CN109755116A - A method of unidirectional TVS chip is made using printing technology - Google Patents
A method of unidirectional TVS chip is made using printing technology Download PDFInfo
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- CN109755116A CN109755116A CN201711057472.0A CN201711057472A CN109755116A CN 109755116 A CN109755116 A CN 109755116A CN 201711057472 A CN201711057472 A CN 201711057472A CN 109755116 A CN109755116 A CN 109755116A
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Abstract
The present invention relates to a kind of methods for making unidirectional TVS chip using printing technology; preparation step includes silicon wafer pretreatment; secondary diffusion making herbs into wool; the blunt printing drawing of glass, metallization and testing, sorting, wherein boron diffusing step is spread using negative pressure; and use wet-method etching or laser making herbs into wool; the blunt process of glass carries out the coating of protective layer and glass paddle by the way of printing, simplifies the blunt process of glass, increases preparation rate.Compared with conventional method, printing technology makes unidirectional TVS chip production course-scale, automation, informationization, few peopleization；Unidirectional TVS chip product production cost is low, quality is high, consistency is high, market is good；Printing technology is high-efficient, precision is high, substitutes the techniques such as coating, plated film, electrophoresis in prior art process, while realizing that automating few people's metaplasia produces, promotes homogeneity of product, reduces environmental protection, security risk.
Description
Technical field
The invention belongs to unidirectional TVS chip technology fields, make unidirectional TVS core using printing technology more particularly, to a kind of
The method of piece.
Background technique
Transient state (transition) voltage inhibits diode, i.e. TVS (Transient Voltage Suppressor) diode is big
Use is measured in various electronic circuit systems, is cooperated with components such as resistance, capacitors, to inhibit protection as high voltage transient
Purposes.In normal operation, TVS is in high impedance status to protected line to unidirectional Transient Voltage Suppressor (unidirectional TVS),
When transient voltage is more than its breakdown voltage, TVS is provided with a low-impedance path and gives immediate current.So that flow direction is protected
The immediate current of component transfers to be diverted to TVS diode, and the voltage at protected component both ends is limited in the both ends TVS
The voltage of strangulation, after this overpressure condition disappears, TVS diode is restored to high impedance status again.TVS is widely used in all kinds of
It protects in electronic circuit, wide market, development space is larger.
Mainly using 3 kinds of techniques for producing unidirectional TVS chip in existing industry: knife scrapes technique, electrophoresis process, photoresist glass
Technique, in this three kinds of techniques, the unidirectional TVS simple process and low cost of knife scraping method but because of mesa edge and passivation glass when welding
The protection of upper No oxided film, scolding tin easily flow on glass, and reliability can reduce, and when application is vulnerable；Electrophoresis process groove wedge angle has
Passivation glass protection, reliability is relatively high, but since platinum production process is more in producing, in addition production is needed using a large amount of
Acetone, there are security risk, relative cost is higher；Photoresist glass method uses 3 layers of passivation protection (SIPOS, glass, titanium dioxide
Silicon), the higher wider, high reliablity using silicon chip resistivity range of backward voltage, but 3 photoetching, production cost are needed in producing
It is higher.
Summary of the invention
In order to solve the above technical problems, the present invention provides a kind of method for making unidirectional TVS chip using printing technology,
Production capacity is further increased on the basis of raising existing product quality.
The technical solution adopted by the present invention is that: a method of unidirectional TVS chip, preparation step are made using printing technology
Include:
Bis- diffusion making herbs into wool of S1；
The blunt printing drawing of S2 glass；
S3 metallization.
Wherein, the secondary diffusion suede of the S1 step comprising steps of
S1-1 spreads pre-treatment；
S1-2 phosphorus diffusion；
The diffusion of S1-3 boron；
S1-4 making herbs into wool；
Preferably, the boron is diffused as negative pressure diffusion；
Preferably, the S1-2 step phosphorus diffusion is that phosphorus source is deposited on silicon wafer by carrying phosphorus oxychloride mode with nitrogen
Phosphorus diffusion is carried out behind surface；
Preferably, in the S1-3 step boron diffusion, boron diffusion source is that silicon wafer boron face to be expanded is coated in a manner of printing,
By the coated silicon wafer of multi-disc to apply the opposite mode lamination in boron face, it is diffused, it is described to be diffused as constant temperature diffusion.
Above technical scheme is preferred, further includes step single side sanding, institute between the S1-2 step and the S1-3 step
It states any one side that single side sanding step is the silicon wafer after phosphorus diffusion and carries out single side sanding；
Preferably, the boron face to be expanded is single side sanding face.
Above technical scheme is preferred, and the S1-4 step making herbs into wool process is wet-method etching or laser making herbs into wool；
Preferably, the wet-method etching includes the cleaning of first order cleaning solution；The cleaning of first order pure water；Second level cleaning solution is clear
It washes；The cleaning of second level pure water；The cleaning of third level cleaning solution；The cleaning of third level pure water；
Preferably, the laser making herbs into wool includes laser making herbs into wool；It is cleaned after making herbs into wool: after the silicon wafer wool making, being set to HF solution
Soaking and washing carries out spilling water cleaning and dries after the cleaning of HF solution.
Wherein, the S2 step glass blunt printing drawing comprising steps of
S2-1, printing protective glue: it is protected when corroding to silicon wafer subsequent trench without erodable section；S2-2, groove are rotten
Erosion fluting: slot treatment is carried out to silicon wafer；S2-3, LPCVD precipitate SiO2: SiO is precipitated by LPCVD technology2, make electrical parameter more
Stablize；S2-4, glass firing: glass powder in the passivation layer is solidified by high temperature, is finally reached the effect of passivation；
Preferably, protective glue is printed in the S2-1 step use screen printing technique.
Above technical scheme is preferred, and the printing protective glue is printed on both sides protective glue；
Preferably, the protective glue is acidproof wax.
Above technical scheme is preferred, and the S2-2 step trench etching fluting includes laser slotting；Acid corrosion；It is sour clear
It washes.
Wherein, S3 step metallization comprising steps of
Nickel plating of S3-1: a nickel is plated in the silicon chip surface；
The sintering of S3-2 nickel: make nickle atom to spreading inside the silicon wafer, nickel layer be combined with each other with silicon layer；
Bis- nickel plating of S3-3: secondary nickel is plated in the silicon chip surface；
S3-4 is gold-plated；It is gold-plated in the silicon chip surface.
Wherein, further include testing, sorting step after the S3 step, specifically include: getting test ready；Laser scribing；Automatic point
Choosing；
Preferably, the test specially needle row multiple spot of getting ready gets test ready.
Wherein, the silicon wafer diameter is 5 inch, and the silicon wafer is sliced using diamond line.
The advantages and positive effects of the present invention are:
1 since unidirectional TVS chip requires concentration high phosphorous diffusion source, the concentration that printing technology does not reach requirement, so not
Phosphorus source is applied using silk-screen printing technique, boron diffusion source is printed in silicon wafer boron face to be coated using silk-screen printing technique, so that silicon wafer liquid
The coating process in state source is simplified, and the process-cycle is reduced；Negative pressure diffusion technique is used after liquid source coating, mitigates silicon
Piece edge returns source situation, and the diffusion process steps simplify, and improve diffuser efficiency, so that the PN junction of production is uniform, so that silicon
The processing cost of piece reduces, and traditional dry method sanding is substituted using wet-method etching or laser making herbs into wool, so that worm is made in silicon chip surface
Poroid flannelette increases the roughness of silicon chip surface, conducive to the coating of the blunt technique protective layer of the subsequent glass of silicon wafer, so that the blunt technique of glass
Adhesive force increases when middle protective layer coats；
2 glass blunt processes reduces oxidation, photoetching, development, gum compared with conventional method, reduces coordinative solvent examination
The use of agent, this programme replaces the hazardous chemicals (such as: acetone, gold potassium cyanide) such as organic and cyanide, so that this technique is more
Safety and environmental protection.
Specific embodiment
Unidirectional TVS three productions technique: knife scraping method, electrophoresis, light blockage method, technical difficulty, product quality successively increase, but
Whole technical difficulty is still relatively low, and investment is low, upper amount is rapid, and as the market demand increases, a large amount of workshop-based producers enter, and makes
Supply exceed demand for product, this just needs a kind of efficient unidirectional TVS chip preparing process of high yield, and this programme is related to a kind of use
The method that printing technology makes unidirectional TVS chip, including silicon wafer pretreatment, secondary diffusion making herbs into wool, the blunt printing drawing of glass, metallization
With the several steps of testing, sorting, cleaned after cleaning, annealing, annealing after specially DW is sliced, silicon wafer sorts, diffusion pre-treatment, phosphorus
Diffusion, single side sanding, boron diffusion, making herbs into wool, print glue, trench etching, LPCVD deposition SIPOS, print glass paste, glass firing,
LPCVD deposits SiO2, print glue, removal SiO2With SIPOS, metallization, test, diamant scribing, sort, be packed and stored.Wherein silicon
The silicon wafer that piece raw material are obtained using 5 inch diamond lines slice, compared with original technique, silicon wafer diameter is changed to 5 inch, phase by 4 inch
Chip monolithic with size goes out core number and increases to original 1.5 times, and single branch chip cost is at low cost, and silicon wafer by being ground originally
Be changed to DW slice, save silicon wafer cutting after grinding, cleaning process, simplify processing step, improve silicon wafer yield, reduce silicon wafer at
This.
One, silicon wafer pre-processes
The silicon wafer obtained by diamond line slice is pre-processed, impurities on surface of silicon chip is cleared up, and removes surface damage
Traumatic part point, specifically includes the following steps:
A slice cleaning: making silicon wafer by cleaning solution, carry out alkali process and nitric acid treatment cleaning silicon chip metallic contaminants from surface,
Wherein sodium hydroxide solution can be used in alkali process, and cleaning silicon chip is stained after annealing in order to prevent.
B annealing: being annealed using automatic sheet-feeding system, liberates manpower, and annealing process is intended to eliminate oxygen donor pair resistance
The influence of rate.
It cleans after C annealing: being corroded using hydrofluoric acid, to remove the oxide layer that annealing rear surface is formed.
Two, secondary diffusion making herbs into wool
Phosphorus diffusion is to carry out phosphorus diffusion by the way that phosphorus source is deposited on after silicon chip surface with nitrogen carrying phosphorus oxychloride mode, single
Face sanding process is that any one side after phosphorus diffusion carries out single side sanding, and boron diffusion source is that silicon wafer is coated in a manner of printing
Boron face to be expanded places the coated silicon wafer of multi-disc in a manner of forward lamination, carries out high temperature negative pressure diffusion technique.The PN of production
Uniformly, source situation is returned in mitigation to knot, improves diffuser efficiency, improves conductive wafer rate, and in silicon chip surface making herbs into wool, is mentioned for the blunt module of glass
For basis, specifically includes the following steps:
The sorting of D silicon wafer: the silicon wafer after cleaning is screened by integrated machine for sorting, to detect the ginseng of appearance and resistivity
Number standard carries out mark and inserts indigo plant, sub-elects the silicon wafer of qualified quality.
E spreads pre-treatment: silicon wafer is placed in 0-15 DEG C of corrosive liquid and corrodes 9-50s, carry out silicon wafer two-sided thinned,
Silicon wafer thickness is changed to 10-20 μm, cleans corrosive liquid after corrosion, the silicon wafer after being thinned is placed in lye
Silicon wafer is put into progress spilling water cleaning in pure water after the completion, removes the lye of silicon chip surface, then is placed in acid solution and carry out acid by reason
Processing also passes through the acid solution of spilling water cleaning removal silicon chip surface, the water and other impurities of drying removal silicon chip surface.
Wherein corrosive liquid is by nitric acid: hydrofluoric acid: glacial acetic acid: pure water 12: 6: 6: 1 mixes, which can be fine
To silicon wafer carry out corrosion thinning.
F phosphorus diffusion: since unidirectional TVS chip requires concentration high phosphorous diffusion source, the concentration that printing technology does not reach requirement,
The silicon wafer to phosphorus diffusion is pushed into when diffusion furnace furnace temperature reaches 1000 DEG C so silk-screen printing technique is not used to apply phosphorus source
Flat-temperature zone is carried after phosphorus source is deposited on silicon chip surface by phosphorus oxychloride mode with nitrogen when temperature rises to 1200 DEG C and carries out phosphorus diffusion
It comes out of the stove after 2 hours；
G single side sanding: it is carried out with any one side of the chain type sand shaker in the case where pressure is 0.12~0.14mpa after phosphorus diffusion
Single side sanding, is cleaned after sanding by 15~20 μm of sanding removal amount；
H prints boron diffusion source: being expanded using sanding face printing boron of the silk-screen printing technique to the cleaned silicon wafer of sanding
Source is dissipated, often prints and is both needed to silicon wafer and is placed in baking oven, diffusion source is dried, drying time 1-30min, drying temperature is
150~180 DEG C, upper Al2O3 powder or silicon powder are sprayed into silicon wafer two sides after the completion of baking, by silicon wafer, opposite lamination fills boat two-by-two,
It is i.e. that silicon wafer boron source face is opposite with boron source face, lamination is carried out by phosphorus source face is opposite with phosphorus source face, is put into silicon carbide boat after lamination,
And baffle is placed in carbonization boat front-rear position, silicon wafer is compressed.
I diffusion: negative pressure diffusion, generally 10-101Kpa, diffusion furnace will be carried out in diffusion furnace mounted in the silicon wafer of carbonization boat
Temperature rises to 1300 DEG C of progress constant temperature diffusions by 650 DEG C, and constant temperature time 5-10h makes silicon chip surface form uniform PN junction.
J diffusion post-processing:
If making herbs into wool uses wet-method etching, post-processing is spread are as follows:
Silicon wafer after diffusion is placed in hydrofluoric acid and is diffused post-processing, silicon wafer is washed by water after separating and steamed using high-temperature water
Gas and hydrofluoric acid mixture clean the surface remove silicon chip surface phosphorus, Pyrex after diffusion.
If making herbs into wool uses laser making herbs into wool, post-processing is spread are as follows:
Silicon wafer after diffusion is placed in glass erosion liquid and is diffused post-processing, soaking time 0.5-4h；It is ultrasonic clear
Wash 5-30min；One time spilling water cleans 5-30min；Nitric acid cleans 5-30min；The cleaning of level Four spilling water is 5-30min；Dryer
Drying.
Glass erosion liquid is that example is 6-10 by volume for hydrofluoric acid ammonium, oxalic acid, ammonium sulfate, glycerol, barium sulfate and hot pure water:
The solution that the ratio of 8-15:20-30:4-15:10-22:110-120 is mixed to form.
K making herbs into wool:
Wet-method etching: being respectively configured level-one cleaning solution, second level cleaning solution and three-level cleaning solution, and by treated, silicon wafer exists
3-10min is placed in 50-70 DEG C of level-one cleaning solution, bath cleaning 10-20min moves again to 70-90 DEG C of second level cleaning solution
Middle placement 20-30min, bath cleaning 10-20min, moves again in third cleaning solution and places 3-10min, bath cleaning 10-
20min tests silicon chip surface roughness after rinsing well.
Wherein level-one cleaning solution is that the potassium hydroxide solution that hydrogen peroxide, pure water and mass fraction are 30% is according to volume ratio
The solution that 6~10:110~120:1~8 ratio is mixed to form；
Second level cleaning solution be mass fraction be 10~30% potassium hydroxide solution, flocking additive and pure water according to volume
Than the solution being mixed to form for 0.35~0.42:0.04~0.09:5~10 ratio；
It according to volume ratio is 10~15:30~40:60~80 ratio that three-level cleaning solution, which is by hydrofluoric acid, hydrochloric acid and pure water,
The solution being mixed to form.
Laser making herbs into wool: being scanned silicon chip surface using laser, the spot diameter control that laser device laser light beam is formed
For system at 10-80 μm, laser beam successively carries out multiple transversal scanning in a longitudinal direction, is formed together in silicon chip surface
Track is scanned, silicon wafer two sides all carries out laser scanning；It is clear that two-stage spilling water is carried out using acid solution soaking and washing, after acid solution cleaning
It washes and dries, the acid solution applied here is hydrofluoric acid solution cleaning；The cleaning of two-stage spilling water；Drying.
When laser scanning, laser used is infrared laser, is also possible to other lasers, and infrared laser swashs
Light frequency is 0.1MHz-1MHz, power 10-50W, and the scanning speed of laser is 3-40m/s so that silicon chip surface roughness by
0.3m is improved to 0.5-1.5 μm；And laser scanning is not by environmental restrictions.
Compared with traditional handicraft, this programme applies boron face in silicon wafer using silk-screen printing technique and prints boron diffusion source, so that silicon
The coating process in chip liquid source is simplified, and the process-cycle is reduced；Work is spread using a negative pressure after liquid source coating
Skill mitigates silicon chip edge and returns source situation, and the diffusion process steps simplify, and improve diffuser efficiency；Enable to the PN of production
Knot is uniform, so that the processing cost of silicon wafer reduces；Traditional dry method sanding is substituted using wet-method etching or laser making herbs into wool, so that silicon
Worm channel shape flannelette is made in piece surface, improves the adhesive force of subsequent printing wax and silicon chip surface.
Three, the blunt printing drawing of glass
Oxide layer plays the role of shielding in original technique, for electrophoresis process, have the electrode surface electrophoresis of oxide layer not on
Glass, do not aoxidize in the groove of layer region can glass on electrophoresis, play the role of passivation protection diffusion junction depth after firing；In we
In case, printed glass replaces electrophoresis process after corrosion, and directly printed glass, electrode surface do not need oxide layer in the trench, therefore
The step of being compared with traditional handicraft, dispensing oxidation, photoetching, development gum, thus reduce the use of coordinative solvent reagent, this
Scheme replaces the hazardous chemicals (such as: acetone, gold potassium cyanide) such as organic and cyanide, so that the safer environmental protection of this technique；It adopts
With the groove production method of first laser slotting trench etching again, the time of groove production is greatly shortened, improves unidirectional TVS production effect
Rate.Specifically includes the following steps:
L print protective glue: printing protective glue include upper piece, mark face identification, overturning silicon wafer, silicon wafer perfecting protective glue and
Several steps are toasted, silicon wafer is two-sided to print protective glue by silk-screen printing technique, and it prepares for trench etching below, makes figure,
Not corrosion area is protected, avoids eroding the place that corrode when trench etching.
Wherein protective glue is acidproof wax, and the main component of acidproof wax includes: butoxy ethanol, talcum powder, does not contain stone
Cotton fiber, acetic acid -2- (2- ethoxy ethoxy) ethyl ester.
Specific steps are as follows:
Upper piece, upper piece purpose is while to carry out appearance detection in order to which product is transmitted to printing place from basket, is preferably made
Carry out upper piece with manipulator.Upper piece place is equipped with visual examination station, rejects bad, damaged silicon wafer, and visual examination is complete by pure road
It is changed to extra quality road.Buffered station is had enough to meet the need in upper piece place's addition, guarantees that not fracture, preferably buffered station have 50-100 piece when silicon wafer basket has enough to meet the need
The buffer capacity of silicon wafer.
The identification of mark face, is identified using mark face of the picture system to silicon wafer.
Silicon wafer is overturn, realizes the arrangement turn over function of silicon wafer, 180 degree is overturn, mark is placed up.
Silicon wafer perfecting protective glue is prepared for trench etching below, and avoiding eroding when trench etching corrode
Place, positioning device is equipped with before printing machine platform, guarantees that silicon wafer is corresponding with template.Specifically include: reverse side print protective glue, drying,
Turn-over, front print protective glue, drying.Wherein the step of positive and negative print protective glue is equal are as follows: 1, two panels silicon wafer is placed on by suction piece device
On slide holder, position of silicon wafer is adjusted in alignment of taking pictures；2, ink-retruning blade feed back presses downwards forward to initial position, scraper is printed
Slurry is pushed, printing end position is reached, scraper lifts；3, product after printing is gone at outflow；4, it will be produced by suction piece device
Product are placed on conveyer belt.It requires to continue feed supplement in printing process in entire printing process；Before print protective glue in transmit process
Increase automatic collecting device, discharge to form interlocking with front end, front end stops discharging after material stock is full.
Baking step is to achieve the purpose that toast printing slurry by high temperature chain examination furnace by product, according to the technological requirements, is printed
The difference of the parameters such as the furnace temperature of material and chain examination furnace of slurry, silicon wafer is also different in the chain examination baking oven roasting time, and standard is
Product just achievees the effect that drying when going out chain examination furnace, it is high temperature resistant material that chain, which tries conveyer belt in furnace,.
Turn-over carries out 180 degree overturning to the silicon wafer after drying.Settable visual examination station at turn-over operation is examined
The fragment arrisdefect of silicon wafer etc. is bad, and rejects defective products.Turnover buffered station can be also added at turn-over operation, in silicon wafer basket turnover
Guarantee not fracture, preferably buffer capacity of the buffered station with (50~100) piece silicon wafer.It is corresponding that buffered station is had enough to meet the need with upper piece place.
Basket is filled, the silicon wafer by perfecting protective glue and after drying carries out dress basket operation, is convenient for subsequent turnover.Every basket is pressed
Certain quantity fills basket, usually 100/basket.
Baking, in an oven toasts the silicon wafer basket for installing silicon wafer, in order to the further guarantor of drying printing
Protect glue.
M laser slotting: the figure formed according to photoresist is slotted at channel figure, it is therefore an objective to eliminate with laser
Burrs on edges caused by glue is printed, while subsequent trench corrosion rate can be accelerated；Specially laser is scanned in silicon chip surface, to silicon
The exposed locations that piece does not print protective glue carry out calcination, achieve the purpose that fluting.
N trench etching: by corrosion, the groove shape and depth removed photoresist with cleaning operation corrosion demand；Wherein corrosion is adopted
Corroded with nitration mixture, nitration mixture is nitric acid: hydrofluoric acid: acetic acid is mixed for 6:4:1, including acid corrosion and acid cleaning, obtains groove
The nitration mixture that silicon chip surface after trench etching carries is rinsed well after shape；Again by (5%~10% KOH solution alkali cleaning
Process removes photoresist, removes the soda acid cleaning agent and impurity of silicon chip surface, miscellaneous liquid by cleaning step.
O LPCVD deposits SIPOS: promoting channel bottom to grow polycrystalline passivation layer by LPCVD technology.
P prints glass paste: with silk-screen printing technique, printed glass starches passivation layer on silicon wafer, and printing process includes printing twice
Brush is both needed to drying silicon wafer every time after printing.
Wherein glass paste is the slurry for being proportionally mixed to form cellulose, thixotropic agent and glass powder.
The cellulose of 2~4g, 30~60min of heating stirring are added in the butyl carbitol of 100ml；Next addition 0.5~
1.5% thixotropic agent, 30~60min of heating stirring；Finally 30~60min of glass powder uniform stirring of 150~220g of addition is
Glass paste is made.
Printed glass slurry passivation layer include upper piece, one-step print, drying, secondary printing, drying, dress the several steps of basket, tool
Body is as follows:
Upper piece use manipulator upper piece, upper piece place also be provided with visual examination station and turnover buffered station.
Before the print station of one-step print be equipped with positioning device, for transmission come silicon wafer position, guarantee silicon wafer with
Template is corresponding.Once, the purpose of secondary printing is printed glass slurry passivation layer, is specifically included:
Two panels silicon wafer is placed on slide holder by a by suction piece device, alignment of taking pictures, and adjusts position of silicon wafer 1 under web plate
~3mm, i.e. version spacing are 1~3mm, and ensure silicon wafer horizontal in suitable printing position；
B ink-retruning blade feed back is contacted to initial position, the downward pressure testing of scraper (preferred scraper moves down 1~3mm) is printed
Web plate upper surface pushes forward slurry, and after reaching printing end position, scraper is lifted；Wherein preferably print each parameter area
As follows: the power that printing equipment gives scraper is (30~120) N, and print speed printing speed is (50~300) mm/S, scraper and silicon wafer plane
Angle be 40 °~90 °, the material hardness of scraper itself is between (40~80) HRC；
C goes to product after printing at outflow, and product is placed on conveyer belt by suction piece device.
It needs to continue feed supplement during one-step print and secondary printing；Increase automatic material receiving dress before printing in transmit process
It sets, discharges to form interlocking with front end, front end stops discharging after material stock is full.
The purpose of drying is that the passivation layer of printing is dried, and product is dried by high temperature chain examination furnace, root
Required according to technique, the difference of the parameters such as furnace temperature of the material of printing passivation layer and chain examination furnace, silicon wafer chain examination baking oven it is roasting when
Between it is also different, standard is that product just achievees the effect that drying when going out chain examination furnace, and it is high temperature resistant material that chain, which tries conveyer belt in furnace,.
Dress basket: the silicon wafer after drying is transferred in silicon wafer basket, in order to subsequent turnover, preferably 100/basket.
The firing of Q glass: the silicon wafer for printing glass passivation layer is entered into firing furnace firing, glass is made to be changed into glass by powdered form
Glass state, and remove the organic matter in glass paste.
R LPCVD deposits SiO2: SiO is precipitated by LPCVD technology2, oxidation ring is made at glass passivation layer edge.
S prints wax: by screen printing technique in the face P printing lithographic glue, as corrosion-resistant protection wax, process is the same as step J.
T removes SiO2And SIPOS: SiO is removed with hydrofluoric acid and nitration mixture respectively2And SIPOS, remove electrode surface oxide layer
(SiO2) and SIPOS and retain the oxide layer (SiO on passivation glass2) and SIPOS.
Four, it metallizes
Plating nickel gold is carried out in silicon chip surface, progress nickel plating twice is once gold-plated altogether, and plating nickel gold makes silicon wafer electrode surface plating metal
Layer is conducive to rear road welding.
U first passes through chemical method and plates a nickel in silicon chip surface, carries out nisiloy sintering using chain-type sintering furnace after nickel plating, burns
Secondary nickel chemically is plated in the sintered silicon chip surface of a nickel again after knot, followed in turn by chemical method after secondary nickel plating
Silicon chip surface it is gold-plated (silver-plated).
10~30min of silicon wafer is impregnated with ammonium fluoride etchant, removes the oxide layer of silicon chip surface, then after removing oxide layer will be removed
Silicon wafer carry out ultrasonic overflow cleaning in the sink；Silicon wafer cleans surface with 5% hydrofluoric acid solution, then clear with pure water
Wash off the hydrofluoric acid on surface；Silicon wafer is impregnated with activating solution, makes silicon chip surface atom activation, clear water cleans after activation；Silicon wafer is soaked
It steeps and carries out nickel plating in 60~100 DEG C of temperature, 7~10 nickel-plating liquid of pH value, shaking the gaily decorated basket keeps its reaction uniform；At 500~650 DEG C
Under silicon wafer is sintered, make nickle atom to spreading inside silicon, nickel layer be combined with each other with silicon layer；Silicon wafer is carried out clearly with nitric acid
It washes, removal surface is by high-temperature oxydation part, and then pure water cleans；Silicon wafer is impregnated with activating solution, makes silicon chip surface atom activation, so
Pure water cleans afterwards；Secondary nickel plating is carried out, silicon wafer is soaked in 60~100 DEG C of temperature, nickel plating is carried out in alkaline nickel-plating liquid, shakes flower
Basket makes its reaction uniformly, and then pure water cleans；With salt acid soak silicon wafer, cleaning neutralizes surface alkalinty residual, then clear with pure water
It washes；Silicon wafer is soaked in 60~100 DEG C of temperature, carried out in acid silver plating liquid it is gold-plated, shake the gaily decorated basket make its reaction uniformly, thus complete
At surface metalation.
Five, testing, sorting
Unidirectional TVS chip is measured by testing, sorting and prepares yields, and defective products is rejected, high-quality chip is filtered out.
V test: the electrically bad core of test carries out getting label ready, rejects electrical defective products, wherein being arranged or being visited using probe needle
The test of needle dials can once test 50~1000 chips, and substitution tradition, which is taken a sample test, gets test ready with single needle.Product is uploaded into survey
Testing needle is lined up needle row or needle plate, contacts with silicon wafer, test electrical performance, carried out with the testing standard set in advance by test-run a machine
It compares, bad core particles is stamped into ink dot
W diamant scribing: chip will be cleaved into the size of needs with high speed diamant cutting mode.
X sliver: silicon wafer passes to sliver region along belt, and automatic sliver stick respectively rolls one time along vertical and horizontal direction, makes chip point
From.
Y sorting: core particles pass to sorting panel region along belt, using CCD technology automatic identification tailing and defective products into
Row removal, and non-defective unit is collected.
Since unidirectional TVS chip requires concentration high phosphorous diffusion source, the concentration that printing technology does not reach requirement, so not adopting
Phosphorus source is applied with silk-screen printing technique, boron diffusion source is printed in silicon wafer boron face to be coated using silk-screen printing technique, so that silicon wafer liquid
The coating process in source is simplified, and the process-cycle is reduced；Negative pressure diffusion technique is used after liquid source coating, mitigates silicon wafer
Edge returns source situation, and the diffusion process steps simplify, and improve diffuser efficiency, so that the PN junction of production is uniform, so that silicon wafer
Processing cost reduce, traditional dry method sanding is substituted using wet-method etching or laser making herbs into wool so that silicon chip surface be made worm channel
Shape flannelette increases the roughness of silicon chip surface, conducive to the coating of the blunt technique protective layer of the subsequent glass of silicon wafer, so that in the blunt technique of glass
Adhesive force increases when protective layer coats；Glass blunt process reduces oxidation, photoetching, development, gum compared with conventional method,
The use of coordinative solvent reagent is reduced, this programme replaces the hazardous chemicals such as organic and cyanide (such as: acetone, aurous cyanide
Potassium) so that the safer environmental protection of this technique.
As used some vocabulary to censure specific components in the specification and claims.Those skilled in the art answer
It is understood that different manufacturers may call the same component with different nouns.Present specification and claims not with
The difference of title is as the mode for distinguishing component, but with the difference of component functionally as the criterion of differentiation.Logical
The "comprising" of piece specification and claim mentioned in is an open language, therefore should be construed to " include but do not limit
In "." substantially " refer within the acceptable error range, those skilled in the art can within a certain error range solve described in
Technical problem basically reaches the technical effect.Specification subsequent descriptions are to implement the better embodiment of the application, so described
Description is not intended to limit the scope of the present application still for the purpose of the rule for illustrating the application.The protection scope of the application
As defined by the appended claims.
It should also be noted that, the terms "include", "comprise" or its any other variant are intended to nonexcludability
Include, so that commodity or system including a series of elements not only include those elements, but also including not clear
The other element listed, or further include for this commodity or the intrinsic element of system.In the feelings not limited more
Under condition, the element that is limited by sentence "including a ...", it is not excluded that in the commodity or system for including the element also
There are other identical elements.
One embodiment of the present invention has been described in detail above, but the content is only preferable implementation of the invention
Example, should not be considered as limiting the scope of the invention.It is all according to all the changes and improvements made by the present patent application range
Deng should still be within the scope of the patent of the present invention.
Claims (10)
1. a kind of method for making unidirectional TVS chip using printing technology, it is characterised in that: preparation step includes:
Bis- diffusion making herbs into wool of S1；
The blunt printing drawing of S2 glass；
S3 metallization.
2. a kind of method for making unidirectional TVS chip using printing technology according to claim 1, it is characterised in that: institute
State the secondary diffusion suede of S1 step comprising steps of
S1-1 spreads pre-treatment；
S1-2 phosphorus diffusion；
The diffusion of S1-3 boron；
S1-4 making herbs into wool；
Preferably, the boron is diffused as negative pressure diffusion；
Preferably, the S1-2 step phosphorus diffusion is that phosphorus source is deposited on silicon chip surface by carrying phosphorus oxychloride mode with nitrogen
After carry out phosphorus diffusion；
Preferably, in the S1-3 step boron diffusion, boron diffusion source is that silicon wafer boron face to be expanded is coated in a manner of printing, will be more
The coated silicon wafer of piece is diffused with applying the opposite mode lamination in boron face, described to be diffused as constant temperature diffusion.
3. a kind of method for making unidirectional TVS chip using printing technology according to claim 2, it is characterised in that: institute
Stating further includes step single side sanding between S1-2 step and the S1-3 step, and the single side sanding step is described after phosphorus diffusion
Any one side of silicon wafer carries out single side sanding；
Preferably, the boron face to be expanded is single side sanding face.
4. a kind of method for making unidirectional TVS chip using printing technology according to claim 2, it is characterised in that: institute
Stating S1-4 step making herbs into wool process is wet-method etching or laser making herbs into wool；
Preferably, the wet-method etching includes the cleaning of first order cleaning solution；The cleaning of first order pure water；The cleaning of second level cleaning solution；
The cleaning of second level pure water；The cleaning of third level cleaning solution；The cleaning of third level pure water；
Preferably, the laser making herbs into wool includes laser making herbs into wool；It is cleaned after making herbs into wool: after the silicon wafer wool making, being set to HF solution and impregnate
Cleaning carries out spilling water cleaning and dries after the cleaning of HF solution.
5. a kind of method using printing technology production FRGPP chip according to claim 1, it is characterised in that: described
S2 step glass blunt printing drawing comprising steps of
S2-1, printing protective glue: it is protected when corroding to silicon wafer subsequent trench without erodable section；S2-2, trench etching are opened
Slot: slot treatment is carried out to silicon wafer；S2-3, LPCVD precipitate SiO2: SiO is precipitated by LPCVD technology2, keep electrical parameter more stable；
S2-4, glass firing: glass powder in the passivation layer is solidified by high temperature, is finally reached the effect of passivation；
Preferably, protective glue is printed in the S2-1 step use screen printing technique.
6. a kind of method using printing technology production FRGPP chip according to claim 5, it is characterised in that: described
Printing protective glue is printed on both sides protective glue；
Preferably, the protective glue is acidproof wax.
7. a kind of method using printing technology production FRGPP chip according to claim 5, it is characterised in that: described
S2-2 step trench etching fluting includes laser slotting；Acid corrosion；Acid cleaning.
8. a kind of method using printing technology production FRGPP chip according to claim 1, it is characterised in that: described
S3 step metallization comprising steps of
Nickel plating of S3-1: a nickel is plated in the silicon chip surface；
The sintering of S3-2 nickel: make nickle atom to spreading inside the silicon wafer, nickel layer be combined with each other with silicon layer；
Bis- nickel plating of S3-3: secondary nickel is plated in the silicon chip surface；
S3-4 is gold-plated；It is gold-plated in the silicon chip surface.
9. a kind of method using printing technology production FRGPP chip according to claim 1, it is characterised in that: described
Further include testing, sorting step after S3 step, specifically include: getting test ready；Laser scribing；Automatic sorting；
Preferably, the test specially needle row multiple spot of getting ready gets test ready.
10. a kind of method using printing technology production FRGPP chip according to claim 1, it is characterised in that: described
Silicon wafer diameter is 5 inch, and the silicon wafer is sliced using diamond line.
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| CN113161230A (en) * | 2020-12-14 | 2021-07-23 | 安徽安芯电子科技股份有限公司 | Diffusion process of phosphorus-boron synchronous one-time diffusion graded junction chip |
| CN114023638A (en) * | 2021-11-02 | 2022-02-08 | 扬州虹扬科技发展有限公司 | Method for removing silicon wafer reverse layer after phosphorus diffusion |
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| CN114023638A (en) * | 2021-11-02 | 2022-02-08 | 扬州虹扬科技发展有限公司 | Method for removing silicon wafer reverse layer after phosphorus diffusion |
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| CN109755116B (en) | 2022-09-23 |
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