CN112435921B - Laser annealing method and laser annealing system of power device - Google Patents

Laser annealing method and laser annealing system of power device Download PDF

Info

Publication number
CN112435921B
CN112435921B CN202011220823.7A CN202011220823A CN112435921B CN 112435921 B CN112435921 B CN 112435921B CN 202011220823 A CN202011220823 A CN 202011220823A CN 112435921 B CN112435921 B CN 112435921B
Authority
CN
China
Prior art keywords
laser
collector region
depth
stop
injecting
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202011220823.7A
Other languages
Chinese (zh)
Other versions
CN112435921A (en
Inventor
蒋一鸣
陈静
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Beijing U Precision Tech Co Ltd
Original Assignee
Beijing U Precision Tech Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Beijing U Precision Tech Co Ltd filed Critical Beijing U Precision Tech Co Ltd
Priority to CN202011220823.7A priority Critical patent/CN112435921B/en
Publication of CN112435921A publication Critical patent/CN112435921A/en
Application granted granted Critical
Publication of CN112435921B publication Critical patent/CN112435921B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26—Bombardment with radiation
    • H01L21/263—Bombardment with radiation with high-energy radiation
    • H01L21/268—Bombardment with radiation with high-energy radiation using electromagnetic radiation, e.g. laser radiation
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer
    • H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having potential barriers, e.g. a PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic Table or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
    • H01L21/324—Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007—Multistep manufacturing processes
    • H01L29/66075—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227—Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66234—Bipolar junction transistors [BJT]
    • H01L29/66272—Silicon vertical transistors

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Manufacturing & Machinery (AREA)
  • Condensed Matter Physics & Semiconductors (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Hardware Design (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Ceramic Engineering (AREA)
  • Optics & Photonics (AREA)
  • Electromagnetism (AREA)
  • Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Thyristors (AREA)

Abstract

The invention relates to a laser annealing method of a power device, wherein short wavelength laser and long wavelength laser are used for annealing and activating in the annealing process, the wavelength range of the short wavelength laser is 300nm-560nm, and the wavelength range of the long wavelength laser is 780nm-1064nm; the ion annealing in different melting ranges and impurity distribution depth ranges and the implantation annealing of multi-layer impurity ions are realized by selecting laser mixing configuration of different wavelengths, and meanwhile, the laser mixing configuration of proper wavelength is selected for use according to the temperature resistance and the fragmentation resistance of different types of wafers in comprehensive consideration, so that shallow surface activation under different thermal budget conditions is realized. The invention provides a laser annealing method and a laser annealing system of a power device, which control the impurity activation efficiency and impurity distribution by using laser annealing and avoid the technical problem of fragments caused by heat accumulation due to excessive heat in the laser annealing process.

Description

Laser annealing method and laser annealing system of power device
Technical Field
The invention relates to the technical field of laser annealing in the semiconductor industry, in particular to a laser annealing method and a laser annealing system for controlling impurity activation and impurity distribution by using laser annealing.
Background
When manufacturing semiconductor chips, ion implantation is performed on the back of a wafer or source/drain of some devices, the lattice is severely damaged, doped impurity ions are not located at the correct lattice positions, so that the material does not have effective electrical activity, and at the moment, the material needs to be subjected to heating treatment to repair the lattice damage, and the impurity ion electrical activity is activated, and the heating treatment process is annealing.
The conventional annealing process, including furnace tube annealing, flash lamp annealing (FLA, flash Lamp Annealing), spike annealing (SPIKE ANNEALING), is limited in use in many process flows due to the disadvantages of low annealing temperature, long annealing time, large heat affected zone, and the like.
Laser pulse annealing refers to a process of heat treating a material using the laser output of a pulse signal. Due to the advantages of high instantaneous temperature, short action time, small heat affected zone and the like, the laser pulse annealing can well meet the process requirement of efficient activation, and becomes one of the key processes of the chip manufacturing process. In particular, for the new generation IGBT device, since the electric Field Stop (Field Stop) technology is adopted, the substrate can be ground to be very thin to reduce on-state loss, and the thickness of the wafer is generally 50-200 μm, when the back annealing is performed on the thin sheet/super thin sheet, in order to ensure that the metal on the front of the device cannot be melted or diffused due to high temperature, the process temperature must be controlled within 450 ℃, and the annealing time can be controlled to be in the order of microseconds by adopting laser annealing, the heat affected zone is controlled to be minimum, and the effective temperature control on the front of the wafer is ensured, so the laser pulse annealing is almost the only scheme for obtaining high annealing performance in this case.
Although laser pulse annealing is a currently existing annealing method, a process matching solution with high activation rate and high uniformity has not been proposed at present for the requirements of different device types and different depth impurity distributions in the production of semiconductor devices.
Disclosure of Invention
In order to solve the technical problems of how to control the impurity activation efficiency and the impurity distribution by using the laser annealing more effectively and fully and avoid fragments caused by heat accumulation caused by excessive heat in the laser annealing process, the invention provides a laser annealing method and a laser annealing system of a power device.
The technical scheme of the invention comprises the following steps:
the invention also provides a laser annealing method of the power device, in the annealing process,
Annealing activation using a short wavelength laser having a wavelength range of 300nm to 560nm and a long wavelength laser having a wavelength range of 780nm to 1064nm;
The method is characterized in that the method comprises the steps of realizing ion annealing in different melting ranges and impurity distribution depth ranges and multi-layer impurity ion implantation annealing by selecting laser mixing configuration of different wavelengths, and comprehensively considering the temperature resistance and the fragment resistance of different types of wafers, and selecting the laser mixing configuration of proper wavelength for use so as to realize shallow surface activation under different thermal budget conditions;
During activation, any one or a combination of the following operations are performed:
Operation one: the characteristic that short-wavelength laser energy is accumulated on the surface of the wafer is utilized to melt the surface, so that impurity ions which are injected at low energy and are accumulated on the shallow surface of the wafer are redistributed below the shallow surface through laser annealing, and the low-energy injection is replaced by the medium-high-energy injection;
And (2) operation II: by utilizing the characteristic of deeper absorption depth of long wavelength laser, non-melting annealing and annealing within a larger depth range are realized;
And (3) operation three: the short wavelength laser and the long wavelength laser are used in a matching way, so that the surface of the wafer is melted, impurity ions which are injected in low energy and are gathered on the shallow surface of the wafer are redistributed through laser annealing, and the impurity ions are further distributed to deeper depth under the annealing action of the long wavelength laser;
operation four: the characteristic of low energy of short wavelength laser is utilized to realize the shallow surface activation with low thermal budget when the ultra-thin sheet is not broken.
According to the preferred embodiment of the invention, the laser annealing method can be applied to the ion implantation and annealing activation process of the field-stop FS-IGBT device, and the thickness of the field-stop FS-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface of the wafer to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be higher than 1100K, so that the laser activates the N-stop;
c) Injecting into the collector region P+: the mode of injecting P-type impurities at a low energy and a large angle is adopted to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the injection energy is less than 200kev, and the angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by utilizing laser, activating a collector region P+ at a temperature of more than 1200K in the temperature field, and forming a PN junction by the collector region P+ and an inverted N-stop after activation; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser with the long wavelength is matched to enable the temperature of the required depth to be higher than 1200K to activate the collecting region P+; the depth is required to be not more than the depth when the concentration of P+ injected into the collector region is equal to that of N-stop activated, so that the P-type impurity and N-stop N-type impurity in the collector region are prevented from being neutralized;
or the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the impurities to be gathered on the shallow surface of the wafer, wherein the low energy is less than or equal to 100keV;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, activating a collector region P+ at a temperature of more than 1200K, and forming a PN junction by the collector region P+ and an inverted N-stop after activation; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser with the long wavelength is matched to enable the temperature of the required depth to be higher than 1200K to activate the collecting region P+; the depth is required to be not more than the depth when the concentration of P+ injected into the collector region is equal to that of N-stop activated, so that the P-type impurity and N-stop N-type impurity in the collector region are prevented from being neutralized;
or the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Injecting into the collector region P+: the mode of injecting P-type impurities at a low energy and a large angle is adopted to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the injection energy is less than 200kev, and the angle is more than or equal to 7 degrees;
c) Laser activated N-stop and collector region P +: the temperature in the depth range of the collecting region P+ is larger than 1200K, and the temperature in the depth range of the N-stop is larger than 1100K by utilizing the cooperation of long wavelength laser and short wavelength so as to activate the collecting region P+ and the N-stop respectively; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser is matched with the long wavelength laser to activate the P+ and N-stop of the collector region under the condition that the temperature of the required depth is higher than 1200K; the depth is required to be not more than the depth at which the concentration of p+ injected into the collector region and the concentration of N-stop activated are equal, so that the neutralization of P-type impurities and N-stop N-type impurities in the collector region is avoided.
According to the preferred embodiment of the invention, the laser annealing method can be applied to the ion implantation and annealing activation process of the reverse-conduction RC-IGBT device, and the thickness of the laser annealing method is 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface, and long wavelength laser is matched to realize the redistribution and activation of impurities with the temperature of more than 1100K at the required depth;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, and activating a collector region P+ at a temperature of more than 1200K in the temperature field; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be more than 1200K so as to realize activation; the required depth is not more than the depth at which the p+ and active N-stop concentrations of the implanted collector region are equal;
e) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
f) Laser activated collector region N +: providing a temperature field by utilizing laser, and activating the collecting region N+ under the condition that the temperature is not more than 1685K and is more than 1200K, so that the collecting region P+ and the collecting region N+ impurities are prevented from being neutralized in the transverse direction;
Or the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the N-type impurities to be gathered on the shallow surface; the low energy is less than or equal to 100kev;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, and activating a collector region P+ at a temperature of more than 1200K in the temperature field; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be more than 1200K so as to realize activation; the required depth is not more than the depth at which the p+ and active N-stop concentrations of the implanted collector region are equal;
e) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
f) Laser activated collector region N +: providing a temperature field by utilizing laser, and activating the collecting region N+ under the condition that the temperature is not more than 1685K and is more than 1200K, so that the collecting region P+ and the collecting region N+ impurities are prevented from being neutralized in the transverse direction;
Or the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and long wavelength laser is matched to realize the redistribution and activation of impurities with the temperature of the required depth being more than 1100K;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
e) Laser activated collector region N +: providing a temperature field by utilizing laser, and activating the collecting region N+ under the condition that the temperature is not more than 1685K and is more than 1200K, so that the collecting region P+ and the collecting region N+ impurities are prevented from being neutralized in the transverse direction;
Or the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the N-type impurities to be gathered on the shallow surface; the low energy is less than or equal to 100kev;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
e) Laser activated collector region N +: providing a temperature field by utilizing laser, and activating the collector region N+ under the condition that the temperature of the temperature field is not more than 1685K and is more than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction;
Or the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
c) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
d) Laser activated N-stop, collector regions p+ and n+: and a laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature of the temperature field is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
The laser annealing method is realized by a laser annealing system, and the laser annealing system comprises:
The movable carrier is used for carrying the wafer and moving according to a preset program to drive the wafer to move; the movable carrier is provided with a chuck for fixing the wafer;
a long wavelength laser having a wavelength range of 780nm to 1064nm;
and at least one short wavelength laser; the wavelength range of the short wavelength laser is 300nm-560nm;
And a system control unit that controls the overall timing of laser pulses of the long wavelength laser and the short wavelength laser. Preferably, the system control unit is a pulse generator and a laser controller;
The laser emitted by the long wavelength laser and the short wavelength laser is synthesized into a laser beam through an optical system which is precisely calibrated, the laser beam is projected onto the surface of a wafer placed on a movable carrier at a certain angle, the movable carrier drives the wafer to reciprocate, the laser beam is made to scan the surface of the wafer, and finally the laser beam is made to scan the whole wafer, so that the laser annealing process is completed.
According to a preferred embodiment of the system of the present invention, the width of the linear spot of the laser emitted by the short wavelength laser on the surface of the wafer is W1, the length of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is C1, and the width of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is W2, the length of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is C2; wherein w2=c×w1, c1=c2; c=0.2-5. The value of c is determined according to the process requirement.
According to a preferred embodiment of the system of the present invention, a line spot of the laser emitted by the short wavelength laser on the surface of the wafer and a line spot of the laser emitted by the long wavelength laser on the surface of the wafer are formed, and the projections of the central lines of the two line spots on the surface of the wafer coincide; the light intensity distribution of the two linear spots is a flat-top distribution in the length direction of the linear spots, and the distribution in the width direction of the linear spots is a Gaussian distribution or a flat-top distribution.
According to a preferred embodiment of the system of the present invention, if the number of the long wavelength laser and the short wavelength laser is 1, the waveform of the output power of the short wavelength laser changing with time is a gaussian waveform, and the pulse width of the pulse is independently adjustable, and the adjustment range is 50-1200ns; the waveform of the output power of the long wavelength laser changing along with time is a square waveform, the pulse frequency is consistent with the pulse frequency of the short wavelength laser, the pulse width of the pulse is adjustable, the adjusting range is 0-T, and T is 1/f (namely, when the pulse width is adjusted to T, the long wavelength laser is in a continuous light output mode; the pulse time interval between the long wavelength laser and the short wavelength laser is adjustable, and the adjustment range is 0-T.
According to a preferred embodiment of the system of the present invention, if the number of the short wavelength lasers is 2, and the number of the long wavelength lasers is 1, the waveform of the variation of the output laser power of the 2 short wavelength lasers with time is a near gaussian waveform, and the pulse width distribution of the pulses is independently adjustable, and the adjustment range is 50-1200ns; the output power of the long wavelength laser changes along with time to form a square waveform, the pulse frequency is kept consistent with the pulse frequency of the 2 short wavelength lasers and is f, the pulse width of the pulse is adjustable, the adjusting range is 0-T, and T is 1/f (namely, in one pulse period time, when the pulse width is adjusted to T, the long wavelength laser is in a continuous light output mode); the pulse time interval of the 2 short wavelength lasers is adjustable, and the adjusting range is 0-T; the pulse time interval between the long wavelength laser and any one of the short wavelength lasers is adjustable, and the adjustment range is 0-T.
The technical effects of the invention include:
the main inventive concept is that the invention utilizes the characteristic that short wavelength light energy is accumulated on the surface, and the surface is easier to melt, thereby realizing the effect of enabling impurities injected with low energy to be distributed more deeply through laser annealing, and replacing medium-high energy injection. On one hand, the non-melting annealing can be realized by using the characteristic of deep long wavelength absorption depth; on the one hand, annealing in a larger depth range can be realized; by combining the selection and the mixed configuration of the two wavelengths, the implantation annealing activation of the multi-layer impurity ions can be realized in a targeted and directional manner.
In some preferred embodiments of the present invention, when preparing a field stop FS-IGBT device or a reverse conducting RC-IGBT device, only low energy injection of N-type impurities is used to collect the N-type impurities on the shallow surface of the wafer, and then the short wavelength laser is used to easily concentrate on the shallow surface of the wafer and quickly reach the characteristic of high temperature field to cause the wafer to melt, so that impurity ions injected on the shallow surface are redistributed and activated, thereby replacing high energy injection of N-type impurities, saving injection cost, and completing activation while redistributing impurity ions.
In particular, the method comprises the steps of,
1) Adjusting laser parameters, controlling the distribution of impurities within a certain depth range through melting, replacing high-energy ion implantation with higher cost to a certain extent, forming the impurity concentration distributed evenly in the depth direction, and improving the device performance of the chip; in addition, according to the different properties of the long wavelength laser and the short wavelength laser, the configuration of the laser with different wavelengths can be selected, and the directional activation of different melting ranges and impurity distribution depth ranges can be realized in a targeted manner.
2) The laser parameters are regulated, non-melting or micro-melting is realized through the control of a temperature field, the simplification of a laser annealing process in some applications is realized, and the production cost is greatly reduced; different solid state activation depth ranges can be achieved by selecting a hybrid configuration of different wavelength lasers.
3) The laser parameters are adjusted to control the thermal budget of the laser to avoid spalling due to heat build-up caused by excessive thermal budget during laser annealing. According to the temperature resistance and the fragmentation resistance of different types of wafers, different laser mixing configurations are selected, and shallow surface activation under different thermal budget conditions can be realized.
The invention is further described below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic diagram of a laser annealing system.
Fig. 2 is a schematic diagram showing overlapping distribution of two wavelength line spots on a wafer.
FIG. 3 is a schematic diagram of a short wavelength laser with a flat-top profile in the length direction and a Gaussian distribution line spot in the width direction.
Fig. 4 is a schematic diagram of a short wavelength laser length-direction flat-top distribution and width-direction flat-top distribution line spot.
FIG. 5 is a timing diagram of the short wavelength and long wavelength light sources for 1 short wavelength laser.
FIG. 6 is a timing diagram of the short wavelength and long wavelength light sources for 2 short wavelength lasers.
Fig. 7 is a schematic diagram of FS-IGBT device structure.
Fig. 8 is a flowchart of FS-IGBT back laser annealing (1).
Fig. 9 is a flowchart of FS-IGBT back laser annealing (2).
Fig. 10 is a schematic diagram of an RC-IGBT device structure.
Fig. 11 is a flowchart of the RC-IGBT backside laser annealing (1).
Fig. 12 is a flowchart of the RC-IGBT backside laser annealing (2).
Fig. 13 is a flowchart of the RC-IGBT backside laser annealing (3).
Fig. 14 shows a laser action temperature field 1.
Fig. 15 shows a laser action temperature field 2.
Fig. 16 shows a laser action temperature field 3.
Fig. 17 shows the laser action temperature field 4.
Fig. 18 shows a laser action temperature field 5.
Fig. 19 shows the laser action temperature field 6.
Fig. 20 shows a laser action temperature field 7.
Detailed Description
Because of the high instantaneous power density of Pulse laser and the high temperature, when the energy density (ENERGY DENSITY) and Pulse Width (Pulse Width) reach a certain threshold, the shallow surface temperature of the wafer in a certain depth range exceeds the melting point (1685K) of monocrystalline silicon, the solid-liquid phase conversion occurs, and the diffusion coefficient (10-4 cm 2/s magnitude) of impurities in the liquid phase is far greater than that in the solid phase (less than 10-7cm 2/s magnitude), so that by utilizing the characteristic, a process matching solution with high activation rate and high uniformity can be provided for the requirements of different device types and different depth impurity distribution in the production of semiconductor devices.
The annealing system for controlling impurity activation and impurity distribution by using laser annealing provided by the invention is shown in figure 1, and comprises two lasers: the first is a short wavelength laser, and the short wavelength laser L1 may be 1 or more; the second type is a long wavelength laser, and the number of long wavelength lasers L2 is 1. L1 is a short wavelength laser, the wavelength is positioned in a short wavelength band of green light, and the range is 300nm-560nm and is adjustable; l2 is a long wavelength laser, the wavelength is located in the infrared longer wave band, the range is 780nm-1064nm, and the wavelength is adjustable.
The annealing system is constructed as shown in fig. 1, the short wavelength laser is L1 and the long wavelength laser is L2, the overall timing control of the laser pulses of the two lasers and the synchronous timing control with the moving stage 6 are performed by the system control unit 1, and the system control unit 1 is in the form of a pulse generator and a laser controller. The laser with two wavelengths passes through an optical system 2 with precise calibration to synthesize a laser beam 3, the laser beam is projected to the same position on the surface of a wafer 4 at a certain angle, a moving stage 6 drives a chuck 5 and the wafer 4 to perform back and forth scanning and stepping movement, and finally the laser beam covers the whole wafer, so that the whole process of laser annealing is completed.
The shape of the two wavelength spots outputted from the precisely calibrated optical system 2 on the wafer is shown in fig. 2. The sizes of the linear spots of the short wavelength light source L1 and the long wavelength light source L2 are respectively B1 and B2, and are generally equal to each other in the length direction B2 and B1, and the values of W2 = c x W1 and c in the width direction are determined according to the process requirements, and the range is 0.2-5.
In the spatial distribution, the projections of the centers (central axes) of the two linear spots on a plane are coincident, the linear spot light intensity I 0 is a flat-top distribution in the Length direction (Length), and is a Gaussian distribution or flat-top distribution in the Width direction (Width), as shown in fig. 3 and 4.
In terms of timing distribution, there are two cases, see fig. 5 and 6, respectively.
(1) If the number of short wavelength light sources is 1, the number of long wavelength lasers is also 1, and the time sequence relationship is shown in fig. 5: the waveform of the output power of the first wavelength main light source L1 changing along with time is near Gaussian, the pulse width of the pulse is PW1 respectively, PW1 can be independently regulated, and the regulating range is 50-1200ns; the output power of the second wavelength auxiliary light source L2 is square along with the time variation waveform, the pulse repetition frequency is consistent with L1, the pulse width PW2 of the pulse is adjustable, the adjusting range is 0-T, T is 1/f, namely, one pulse period time, and when the pulse width is adjusted to T, the continuous light output mode is realized. Meanwhile, the time interval D2 between the L1 and the L2 can be adjusted, and the adjusting range is 0-T;
(2) If the number of short wavelength light sources is 2, the number of long wavelength lasers is also 1, and the time sequence relationship is shown in fig. 6: the output power of the first wavelength main light sources L11 and L12 has a time-varying waveform of nearly Gaussian, the pulse widths of pulses of the first wavelength main light sources are PW11 and PW12 respectively, and the PW11 and PW12 can be independently regulated within the regulation range of 50-1200ns; the second wavelength auxiliary light output power has a square waveform along with time, the pulse repetition frequency is consistent with L11 and L12, the pulse repetition frequency is f, the pulse width PW2 of the pulse is adjustable, the adjusting range is 0-T, T is 1/f, namely, one pulse period time, and when the pulse width is adjusted to T, the pulse is in a continuous light output mode. Meanwhile, the time interval D1 between the L11 and the L12 is adjustable, the adjusting range is 0-T, the time interval D2 between the L11 and the L2 is adjustable, and the adjusting range is 0-T.
The laser annealing system can be applied to ion implantation and annealing activation processes of field stop (FS-IGBT) devices or reverse-conduction (RC-IGBT) devices.
The device structure of the field-stop FS-IGBT is shown in fig. 7, and in the new generation of IGBT devices, the FS-IGBT is named with a specific field stop layer (N-stop) with a thickness in the range of 40-300 um, and due to the special back side process requirements, the back side implanted impurities need to be activated without affecting the front side device, including a low concentration deep implanted N-stop layer (typically implanted with an impurity of P) and a relatively high concentration shallow implanted p+ layer (typically implanted with an impurity of B or BF 2).
The thickness of the N-stop layer influences the pressure resistance of the device on one hand, the thicker the N-stop is, the stronger the pressure resistance is under the condition that the concentration of the N-stop is unchanged theoretically, and the thickness of the N-stop depends on the thickness of activated impurity distribution, so that the deeper and better the depth of laser can be activated is required; on the other hand, under the same pressure-resistant requirement, the thickness of the N-stop layer can be increased to reduce the thickness of the N-drift in a variable manner, so that the conduction voltage drop is reduced, and the loss in the on state is reduced, and the thickness of the N-drift is reduced, which means that the wafer is thinner and the temperature resistance is poorer, and the minimum thermal budget is required to deactivate the thin sheet and the ultrathin sheet.
Meanwhile, the P+ injection of the collector region needs to be activated, but the laser melting depth cannot neutralize the N-stop layer and the P+ layer, and the neutralization of inversion impurities in a large range can greatly influence the overall performance of the device, so that the process can be performed according to the following examples 1-5.
Wherein example 1-example 3 consisted of a four step process, with ion activation once per implant. Namely, comprises: a) Injecting N-stop; b) Laser activating the N-stop; c) Implanting a collector region P+ with impurity concentration higher than that of the N-stop; d) The laser activates collector region p+, as shown in fig. 8.
Example 1
(A) N-stop is injected, in order to realize deeper distribution of the N-stop, N-type impurities are usually injected at a medium and high energy small angle (more than 100kev and less than 0 DEG) to form a curve of near Gaussian distribution of the impurity concentration along the depth direction, and the dotted line represents the distribution of the injected impurities.
(B) The laser activates the N-stop, which is typically low in concentration and deep in depth, typically ranging from 0 to 10um. The laser emitted by the laser annealing system is used for providing a temperature field, so that the temperature is higher than the required depth and is higher than 1100K, the activation within the full depth range can be met, and the solid line represents the distribution of activated impurities.
(C) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is generally higher in concentration and shallower in depth, the laser emitted by the laser annealing system is used for providing a temperature field, so that the depth is more than required, the temperature is more than 1200K, the activation within the full depth range can be met, the solid line represents the distribution of activated impurities, and the collector region P+ and the inverted N-stop form PN junctions after activation;
example 2
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, a mode of medium-high energy injection (more than 100 kev) of N-type impurities is generally adopted to form a curve of near Gaussian distribution of impurity concentration along the depth direction, and a dotted line represents the distribution of injected impurities;
(b) The laser activates N-stop, the injection is generally low in concentration and deep in depth, the depth range is generally 0-10 um, when the laser adjustable space is limited and the temperature field distribution is very steep, the laser annealing system needs to be used for carrying out surface melting by using the short wavelength laser and is matched with the long wavelength laser to realize the deeper temperature of more than 1100K, so that activation is realized, the melting depth a is the depth from solid phase to liquid phase, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is generally higher in concentration, the depth is shallower, the depth range is generally 0-1 um, when the laser (parameter) adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser of the laser annealing system is required to be used for carrying out surface melting, and the temperature of the depth required by the laser is higher than 1200K in combination with the long wavelength laser, so that activation is realized, the melting depth b is the depth of solid phase to liquid phase, the melting depth b cannot exceed the depth D when the concentration of the injected collector region P+ and the concentration of the activated N-stop are equal, otherwise, the neutralization of a large amount of P-type impurities and N-stop N-type impurities of the collector region is caused, the performance of the device is influenced, the solid line represents the distribution of the activated impurities, and the activated collector region P+ and the N-stop form PN junction.
Example 3
(A) N-stop is injected, and because the mode of medium-high energy injection (more than 100 kev) of N-type impurities is high in cost, the N-type impurities are injected by adopting low-energy high-volume concentration in the embodiment, the impurities are accumulated on the shallow surface, and the dotted line represents the distribution of the injected impurities;
(b) The N-stop is activated by laser, the surface of a wafer is melted to a required depth by utilizing the short-wavelength laser of the laser annealing system according to the design requirement of a device, so that flat top distribution of impurity concentration along the depth direction is realized, the melting depth c is the depth of solid phase to liquid phase, the temperature in the depth range after melting is higher than 1685K by matching with long-wavelength laser, the impurities are completely activated, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is generally higher in concentration, shallower in depth and generally in the depth range of 0-1 um, the temperature above the required depth is higher than 1200K by utilizing the laser annealing system, the activation within the full depth range can be met, the solid line represents the distribution of activated impurities, and the collector region P+ and the inverted N-stop form PN junctions after activation; when the adjustable space of laser (parameters) is limited and the distribution of a temperature field is very steep, the short wavelength laser of the laser annealing system can be used for melting the surface of a wafer and matching with long wavelength laser to realize the temperature of the depth required by the depth is more than 1200K, so that the activation is realized, the melting depth cannot exceed the depth D when the concentration of the injected collector region P+ and the concentration of the activated N-stop are equal, otherwise, the neutralization of a large number of P-type impurities and N-stop N-type impurities in the collector region is caused, the performance of the device is influenced, the solid line represents the distribution of the activated impurities, and the P+ and the inverted N-stop in the collector region form PN junctions after the activation;
Example 4-example 5 consisted of a three-step process, followed by a final activation after implantation of impurity ions. To simplify the process flow, activation may be performed after all implants are completed; a) Injecting N-stop; b) Implanting a collector region P+ with impurity concentration higher than that of the N-stop; c) Laser activated N-stop and collector region P+; as in fig. 9.
Example 4
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(c) The laser activates N-stop and the collector region P+, the laser annealing system is utilized to provide a temperature field, long wavelength laser and short wavelength laser are mixed and configured, so that the temperature in the depth range of the collector region P+ is more than 1200K, the temperature in the depth range of the N-stop is more than 1100K, the activation in the full depth range can be satisfied, the solid line represents the distribution of activated impurities, and the collector region P+ and the inverted N-stop form PN junctions after the activation;
Example 5
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(c) When the laser is used for activating the N-stop and the collector region P+, the laser (working parameters) has limited adjustable space and the temperature field distribution is very steep, the short-wavelength laser using the laser annealing system can be used for melting the surface of the wafer and matching with long-wavelength laser to realize the temperature of the depth required to be greater than 1200K, so that activation is realized, the melting depth b cannot exceed the depth D when the concentration of the injected collector region P+ and the concentration of the injected collector region N+ are equal, otherwise, the neutralization of a large amount of P-type impurities and N-stop N-type impurities of the collector region can be caused, the performance of the device is influenced, the solid line represents the distribution of activated impurities, and the N-stop of the collector region P+ and the inverted collector region after activation forms PN junction.
The device structure of the reverse-conducting RC-IGBT is shown in fig. 10, and has a thickness in the range of 40-300 um, and due to the special back surface process requirement, the back surface implanted impurities need to be activated under the condition of not affecting the front surface device, and the device structure comprises a low-concentration deep implanted N-stop layer (usually implanted impurities are P) and a relatively high-concentration shallow implanted collector region P+ layer (usually implanted impurities are B and BF 2) and an N+ layer (usually implanted impurities are P).
The thickness of the N-stop layer influences the pressure resistance of the device on one hand, the thicker the N-stop is, the stronger the pressure resistance is under the condition that the concentration of the N-stop is unchanged theoretically, and the thickness of the N-stop depends on the thickness of activated impurity distribution, so that the deeper and better the depth of laser can be activated is required; on the other hand, under the same pressure-resistant requirement, the thickness of the N-stop layer is increased to reduce the N-drift thickness in a variable manner, so that the conduction voltage drop is reduced, and the loss in the on state is reduced, which means that the wafer is thinner and the temperature resistance is poorer, and the requirement of using the minimum thermal budget to deactivate the thin sheet and the ultrathin sheet is important.
Meanwhile, the p+ and n+ injection of the collector region also needs to be activated, and the laser melting depth cannot cause the neutralization of the N-stop layer and p+ in the longitudinal direction, and the neutralization of the collector region p+ and n+ cannot occur in the transverse direction, so that the neutralization of the inversion impurities in a large range can greatly affect the overall performance of the device, and thus, the process of the following examples 6-12 can be performed.
Examples 6-8 are activated once every implantation of a layer of impurity ions, and include 6 steps: a) Injecting N-stop; b) Laser activating the N-stop; c) Implanting a collector region P+ with impurity concentration higher than that of the N-stop; d) Laser activated collector region p+; e) Masking and implanting a collector region N+ with a concentration higher than that of the collector region P+; f) The laser activates collector region n+ as shown in fig. 11.
Example 6
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) The laser activates N-stop, the injection is generally low in concentration and deep in depth, the depth range is generally 0-10 um, the laser annealing system is utilized to provide a temperature field, under the action of laser, the required depth is higher than the required depth, the temperature is higher than 1100K, the activation in the full depth range can be met, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is generally higher in concentration and shallower in depth, the temperature field is provided by the laser annealing system, the temperature is higher than the required depth and is higher than 1200K under the action of laser, the activation can be realized within the full depth range, the solid line represents the distribution of activated impurities, and the collector region P+ and the inverted N-stop form a PN junction after activation;
(e) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(f) The laser activates the collector region N+ with higher concentration and shallower depth, the laser annealing system is used for providing a temperature field, the laser is used for activating the collector region N+ with the depth above the required depth and the temperature above 1200K within the full depth range, or else, the collector region P+ and the collector region N+ are neutralized transversely to affect the performance of the device, the solid line represents the distribution of the activated impurities, and the collector region N+ and the N-stop of the same type form homotype conduction after activation.
Example 7
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) The laser activates N-stop, the injection is generally low in concentration and deep in depth, the depth range is generally 0-10 um, when the adjustable space of laser (working parameter) is limited and the distribution of a temperature field is very steep, the surface is required to be melted by using the short-wavelength laser of the laser annealing system and matched with the long-wavelength laser to realize the temperature of more depth being more than 1100K, so that activation is realized, the melting depth a is the depth of solid phase to liquid phase, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is higher in general concentration and shallower in depth, when the laser adjustable space is limited and the temperature field distribution is very steep, the surface is required to be melted by using the short wavelength laser of the laser annealing system and the temperature of the required depth is higher than 1200K in cooperation with the long wavelength laser, so that activation is realized, the melting depth b is the depth of a solid phase to a liquid phase, the melting depth b cannot exceed the depth D when the concentration of the injected collector region P+ and the concentration of the activated N-stop are equal, otherwise, the neutralization of a large amount of P-type impurities and N-stop N-type impurities of the collector region is caused, the device performance is influenced, the solid line represents the distribution of the activated impurities, and the activated collector region P+ and the N-stop form PN junction;
(e) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(f) The laser activates the collector region N+ with higher concentration and shallower depth, the laser annealing system is used for providing a temperature field, the laser is used for activating the collector region N+ with the depth above the required depth and the temperature above 1200K within the full depth range, or else, the collector region P+ and the collector region N+ are neutralized transversely to affect the performance of the device, the solid line represents the distribution of the activated impurities, and the collector region N+ and the N-stop of the same type form homotype conduction after activation.
Example 8
(A) N-stop is injected, and because the mode of medium-high energy injection (more than 100 kev) of N-type impurities is high in cost, the N-type impurities are injected by adopting low-energy high-volume concentration in the embodiment, the impurities are accumulated on the shallow surface, and the dotted line represents the distribution of the injected impurities;
(b) The N-stop is activated by laser, the surface is melted to the required depth by utilizing short-wavelength laser which needs to utilize the laser annealing system according to the design requirement of a device, so that flat top distribution of impurity concentration along the depth direction is realized, the melting depth c is the depth of solid phase to liquid phase, the temperature in the depth range is larger than 1685K after being melted by matching with long-wavelength laser, the laser is completely activated, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The laser activates the collector region P+, the injection is generally higher in concentration and shallower in depth, the temperature field is provided by the laser annealing system, the temperature is higher than the required depth and is higher than 1200K under the action of laser, the activation can be realized within the full depth range, the solid line represents the distribution of activated impurities, and the collector region P+ and the inverted N-stop form a PN junction after activation; when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser of the laser annealing system can be used for melting the surface and matching with the long wavelength laser to realize the temperature of the depth required to be greater than 1200K, so that the activation is realized, the melting depth cannot exceed the depth D when the concentration of the injected collector region P+ and the concentration of the activated N-stop are equal, otherwise, the neutralization of a large number of P-type impurities and N-stop N-type impurities in the collector region is caused, the performance of the device is influenced, the solid line represents the distribution of the activated impurities, and the P+ and the N-stop of the collector region form PN junctions after the activation;
(e) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(f) The laser activates the collector region N+ with higher concentration and shallower depth, the laser annealing system is used for providing a temperature field, the laser is used for activating the collector region N+ with the depth above the required depth and the temperature above 1200K within the full depth range, or else, the collector region P+ and the collector region N+ are neutralized transversely to affect the performance of the device, the solid line represents the distribution of the activated impurities, and the collector region N+ and the N-stop of the same type form homotype conduction after activation.
Examples 9-11 are laser activated collector regions p+, n+ after injection of collector regions p+ and n+. A total of 5 steps are included: a) Injecting N-stop; b) Laser activating the N-stop; c) Implanting a collector region P+ with impurity concentration higher than that of the N-stop; d) Masking and implanting a collector region N+ with a concentration higher than that of the collector region P+; e) Laser activated collector regions p+, n+, as shown in fig. 12; the 2 nd case includes three schemes:
Example 9
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) The laser activates N-stop, the injection is generally low in concentration and deep in depth, the depth range is generally 0-10 um, the laser annealing system is utilized to provide a temperature field, under the action of laser, the required depth is higher than the required depth, the temperature is higher than 1100K, the activation in the full depth range can be met, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(e) The laser activates the collector region P+ and the collector N+, the injection is generally higher in concentration and shallower in depth, the temperature field is provided by the laser annealing system, under the action of laser, the temperature is higher than the required depth and is higher than 1200K, the activation can be realized within the full depth range, the temperature in the process cannot exceed 1685K, otherwise, in the transverse direction, the collector region P+ and the collector region N+ are neutralized to influence the performance of the device, the solid line represents the distribution of activated impurities, after activation, the collector region P+ and the inversed N-stop form PN junctions, and the collector region N+ and the N-stop of the same type form homotype conduction;
example 10
(A) Injecting N-stop, in order to realize deeper distribution of N-stop, generally adopting a mode of injecting N-type impurities at a medium-high energy small angle (more than 100kev and a tilt of 0 DEG), forming a curve of near Gaussian distribution of the impurity concentration along the depth direction, wherein a dotted line represents the distribution of injected impurities;
(b) The laser activates N-stop, the injection is generally low in concentration, deeper, the depth range is generally 0-10 um, when the laser (parameter) adjustable space of the laser annealing system is limited and the temperature field distribution is very steep, the laser annealing system needs to be used for melting the surface and matching with long wavelength laser to realize the temperature of more depth being higher than 1100K, so that activation is realized, the melting depth a is the depth of solid phase to liquid phase, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(e) The laser activates the collector region P+ and the collector N+, the injection is generally higher in concentration and shallower in depth, the laser annealing system is used for providing a temperature field, under the action of laser, the temperature is higher than the required depth and is higher than 1200K, the activation can be realized within the full depth range, the temperature in the process cannot exceed 1685K, otherwise, in the transverse direction, the collector region P+ and the collector region N+ are neutralized to influence the performance of the device, the solid line shows the distribution of activated impurities, after activation, the collector region P+ and the inversed N-stop form PN junctions, and the collector region N+ and the N-stop of the same type form homotype conduction.
Example 11
(A) N-stop is injected, and because the mode of medium-high energy injection (more than 100 kev) of N-type impurities is high in cost, the N-type impurities are injected by adopting low-energy high-volume concentration in the embodiment, the impurities are accumulated on the shallow surface, and the dotted line represents the distribution of the injected impurities;
(b) The laser activates N-stop, the surface is melted to the required depth by utilizing the short wavelength laser of the laser annealing system according to the design requirement of a device, so that the flat top distribution of the impurity concentration along the depth direction is realized, the melting depth c is the depth of solid phase to liquid phase, the temperature in the depth range after melting is more than 1685K by matching with long wavelength laser, the laser is completely activated, and the solid line represents the distribution of activated impurities;
(c) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(d) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(e) The laser activates the collector region P+ and the collector N+, the injection is generally higher in concentration and shallower in depth, the laser annealing system is used for providing a temperature field, under the action of laser, the temperature is higher than the required depth and is higher than 1200K, the activation can be realized within the full depth range, the temperature in the process cannot exceed 1685K, otherwise, in the transverse direction, the collector region P+ and the collector region N+ are neutralized to influence the performance of the device, the solid line shows the distribution of activated impurities, after activation, the collector region P+ and the inversed N-stop form PN junctions, and the collector region N+ and the N-stop of the same type form homotype conduction.
Example 12 is a one-time laser activated N-stop, collector p+ and n+ after implantation of N-stop, collector p+, collector n+ comprising 4 steps: a) Injecting N-stop; b) Implanting a collector region P+ with impurity concentration higher than that of the N-stop; c) Masking and implanting a collector region N+ with a concentration higher than that of the collector region P+; d) The laser activates N-stop, collector regions p+ and n+, as shown in fig. 12.
Example 12
In the scheme 1, (a) N-stop is injected, in order to realize deeper distribution of the N-stop, N-type impurities are usually injected at a medium and high energy small angle (more than 100kev and tilt 0 DEG), a curve of near Gaussian distribution of the impurity body concentration along the depth direction is formed, and the distribution of the injected impurities is shown by a dotted line;
(b) Injecting the P+ into the collector region, and in order to realize the shallower distribution of the P+ in the collector region, generally adopting a mode of injecting the P-type impurities at a lower angle (less than 200kev and 7 ℃ tit) to form a curve of nearly Gaussian distribution of the concentration of the impurity along the depth direction, wherein the distribution of the injected impurities is represented by a dotted line;
(c) The concentration of the N+ in the mask injection collecting region is higher than that of the P+ in the collecting region, and the distribution of the injected impurities is shown by a dotted line in the right diagram of the step e;
(d) The laser activates N-stop, collector region P+ and collector N+, the injection is generally higher in concentration and shallower in depth, the temperature field is provided by the laser annealing system, under the action of laser, the temperature is higher than the required depth and is higher than 1200K, activation in the full depth range can be satisfied, the temperature in the process cannot exceed 1685K, otherwise, in the transverse direction, the collector region P+ and collector region N+ impurities are neutralized to influence the performance of the device, the solid line represents the distribution of activated impurities, after activation, the collector region P+ and the inverted N-stop form PN junctions, and the collector region N+ and the N-stop of the same type form homotype conduction;
In the process flows set forth above, the different process schemes require a laser to provide a corresponding temperature field to meet the activation and melting requirements. The temperature fields that the laser needs to meet are of the following types for the needs of the process:
1) The melting range with larger depth is provided so as to realize impurity redistribution within a certain depth range through melting when the N-stop cannot perform high-energy injection;
2) A relatively slow solid state temperature gradient range to meet the activation of impurities at a large depth range when the impurities cannot be melted in a large range or cannot be melted at all;
3) The method has a steeper solid-state temperature gradient range so as to realize the activation of ultra-shallow impurities under the condition of lower thermal budget and avoid fragments of the ultra-thin sheet caused by high thermal budget;
aiming at the three application scenes of the laser temperature fields, corresponding simulation experiments are carried out;
1) To achieve a large depth of melting range:
When short wavelength laser (527 nm, energy density 5.4J/cm 2, pulse width 300 ns) is adopted for action, a temperature field 1 provided by the laser is shown in fig. 14, the depth of the laser above 1685K is about 1.5um, the laser can melt an N-stop layer injected with low energy (less than 100 keV) and then redistribute the N-stop layer to the depth of 1.5um, and 200keV and Tilt 0 DEG energy injection can be replaced;
Under the condition that short wavelength laser (527 nm, energy density 5.4J/cm 2 and pulse width 300 ns) and long wavelength laser (808 nm, power density 320kW/cm 2 and pulse width 20 us) are adopted to be matched, the temperature field 2 provided by the laser is shown in figure 15, the depth of the laser above 1685K is about 2.5um, the laser can be used for redistributing an N-stop layer injected with low energy (< 100 keV) to the depth of 2.5um after melting, and 600keV and Tilt 0 DEG energy injection can be replaced;
in summary, by selecting a hybrid configuration of different laser wavelengths, different melting ranges and depth ranges of impurity distribution can be achieved, and annealing activation can be directionally achieved for impurity ions of specific thickness or shallow.
2) To achieve large depth range solid state activation:
When long wavelength laser (808 nm, power density 320kW/cm 2, pulse width 20 us) is used, the temperature field 3 provided by the laser is shown in fig. 16, because the temperature gradient in the depth direction is relatively slow due to the deep characteristic of long wavelength laser absorption, the activation of the 4um low concentration N-stop layer can be realized at a depth above 1100K more than 4um, and the activation of the shallow surface collector regions P+ and N+ can be realized at a temperature within 1um depth more than 1300K.
When long wavelength laser (808 nm, power density 320kW/cm 2, pulse width 30 us) is used, the temperature field 3 provided by the laser is shown in fig. 17, because the temperature gradient in the depth direction is relatively slow due to the deep characteristic of long wavelength laser absorption, the activation of the 8um low concentration N-stop layer can be realized at a depth above 1100K more than 8um, and the activation of the shallow surface collector regions P+ and N+ can be realized at a temperature within 1um depth more than 1400K.
In summary, by selecting different laser configurations, different solid state activation depth ranges may be achieved.
3) Shallow surface activation for low thermal budget when the ultra-thin sheet is not fragmented:
When a short wavelength laser (527 nm, energy density 1.3J/cm 2, pulse width 300 ns) is used, as shown in FIG. 18, the temperature field 5 provided by the laser needs to be as low as possible to achieve activation at a low thermal budget for ultra-shallow layer activation of the ultra-thin sheet to prevent fragments caused by over-high thermal budget, and 1.3J/cm 2 thermal budget is required for a 527nm short wavelength laser at 300ns pulse width to achieve a 0.2um shallow depth temperature greater than 1500K for high concentration full activation;
when a short wavelength laser (527 nm, energy density 0.9J/cm 2, pulse width 150 ns) is used, as shown in FIG. 19, the temperature field 6 provided by the laser needs to be activated at a low thermal budget as much as possible for ultra-shallow activation of the ultra-thin sheet to prevent fragments caused by excessively high thermal budget, and 0.9J/cm 2 thermal budget is needed at 300ns pulse width for 527nm short wavelength laser to achieve high concentration full activation at a shallow depth temperature of 0.2um greater than 1500K;
When a short wavelength laser (527 nm, energy density 0.9J/cm 2, pulse width 150 ns) is used, as shown in FIG. 20, the temperature field 7 provided by the laser needs to be activated at a low thermal budget as much as possible for ultra-shallow activation of the ultra-thin sheet to prevent fragments caused by over-high thermal budget, and 0.6J/cm 2 thermal budget is needed at 300ns pulse width for a 527nm short wavelength laser to achieve a shallow depth temperature of 0.2um greater than 1500K and high concentration of full activation;
In summary, shallow surface activation under different thermal budget conditions can be achieved by selecting different laser configurations based on the temperature resistance and spall resistance of the type of wafer.
In the actual production and application process, short-wavelength laser and long-wavelength laser are used for annealing and activating, wherein the wavelength range of the short-wavelength laser is 300nm-560nm, and the wavelength range of the long-wavelength laser is 780nm-1064nm;
the method is characterized in that the method comprises the steps of realizing ion annealing in different melting ranges and impurity distribution depth ranges and multi-layer impurity ion implantation annealing by selecting laser mixing configuration of different wavelengths, and comprehensively considering the temperature resistance and the fragment resistance of different types of wafers, and selecting the laser mixing configuration of proper wavelength for use so as to realize shallow surface activation under different thermal budget conditions; during activation, any one or a combination of the following operations are performed:
Operation one: the characteristic that short-wavelength laser energy is accumulated on the surface of the wafer is utilized to melt the surface, so that impurity ions which are injected at low energy and are accumulated on the shallow surface of the wafer are redistributed below the shallow surface through laser annealing, and the low-energy injection is replaced by the medium-high-energy injection;
And (2) operation II: by utilizing the characteristic of deeper absorption depth of long wavelength laser, non-melting annealing and annealing within a larger depth range are realized;
And (3) operation three: the short wavelength laser and the long wavelength laser are used in a matching way, so that the surface of the wafer is melted, impurity ions which are injected in low energy and are gathered on the shallow surface of the wafer are redistributed through laser annealing, and the impurity ions are further distributed to deeper depth under the annealing action of the long wavelength laser;
operation four: the characteristic of low energy of short wavelength laser is utilized to realize the shallow surface activation with low thermal budget when the ultra-thin sheet is not broken.
The above examples are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solution of the present invention should fall within the scope of protection defined by the claims of the present invention without departing from the spirit of the present invention.

Claims (10)

1. A laser annealing method of a power device is characterized in that, in the annealing process,
Annealing activation using a short wavelength laser having a wavelength range of 300nm to 560nm and a long wavelength laser having a wavelength range of 780nm to 1064nm;
The method is characterized in that the method comprises the steps of realizing ion annealing in different melting ranges and impurity distribution depth ranges and multi-layer impurity ion implantation annealing by selecting laser mixing configuration of different wavelengths, and comprehensively considering the temperature resistance and the fragment resistance of different types of wafers, and selecting the laser mixing configuration of proper wavelength for use so as to realize shallow surface activation under different thermal budget conditions;
The power device is a field-stop FS-IGBT device or a reverse-conduction RC-IGBT device, and in the preparation process, only low-energy injection of N-type impurities is adopted to enable the N-type impurities to be gathered on the shallow surface of the wafer;
During activation, the following operations are performed:
the characteristic that short-wavelength laser energy is accumulated on the surface of the wafer is utilized to melt the surface, so that impurity ions which are injected at low energy and are accumulated on the shallow surface of the wafer are redistributed below the shallow surface through laser annealing, and the low-energy injection is replaced by the medium-high-energy injection; by utilizing the characteristic of deeper absorption depth of long wavelength laser, non-melting annealing and annealing in a depth range are realized.
2. The laser annealing method of a power device according to claim 1, wherein the power device is a field stop FS-IGBT device having a thickness of 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface of the wafer to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be higher than 1100K, so that the laser activates the N-stop;
c) Injecting into the collector region P+: the mode of injecting P-type impurities at a low energy and a large angle is adopted to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the injection energy is less than 200kev, and the angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by utilizing laser, activating a collector region P+ at a temperature of more than 1200K in the temperature field, and forming a PN junction by the collector region P+ and an inverted N-stop after activation; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser with the long wavelength is matched to enable the temperature of the required depth to be higher than 1200K to activate the collecting region P+; the depth is required to be not more than the depth at which the concentration of p+ injected into the collector region and the concentration of N-stop activated are equal, so that the neutralization of P-type impurities and N-stop N-type impurities in the collector region is avoided.
3. The laser annealing method of a power device according to claim 1, wherein the power device is a field stop FS-IGBT device having a thickness of 40-300um; the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the impurities to be gathered on the shallow surface of the wafer, wherein the low energy is less than or equal to 100keV;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, activating a collector region P+ at a temperature of more than 1200K, and forming a PN junction by the collector region P+ and an inverted N-stop after activation; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser with the long wavelength is matched to enable the temperature of the required depth to be higher than 1200K to activate the collecting region P+; the depth is required to be not more than the depth at which the concentration of p+ injected into the collector region and the concentration of N-stop activated are equal, so that the neutralization of P-type impurities and N-stop N-type impurities in the collector region is avoided.
4. The laser annealing method of a power device according to claim 1, wherein the power device is a field stop FS-IGBT device having a thickness of 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Injecting into the collector region P+: the mode of injecting P-type impurities at a low energy and a large angle is adopted to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the injection energy is less than 200kev, and the angle is more than or equal to 7 degrees;
c) Laser activated N-stop and collector region P +: the temperature in the depth range of the collecting region P+ is larger than 1200K, and the temperature in the depth range of the N-stop is larger than 1100K by utilizing the cooperation of long wavelength laser and short wavelength so as to activate the collecting region P+ and the N-stop respectively; or when the laser adjustable space is limited and the temperature field distribution is very steep, the surface of the wafer is fused to the required depth by utilizing the short wavelength, and the laser is matched with the long wavelength laser to activate the P+ and N-stop of the collector region under the condition that the temperature of the required depth is higher than 1200K; the depth is required to be not more than the depth at which the concentration of p+ injected into the collector region and the concentration of N-stop activated are equal, so that the neutralization of P-type impurities and N-stop N-type impurities in the collector region is avoided.
5. The laser annealing method of the power device according to claim 1, wherein the power device is a reverse-conducting type RC-IGBT device, and the thickness of the reverse-conducting type RC-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface, and the long wavelength laser is matched to realize the temperature of the required depth of more than 1100K so as to redistribute and activate impurities;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, and activating a collector region P+ at a temperature of more than 1200K in the temperature field; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be more than 1200K so as to realize activation; the required depth is not more than the depth at which the p+ and active N-stop concentrations of the implanted collector region are equal;
e) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
f) Laser activated collector region N +: the laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
6. The laser annealing method of the power device according to claim 1, wherein the power device is a reverse-conducting type RC-IGBT device, and the thickness of the reverse-conducting type RC-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the N-type impurities to be gathered on the shallow surface; the low energy is less than or equal to 100kev;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Laser activated collector region p+: providing a temperature field by using laser, and activating a collector region P+ at a temperature of more than 1200K in the temperature field; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and the long wavelength laser is matched to enable the temperature of the required depth to be more than 1200K so as to realize activation; the required depth is not more than the depth at which the p+ and active N-stop concentrations of the implanted collector region are equal;
e) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
f) Laser activated collector region N +: the laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
7. The laser annealing method of the power device according to claim 1, wherein the power device is a reverse-conducting type RC-IGBT device, and the thickness of the reverse-conducting type RC-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Laser activated N-stop: providing a temperature field by using laser, and activating the N-stop by using the laser under the condition that the temperature of the temperature field is more than 1100K; or when the laser adjustable space is limited and the temperature field distribution is very steep, the short wavelength laser is utilized to melt the surface to the required depth, and the long wavelength laser is matched to realize the temperature of the required depth of more than 1100K so as to redistribute and activate impurities;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
e) Laser activated collector region N +: the laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
8. The laser annealing method of the power device according to claim 1, wherein the power device is a reverse-conducting type RC-IGBT device, and the thickness of the reverse-conducting type RC-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: injecting N-type impurities with low energy to enable the N-type impurities to be gathered on the shallow surface; the low energy is less than or equal to 100kev;
b) Laser activated N-stop: melting the surface of the wafer to a required depth by utilizing the short wavelength laser, and matching the long wavelength laser to ensure that the temperature of the required depth is higher than 1685K, so as to realize the redistribution and complete activation of the N-type impurity concentration along the depth direction;
c) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
d) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
e) Laser activated collector region N +: and a laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature of the temperature field is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
9. The laser annealing method of the power device according to claim 1, wherein the power device is a reverse-conducting type RC-IGBT device, and the thickness of the reverse-conducting type RC-IGBT device is 40-300um; the method comprises the following steps:
a) Injecting N-stop: the method comprises the steps of adopting a mode of injecting N-type impurities at medium and high energy to form near Gaussian distribution of impurity body concentration along the depth direction, wherein the medium and high energy is more than 100kev;
b) Injecting into the collector region P+: the method comprises the steps of adopting a mode of injecting P-type impurities at a low energy and a large angle to form near Gaussian distribution of the concentration of the impurity body along the depth direction; the low-energy large angle is less than 200kev, and the inclination angle is more than or equal to 7 degrees;
c) Mask implant collector region N +: forming near Gaussian distribution of impurity concentration along depth direction by adopting a mode of injecting N-type impurities at lower energy, wherein the concentration of N+ injected into the collector region by the mask is higher than that of P+ in the collector region; the implantation energy is < 300kev;
d) Laser activated N-stop, collector regions p+ and n+: and a laser is used for providing a temperature field, and the collector region N+ is activated under the condition that the temperature of the temperature field is not more than 1685K and is higher than 1200K, so that the collector region P+ and the collector region N+ impurities are prevented from being neutralized in the transverse direction.
10. The laser annealing method of a power device according to any one of claims 1 to 9, characterized in that the laser annealing method is realized by a laser annealing system, characterized in that the laser annealing system comprises:
The movable carrier is used for carrying the wafer and moving according to a preset program to drive the wafer to move; the movable carrier is provided with a chuck for fixing the wafer;
a long wavelength laser having a wavelength range of 780nm to 1064nm;
and at least one short wavelength laser; the wavelength range of the short wavelength laser is 300nm-560nm;
a system control unit for controlling the overall time sequence of the laser pulses of the long wavelength laser and the short wavelength laser; the system control unit is a pulse generator and a laser controller;
The laser emitted by the long wavelength laser and the short wavelength laser is synthesized into a laser beam through an optical system which is precisely calibrated, the laser beam is projected onto the surface of a wafer placed on a movable carrier at a certain angle, the movable carrier drives the wafer to reciprocate, the laser beam is made to scan the surface of the wafer, and finally the laser beam is made to scan the whole wafer, so that the laser annealing process is completed;
The width of the linear spot of the laser emitted by the short wavelength laser on the surface of the wafer is W1, the length of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is C1, and the width of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is W2, and the length of the linear spot of the laser emitted by the long wavelength laser on the surface of the wafer is C2; wherein w2=c×w1, c1=c2; c=0.2-5;
the line spots of the laser emitted by the short wavelength laser on the surface of the wafer and the line spots of the laser emitted by the long wavelength laser on the surface of the wafer are overlapped in projection of the central lines of the two line spots on the surface of the wafer; the light intensity of the two linear spots is distributed in the linear spot length direction as a flat-top distribution, and the light intensity of the two linear spots is distributed in the linear spot width direction as a Gaussian distribution or a flat-top distribution;
When the number of the long wavelength lasers and the short wavelength lasers is 1, the waveform of the output power of the short wavelength lasers changing along with time is Gaussian, the pulse width of the pulse is independently adjustable, and the adjustment range is 50-1200ns; the waveform of the output power of the long wavelength laser changing along with time is a square waveform, the pulse frequency is consistent with the pulse frequency of the short wavelength laser, the pulse frequencies are f, the pulse width of the pulse is adjustable, the adjusting range is 0-T, and T is 1/f; the pulse time interval between the long wavelength laser and the short wavelength laser is adjustable, and the adjusting range is 0-T;
When the number of the short wavelength lasers is 2 and the number of the long wavelength lasers is 1, the waveform of the variation of the power of the 2 short wavelength lasers with time is a near Gaussian waveform, the pulse width distribution of the pulse is independently adjustable, and the adjustment range is 50-1200ns; the waveform of the output power of the long wavelength laser changing along with time is a square waveform, the pulse frequency is consistent with the pulse frequency of the 2 short wavelength lasers and is f, the pulse width of the pulse is adjustable, the adjusting range is 0-T, and T is 1/f; the pulse time interval of the 2 short wavelength lasers is adjustable, and the adjusting range is 0-T; the pulse time interval between the long wavelength laser and any one of the short wavelength lasers is adjustable, and the adjustment range is 0-T.
CN202011220823.7A 2020-11-05 2020-11-05 Laser annealing method and laser annealing system of power device Active CN112435921B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202011220823.7A CN112435921B (en) 2020-11-05 2020-11-05 Laser annealing method and laser annealing system of power device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202011220823.7A CN112435921B (en) 2020-11-05 2020-11-05 Laser annealing method and laser annealing system of power device

Publications (2)

Publication Number Publication Date
CN112435921A CN112435921A (en) 2021-03-02
CN112435921B true CN112435921B (en) 2024-05-17

Family

ID=74695396

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202011220823.7A Active CN112435921B (en) 2020-11-05 2020-11-05 Laser annealing method and laser annealing system of power device

Country Status (1)

Country Link
CN (1) CN112435921B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN113345806B (en) * 2021-04-23 2024-03-05 北京华卓精科科技股份有限公司 Laser annealing method of SiC-based semiconductor

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101217109A (en) * 2008-01-10 2008-07-09 清华大学 A double-light source laser annealing device and method
WO2012107979A1 (en) * 2011-02-09 2012-08-16 住友重機械工業株式会社 Laser annealing method and laser annealing apparatus
CN102668039A (en) * 2009-11-30 2012-09-12 株式会社日本制钢所 Laser annealing device and laser annealing method
CN103021826A (en) * 2011-09-27 2013-04-03 住友重机械工业株式会社 Laser annealing device and laser annealing method
TW201340177A (en) * 2012-03-29 2013-10-01 Newsouth Innovations Pty Ltd Formation of localised molten regions in silicon containing multiple impurity types
CN104508796A (en) * 2012-08-08 2015-04-08 住友重机械工业株式会社 Semiconductor device producing method
CN109075042A (en) * 2016-04-27 2018-12-21 住友重机械工业株式会社 Laser anneal method and laser anneal device
CN109686686A (en) * 2019-01-30 2019-04-26 北京华卓精科科技股份有限公司 Laser heat treatment equipment and laser heat treatment method
CN110181165A (en) * 2019-05-27 2019-08-30 北京华卓精科科技股份有限公司 Laser preheats annealing system and method

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101217109A (en) * 2008-01-10 2008-07-09 清华大学 A double-light source laser annealing device and method
CN102668039A (en) * 2009-11-30 2012-09-12 株式会社日本制钢所 Laser annealing device and laser annealing method
WO2012107979A1 (en) * 2011-02-09 2012-08-16 住友重機械工業株式会社 Laser annealing method and laser annealing apparatus
CN103021826A (en) * 2011-09-27 2013-04-03 住友重机械工业株式会社 Laser annealing device and laser annealing method
TW201340177A (en) * 2012-03-29 2013-10-01 Newsouth Innovations Pty Ltd Formation of localised molten regions in silicon containing multiple impurity types
CN104508796A (en) * 2012-08-08 2015-04-08 住友重机械工业株式会社 Semiconductor device producing method
CN109075042A (en) * 2016-04-27 2018-12-21 住友重机械工业株式会社 Laser anneal method and laser anneal device
CN109686686A (en) * 2019-01-30 2019-04-26 北京华卓精科科技股份有限公司 Laser heat treatment equipment and laser heat treatment method
CN110181165A (en) * 2019-05-27 2019-08-30 北京华卓精科科技股份有限公司 Laser preheats annealing system and method

Also Published As

Publication number Publication date
CN112435921A (en) 2021-03-02

Similar Documents

Publication Publication Date Title
US7674999B2 (en) Fast axis beam profile shaping by collimation lenslets for high power laser diode based annealing system
US20170221712A1 (en) Laser annealing apparatus and laser annealing method
US7485920B2 (en) Process to create buried heavy metal at selected depth
JP4590880B2 (en) Manufacturing method of semiconductor device
US9431290B2 (en) Semiconductor device and manufacturing method therefor
KR101466848B1 (en) Laser annealing apparatus and laser annealing method
JP2007123300A (en) Method for activating impurities, laser annealer, semiconductor device and method for fabricating same
JP2006351659A (en) Method of manufacturing semiconductor device
JP2001015448A (en) Manufacture of semiconductor device
US7135387B2 (en) Method of manufacturing semiconductor element
US10074648B2 (en) Method of manufacturing semiconductor device
JP2009176892A (en) Semiconductor device and manufacturing method therefor
SG186542A1 (en) Ultrafast laser annealing with reduced pattern density effects in integrated circuit fabrication
CN110181165B (en) Laser preheat annealing system and method
CN112435921B (en) Laser annealing method and laser annealing system of power device
CN102163551B (en) Reverse block-type insulated gate bipolar transistor manufacture method
JP2003224281A (en) Semiconductor device and method for manufacturing the same
JP5201305B2 (en) Manufacturing method of semiconductor device
CN112435920B (en) Long wavelength laser annealing method and device
US20140363986A1 (en) Laser scanning for thermal processing
JP5610493B2 (en) Semiconductor device manufacturing method and manufacturing apparatus
JP5307093B2 (en) Manufacturing method of semiconductor device
WO2008024211A2 (en) Fast axis beam profile shaping
JP2014195004A (en) Process of manufacturing semiconductor element and manufacturing apparatus of semiconductor element
WO2022176443A1 (en) Method for producing semiconductor element, and semiconductor element

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
CB02 Change of applicant information

Address after: 100176 floor 2, building 2, yard 19, Kechuang 10th Street, Beijing Economic and Technological Development Zone, Daxing District, Beijing (Yizhuang group, high-end industrial area of Beijing Pilot Free Trade Zone)

Applicant after: BEIJING U-PRECISION TECH Co.,Ltd.

Address before: 100176 4th floor, building 10, No.156 courtyard, Jinghai 4th Road, economic and Technological Development Zone, Daxing District, Beijing

Applicant before: BEIJING U-PRECISION TECH Co.,Ltd.

CB02 Change of applicant information
GR01 Patent grant
GR01 Patent grant