Background technology
High power device due to during the work time by electric current it is very big, minimal amount of defect is possible to cause device
Failure, it is therefore in its manufacturing process, very high to the quality requirement of raw material.If raw material surface is lacked there are more
It falls into, will result in that device creepage is excessive, blocking voltage is too low.Therefore, after silicon single crystal bar is cut into silicon single crystal disk,
Fine grinding must be carried out, also needs to carry out chemical attack after grinding, further to remove the defect of abradant surface.Silicon single crystal is justified
Requirement of the slice lapping technique to milling apparatus is extremely harsh, should ensure that surface lacks silicon single crystal disk there is no apparent after grinding
It falls into, ensures that the thickness control of silicon single crystal disk has higher precision, in general, the thickness deviation between silicon single crystal disk again
Less than ± 10 microns, therefore, the cost of such equipment is sufficiently expensive, causes that the production cost is very high.
A kind of manufacturing method of traditional power rectifier pipe tube core includes:In silicon wafer surface pre-deposition aluminium impurity;
The yin, yang pole-face of the silicon wafer carries out the knot diffusion deeply of aluminium impurity;Single side is carried out to the cathode plane of the silicon wafer to grind to remove
Extra PN junction;In silicon wafer surface pre-deposition phosphorus impurities;Phosphorus impurities diffusion is carried out in the cathode plane of the silicon wafer;Described
The anode surface of silicon wafer carries out boron impurity diffusion;Aluminium layer evaporates;Alloying;Die-size is cut;Table top moulding and protection;Spoke
According to.In above-mentioned manufacturing process, aluminium pre-deposition technique is adulterated in the very shallow aluminium impurity of the two-sided formation junction depth of silicon wafer, and junction depth is usual
Less than 3 microns, carries out aluminium impurity depth-diffusion process immediately later, positive-negative-positive vertical structure, PN junction depth can be formed in silicon wafer
It is some tens of pm to microns up to a hundred, needs, using the extra PN junction of single side grinding process removal chip cathode plane, silicon chip to be made to form PN
Type vertical structure.
However, the single side grinding process used in above-mentioned manufacturing method can cause silicon wafer surface a large amount of defects or small occur
Crackle, defect can lead to that power rectifier pipe tube core leakage current is bigger than normal, reverse BV is relatively low, reduce the finished product of tube core
Rate, in the tube core course of work, fine crack can constantly increase under effect effect of expanding with heat and contract with cold, and eventually lead to component failure,
Reduce the long-term reliability of tube core.
Invention content
To solve the above problems, the present invention provides a kind of production method of power rectifier pipe tube core, silicon can be avoided
The generation of disk surfaces defect and fine crack, so as to improve the yield rate and reliably and with long-term of power rectifier pipe tube core
Property.
A kind of production method of power rectifier pipe tube core provided by the invention, including:
At least one side of silicon wafer is marked;
Aluminium impurity doping is carried out by aluminium pre-deposition technique on the silicon wafer surface;
The cathode plane of the silicon wafer is corroded, the aluminium impurity of the cathode plane of the silicon wafer is removed;
The knot diffusion deeply of aluminium impurity is carried out in the silicon wafer anode surface.
Preferably, in above-mentioned production method, the minimizing technology of the aluminium impurity of the cathode plane of the silicon wafer is:
Protection is formed to the anode surface of the silicon wafer using Protection glue;
The aluminium impurity of the cathode plane of the silicon wafer is removed using corrosive liquid;
Remove the Protection glue.
Preferably, in above-mentioned production method, the removal depth of the aluminium impurity of the cathode plane of the silicon wafer be 5 microns extremely
10 microns, including endpoint value.
Preferably, in above-mentioned production method, the corrosive liquid is acid corrosion liquid or caustic corrosion liquid.
Preferably, in above-mentioned production method, the Protection glue is photoresist.
Preferably, in above-mentioned production method, the anode surface or cathode plane of the silicon wafer are marked.
Preferably, in above-mentioned production method, using laser marking or machinery carve characters method the silicon wafer at least
It is marked on one side.
Preferably, in above-mentioned production method, aluminium impurity is carried out by aluminium pre-deposition technique on the silicon wafer surface and is mixed
Miscellaneous method is:
The silicon wafer is cleaned and dried;
Using vacuum aluminum pre-deposition diffusion furnace aluminium impurity doping is carried out on the silicon wafer surface.
Preferably, in above-mentioned production method, the method for the aluminium impurity knot diffusion deeply of the silicon wafer anode surface is:
The silicon wafer is cleaned and dried;
Technique diffusion furnace is promoted to carry out the knot diffusion deeply of aluminium impurity to the silicon wafer anode surface using aluminium.
By foregoing description it is found that in a kind of production method of power rectifier pipe tube core provided by the invention, first to silicon
At least one side of disk is marked, so as to the anode surface and cathode plane of silicon wafer can be distinguished in workflow, then in institute
It states silicon wafer surface and aluminium impurity doping is carried out by aluminium pre-deposition technique, the diffusion depth of aluminium impurity is shallower at this time, then to described
The cathode plane of silicon wafer is corroded, and the aluminium impurity of the cathode plane of the silicon wafer is removed, then is carried out subsequent aluminium impurity and tied deeply
Diffusion technique.The processing step for thus effectively avoiding single side mill so as to avoid silicon wafer surface defect and small is split
The generation of line, so as to improve the yield rate and long-term reliability of power rectifier pipe tube core.
Specific implementation mode
Following will be combined with the drawings in the embodiments of the present invention, and technical solution in the embodiment of the present invention carries out clear, complete
Site preparation describes, it is clear that described embodiments are only a part of the embodiments of the present invention, instead of all the embodiments.It is based on
Embodiment in the present invention, it is obtained by those of ordinary skill in the art without making creative efforts every other
Embodiment shall fall within the protection scope of the present invention.
As shown in FIG. 1, FIG. 1 is the application for a kind of production method of power rectifier pipe tube core provided by the embodiments of the present application
A kind of schematic diagram of the production method for power rectifier pipe tube core that embodiment provides.This method comprises the following steps:
S1:At least one side of silicon wafer is marked;
It, cannot be again with the surface polishing scratch situation of silicon wafer due to the step of being ground there is no single side in the embodiment of the present application
Anode surface and cathode plane are effectively distinguished, therefore, it is necessary to the cathode for the tagging chip that before size is cut, takes measures
Face and anode surface can be marked by writing the methods of mark in aluminium electrode, be brought convenience for follow-up work.
S2:Aluminium impurity doping is carried out by aluminium pre-deposition technique on the silicon wafer surface;
In this step, the aluminium impurity doping very shallow in the two-sided formation junction depth of silicon wafer of aluminium pre-deposition technique, junction depth are less than 3
Micron, therefore be easier to remove.It should be noted that step S1 and step S2 can be interchanged, that is to say, that the process of label can be with
It is arranged in before or after aluminium impurity doping process, the present embodiment will not be had an impact.
S3:The cathode plane of the silicon wafer is corroded, the aluminium impurity of the cathode plane of the silicon wafer is removed;
Since the junction depth of the step S2 aluminium impurity doping generated is very shallow, only it need to remove relatively small thickness in this step
Aluminium impurity, greatly reduces the difficulty of removal, and does not interfere with the surface characteristic and flatness of silicon wafer, it is even more important that
It can be thus removed by way of corrosion, thus the defect or split that single side grinding belt comes would not occur in silicon chip surface
Line improves the yield rate of power rectifier pipe tube core so as to ensure the excellent electrology characteristic of power rectifier pipe tube core
And long-term reliability.
S4:The knot diffusion deeply of aluminium impurity is carried out in the silicon wafer anode surface.
In this step, aluminium impurity is advanced into design junction depth, wherein design junction depth according to chip voltage grade and
It is fixed, it is accompanied by oxidation process during this aluminium impurity promotes, grows certain thickness titanium dioxide on silicon wafer surface
Silicon layer, the silicon dioxide layer can be as the masking layers of subsequent technique.
In a kind of production method for power rectifier pipe tube core that above-described embodiment provides, first at least one side of silicon wafer
It is marked, so as to the anode surface and cathode plane of silicon wafer can be distinguished in workflow, it is then logical on the silicon wafer surface
It crosses aluminium pre-deposition technique and carries out aluminium impurity doping, the diffusion depth of aluminium impurity is shallower at this time, then to the cathode plane of the silicon wafer
Corroded, remove the aluminium impurity of the cathode plane of the silicon wafer, removal depth is shallower, then carries out subsequent aluminium impurity knot deeply and expand
Day labor skill.The processing step for thus effectively avoiding single side mill, so as to avoid silicon wafer surface defect and fine crack
Generation, so as to improve the yield rate and long-term reliability of power rectifier pipe tube core.
In above-mentioned production method, the minimizing technology of the aluminium impurity of the cathode plane of the silicon wafer can be preferably:
Protection is formed to the anode surface of the silicon wafer using Protection glue;
The aluminium impurity of the cathode plane of the silicon wafer is removed using corrosive liquid;
Remove the Protection glue.
Above-mentioned preferred embodiment can remove the aluminium impurity of cathode plane in the case where forming effective protection to anode surface.
In above-mentioned production method, the removal depth of the aluminium impurity of the cathode plane of the silicon wafer can be preferably 5 microns
To 10 microns, including endpoint value.Removal depth in compared with the existing technology reaches the single side of even up to a hundred microns of some tens of pm
Mill method, this method can select thinner silicon wafer to make power rectifier pipe tube core, and the cost of raw material of saving can reach
To 15% or so.
In above-mentioned production method, the corrosive liquid can be preferably acid corrosion liquid or caustic corrosion liquid, and the Protection glue can
To be preferably photoresist.This makes it possible under the premise of being effectively protected to anode surface formation, to the aluminium impurity of cathode plane into
The effective quickly removal of row, improves working efficiency.
In above-mentioned production method, preferably the anode surface or cathode plane of the silicon wafer can be marked.As long as
It appoints rule in advance, effectively the anode surface of silicon wafer and cathode plane can be distinguished.Furthermore it is possible to preferred
It is marked in at least one side of the silicon wafer using laser marking or mechanical method of carving characters, this makes it possible to make label more
It is apparent, convenient for identification.
In above-mentioned production method, carrying out the doping of aluminium impurity by aluminium pre-deposition technique on the silicon wafer surface can be excellent
It is selected as:
The silicon wafer is cleaned and dried;
Using vacuum aluminum pre-deposition diffusion furnace aluminium impurity doping is carried out on the silicon wafer surface.
In above-mentioned production method, the method for the aluminium impurity knot diffusion deeply of the silicon wafer anode surface can be preferably:
The silicon wafer is cleaned and dried;
Technique diffusion furnace is promoted to carry out the knot diffusion deeply of aluminium impurity to the silicon wafer anode surface using aluminium.
Further include that phosphorus is pre- after the above step it should be noted that in the method for making power rectifier pipe tube core
Deposition, phosphorus propulsion, boron diffusion, aluminium layer evaporation, alloying, die-size cutting, table top moulding protection and irradiation and etc., due to
These steps are consistent with step in the prior art, therefore repeat no more.
By foregoing description it is found that using the above method, the generation of silicon wafer surface defect and fine crack can be avoided,
So as to improve the yield rate and long-term reliability of power rectifier pipe tube core, in addition, production cost can also be reduced.
The foregoing description of the disclosed embodiments enables those skilled in the art to implement or use the present invention.
Various modifications to these embodiments will be apparent to those skilled in the art, as defined herein
General Principle can be realized in other embodiments without departing from the spirit or scope of the present invention.Therefore, of the invention
It is not intended to be limited to the embodiments shown herein, and is to fit to and the principles and novel features disclosed herein phase one
The widest range caused.