CN202332844U - Special square-type rectification chip for power electronic module - Google Patents

Abstract

The utility model provides a technical scheme of structural design of a special square-type rectification chip for a power electronic module and belongs to the field of semi-conductor technology. Based on the technical scheme, the square-type rectification chips with low cost and high performance, which are is specially used for meeting the assembly requirements of various power electronic modules, can be produced. The square-type rectification chip is structurally characterized in that the chip actually is a production entity consisting of a square-type silicon chip with resistivity of 5-80 Ohm-centimeter, thickness of 190-400 micron and an internal PN junction, a square-type positive electrode, a square-type negative electrode, solder, insulating protection glue.

Description

The special-purpose square rectification chip of electric power electronic module

Technical field

It is special-purpose that the utility model relates to a kind of electric power electronic module assembly, and the structural design of square rectification chip belongs to semiconductor technology.

Background technology

Power electronic product since energy-conservation with can improve automaticity, be called as new high-tech product.On the present power electric component market, the electric power electronic module assembly that adopts various functional chips to be assembled into, because volume is little, function is wide, and is cheap, plurality of advantages such as reliability height obtain application more and more widely.

Electric power electronic module is to rely on its inner all kinds of power electronics functional chips of packing into, decide the electric work of module own can.Power electronics functional chip kind is a lot, but the maximum first-elected rectifier diode chip (abbreviation rectification chip) of consumption comprises common rectification chip and quick rectification chip, nearly 1,000,000,000 of the annual demand in rough estimate China domestic market.Because the electric power electronic module external form is square, so the chip that requires to pack into square preferably can improve the inside modules space availability ratio, increase modular power capacity like this.But owing to making reasons such as square rectification chip difficulty in process and finished product rate are low, China has only circular rectification chip supply in the market.In recent years, existing manufacturer has produced square shape rectification chip as a trial, but the complete foreign imitation product of its product structure.For example: adopt and shine monocrystalline in the top grade, form the potential isolation wall with laser beam perforation, silicon chip surface grooving corrosion moulding utilizes glass passivation protection etc.This structural manufacturing process must dispose expensive tooling device, and technology is long in time limit, and production cost is very high, and its product price is three times of common same specification garden, market shape rectification chip; This structure is also brought a defective that can't overcome, and it can only produce the little chip of the very big positive electrode of negative electricity, and the sense of current just can not assembled simultaneously.The square shape rectification chip that adopts this structural design to produce is difficult to be exclusively used in the production of electric power electronic module.

Summary of the invention

In order to overcome the imitative structural shortcoming of external product; The utility model provides the product structure design technical scheme of the special-purpose square rectification chip of a cover electric power electronic module; Can produce low cost, high performance square rectification chip, be exclusively used in the assembling needs that satisfy all kinds of electric power electronic modules.

Square silicon chip and square positive electrode, square negative electrode, braze, insulation protection glue that the product entity of the square rectification chip that is designed adopts resistivity 5～80 ohmcms, 190～400 microns of thickness, inside to have a PN junction are formed jointly.

Adopting resistivity is that the reason of 5～80 ohmcms is: the relational expression of and silicon chip resistivity withstand voltage about the power electronics chip according to General Electric Apparatus Co.(U.S.A.): withstand voltage=94x resistivity (0.75 power); Resistivity is the rectification chip that the silicon chip of 5～80 ohmcms can produce 300～2500 volts of voltages, is enough to cover whole voltage ranges that electric power electronic module uses.Adopt the reason of the silicon chip of 190～400 microns of thickness to be: the relational expression of depletion layer and resistivity in the root a tree name power electronics chip: depletion layer thickness=4.95x resistivity (0.875 power); Resistivity is the silicon chip of 5～80 ohmcms; Its corresponding depletion layer thickness is 20～230 microns; Add 170 microns of thickness of diffusion layer, so gross thickness is 190～400 microns.For chip has the rectification characteristic of unilateal conduction, use diffusion technique and in silicon chip, form a PN junction.For import, derived current, also in order to support silicon chip, must adopt a positive electrode and a negative electrode, the optional usefulness of its material has better conductive and heat-conductive ability, and the thermal coefficient of expansion metal or alloy close with silicon materials.Soldering is adopted in being connected of positive electrode, negative electrode and silicon chip, and good tin of lubricant nature or aluminum metal are stained with in the braze use.For preventing that high voltage produces electric leakage or gas breakdown phenomenon between positive electrode and the negative electrode, be coated with between two electrodes and apply insulation protection glue.

Mostly the electric power electronic module external shape is square or rectangle, in adorn one to several chips, its rated current has many specifications.The square rectification chip should cooperate the requirement of electric power electronic module to come design shape and size, so, the square rectification chip of the present invention's design, its outward flange shape can be a square, also can be rectangle, the monolateral line length of square is 6～40 millimeters.Can satisfy electric power electronic module about the requirement of rated current from 5 amperes to 500 amperes.

According to the production experience of rectification chip, prove that silicon chip has place, projecting part position electric field and concentrates, electric field strength strengthens, and is directed at product quality and seriously descends with the rate that manufactures a finished product.Be 4 influences that the right angle brought at solution square rectification chip edge, the square silicon chip in the design's the square rectification chip, the arc transition structure is adopted at the position at its 4 angles, edge, and transition arc radius is 1～5 millimeter.

The edge moulding of rectification chip is the place of the key technology in such production always, traditional process using edge angle lapping technique, but be not suitable for the production of square rectification chip.Along with the raising of insulation protection colloidality ability and the continuous progress of acid etch technique, the design's square silicon chip, its edge adopts the modeling structure vertical with the silicon chip plane.The square silicon chip of band transition garden arc can adopt line cutting or laser cutting method, cuts easily and makes.Through test, show that this structure has better reverse hot properties and better forward voltage drop characteristic than traditional garden type rectification chip to the square rectification chip sample produced with the design.

Round or square rectification chip no matter, two electrodes of its yin, yang are anisometric, lower electrode is bigger than normal than silicon chip usually, and upper electrode is less than normal than silicon chip.This structural design mainly is based on following reason: bottom electrode is bigger than normal, helps chip heat conduction; Leaving space between two electrodes, favourable coating insulation protection glue; Arcing distance is far away between two electrodes, helps withstand voltage; The user is prone to differentiate polarity.Tradition garden type rectification chip can only be produced positive electricity greatly (below chip) owing to adopt silicon chip edge angle lap technology, negative electricity minimum (above chip), so-called " positive polarity " chip; And imitative external technology, like the above-mentioned negative electricity greatly (below chip) of can only producing, positive electricity minimum (above chip), so-called " reversed polarity " chip.The design can avoid above two kinds of structural shortcomings owing to adopted silicon chip edge vertical forming structure.The square rectification chip that is designed, its structure can be positive electrode greater than negative electrode, also can be that negative electrode is greater than positive electrode.In other words, the design both can produce what is called " positive polarity " chip, can also produce what is called " reversed polarity " chip.Thoroughly solved the demand of electric power electronic module to the various senses of current and mounting direction.

Description of drawings

Fig. 1 is the utility model product plane figure.

D1 is the top electrode planar dimension, and different according to product electricity rated current, its value is got 4～38mm.D2 is the silicon chip planar dimension, and different according to product electricity rated current, its value is got 5～39mm.D3 is the bottom electrode planar dimension, and different according to product electricity rated current, its value is got 6～40mm.

Fig. 2 is the utility model product profile.

H1 is the silicon wafer thickness size, and different according to product voltage, its value is got 190～400um.H2 is the top electrode gauge, and its value is got 0.2～1mm.H3 is the bottom electrode gauge, and its value is got 0.5～1mm.H is the product thickness overall size, is H1, H2, and the summation of H3 and braze thickness, its value are 1.2～3mm.The peripheral edge portion of silicon chip promptly and between the upper/lower electrode, scribbles insulation protection glue, shown in the J position in the accompanying drawing 2.

That this Figure of description provides is positive square product structure figure, but the extensible rectangle product that is used for.

Embodiment

The utility model technical scheme belongs to the semiconductor technology category, so process implementing is comparatively complicated, below successively narrates as follows respectively by process (operation):

1, buy by setting resistivity, set thickness, set the nickel plating silicon chip of diffusion junction depth and concentration.

2, use wire cutting machine, silicon chip is slit into single silicon chip of square or rectangular of band transition garden arc.

Use wire cutting method, cut single silicon of square or rectangular of band transition garden arc down from big silicon chip, belong to present domestic blank technology, not only speed is fast, work efficiency is high, and accurate especially.This is an advantage of the utility model design.

3, the square of cutting off (or rectangle) silicon and top electrode, bottom electrode are used the anchor clamps clamping, immerse in the high survey pin brazier, be aided with scaling powder, carry out soldering; Or fold between the three into soldering lug and carry out the sintering soldering with vacuum brazing stove.

4, with the mixed liquor corrosion two negative angle table tops of hydrofluoric acid, remove injured layer of machinery and pollutant with addition of nitric acid; After the oven dry, silicon chip edge is coated with and applies the insulating cement protection immediately.

5, product deposits baking oven in, progressively is raised to high temperature from low temperature, and until rated junction temperature, aging certain hour is in order to passivation silicon table top and heavy insulation protection glue, stable prod electrical characteristics.

6, each item electrical characteristics data of measurement products are rejected defective products.

Specification is finished.

Claims (5)

1. the special-purpose square rectification chip of an electric power electronic module; It is characterized in that: square silicon chip and square positive electrode, square negative electrode, braze, insulation protection glue that said chip adopts resistivity 5～80 ohmcms, 190～400 microns of thickness, inside to have a PN junction are formed product entity jointly.

2. rectification chip according to claim 1 is characterized in that: said square rectification chip, its outward flange shape can be squares, also can be rectangles, and the monolateral line length of square is 6～40 millimeters.

3. rectification chip according to claim 1 is characterized in that: the square silicon chip in the said chip, and the arc transition structure is adopted at the position at its 4 angles, edge, and transition arc radius is 1～5 millimeter.

4. rectification chip according to claim 1 is characterized in that: the square silicon chip in the said chip, its edge adopts the modeling structure vertical with the silicon chip plane.

5. rectification chip according to claim 1 is characterized in that: said square rectification chip, its structure can be positive electrode greater than negative electrode, also can be that negative electrode is greater than positive electrode.

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