CN107748487A - A kind of local surface plasma contact direct-write lithography machine levelling device and method - Google Patents

Abstract

The invention relates to a leveling device of a lithography machine, which is used for leveling a sample sheet and a lithography direct-writing probe in localized surface plasma contact direct-writing lithography. The device is based on the absolute zero plane of the two z-direction offsets, and uses the device to measure the angle deflection of the silicon wafer and the probe relative to their respective absolute zero planes, so as to realize that the silicon wafer is parallel to the zero plane from the initial position. Process parallel to the probe surface.

Description

A leveling device and method for a localized surface plasma contact direct writing lithography machine

technical field

In the technical field of special equipment for semiconductors, it particularly relates to a leveling device for leveling the samples of local surface plasma contact direct-writing lithography machines and the leveling of lithography direct-writing probes.

Background technique

In this era of rapid development, semiconductor equipment technology has been used in all aspects of human social life in an all-round way. The feature size of integrated circuits has been shrinking continuously, and has been reduced to the stage of 10nm and 7nm. As an integrator of lithography technology, lithography machines , not only symbolizes the cutting-edge achievements of lithography technology, but also the interdisciplinary results of various disciplines.

The local surface plasma contact direct writing lithography machine mainly uses the CCD to amplify the contact state between the probe and the sample contact plane in two perpendicular directions, and repeatedly adjusts the deflection angle of the lithography probe in these two directions, so that Keep the gap between the probe and the sample consistent in these two directions, which is regarded as the best result of leveling the two. This method requires gradual and repeated adjustments, the leveling efficiency is not high, and the probe and the silicon wafer must be in a close contact state. When the deflection angle is adjusted, the surface of the sample may be damaged and affect the subsequent photolithography.

Contents of the invention

In order to solve the problems of low leveling accuracy, complicated operation and low leveling efficiency existing in the leveling device of the existing localized surface plasma contact direct writing lithography machine. The object of the present invention is to provide a set of high-precision and high-efficiency leveling devices for samples and photolithography direct-writing probes applied to localized surface plasma contact direct-writing photolithography machines.

In order to achieve the purpose of the present invention, the present invention is used for the leveling device of the local surface plasma contact direct writing lithography machine, and the technical solution to solve the technical problem includes a laser, a laser adjustment mounting frame, a laser mounting sleeve, a sample, a bearing stage, nano fine movement stage, coarse movement stage, flexible hinge, lithography direct writing probe, probe sleeve, xy direction horizontal two-dimensional moving stage, moving stage fixing frame, moving stage connecting frame, z direction vertical moving stage, Five-dimensional adjustment frame, position sensitive photodetector (PSD), fixed back plate.

Among them: the laser adjustment mounting frame clamps the laser and fixes it on the sleeve and installs it on the back plate; the probe is installed on the elastic hinge and connected to the five-dimensional adjustment frame through the sleeve, and the five-dimensional adjustment frame is fixed on the z-direction vertical displacement platform. The z-direction vertical translation platform is connected to the xy-direction two-position horizontal translation platform through the connecting plate, and the horizontal translation platform is fixed on the back plate; the PSD is fixed on the five-dimensional adjustment frame, and the five-dimensional adjustment frame is connected to the back plate; The fine motion table and the coarse motion table form a whole and are located under the probe, and the silicon wafer is on the wafer support table. The leveling method of the leveling device of the local surface plasma contact direct writing lithography machine mainly includes the following steps.

Step 1: Fix the leveling device according to the specified positional relationship, adjust the laser to irradiate the center of the upper surface of the direct writing probe, and the reflected laser irradiates the receiving screen of the position sensitive photodetector (PSD), The reflection spot is formed, and the z-direction position information is obtained through software processing, and the silicon wafer is placed on the wafer stage, directly below the probe.

Step 2: The first point where the laser irradiates on the upper surface of the probe is the initial point, and the coordinates of this point as the origin of the absolute zero plane are (0, 0, 0), and the five-dimensional adjustment frame is driven by the x, y moving platform, thereby Drive the probe to move in the x and y directions, so as to measure the value of the laser reflected from different points on the probe to the PSD, and obtain the displacement value in the z direction relative to the initial point. At the same time, the values changed in the x, y directions can be used as The x and y coordinate values of the new point X1, and the light spot information detected by the position sensitive photodetector PSD are processed by software to obtain the change amount in the z direction, and the z coordinate of the new point X1. Thus the coordinates of X1 on the zero plane are obtained.

Step 3: Repeat step 2 multiple times to obtain the coordinates of multiple new points, fit the plane equation of the upper surface of the probe, and calculate the normal vector of the plane.

Step 4: Adjust the inclination angle of the laser so that the laser is irradiated on the silicon chip, and the reflected laser light on the silicon chip is irradiated on the receiving screen of the position-sensitive photodetector (PSD) to form a reflected spot, and the z-direction position information is obtained through software processing.

Step 5: The first point where the laser is irradiated on the surface of the silicon wafer is the initial point. This point is the origin coordinate of the new absolute zero plane of the silicon wafer (0, 0, 0). The coarse motion table drives the fine motion table and the support piece stage, so as to drive the silicon wafer to move in the x and y directions, so as to measure the value of the laser reflected from different points on the probe to the PSD, and obtain the displacement value of the z direction relative to the initial point, and at the same time, the x., y direction changes The value can be used as the x and y coordinate values of the new point X1, and at the same time, the light spot information detected by the position sensitive photodetector PSD is used to obtain the change amount in the z direction and the z coordinate of the new point X1 through software processing. Thus the coordinates of X1 on the zero plane are obtained.

Step 6: Repeat step 5 multiple times to obtain the coordinates of multiple new points, fit the plane equation of the silicon wafer surface, and calculate the normal vector of the plane.

Step 7: Calculate the angular deflection of the two normal vectors relative to the positive unit vector of the Z-axis on the absolute zero plane, first adjust the silicon wafer through the nano-precision stage to make the normal vector parallel to the positive unit vector of z, and use the surface method on the reverse probe The vector is deflected by the angle of the positive unit vector of the Z axis of the absolute zero plane, so that the surface of the silicon wafer and the lithography direct writing probe are parallel to each other.

Among them, in view of the parallelism of the upper and lower surfaces during probe processing, we replace the lower surface with the silicon wafer by leveling the upper surface of the probe with the silicon wafer.

Among them, the absolute zero plane of the silicon chip and the absolute zero plane of the upper surface of the probe are two z-direction offset absolute zero planes, and the whole device should be installed on the vibration-isolated air-floating platform to eliminate vibration interference.

Description of drawings

Fig. 1 Detailed structural diagram of the leveling device of the local surface plasma contact direct writing lithography machine.

101 Secure the back plate.

102 Connection board.

103 Laser mounting sleeve.

104 Laser mounting adjustment frame.

105 lasers.

106 z-direction stage.

107 five-dimensional adjustment frame.

108nm precision stage.

109 Coarse motion table.

110 film holder.

111 silicon wafers.

112 Lithography probes.

113 Socket.

114 Position Sensitive Photo Detector (PSD).

115 five-dimensional adjustment frame.

116 xy two-dimensional mobile station.

117 Mobile station holder.

specific implementation plan

Fix the leveling device on the air flotation table, open the air flotation table and start leveling after it is stable. Step 1: Fix the leveling device according to the positional relationship described, and adjust the laser 105 to irradiate the direct writing probe. At the center of the upper surface, the reflected laser light is irradiated onto the receiving screen of the position sensitive photodetector (PSD) 114 to form a reflected light spot, and the z-direction position information is obtained through software processing. Directly below the needle 113; step 2: the first point where the laser is irradiated on the upper surface of the probe 113 is the initial point, and the coordinates of this point as the origin of the absolute zero plane are (0, 0, 0). Drive the five-dimensional adjustment frame to drive the probe to move in the x and y directions, so as to measure the value of the laser reflected from different points on the probe to the PSD114, and obtain the displacement value in the z direction relative to the initial point. At the same time, x., The value changed in the y direction can be used as the x and y coordinate values of the new point X1. At the same time, the light spot information detected by the position sensitive photodetector PSD114 is used to obtain the change in the z direction and the z coordinate of the new point X1 through software processing. Thus obtain the coordinates of X1 on the zero plane; Step 3: Repeat Step 2 multiple times to obtain the coordinates of multiple new points, fit the plane equation on the upper surface of the probe, and calculate the normal vector of the plane; Step 4: Adjust the laser 105 The inclination angle makes the laser irradiate on the silicon chip 111, and the laser light reflected by the silicon chip 111 is irradiated on the receiving screen of the position-sensitive photodetector (PSD) 114 to form a reflected spot, and the z-direction position information is obtained through software processing.

Step 5: The first point where the laser is irradiated on the surface of the silicon wafer 111 is the initial point, and this point is used as the origin coordinate of the new absolute zero plane of the silicon wafer (0, 0, 0), and the fine motion table 108 is driven by the coarse motion table 109 and the wafer stage 110, so as to drive the silicon wafer 111 to move in the x and y directions, thereby measuring the values of the reflected laser light from different points on the probe 112 to the PSD114, and obtaining the displacement value of the z direction relative to the initial point, and at the same time x ., the value changed in the y direction can be used as the x and y coordinate values of the new point X1, and at the same time use the light spot information detected by the position sensitive photodetector PSD114 to obtain the change amount in the z direction and the z coordinate of the new point X1 through software processing. Thus obtain the coordinates of X1 on the zero plane; Step 6: Repeat Step 5 multiple times to obtain the coordinates of multiple new points, fit the plane equation on the surface of the silicon wafer, and calculate the normal vector of the plane; Step 7: Calculate the two methods The angle deflection of the vector relative to the positive unit vector of the z-axis on the absolute zero plane, the silicon chip 111 is first adjusted through the nano precision stage 108 so that the normal vector is parallel to the z positive unit vector, and the surface normal vector on the reverse probe 112 is aligned with the absolute zero The Z-axis of the plane is deflected by the angle of the positive unit vector, so that the surface of the silicon wafer 111 and the lithography direct writing probe 112 are parallel to each other.

Claims (4)

1. a kind of levelling device of local surface plasma contact direct-write lithography machine, it is characterised in that include laser, laser Mounting bracket, laser installation sleeve are adjusted, print, wafer-supporting platform, the dynamic platform of nanometer essence, coarse motion platform, flexible hinge, photoetching direct write are visited Pin, probe sleeve, xy to horizontal two-dimension mobile station, mobile station fixed mount, mobile station link, z to vertically move platform, five dimension adjust Save frame, Position sensitive detectors (PSD), stationary backplate, air supporting experiment porch, leveling dress according to claim 1 Put, it is characterised in that laser adjustment mounting bracket clamping laser is fixed on sleeve, on backboard；Probe is mounted in elasticity By sleeve connection five times regualting frame on hinge, five times regualting frame is fixed on z on vertical displacement platform, and z leads to vertical displacement platform Cross connecting plate to be connected to two horizontal position moving stage with xy, horizontal position moving stage is fixed on backboard；PSD is fixed on five times regualting frame On, five times regualting frame is connected on backboard；The dynamic platform of wafer-supporting platform, essence, coarse motion platform form a whole below probe, and silicon chip exists On wafer-supporting platform.

2. levelling device according to claim 1, it is characterised in that multiple phases respectively in plane on measurement silicon chip and probe For the coordinate of the respective definitely point of zero plane, so as to obtain plane equation, obtain relative to the inclined of respective definitely zero plane Gyration, so as to realize silicon chip from initial position to parallel with zero plane, to the process parallel with detecting probe surface.

3. levelling device according to claim 1, it is characterised in that probe measurement method mainly includes:Step 1：It will adjust The position relationship of leveling device illustratively, which fixes, to be set, and regulation laser makes it be radiated at the upper surface center of direct write probe, instead Laser after penetrating is irradiated on Position sensitive detectors (PSD) receiving screen, is formed flare, is obtained by software processing It is placed in z to positional information, silicon chip on wafer-supporting platform, immediately below probe；Step 2：Laser is radiated at the of probe upper surface It is some initial point, this point is (0,0,0) as the origin of absolute zero plane, and by x, y drives five dimensions to adjust to mobile station Frame, so as to drive probe carry out x, y to movement, so as to measure the upper difference reflection laser of probe to PSD numerical value, obtain Relative to the z of initial point to moving displacement value, while the value that x., y direction change can be as the coordinate in new point X1 x, y direction Value, at the same using the facula information that Position sensitive detectors PSD is detected by software processing obtain z to knots modification, New point X1 z coordinate, so as to obtain coordinates of the X1 in zero plane；Step 3：Step 2 is repeated several times and obtains the seat of multiple new points Mark, the plane equation of probe upper surface is fitted, calculate the normal vector of the plane.

4. levelling device according to claim 1, it is characterised in that silicon chip measures leveling method, mainly including step 4： Laser inclination angle is adjusted, laser is irradiated on silicon chip, through silicon chip refracted laser illumination to Position sensitive detectors (PSD) Receiving screen on, formed flare, z is obtained to positional information by software processing；Step 5：Laser is radiated at silicon chip surface First point be initial point, this point be (0,0,0) as the origin of the new absolute zero plane of silicon chip, smart by the drive of coarse motion platform Dynamic platform and wafer-supporting platform, so as to drive silicon chip to carry out x, y to movement, so as to measure the upper difference reflection laser of probe to PSD Numerical value, obtain z relative to initial point to moving displacement value, while the value that changes of x., y direction can be used as newly point X1 x, y Coordinate value, at the same using the facula information that Position sensitive detectors PSD is detected by software processing obtain z to change Amount, new point X1 z coordinate, so as to obtain coordinates of the X1 in zero plane；Step 6：Step 5 is repeated several times and obtains multiple new points Coordinate, the plane equation of silicon chip surface is fitted, calculate the normal vector of the plane；Step 7：It is relative to calculate two normal vectors The angular deflection of the positive unit vector of absolute zero plane Z axis, first adjusting silicon chip by the dynamic platform of nanometer essence makes its normal vector positive single with z Bit vector is parallel, in the angular deflection of turnover probes upper surface normal vector and the absolute positive unit vector of zero plane Z axis, so that silicon Piece surface is parallel to each other with photoetching direct write probe.