CN109530928B - Method and device for processing chip by laser - Google Patents
Method and device for processing chip by laser Download PDFInfo
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- CN109530928B CN109530928B CN201811607499.7A CN201811607499A CN109530928B CN 109530928 B CN109530928 B CN 109530928B CN 201811607499 A CN201811607499 A CN 201811607499A CN 109530928 B CN109530928 B CN 109530928B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/362—Laser etching
- B23K26/364—Laser etching for making a groove or trench, e.g. for scribing a break initiation groove
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0643—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising mirrors
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/02—Positioning or observing the workpiece, e.g. with respect to the point of impact; Aligning, aiming or focusing the laser beam
- B23K26/06—Shaping the laser beam, e.g. by masks or multi-focusing
- B23K26/064—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms
- B23K26/0648—Shaping the laser beam, e.g. by masks or multi-focusing by means of optical elements, e.g. lenses, mirrors or prisms comprising lenses
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
Abstract
The invention provides a method and a device for processing a chip by laser, wherein the method comprises the following steps: moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of a laser processing system, and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incident surface to be in a horizontal position; processing a group of grooves on two opposite edges by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; rotating a workbench for placing the refrigeration type infrared detection chip for 90 degrees; then processing the grooves on the two opposite edges of another group by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges and form a closed annular groove. The invention can process two opposite grooves at one time by using the principle of controlling the time-sharing multiplexing of the galvanometer. On the basis of the intermittent processing of each groove, the heat accumulation is effectively reduced under the condition of ensuring the processing efficiency.
Description
Technical Field
The invention relates to the technical field of laser micromachining, in particular to a method and a device for machining a chip by laser.
Background
The infrared detector is well applied to civil use and military use, and the refrigeration type infrared detector has particularly excellent performance. In order to ensure normal working performance, liquid nitrogen refrigeration needs to be carried out on the infrared detection chip in the detector in a working state, the temperature at the moment is about-200 ℃, but in a non-working period, the infrared detection chip is exposed to the atmospheric temperature, for example, the highest temperature in desert can reach about 70 ℃ sometimes, so that the ambient temperature of the infrared detection chip is constantly changed between-200 ℃ and 70 ℃.
The infrared detection chip is structurally divided into three layers, namely a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom, wherein the photosensitive layer comprises tellurium-cadmium-mercury, tellurium-cadmium-indium and the like. Therefore, the tellurium-cadmium-mercury layer is tightly connected with the epoxy resin layer, and due to the fact that the thermal expansion coefficients of the tellurium-cadmium-mercury layer and the epoxy resin layer are greatly different, under the condition of long-term severe change of the environmental temperature, the two layers are easy to shift in position. The position deviation caused by the repeated thermal stress causes the indium column connected with the mercury cadmium telluride layer to break, and the breakage of the indium column causes the mercury cadmium telluride layer (photosensitive layer) to break in connection with a chip circuit layer at the bottom of a chip, so that the infrared detector cannot be used directly.
The existing method for solving the problems is to prepare a groove at a position close to the edge of the chip, wherein the groove can effectively buffer the action of thermal stress between the tellurium-cadmium-mercury layer and the epoxy resin layer, and reduce the influence of the thermal stress on the infrared detection chip structure. The narrower the width of the preparation trench, the better, and the depth of the preparation trench penetrates through the circuit layer of the bottom chip. The traditional trench preparation methods are mainly divided into two categories: wet etching and dry etching.
The wet etching is used for preparing a groove, and the sample is soaked in a certain chemical reagent or reagent solution, so that the part of the surface of the film which is not masked by the resist is removed by chemical reaction with the reagent. The method has the advantages that: the operation is simple, the equipment requirement is low, and the etching selectivity is good; the disadvantages are as follows: firstly, the photoetching process is needed to be carried out on each chip, time and labor are wasted, the second etching of the antimony, cadmium and mercury and the epoxy resin needs different etching solutions, the etching process is complex, the precision is low, and a bottom reading circuit is easily damaged.
The groove is prepared by dry etching, the sample is in a low-vacuum specific gas environment, gas exists in a plasma state, the gas bombards a region to be processed of the sample through the acceleration of an electric field, and the plasma can chemically react with the sample material and knock out atoms on the surface of the sample material, so that the purpose of etching and removing is achieved. The dry etching method has the advantages that: the first etching selectivity and the anisotropy are good, the second etching pattern can be accurately controlled, and the resolution ratio is high; the disadvantages are as follows: firstly, the single chip needs to be photoetched, which wastes time and labor, and secondly, the bottom reading circuit is damaged.
Meanwhile, as the height of the refrigeration type infrared detector wafer is more than 500 microns, high-frequency laser is required to be used for cutting for many times, and heat accumulation is likely to occur in repeated cutting for thousands of times, so that the cold machining effect is changed, and the effective area of a chip is affected.
Disclosure of Invention
The method and the device for processing the chip by the laser can process two opposite grooves at one time by using the principle of controlling the galvanometer to perform time-sharing multiplexing. On the basis of the intermittent processing of each groove, the heat accumulation is effectively reduced under the condition of ensuring the processing efficiency.
In a first aspect, the present invention provides a method for laser processing a chip, comprising:
moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of a laser processing system, and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incident surface to be in a horizontal position;
processing a group of grooves on two opposite edges by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence;
rotating a workbench for placing the refrigeration type infrared detection chip for 90 degrees;
then processing the grooves on the two opposite edges of another group by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges and form a closed annular groove.
Optionally, the sequentially processing the grooves on the group of two opposite edges through a laser, a galvanometer and a flat-field lens in the laser processing system includes:
starting a vibrating mirror and opening a laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and a flat field lens to serve as a first procedure;
and starting the galvanometer and delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the galvanometer and the flat field lens to be used as a second procedure.
Optionally, the processing, by the galvanometer and the flat-field lens, the laser beam emitted by the laser into a group of grooves on two opposite edges includes:
processing the groove at the first edge n times at the first position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing the groove at the first edge n times at the second position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing other preset positions on the groove as a group by repeatedly reciprocating according to the processing modes of the first position and the second position;
then repeating the processing of N groups of grooves; wherein N is more than or equal to 1, and N is more than or equal to 2.
Optionally, before or after the center of the refrigeration-type infrared detection chip to be processed is moved to a position right below a galvanometer of the laser processing system, the position and the angle of the refrigeration-type infrared detection chip to be processed are adjusted to make the groove and the laser spot incident surface be in a horizontal position, the method further includes:
acquiring groove shape information of a closed annular groove to be processed, and determining one or any combination of laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove shape information;
and determining the preset time of the time delay required for opening the laser according to the laser spot.
Optionally, the laser spot size ranges from 8 microns to 12 microns.
Optionally, the galvanometer processing speed is greater than 3000 mm/s.
Optionally, the repetition rate of the laser is less than 200 kHz.
In a second aspect, the present invention provides an apparatus for laser processing a chip, comprising:
the laser processing system is built by a laser, a galvanometer and a flat field lens;
the workbench is used for placing the refrigeration type infrared detection chip to be processed and rotating the chip for 90 degrees;
the moving system is used for moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of the laser processing system and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incidence surface to be in a horizontal position;
the control system is used for controlling a group of grooves on two opposite edges to be processed by a laser, a vibrating mirror and a flat field lens in the laser processing system in sequence; then, after rotating for 90 degrees, processing another group of grooves on two opposite edges through a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges and form a closed annular groove.
Optionally, the control system comprises:
the first process control unit is used for starting the vibrating mirror and opening the laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a first process;
and the second process control unit is used for starting the vibrating mirror, delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a second process.
Optionally, the control system further comprises:
the parameter determining unit is used for acquiring the groove shape information of the closed annular groove to be processed and determining one or any combination of laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove shape information; then determining the preset time of the time delay required for opening the laser according to the laser spot;
preferably, the laser spot size ranges from 8 microns to 12 microns;
preferably, the processing speed of the galvanometer is greater than 3000 mm/s;
preferably, the repetition frequency of the laser is less than 200 kHz.
In the method and the device for processing the chip by the laser, the groove on one group of two opposite edges is processed by the laser, the vibrating mirror and the flat-field lens in the laser processing system in sequence, or the groove on the other group of two opposite edges is processed by the laser, the vibrating mirror and the flat-field lens in the laser processing system in sequence, and the two opposite grooves are processed at one time mainly by using the principle of controlling the vibrating mirror to be time-sharing multiplexed. On the basis of the intermittent processing of each groove, the heat accumulation is effectively reduced under the condition of ensuring the processing efficiency.
Drawings
FIG. 1 is a flow chart of a method for laser processing a chip according to an embodiment of the invention;
FIG. 2 is a schematic structural diagram of a closed annular groove laser-machined on a refrigeration-type infrared detection chip according to an embodiment of the present invention;
FIG. 3 is a schematic structural diagram of a closed annular groove laser-machined on a refrigeration-type infrared detection chip according to an embodiment of the present invention;
FIG. 4 is a schematic structural diagram of an apparatus for laser processing a chip according to an embodiment of the present invention;
FIG. 5 is a schematic diagram of a laser processing system according to an embodiment of the present invention;
FIG. 6 is a flowchart of a method for laser processing a chip according to a second embodiment of the present invention;
FIG. 7 is a schematic structural diagram of a second laser-machined groove according to an embodiment of the present invention;
FIG. 8 is a flow chart of a method of processing a chip with three lasers according to an embodiment of the present invention;
FIG. 9 is a schematic structural diagram of a groove machined by three lasers according to an embodiment of the present invention;
FIG. 10 is a schematic structural diagram of a triple laser machined groove in accordance with an embodiment of the present invention;
FIG. 11 is a schematic view of a nozzle structure disposed on a third worktable according to an embodiment of the present invention;
FIG. 12 is a flowchart of a method of four laser processing chips according to an embodiment of the present invention;
FIG. 13 is a schematic structural diagram of a four-laser machined groove according to an embodiment of the present invention;
FIG. 14 is a flow chart of a method of laser processing a chip according to an embodiment of the present invention;
FIG. 15 is a flowchart of four laser processes for machining a trench, in accordance with an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Example one
An embodiment of the present invention provides a method for processing a chip by using laser, as shown in fig. 1, the method includes:
s11, building a laser processing system by the laser and the optical element;
s12, acquiring the position information of the workbench for placing the refrigeration type infrared detection chip;
s13, setting processing parameters of the laser processing system according to the position information, and generating laser processing beams by the laser processing system according to the processing parameters;
and S14, changing the relative position of the laser processing beam and the refrigeration type infrared detection chip to form a closed annular groove between the pixel layer and the edge of the refrigeration type infrared detection chip.
The method for processing the chip by the laser mainly comprises the steps of preparing a closed annular groove on the surface between an image element layer and an edge on a refrigeration type infrared detection chip by generating a laser beam by a laser processing system, rapidly increasing the temperature of a photosensitive layer by utilizing the laser processing beam to directly vaporize, and simultaneously controlling a laser running track or a sample displacement track to realize the purpose of patterning the groove on the surface of the refrigeration type infrared detection chip, wherein the laser processing system is used for processing and has the following advantages: the first laser pulse time is short, the method belongs to cold processing, the heat affected zone is small, and the characteristics of the photosensitive layer cannot be changed; the second laser processing technological process is in non-contact with the refrigeration type infrared detection chip to be processed, so that the damage of mechanical stress to a processed object can be reduced; the third laser processing has high automation degree, high precision and high processing speed.
In addition, the method can also uniformly reduce the dragging and traction of the filling adhesive overflowing around the pixel layer on the refrigeration type infrared detection chip when the temperature is circulated, further can efficiently and uniformly eliminate the influence of thermal stress on the position deviation between the photosensitive layer and the epoxy resin layer of the refrigeration type infrared detection chip, prevent the indium columns connected with the photosensitive layer from being broken, improve the service life of the infrared detection chip, and ensure that the prepared groove is narrower and narrower as well as the depth of the groove just penetrates through the circuit layer of the bottom chip.
Meanwhile, compared with the existing technology of improving filling adhesive and adding a fixing layer, the method does not introduce new materials and new structures (particularly structures with an additional fixing layer), does not influence the original process in the manufacturing process of the refrigeration type infrared detection chip, and only needs to add a new slotting process after the chip is interconnected, mixed and filled with the adhesive. Therefore, compared with other methods for improving the reliability, the method has the advantages of simple implementation, low research and development cost, high efficiency and good effect.
And experimental results show that after the refrigeration type infrared detection chip is processed by the laser processing system, a closed annular groove penetrating through the photosensitive layer and the sealing glue water layer is formed between the pixel layer and the edge of the refrigeration type infrared detection chip, the structure of the closed annular groove is neat and smooth, no residue exists in the closed annular groove, the heat affected zone is small, the photosensitive layer material around the groove has no defects of micro damage, micro crack and the like, the processing technology is controlled not to damage the chip circuit layer at the bottom, and the physical isolation between the refrigeration type infrared detection chip core area and the peripheral glue wall can be realized based on the closed annular groove, so that the influence of thermal stress on the reliability of the chip is eliminated fundamentally.
Optionally, as shown in fig. 2 and 3, optionally, before the laser processing system is built by a laser and an optical element, the method further includes:
acquiring refrigeration type infrared detection chip information, and determining a laser spot according to the refrigeration type infrared detection chip information; wherein the laser spot comprises a Gaussian spot or a flat-topped spot.
For example, the method of the embodiment can freely switch the required laser spots for processing according to the chip structure, the photosensitive layer material and the chip processing requirements in the information of the refrigeration type infrared detection chip; the photosensitive layer material comprises mercury cadmium telluride and indium cadmium telluride.
Optionally, after the obtaining of the position information of the workbench on which the refrigeration-type infrared detection chip is placed, the method further includes:
establishing a processing chamber, and setting a processing environment of the processing chamber; wherein the content of the first and second substances,
the processing chamber is a vacuum chamber, or a totally-enclosed non-vacuum chamber, or a semi-enclosed chamber.
Optionally, the processing environment of the processing chamber is set to introduce an auxiliary gas into the processing chamber so that the processing chamber is in a low-pressure state.
Specifically, in the method of this embodiment, the auxiliary gas is introduced into the processing chamber, so that the processing chamber is in a low-pressure state, and impurities generated by the action of the laser and various materials are effectively blown to the inactive area of the chip; on the other hand, the epoxy resin rapidly reacts with oxygen in the auxiliary gas to generate CO2 to be released into the atmosphere, and therefore laser processing errors are reduced.
Optionally, the setting processing parameters of the laser processing system, and the generating the laser processing beam by the laser processing system according to the processing parameters includes:
determining laser processing parameters according to the refrigeration type infrared detection chip information and the groove information;
and generating a corresponding laser processing beam by the laser processing system according to the laser processing parameters.
Optionally, the laser processing parameters include one or any combination of laser beam energy, repetition rate, pulse width, and laser wavelength.
Optionally, the pulse width is in a range of 10fs to 10 ps;
preferably, the laser wavelength is 200nm to 400 nm.
Optionally, the changing the relative position of the laser processing beam and the refrigeration-type infrared detection chip to form a closed annular groove between the pixel layer and the edge on the refrigeration-type infrared detection chip includes:
determining a galvanometer in the laser processing system according to the information of the refrigeration type infrared detection chip;
and the galvanometer is used for controlling the movement track of the laser beam according to the information of the groove to etch the space between the image element layer and the edge of each side of the refrigeration type infrared detection chip into a groove, and the groove etched on each side forms a closed annular groove.
Optionally, the groove information includes one or any combination of a groove shape, a groove width, and a groove depth.
Optionally, the refrigeration type infrared detection chip is sequentially provided with a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom; wherein the content of the first and second substances,
the depth D of the groove is within the range of the thickness D1< D < the thickness D1+ the thickness D2 of the photosensitive layer of the refrigeration type infrared detection chip.
Specifically, in the method of this embodiment, a closed annular groove is processed between the pixel layer and the edge of the refrigeration-type infrared detection chip, and the groove is deep enough to penetrate through the refrigeration-type infrared detector material layer but not reach the chip circuit layer, so that the thermal stress is eliminated to the maximum extent and the chip circuit layer at the bottom is not damaged.
An embodiment of the present invention further provides a device for laser processing a chip, as shown in fig. 2 to 4, the device includes:
the workbench is used for placing a refrigeration type infrared detection chip to be processed;
the control system is used for acquiring the position information of the workbench for placing the refrigeration type infrared detection chip, then setting the processing parameters of the laser processing system according to the position information, and controlling the laser processing system to generate laser processing beams according to the processing parameters;
the laser processing system is formed by constructing a laser, a beam expanding and collimating element and a vibrating mirror and is used for expanding and collimating a laser processing beam emitted by the laser through the beam expanding and collimating element and then changing the relative position of the laser processing beam and a refrigeration type infrared detection chip through the vibrating mirror so as to form a closed annular groove between an image element layer and an edge on the refrigeration type infrared detection chip.
Preferably, at least one laser is arranged in the laser processing system and used for controlling and switching to different lasers to emit laser beams with different wavelengths according to the information of the refrigeration type infrared detection chip, so that the processing efficiency of the laser processing system is improved.
Alternatively, as shown in fig. 2 to 5, the control system includes:
the detection subsystem is used for detecting and acquiring the groove information; the groove information comprises one or any combination of groove shape, groove width and groove depth;
the upper computer is used for determining laser processing parameters according to the information of the refrigeration type infrared detection chip to be processed and the groove information acquired by the detection subsystem; and then controlling the laser processing system to generate a corresponding laser processing beam according to the laser processing parameters.
Optionally, the upper computer includes:
the first determining module is used for determining laser processing parameters according to the information of the refrigeration type infrared detection chip to be processed and the groove information, or the positioning detection information, or the processing position positioning information acquired by the detection subsystem;
the second determination module is used for determining a galvanometer in the laser processing system according to the information of the refrigeration type infrared detection chip;
and the control module is used for etching the space between the image element layer and the edge of each side of the refrigeration type infrared detection chip into a groove by controlling the movement track of the laser beam through the vibrating mirror according to the information of the groove, and forming a closed annular groove by the etched grooves on each side.
Optionally, the apparatus further comprises:
the coaxial detection system is used for positioning the groove on the refrigeration type infrared detection chip and generating positioning detection information;
the paraxial detection system is used for positioning the vibrating mirror at the processing position on the refrigeration type infrared detection chip and generating processing position detection information; wherein the content of the first and second substances,
the upper computer controls the laser beam to keep the same preset direction on the outer edge of each edge of the refrigeration type infrared detection chip in the corresponding XY direction according to the groove information, the positioning detection information and the processing position detection information, and the groove is etched under the vibrating mirror to form a closed annular groove, wherein the outer edge of each edge of the refrigeration type infrared detection chip is the position between the image element layer and the edge of each edge.
Optionally, the refrigeration type infrared detection chip is sequentially provided with a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom; wherein the content of the first and second substances,
the depth D of the groove is within the range of the thickness D1< D < the thickness D1+ the thickness D2 of the photosensitive layer of the refrigeration type infrared detection chip.
Optionally, the laser processing system further comprises:
the shaping element is used for shaping the laser processing light beam into a laser spot corresponding to the type of the refrigeration type infrared detection chip; wherein the laser spot comprises a Gaussian spot or a flat-topped spot.
Optionally, the laser processing system further comprises:
and the beam splitter is used for detecting the shaping state of the laser processing beam shaped by the shaping element.
Optionally, the apparatus further comprises:
the dust removal device is arranged between the laser processing system and the workbench, establishes a processing chamber on the workbench, and is used for introducing gas into the processing chamber so as to enable the processing chamber to be in a low-pressure state and sucking out generated dust by utilizing the pressure difference between the processing chamber and the atmospheric pressure.
Optionally, the laser processing parameters include one or any combination of laser beam energy, repetition frequency, pulse width and laser wavelength;
in summary, in the apparatus of this embodiment, a laser beam in a laser processing system is emitted from a laser in a traveling direction of 0 °, and is reflected by a reflector 1 onto a beam expanding and collimating element to expand the laser beam, and then the laser beam passes through a beam splitter to detect laser energy and a state of the laser beam, and is reflected by the reflector 2 in a direction of 90 °; the laser beam is reflected by the reflecting mirror 2 and is reflected on the reflecting mirror 3 in a direction of 90 degrees; the laser beam is reflected by a reflector 3, the laser beam is reflected on a reflector 4 in a-90-degree direction, the laser beam is reflected by the reflector 4, the laser beam is reflected on a shaping element in a 90-degree direction, then the shaping state of the laser beam shaped by the shaping element is detected by a low-reflectivity beam splitter, then the laser beam is irradiated to a vibrating mirror, and a paraxial detection system is used for positioning and online monitoring a processing position; and finally, focusing the laser beam on a refrigeration type infrared detection chip fixed on the workbench for cutting.
The apparatus of this embodiment may be configured to implement the technical solutions of the above method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
Example two
The present embodiment is different from the first embodiment in that it is solved that a groove bottom structure with high flatness cannot be obtained by performing laser cutting with a single laser processing beam, and therefore, an embodiment of the present invention provides a method for laser processing a chip, as shown in fig. 6, the method includes:
s41, building a laser processing system by the laser and the optical element;
s42, acquiring the position information of the workbench for placing the refrigeration type infrared detection chip;
s43, setting processing parameters of the laser processing system according to the position information, and generating laser processing beams by the laser processing system according to the processing parameters;
s44, processing the photosensitive layer of the refrigeration type infrared detector chip by the laser processing beam with the first power to form two parallel grooves, and processing the epoxy glue in the refrigeration type infrared detector chip between the two parallel grooves by the laser processing beam with the second power to form a closed annular groove between the image element layer and the edge of the refrigeration type infrared detector chip.
In the method for processing the chip by using the laser, provided by the embodiment of the invention, in order to release the cold and hot change of the device, two beams of sub-beams with higher power are used between the effective pixel layer and the edge of the refrigeration type infrared detection chip to process the photosensitive layer of the refrigeration type infrared detection chip along two sides of the pressure release groove, and then the epoxy glue in the chip is removed by using the low-power laser, so that the effect of leveling the bottom of the groove is realized. For example, a laser processing beam with first power is used for cutting 8-10 microns of mercury cadmium telluride or 12-15 microns of indium antimonide (namely a photosensitive layer) firstly, and then a laser beam with second power is used for cutting an epoxy glue layer of about 10 microns to a position of about 8 microns between two parallel grooves, so that the optimal stress release effect is achieved; therefore, according to the method, the cadmium telluride mercury layer or the indium antimonide layer on the surface is completely removed under the action of larger laser power on two sides of the channel, the epoxy adhesive layer is cut at a certain depth, and finally, the laser with smaller energy is used for flattening the inner epoxy adhesive layer.
Alternatively, as shown in fig. 6 and 7, the step of grooving the photosensitive layer of the refrigeration-type infrared detector chip by the laser processing beam with the first power to form two parallel grooves, and then grooving the epoxy glue inside the refrigeration-type infrared detector chip between the two parallel grooves by the laser processing beam with the second power so as to form a closed annular groove between the pixel layer and the edge on the refrigeration-type infrared detector chip includes:
adjusting the position and the angle of the refrigeration type infrared detection chip to enable the groove to be scribed to be positioned under the galvanometer, and enabling the whole groove to be scribed and a light spot incident surface of the laser processing light beam to be positioned at a horizontal position;
the movable galvanometer simultaneously processes a photosensitive layer of the infrared detector chip through two first laser processing light beams with first power to form two parallel grooves; or the movable galvanometer respectively processes the photosensitive layer of the infrared detector chip through a beam of first laser processing beam with first power to form two parallel grooves;
restoring the workbench platform for placing the refrigeration type infrared detection chip to the initial position, and keeping the refrigeration type infrared detection chip horizontal;
and then the vibrating mirror is moved to process the epoxy glue in the refrigeration type infrared detection chip between the two parallel grooves through a beam of second laser processing light beam with second power so as to form a closed annular groove between the pixel layer and the edge of the refrigeration type infrared detection chip.
Optionally, the first power is greater than the second power;
preferably, the first power is greater than 300 mW;
preferably, the second power range is 80mW to 150 mW.
Optionally, the laser machining beam width is 8um-12 um.
Optionally, the refrigeration type infrared detection chip is sequentially provided with a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom; wherein the content of the first and second substances,
the depth D of the groove is within the range of the thickness D1< D < the thickness D1+ the thickness D2 of the photosensitive layer of the refrigeration type infrared detection chip.
Optionally, the processing speed of the laser processing system is greater than 3000mm/s and less than 5000 mm/s.
An embodiment of the present invention further provides an apparatus for processing a chip by using laser, as shown in fig. 4 and 7, the apparatus includes:
the workbench is used for placing a refrigeration type infrared detection chip to be processed;
the laser processing system is built by a laser and an optical element and is used for carrying out laser processing on the refrigeration type infrared detection chip by changing the relative position of a laser processing beam and the refrigeration type infrared detection chip;
the control system is used for acquiring the position information of the workbench for placing the refrigeration type infrared detection chip; setting processing parameters of the laser processing system according to the position information, and generating laser processing beams by the laser processing system according to the processing parameters; and controlling the laser processing system to process the photosensitive layer of the refrigeration type infrared detection chip by the laser processing beam with first power to form two parallel grooves, and then processing the epoxy glue in the refrigeration type infrared detection chip between the two parallel grooves by the laser processing beam with second power so as to form a closed annular groove between the image element layer and the edge on the refrigeration type infrared detection chip.
In the device for processing the chip by using the laser, which is provided by the embodiment of the invention, in order to release the cold and hot changes of the device, the control system controls the laser processing system to process the photosensitive layer of the refrigeration type infrared detection chip by using two beams of sub-beams with higher power along two sides of the pressure release groove in order to release the cold and hot changes of the device, and then the epoxy glue in the chip is removed by using low-power laser, so that the effect of leveling the bottom of the groove is realized. For example, a laser processing beam with first power is used for cutting 8-10 microns of mercury cadmium telluride or 12-15 microns of indium antimonide (namely a photosensitive layer) firstly, and then a laser beam with second power is used for cutting an epoxy glue layer of about 10 microns to a position of about 8 microns between two parallel grooves, so that the optimal stress release effect is achieved; therefore, the device of the embodiment can completely remove the tellurium-cadmium-mercury layer or the indium antimonide layer on the surface under the action of larger laser power on two sides of the channel, realize cutting with a certain depth on the epoxy glue layer, and finally level the inner epoxy glue layer by using laser with smaller energy, so that the device of the embodiment can obtain different groove-shaped structures by using different energy laser combinations aiming at the layered structure of the refrigeration type infrared detection chip.
Optionally, the control system comprises:
the first process control unit is used for controlling the movable galvanometer to simultaneously process the photosensitive layer of the refrigeration type infrared detection chip through two first laser processing light beams with first power to form two parallel grooves; or the movable galvanometer respectively processes the photosensitive layer of the refrigeration type infrared detection chip through a beam of first laser processing beam with first power to form two parallel grooves;
and the second process control unit is used for controlling the movable galvanometer to process the epoxy glue in the refrigeration type infrared detection chip between the two parallel grooves through one beam of second laser processing light beam with second power so as to form a closed annular groove between the image element layer and the edge on the refrigeration type infrared detection chip.
Optionally, the work table comprises:
the adsorption jet hole is used for adsorbing the refrigeration type infrared detection chip;
the displacement adjusting module is used for adjusting the position of the refrigeration type infrared detection chip or restoring the workbench platform for placing the refrigeration type infrared detection chip to the initial position;
and the angle adjusting module is arranged on the workbench and used for adjusting the angle of the refrigeration type infrared detection chip.
Optionally, the first power is greater than the second power;
preferably, the first power is greater than 300 mW;
preferably, the second power range is 80mW to 150 mW.
The apparatus of this embodiment may be configured to implement the technical solutions of the above method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
EXAMPLE III
The difference between the embodiment and the above embodiment is that the narrower the width of the prepared groove is, the better the groove is, and the depth of the groove just penetrates through the circuit layer of the bottom readout chip, and the two sides of the groove are steep, so that the stress release is facilitated; accordingly, an embodiment of the present invention provides a method for laser processing a chip, as shown in fig. 8, the method includes:
s51, building an angle-adjustable workbench, and placing a refrigeration type infrared detection chip to be processed on the workbench;
s52, setting adjustment and compensation process parameters of the workbench and laser parameters of a laser processing system constructed by a laser and an optical element;
and S53, changing the angle of the workbench at least once according to the laser parameters and the adjustment and compensation process parameters, so that the laser processing system can obliquely process the image element layer and the edge on the refrigeration type infrared detection chip and form a shallow groove with a small included angle at the edge.
The method for processing the chip by the laser mainly irradiates a laser processing beam to the surface of a refrigeration type infrared detection chip in a processing chamber, forms a closed annular groove penetrating through a photosensitive layer, an epoxy resin layer and an encapsulation glue layer at the edge close to the refrigeration type infrared detection chip, and simultaneously uses an angle-adjustable workbench to carry out conversion of different angles and corresponding compensation process parameters, so that a closed annular small-included-angle shallow groove penetrating through the photosensitive layer, the epoxy resin layer and the encapsulation glue layer is finally formed at the edge close to the refrigeration type infrared detection chip, the physical isolation effect among the photosensitive layer, the epoxy resin layer, the encapsulation glue layer core area (image element layer) and an edge thick glue wall is increased, and the reliability of the chip is fundamentally improved. According to the method, the prepared groove-shaped structure is improved, the heat effect area of the groove in the laser processing process is effectively controlled, the performance of the refrigeration type optimized infrared detection chip is further optimized, and the prepared yield is improved.
Alternatively, as shown in fig. 8 to 11, the at least one stage angle change is performed such that the stage is tilted to both sides with respect to the center line of the trench, so as to control the trench included angle.
Optionally, the laser processing system performing oblique processing between an image element layer and an edge on the refrigeration-type infrared detection chip and forming a shallow trench with a small edge included angle includes:
according to the laser parameters and the adjustment and compensation process parameters, the workbench is inclined to one side to a first angle by taking the central line of the groove as a reference;
adjusting the Z-axis direction position of the workbench to perform focal length compensation so that the processing position of the laser processing system on the refrigeration type infrared detection chip is in a focus position;
according to the laser parameters and the adjustment and compensation process parameters, the workbench is inclined to the other side to a second angle by taking the central line of the groove as a reference;
and adjusting the Z-axis direction position of the workbench to perform focal length compensation so that the processing position of the laser processing system on the refrigeration type infrared detection chip is in a focus position.
Optionally, after adjusting the Z-axis position of the workbench to perform focus compensation, so that the processing position of the refrigeration-type infrared detection chip by the laser processing system is in the focus position, the method further includes:
and adjusting the laser beam to a low-power mode for processing.
Optionally, the adjusting and compensating process parameters of the workbench include: one or any combination of groove shape parameters, angle adjusting parameters, focal length compensation parameters, laser spots and spot energy;
the angle adjustment parameter corresponds to the groove information.
Optionally, before the tilting the stage to a side to a first angle with reference to the center line of the trench according to the laser parameter, the adjusting and compensating process parameter, the method further includes:
and adjusting the position and the angle of the refrigeration type infrared detection chip to enable the groove to be positioned under a vibrating mirror of the laser processing system, and enabling the whole groove and a light spot incident surface of the laser beam to be in a horizontal position.
Optionally, after the stage is tilted to a second angle and the laser beam is adjusted to a low power mode for processing, the method further comprises:
restoring the workbench to an initial position, and keeping the refrigeration type infrared detection chip horizontal;
and adjusting the laser beam to a low-power mode and reducing the cutting times to enable the laser beam to carry out leveling processing on the bottom surface of the groove.
Optionally, the shallow trench with a small included angle at the edge is a square trench.
Optionally, as shown in fig. 11, the method further includes:
the refrigeration type infrared detection chip is adsorbed through the spray hole arranged below the workbench.
Optionally, the stage flatness is better than 1um/20 mm.
Example four
Because the height of the refrigeration type infrared detector wafer is more than 500 micrometers, high-frequency laser is required to be used for cutting for multiple times, and heat accumulation is likely to occur in repeated cutting for thousands of times, so that the cold machining effect is changed, and the effective area of a chip is influenced; accordingly, an embodiment of the present invention provides a method for laser processing a chip, as shown in fig. 12, the method includes:
s61, moving the center of the refrigeration type infrared detection chip to be processed to the position under a galvanometer of the laser processing system, and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed to enable the cutting channel groove and the laser spot incidence surface to be in a horizontal position;
s62, processing a group of grooves on two opposite edges sequentially through a laser, a vibrating mirror and a flat field lens in a laser processing system;
s63, rotating the workbench for placing the refrigeration type infrared detection chip for 90 degrees;
s64, processing the grooves on the two opposite edges of the other group by a laser, a vibrating mirror and a flat field lens in the laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges and form a closed annular groove.
In the method for processing the chip by using the laser, the vibrating mirror and the flat-field lens provided by the embodiment of the invention, the grooves on one group of two opposite edges are processed by the laser, the vibrating mirror and the flat-field lens in the laser processing system in sequence, or the grooves on the other group of two opposite edges are processed by the laser, the vibrating mirror and the flat-field lens in the laser processing system in sequence, and the two opposite grooves are processed at one time mainly by using the principle of controlling the vibrating mirror to be time-division multiplexed. On the basis of the intermittent processing of each groove, the heat accumulation is effectively reduced under the condition of ensuring the processing efficiency.
Alternatively, as shown in fig. 12 and 13, the sequentially processing the grooves on the two opposite edges through the laser, the galvanometer and the flat-field lens in the laser processing system includes:
starting a vibrating mirror and opening a laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and a flat field lens to serve as a first procedure;
and starting the galvanometer and delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the galvanometer and the flat field lens to be used as a second procedure.
Optionally, the processing, by the galvanometer and the flat-field lens, the laser beam emitted by the laser into a group of grooves on two opposite edges includes:
processing the groove at the first edge n times at the first position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing the groove at the first edge n times at the second position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing other preset positions on the groove as a group by repeatedly reciprocating according to the processing modes of the first position and the second position;
then repeating the processing of N groups of grooves; wherein N is more than or equal to 1, and N is more than or equal to 2.
Optionally, before or after the center of the refrigeration-type infrared detection chip to be processed is moved to a position right below a galvanometer of the laser processing system, the position and the angle of the refrigeration-type infrared detection chip to be processed are adjusted to make the groove and the laser spot incident surface be in a horizontal position, the method further includes:
acquiring groove shape information of a closed annular groove to be processed, and determining one or any combination of laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove shape information;
and determining the preset time of the time delay required for opening the laser according to the laser spot.
Optionally, the laser spot size ranges from 8 microns to 12 microns.
Optionally, the galvanometer processing speed is greater than 3000 mm/s.
Optionally, the repetition rate of the laser is less than 200 kHz.
An embodiment of the present invention further provides an apparatus for processing a chip by using laser, as shown in fig. 4 and 13, the apparatus includes:
the laser processing system is built by a laser, a galvanometer and a flat field lens;
the workbench is used for placing the refrigeration type infrared detection chip to be processed and rotating the chip for 90 degrees;
the moving system is used for moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of the laser processing system and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incidence surface to be in a horizontal position;
the control system is used for controlling a group of grooves on two opposite edges to be processed by a laser, a vibrating mirror and a flat field lens in the laser processing system in sequence; then, after rotating for 90 degrees, processing another group of grooves on two opposite edges through a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges and form a closed annular groove.
In the device for processing the chip by the laser, provided by the embodiment of the invention, the controller controls the laser, the vibrating mirror and the flat field lens in the laser processing system to process the grooves on one group of two opposite edges in sequence, or the laser, the vibrating mirror and the flat field lens in the laser processing system to process the grooves on the other group of two opposite edges in sequence, and the two opposite grooves are processed at one time mainly by using the principle of time-sharing multiplexing of the control of the vibrating mirror. On the basis of the intermittent processing of each groove, the heat accumulation is effectively reduced under the condition of ensuring the processing efficiency.
Optionally, the control system comprises:
the first process control unit is used for starting the vibrating mirror and opening the laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a first process;
and the second process control unit is used for starting the vibrating mirror, delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a second process.
Optionally, the control system further comprises:
the parameter determining unit is used for acquiring the groove shape information of the closed annular groove to be processed and determining one or any combination of laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove shape information; then determining the preset time of the time delay required for opening the laser according to the laser spot;
preferably, the laser spot size ranges from 8 microns to 12 microns;
preferably, the processing speed of the galvanometer is greater than 3000 mm/s;
preferably, the repetition frequency of the laser is less than 200 kHz.
The apparatus of this embodiment may be configured to implement the technical solutions of the above method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
EXAMPLE five
Because, prior art is through laser grooving's mode, when utilizing the mirror that shakes to control the relative motion of laser facula and detector chip, because the limitation of mirror control mode that shakes, when carrying out the fluting of mouth style of calligraphy and forming closed annular slot, the arc can appear in the corner to the degree of depth, the width that lead to the slot of corner are inhomogeneous, and have influenced the area in effective pixel district. Accordingly, an embodiment of the present invention provides a method for laser processing a chip, as shown in fig. 14, the method includes:
s71, building a laser processing system by the laser and the optical element;
s72, detecting the machining deviation amount of the built laser machining system;
s73, calculating drawing parameters of the groove to be machined according to the machining deviation amount;
and S74, processing the refrigeration type infrared detection chip by the laser processing system according to the drawing parameters of the groove to be processed so as to form a closed annular groove between the pixel layer and the edge of the refrigeration type infrared detection chip.
The method for processing the chip by the laser mainly comprises the steps that when a closed annular groove is processed by the laser, the processing deviation amount of a built laser processing system is detected; and then, calculating drawing parameters of the groove to be processed according to the detected processing deviation amount, fixing the delay time of laser light on and off, and the like, effectively improving the reliability of the focal plane detector in the temperature cycle process, and realizing that when the refrigeration type infrared detection chip is grooved by laser, the corners are right angles and the width and the depth are uniform. Therefore, compared with the method for drawing and processing the closed annular groove directly, the method has the advantages that the pixel utilization rate at the corner of the closed annular groove is effectively improved, the influence of the corner on the groove width and the depth uniformity is reduced, and the laser grooving effect and the chip reliability are finally improved.
Meanwhile, after a closed annular groove is formed around the refrigeration type infrared detection chip, physical isolation is actually realized between the overflowing glue edge after the glue filling process and the effective pixel area, so that in temperature circulation, pulling force caused by thermal stress on a large number of overflowing glue edges cannot act on the pixel area, and the reliability of the refrigeration type infrared detection chip is effectively improved.
Alternatively, as shown in fig. 14 and 15, the detecting the processing deviation amount of the built laser processing system includes:
pre-drawing a straight line with the length of X, and processing by a laser processing system;
and after the machining is finished, measuring the deviation amount between the machining result and the straight line.
Optionally, the measuring the deviation amount of the processing result from the straight line includes:
measuring the position difference N between the position of the actual starting point and the starting point of the drawn straight line;
measuring a position difference M between the position of the actual end point and the end point of the drawn straight line;
taking the closed annular grooves connected end to end as four disconnected independent linear grooves, and calculating the length of each independent linear groove according to the following formula:
(N-D/2) + X + (M-D/2); wherein the content of the first and second substances,
and D is the spot diameter of the laser processing beam in the laser processing system.
Optionally, before the difference between the position of the actual end point and the position of the end point of the drawn straight line is M, the method further includes:
detecting whether the actual end point exceeds the end point of the drawn straight line;
when the actual end point does not exceed the end point of the drawn straight line, directly measuring the position difference M between the position of the actual end point and the end point of the drawn straight line;
when the actual end point exceeds the end point of the drawn straight line, adjusting the delay strategy of opening and closing the laser according to the position of the actual end point and the position of the end point of the drawn straight line, then fixing the adjusted delay strategy of opening and closing the laser and processing according to the delay strategy, and finally measuring the position difference M between the position of the actual end point and the position of the end point of the drawn straight line;
and adjusting the delay strategy of opening and closing the laser to reduce the delay time of closing the laser beam of the laser and enable the actual end point to be smaller than the end point of the drawn straight line.
Optionally, the drawing parameter of the groove to be processed includes one or any combination of a groove length, a groove shape, a groove width and a groove depth.
Optionally, the refrigeration type infrared detection chip is sequentially provided with a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom; wherein the content of the first and second substances,
the depth D of the groove is within the range of the thickness D1< D < the thickness D1+ the thickness D2 of the photosensitive layer of the refrigeration type infrared detection chip.
An embodiment of the present invention further provides an apparatus for processing a chip by using laser, as shown in fig. 4 and 15, the apparatus includes:
the detection unit is used for detecting the processing deviation amount of the set laser processing system;
the calculation unit is used for calculating drawing parameters of the groove to be processed according to the processing deviation amount;
the laser processing system is built by a laser and an optical element and is used for processing the refrigeration type infrared detection chip according to the drawing parameters of the groove to be processed, so that a closed annular groove is formed between the image element layer and the edge of the refrigeration type infrared detection chip.
The device for processing the chip by the laser mainly detects the processing deviation amount of the built laser processing system when the closed annular groove is processed by the laser; and then, calculating drawing parameters of the groove to be processed according to the detected processing deviation amount, fixing the delay time of laser light on and off, and the like, effectively improving the reliability of the focal plane detector in the temperature cycle process, and realizing that when the refrigeration type infrared detection chip is grooved by laser, the corners are right angles and the width and the depth are uniform. Therefore, compare with directly carrying out closed annular groove drawing processing, this embodiment the device effectively improves the pixel utilization ratio of closed annular groove corner, reduces the influence of corner to groove width and degree of depth homogeneity, finally improves laser grooving's effect and chip reliability.
Meanwhile, after a closed annular groove is formed around the refrigeration type infrared detection chip, physical isolation is actually realized between the overflowing glue edge after the glue filling process and the effective pixel area, so that in temperature circulation, pulling force caused by thermal stress on a large number of overflowing glue edges cannot act on the pixel area, and the reliability of the refrigeration type infrared detection chip is effectively improved.
Optionally, the detection unit includes:
the preprocessing module is used for pre-drawing a straight line with the length of X and processing the straight line by a laser processing system;
and the measuring module is used for measuring the deviation between the processing result and the straight line after the processing is finished.
Optionally, the measurement module comprises:
the first measuring submodule is used for measuring the position difference N between the position of the actual starting point and the starting point of the drawn straight line;
a detection submodule for detecting whether the actual end point exceeds the end point of the drawn straight line; when the actual end point does not exceed the end point of the drawn straight line, directly measuring the position difference M between the position of the actual end point and the end point of the drawn straight line; when the actual end point exceeds the end point of the drawn straight line, adjusting the delay strategy of opening and closing the laser according to the position of the actual end point and the position of the end point of the drawn straight line, then fixing the adjusted delay strategy of opening and closing the laser and processing according to the delay strategy, and finally measuring the position difference M between the position of the actual end point and the position of the end point of the drawn straight line; the delay strategy for adjusting the opening and closing of the laser is to reduce the delay time for closing the laser beam of the laser and make the actual end point smaller than the end point of the drawn straight line;
a second measuring submodule for measuring a position difference M between a position of the actual end point and an end point of the drawn straight line;
the calculation submodule is used for taking the closed annular grooves connected end to end as four disconnected independent linear grooves, and the length of each independent linear groove is calculated according to the following formula:
(N-D/2) + X + (M-D/2); wherein the content of the first and second substances,
and D is the spot diameter of the laser processing beam in the laser processing system.
Optionally, the drawing parameter of the groove to be processed includes one or any combination of a groove length, a groove shape, a groove width and a groove depth;
preferably, the refrigeration type infrared detection chip is sequentially provided with a photosensitive layer, an epoxy resin layer and a chip circuit layer from top to bottom; the depth D of the groove is within the range of the thickness D1< D < the thickness D1+ the thickness D2 of the photosensitive layer of the refrigeration type infrared detection chip.
The apparatus of this embodiment may be configured to implement the technical solutions of the above method embodiments, and the implementation principles and technical effects are similar, which are not described herein again.
The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A method of laser processing a chip, comprising:
moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of a laser processing system, and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incident surface to be in a horizontal position;
processing a group of grooves on two opposite edges by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence;
rotating a workbench for placing the refrigeration type infrared detection chip for 90 degrees;
then processing the grooves on the two opposite edges of another group by a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges to form a closed annular groove;
wherein, the groove on a set of relative both edges of laser instrument, galvanometer, flat field lens processing in the laser processing system in proper order includes:
starting a vibrating mirror and opening a laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and a flat field lens to serve as a first procedure;
and starting the galvanometer and delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the galvanometer and the flat field lens to be used as a second procedure.
2. The method of claim 1, wherein machining the laser beam from the laser through the galvanometer and the field flattener lens into a set of grooves on two opposite edges comprises:
processing the groove at the first edge n times at the first position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing the groove at the first edge n times at the second position of the groove by a laser beam emitted by a laser through a vibrating mirror and a flat field lens, and then processing the groove at the second edge n times;
processing other preset positions on the groove as a group by repeatedly reciprocating according to the processing modes of the first position and the second position;
then repeating the processing of N groups of grooves; wherein N is more than or equal to 1, and N is more than or equal to 2.
3. The method according to any one of claims 1-2, wherein before or after the step of moving the center of the refrigerated infrared detection chip to be processed to a position right below a galvanometer of the laser processing system and adjusting the position and the angle of the refrigerated infrared detection chip to be processed to make the groove and the laser spot incidence surface be in a horizontal position, the method further comprises the steps of:
acquiring groove shape information of a closed annular groove to be processed, and determining laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove shape information;
and determining the preset time of the time delay required for opening the laser according to the laser spot.
4. The method of claim 3, wherein the laser spot size ranges from 8 microns to 12 microns.
5. The method of claim 1, wherein the galvanometer machining speed is greater than 3000 mm/s.
6. The method of claim 5, wherein the laser has a repetition rate of less than 200 kHz.
7. An apparatus for laser processing a chip, comprising:
the laser processing system is built by a laser, a galvanometer and a flat field lens;
the workbench is used for placing the refrigeration type infrared detection chip to be processed and rotating the chip for 90 degrees;
the moving system is used for moving the center of the refrigeration type infrared detection chip to be processed to be right below a galvanometer of the laser processing system and adjusting the position and the angle of the refrigeration type infrared detection chip to be processed so as to enable the groove and the laser spot incidence surface to be in a horizontal position;
the control system is used for controlling a group of grooves on two opposite edges to be processed by a laser, a vibrating mirror and a flat field lens in the laser processing system in sequence; then, after rotating for 90 degrees, processing another group of grooves on two opposite edges through a laser, a vibrating mirror and a flat field lens in a laser processing system in sequence; the two groups of grooves on the two opposite edges are arranged between the image element layer of the refrigeration type infrared detection chip and the two opposite edges to form a closed annular groove;
wherein the control system comprises:
the first process control unit is used for starting the vibrating mirror and opening the laser, and then processing a group of grooves on two opposite edges of a laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a first process;
and the second process control unit is used for starting the vibrating mirror, delaying the preset time to open the laser, and then processing a group of grooves on two opposite edges of the laser beam emitted by the laser through the vibrating mirror and the flat field lens to serve as a second process.
8. The apparatus of claim 7, wherein the control system further comprises:
the parameter determining unit is used for acquiring groove information of a closed annular groove to be processed and determining laser spots, energy distribution, galvanometer processing speed and laser repetition frequency according to the groove information; then determining the preset time of the time delay required for opening the laser according to the laser spot;
the laser spot size range is 8-12 microns;
the processing speed of the galvanometer is greater than 3000 mm/s;
the repetition frequency of the laser is less than 200 kHz.
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| GB2444037A (en) * | 2006-11-27 | 2008-05-28 | Xsil Technology Ltd | Laser Machining |
| CN103433619B (en) * | 2013-08-30 | 2015-10-21 | 大族激光科技产业集团股份有限公司 | The preparation method of laser melting coating printer and wiring board |
| DE102013112070A1 (en) * | 2013-11-01 | 2015-05-07 | VACUTEC Hochvakuum- & Präzisionstechnik GmbH | Sealing surface, in particular for a vacuum chamber of a mass spectrometer, and method for producing such a sealing surface |
| US10357848B2 (en) * | 2015-01-19 | 2019-07-23 | General Electric Company | Laser machining systems and methods |
| CN107378232B (en) * | 2017-07-14 | 2019-03-15 | 中国科学院微电子研究所 | A kind of method and system laser machining wafer |
| CN207077113U (en) * | 2017-08-25 | 2018-03-09 | 青岛理工大学 | A kind of laser Multi-angle inclined hole precise fine processing unit (plant) |
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2018
- 2018-12-27 CN CN201811607499.7A patent/CN109530928B/en active Active
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