lithography device based on white light interference gap detection and ultra-precise alignment overlay technology, where Figure 2(a) is According to the top view of the lithography lens module, the gap detection system and the alignment module of the present invention, Fig. 2(b) is a top view (pattern area and window area distribution diagram) and a side view of the reticle in the lithography lens module;

Fig. 3 is a structural diagram of a gap detection system according to the present invention;

Fig. 4 is a schematic diagram of the structure of the wafer stage module according to the present invention, wherein Fig. 4(a) is a schematic diagram of the overall structure of the wafer stage module, and Fig. 4(b) is a schematic diagram of the structure of a six-axis precision translation stage.

The reference signs mean:

1 Ultra-precise environmental control system

2 Active vibration isolation platform

3 marble slabs

4 Support frame

5 main board

6 UV exposure light source

7 Lithography lens module

8 Gap detection system

9 Alignment module

10 wafer stage modules

11 Control system

12 reticle

13 Photolithographic pattern area

14 Align graphics area

15 Gap detection window area

16 fiber optic probe

17 collimator

18 Halogen light source

19 spectrometer

20 light input port

21 light outlet

22 probe end

23 Dual frequency laser interferometer

24 six-axis precision translation stage

25 Six-Axis Nanostages

26 film holder

27 substrate

28 Y-axis translation stage

29 X-axis translation stage

30 R _X /R _Y Rotary Stage

31 T _Z axis electric cylinder

32 T _Z- axis adapter plate

Detailed ways

In order to make the purpose, technical solution, device and other advantages of the present invention clearer, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. However, the following embodiments are only limited to explain the present invention, and the protection scope of the present invention should include the entire contents of the claims, and through the following embodiments, those skilled in the art can realize the entire contents of the claims of the present invention.

Referring to Figure 1, the separated near-field micro-nano lithography device based on white light interference gap detection and ultra-precision alignment overlay technology consists of an ultra-precision environmental control system 1, an active vibration isolation platform 2, a marble plate 3, a support frame 4, The main substrate 5, the ultraviolet exposure light source 6, the lithography lens module 7, the gap detection system 8, the alignment module 9, the wafer stage module 10 and the control system 11 are composed of 11 parts, among which the ultra-precision environment control system 1 is the whole near The field micro-nano lithography device provides a good lithography environment with a temperature of 22±0.1°, a humidity of 55±5%, and a cleanliness of 100; the active vibration isolation platform 2 and the marble plate 3 provide vibration isolation levels of VC-F, Ensure the stability of gap detection, alignment overlay and separate exposure functions; the marble plate 3, support frame 4 and main substrate 5 have good structural stability, and a film carrier module 10 is installed on the marble plate 3. A UV exposure light source 6, a lithography lens module 7, a gap detection system 8 and an alignment module 9 are installed on the substrate 5; the UV exposure light source 6 provides a UV exposure beam for the entire lithography device; the control system 9 is used for the entire lithography system device automated control operations.

Referring to Fig. 2, a reticle 12 is installed in the lithography lens module 7 of the device, and a lithography pattern area 13, an alignment pattern area 14 and a gap detection window area 15 are processed on the reticle 12, wherein the lithography pattern area 13 Located on the boss with a height of h on the mask plate 12, the gap detection window area 15 is plated with a chromium (Cr) film with a thickness of 5-10 nm; the gap detection system 8 includes 3 sets of the same gap detection modules 8-1, 8-2, 8-3; the alignment module 9 includes two sets of left and right alignment modules 9-1, 9-2.

Referring to Fig. 3, the gap detection system 8 of the device includes an optical fiber probe 16, a collimator 17, a halogen light source 18 and a spectrometer 19, wherein the optical fiber probe 16 has 3 ends, which are respectively the light inlet end 20, the light outlet end 21 and the probe end 22, wherein the light input end 20 is connected to the halogen lamp light source 18, the light output end 21 is connected to the spectrometer 19, the probe end 22 is installed in the center sinker of the main substrate 5 at 90° to the mask plate 12, and the collimator 17 is installed in the probe end 22 front end.

Referring to Fig. 4 (a), the wafer stage module 10 of the device includes a dual-frequency laser interferometer 23, a six-axis precision displacement stage 24, a six-axis nanometer displacement stage 25, a wafer stage 26, and a substrate 27, wherein two sets The dual-frequency laser interferometers 23-1 and 23-2 and the six-axis precision translation stage 24 with the accuracy of μm/mrad are installed on the marble plate 3, and the six-axis nano-translation stage 25 with the accuracy of nm/μrad is installed on the six-axis precision translation platform On the platform 24 , the wafer-supporting platform 26 is installed on the six-axis nanometer displacement platform 25 , and the substrate 27 is adsorbed on the wafer-supporting platform 26 .

Referring to Figure 4(b), the six-axis precision translation stage 24 includes a Y-axis translation stage 28, an X-axis translation stage 29, an R _X /R _Y rotation stage 30, a T _Z- axis electric cylinder 31 and a T _Z- axis adapter plate 32, Among them, the two Y-axis translation stages 28-1 and 28-2 are fixed on the marble plate 3, the X-axis translation stage 29 is installed on the Y-axis translation stage 28, and the R _X / R _Y rotary table 30 is installed on the X-axis translation stage 29, three T _Z axis electric cylinders 31-1, 31-2, 31-3 are installed on the R _X / R _Y rotary table 30 through two T _Z axis adapter plates 32-1, 32-2.

Referring to Fig. 2, Fig. 3 and Fig. 4, when the device performs gap detection and leveling, it controls the substrate on the wafer stage module 10 to enter the exposure position, and then simultaneously moves the three T _{and Z} axis electric cylinders of the six-axis precision translation stage 24 31-1, 31-2, 31-3, monitor the spectral signal output by the optical fiber probe 16 in real time through the spectrometer 19 in the gap detection system 8, when the spectrometer 19 detects an effective interference signal, through 3 sets of gap detection systems 8- 1, 8-2, 8-3 real-time feedback gap value H (H ₁ , H ₂ , H ₃ ) to guide the three T _Z- axis electric cylinders 31-1, 31-2, 31-3 for active rough leveling , the active fine-leveling is performed through the six-axis nano-shift stage 25, and the gap value is fed back to the dual-frequency laser interferometer 23 in real time to realize closed-loop control.

Referring to Fig. 1, Fig. 2, Fig. 3 and Fig. 4, the operation flow of the near-field micro-nano lithography device is as follows:

In the first step, the control system 11 controls each axis of the six-axis precision translation stage 24 and the six-axis nano-translation stage 25 to reset, then controls the wafer stage module 10 to enter the loading position, installs the substrate 36, and finally sets the exposure parameters and leveling Target clearance, coarse leveling and fine leveling accuracy.

In the second step, control the wafer stage module 10 to enter the exposure position to ensure that the center of the reticle 12 and the substrate 27 are aligned, and then feed back the reticle 12 and the substrate 27 in real time through three sets of gap detection systems 8-1, 8-2, and 8-3. The gap value G (G=Hh) between the plates 27 guides the three T _Z -axis electric cylinders 31-1, 31-2, and 31-3 of the six-axis precision displacement table 24 to perform active rough leveling until the set When the target clearance and coarse leveling accuracy are met, stop the coarse leveling.

In the third step, after the rough leveling is completed, the six-axis nano-translation stage 25 is guided to carry out active fine leveling and gap control through the gap values fed back by the three sets of gap detection systems 8-1, 8-2, and 8-3 in real time until the setting The specified leveling accuracy and clearance value.

The fourth step is to move the alignment module 9 to the detection area, maintain the gap value and parallel state between the reticle 12 and the substrate 27 through closed-loop control, and align the reticle 12 and the substrate 27 through the Moiré fringe mark.

Step five, after finishing the leveling and alignment, start the exposure.

Step 6, after the exposure is completed, reset all modules, shut down the control system 11, and turn off the power supply.

The above descriptions are only specific implementation methods in the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technology within the technical scope disclosed in the present invention can understand that any transformation or replacement conceivable is covered by the scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (8)

1. a kind of separate type near field micro-nano lithographic equipment based on white light interference gap detection and ultraprecise alignment sleeve lithography, its It is characterized in that：The device includes ultraprecise environmental control system (1), Active Vibration Isolation Platform (2), marble tablet (3), support frame (4), main substrate (5), uv-exposure light source (6), projective lens module (7), clearance detecting system (8), alignment modules (9), hold Piece platform module (10) and control system (11), Active Vibration Isolation Platform (2), marble tablet (3), support frame (4), main substrate (5), uv-exposure light source (6), projective lens module (7), clearance detecting system (8), alignment modules (9) and wafer-supporting platform module (10) it is installed in ultraprecise environmental control system (1) case, Active Vibration Isolation Platform (2) is installed on vibration damping ground, marble tablet (3) it is installed on Active Vibration Isolation Platform (2), support frame (4) and wafer-supporting platform module (10) are installed on marble tablet (3), Main substrate (5) be installed on support frame (4) on, uv-exposure light source (6), projective lens module (7), clearance detecting system (8), Alignment modules (9) are installed on main substrate (5), and control system (11) is installed on outside ultraprecise environmental control system (1) case；Photoetching mirror Head module (7) is installed in the center deep gouge of main substrate (5), and mask (12), mask are provided with projective lens module (7) (12) litho pattern area (13), alignment patterns area (14) and gap detection window region (15) are machined with, wherein, litho pattern area (13) highly on the boss of h on mask (12).

2. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：Clearance detecting system (8) includes three sets of identical gap detection module (8-1,8-2,8- 3), each gap detection module includes fibre-optical probe (16), collimater (17), halogen light source (18), spectrometer (19), its In, fibre-optical probe (16) has 3 ends, respectively light inlet (20), light extraction end (21) and sound end (22), wherein, light inlet (20) Halogen light source (18), light extraction end (21) connection spectrometer (19) are connected, sound end (22) is installed on mask (12) in 90 ° In the center deep gouge of main substrate (5), collimater (17) is installed on sound end (22) front end, halogen light source (18) and spectrometer (19) in the cabinet of control system (11).

3. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：Alignment modules (9) include left alignment modules (9-1) and right alignment modules (9-2), both Projective lens module (7) both sides on main substrate (5) are left and right symmetrically arranged, for monitoring the shape of alignment patterns area (14) in real time State.

4. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：Wafer-supporting platform module (10) includes two-frequency laser interferometer (23), six axis precision displacement tables (24), six axis nanometer displacement platforms (25), wafer-supporting platform (26), substrate (27), wherein, two-frequency laser interferometer (23) and six axis are accurate Displacement platform (24) is installed on marble tablet (3), and six axis nanometer displacement platforms (25) are installed in six axis precision displacement tables (24), Wafer-supporting platform (26) is installed on six axis nanometer displacement platforms (25), and substrate (27) is adsorbed on wafer-supporting platform (26).

5. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：The separate type near field photolithography of single game 10mm × 10mm can be achieved, wherein, it is desirable to ultraprecise Cleanliness factor in environmental control system (1) reaches 100 grades；It is required that Active Vibration Isolation Platform (2) reaches VC-F standards；It is required that mask (12) Reach λ/20 with the PV values of substrate (27) face type, wherein λ is the wavelength of uv-exposure light source (6)；It is required that on mask (12) Boss height h=(10~80) μm of ± 20nm；It is required that cleanliness factor detection and particulate matter are carried out to mask (12) and substrate (27) Remove；It is required that by the clearance control between mask (12) and substrate (27) in 200~300nm.

6. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：It is required that the gap detection window region (15) on mask (12) plates 5~10nm's of thickness Chromium (Cr) film；It is required that the accuracy of detection of clearance detecting system (8) reaches 10nm；It is required that the leveling precision of wafer-supporting platform module (10) reaches To 20nm.

7. the separate type near field according to claim 1 based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：The alignment sleeve lithography of tens nano-precisions can be achieved, it is desirable to the inspection of alignment modules (9) Survey precision and reach nanometer scale, it is desirable to which the positioning accuracy of six axis nanometer displacement platforms (25) reaches nanometer scale.

8. a kind of separate type near field micro-nano photolithography method based on white light interference gap detection and ultraprecise alignment sleeve lithography, profit With separate type near field of the claim 1-8 any one of them based on white light interference gap detection and ultraprecise alignment sleeve lithography Micro-nano lithographic equipment, it is characterised in that：This method can realize the exposure of large area separate type and ultraprecise alignment alignment, pass through white light Interference spectrum e measurement technology exposes, it can be achieved that the online gap detection of nanometer scale and leveling so as to fulfill separate type；By not That striped technique of alignment is, it can be achieved that ultraprecise alignment sleeve lithography.