CN106409772B

CN106409772B - A highly reliable surface mount diode and its preparation method

Info

Publication number: CN106409772B
Application number: CN201611083008.4A
Authority: CN
Inventors: 张宝财; 迟鸣; 迟一鸣; 李东华; 马捷; 侯杰
Original assignee: JINAN SEMICONDUCTOR RESEARCH INSTITUTE
Current assignee: JINAN JINGHENG ELECTRONICS CO Ltd
Priority date: 2016-11-30
Filing date: 2016-11-30
Publication date: 2019-01-22
Anticipated expiration: 2036-11-30
Also published as: CN106409772A

Abstract

The invention provides a highly reliable surface-mounted diode and a preparation method thereof. The diode device uses a metal ceramic shell, a chip is sintered and fixed in the sintering area of the shell by solder, and ultrasonic bonding is used to bond the chip with a bonding wire. The bonding area is connected to the bonding area of the shell and is sealed by parallel seam welding, which overcomes the problem that the original plastic packaged devices cannot be used in the field of high-reliability devices due to the limited working environment. Changing the pad size, that is, in-situ replacement is realized without changing the circuit board, and the reliability is improved, the production and processing technology is relatively simple, and it is convenient for mass production.

Description

Highly reliable surface-pasted diode of one kind and preparation method thereof

Technical field

The present invention relates to technical field of semiconductor encapsulation, more particularly, to a kind of highly reliable surface-pasted diode and its Preparation method.

Background technique

Currently, the fields such as space flight, aviation, ship, weapons largely use the surface mount diode of a constant current or power Device, it is desirable that the features such as thermal resistance is small, impact resistance is good, high reliablity provides premise to improve whole aircraft reliability.

Currently, most of surface-pasted diode component with a constant current or power is Plastic Package.

The semiconductor devices of Plastic Package, is shown in Fig. 1, by plastic packaging material and production technology limited its operating temperature range and Reliability all can not meet the requirement of adverse circumstances, especially be unable to long-term work in the case where moist and salt gas weight, The characteristics of it is encapsulated determines that it cannot be used for highly reliable field.

Therefore, how a kind of high reliablity is provided and production and processing technology is simpler, convenient for the diode of mass production The problem of device is those skilled in the art's urgent need to resolve.

Summary of the invention

The purpose of the present invention is to provide a kind of highly reliable surface-pasted diode, the high reliablity of the diode and life It is simpler to produce processing technology, convenient for producing in enormous quantities.Another object of the present invention is to provide a kind of above-mentioned highly reliable surface The preparation method of mounted diode.

In order to solve the above technical problems, technical solution provided by the invention are as follows:

A kind of highly reliable surface-pasted diode, including for the shell of encapsulation, chip, for the chip to be fixed In the solder on the shell and the bonding wire for connecting the electrode of the electrode of the chip and shell；

The shell includes two pieces of conductive sheets, metal connecting column, base of ceramic, molybdenum sheet, routing piece, becket frame and gold Belong to cover board；

The pit for placing the chip, the interior bottom of the pit are offered on the portion of upper surface of the base of ceramic The first connecting hole is offered on face, and the second connecting hole, the base of ceramic are offered on the remaining upper surface of the base of ceramic Surrounding side on be provided with side metal layer；

The molybdenum sheet is fixed on the first company in the pit on the base of ceramic and in the covering pit by soldering Connect hole；

The routing piece is fixed on the remaining upper surface of the base of ceramic by soldering and covers second connection Hole；

The conductive sheet is fixed on the bottom surface of the base of ceramic by soldering；

Metal connecting column, and the upper end of the metal connecting column in first connecting hole are provided in first connecting hole With the lower surface soldering connection of the molybdenum sheet, the lower end of the metal connecting column in first connecting hole and one piece of conductive sheet Upper surface soldering connection；

Metal connecting column, and the upper end of the metal connecting column in second connecting hole are provided in second connecting hole With the lower surface soldering connection of the routing piece, the lower end of the metal connecting column in second connecting hole with led described in another piece The upper surface soldering connection of electric piece；

The becket frame is fixed at the surrounding edge on the upper surface of the base of ceramic by soldering；

The metal cover board is fixed on the upper surface of becket frame opening by parallel seam welding sealing；

The chip is sintered to fix on the molybdenum sheet by solder；

One end of the bonding wire is connect with the bonding region of the chip, and the other end of the bonding wire and the shell In routing piece connection.

Preferably, the back side of the chip is provided with three layers composite metal layer, from inside to outside successively titanium-nickel-silver, described The front of chip is aluminium layer, and the thickness of the aluminium layer is greater than 2 microns.

Preferably, the solder is slicker solder silver solder.

Preferably, the bonding wire is aluminium wire, and diameter is 250 μm.

Present invention also provides a kind of preparation methods of above-mentioned highly reliable surface-pasted diode, including following step It is rapid:

1) chip is sintered:

After die Bonder temperature is stablized, sufficiently connect with the preheating zone of sintering furnace with sintering zone respectively with the temperature measuring head of point thermometer Touching controls preheating zone and sintering zone surface temperature in process conditions prescribed limit；

Then shell is taken out from nitrogen cabinet, is then started to supply hydrogen and nitrogen into sintering furnace, is controlled hydrogen flowing quantity For 600mL/min ± 100mL/min, nitrogen flow is 5L/min ± 1L/min；

It takes a shell to put to preheating zone and carries out the pre-heat treatment, control preheating zone surface temperature is 200 DEG C ± 5 DEG C, preheating Time is 4min~6min；

Then shell is put to sintering zone and is sintered, control sintering zone surface temperature is 400 DEG C ± 10 DEG C, sintering Time is not more than 2min；

Then welding wire is picked up, makes the molybdenum sheet of wire tip contact shell, wire tip melted by heat is at solder droplets in shell Molybdenum sheet on, then chip is lain on solder, moving chip until chip surrounding edge outside it can be seen that solder；

Then bluff piece of going bail for is lain on chip, and it is cold that the shell with chip is then placed on the progress of nitrogen nozzle But, screening glass 2s~3s is then pushed, removes screening glass after cooling 10min；

2) ultrasonic bond

It first passes through ultrasonic bond processing to connect one end of the bonding wire with the routing piece in the shell, then by super The other end of the bonding wire is connect by sound bonding processing with the bonding region of the chip, opposite in control ultrasonic bond processing Ultrasonic power is 100~150W, and opposite ultrasonic time is 150~300ms, and opposite ultrasonic pressure is 20~26gf；

3) parallel seam welding

Metal cover board sealing is fixed on the upper surface of becket frame opening by parallel seam welding, controls spot welding Power is 1400W~1600W, and seam weld power is 1600W~1800W, and seam weld pressure is 0.98N~1.176N, and the pulse period is 90ms~110ms, pulse width are 6ms~10ms, and speed is 2.0mm/s~3.0mm/s；So far diode preparation is completed.

Preferably, the welding wire is slicker solder silver wire, and ingredient is Pb92.5%-Sn5%-Ag2.5%.

Preferably, the bonding wire is aluminium wire, and diameter is 250 μm, and purity is more than or equal to 99.99%.

Compared with prior art, the present invention provides a kind of highly reliable surface-pasted diodes and preparation method thereof, originally Application meets semiconductor devices to the reliability requirement of shell using ceramic and metal package, meets the electricity in semiconductor devices Requirement of the road to sealing and high dielectric withstanding voltage, and structure is simple, and the shell adapts to the envelope of a plurality of types of chips Dress especially needs to be bonded the encapsulation of the chip of more bonding wires or line row or sintering conduction band, metal pottery with big surge current Ceramic shell belongs to leakproofness shell, can solve the moisture sucking problem of plastic packaged device in wet condition, cermet Envelope operating temperature range is wider than plastic packaging, has the operating temperature of the plastic packaged device of a constant current or power requirement general At 85 DEG C hereinafter, and the limit of working temperature range of chip may be implemented in ceramic and metal package；

Chip is sintered to fix on the sintering zone of shell by the application by solder, is carried out using low-temperature alloy solder quick Alloy sintering solves the problems, such as the matched coefficients of thermal expansion between housing base material and chip, cooperates nitrogen in sintering process The control of hydrogen protective atmosphere prevents the appearance of oxide layer, reduces sintering temperature and sintering time to the shadow of product high-temperature behavior It rings；

Plastic packaged device operating temperature be limited reason first is that connected by way of sintering between exit, When temperature change is larger, the thermal expansion coefficient difference of different materials, which generates internal stress, to be discharged, it is easy to chip be caused to damage Hurt and lead to component failure, thus the application by the way of ultrasonic bond with bonding wire the bonding region of chip and the key of shell It closes area to be connected, adopts high-purity aluminium wire ultrasonic bond, bonding wire has certain radian, and material thermal expansion coefficient is different in temperature change The internal stress of generation can discharge, it is ensured that the reliability of semiconductor devices work, while device is carried out before being bonded Plasma cleaning removes chip surface, oxide layer and impurity in wire bonding area, guarantees that contact is reliable between sintering solder joint, To guarantee product long-term reliability；

The mode of parallel seam welding is finally taken to be sealed connected together the becket frame in the cover board and shell in shell, The entirety of a sealing is formed, so that product of the present invention is cavity air locking, for the semitight of plastic device, Quality and reliability are increased dramatically.

To sum up, this application provides a kind of highly reliable surface-pasted diode and preparation method thereof, the diode components Using ceramic and metal package, chip with bonding in such a way that solder is sintered to fix in the sintering zone of shell, using ultrasonic bond The bonding region of chip is connected silk with the bonding region of shell and parallel seam welding seals, and overcomes original plastic packaged device because of work Make environment limited the problem of cannot be used for highly reliable devices field, which makes original circuit not change weldering Disk size, that is, circuit board without modification in the case where realize substitution in situ, and reliability is improved, production and processing technology compared with Simply, convenient for mass production.

Detailed description of the invention

Fig. 1 is the structural schematic diagram of surface pasted plastic packaged device in the prior art；

Fig. 2 is the decomposition texture signal of the shell of the highly reliable surface-pasted diode of one kind provided in an embodiment of the present invention Figure；

Fig. 3 removes the structural schematic diagram of the base of ceramic and becket frame after cover board for the shell in Fig. 2；

Fig. 4 is the schematic cross-sectional view of the highly reliable surface-pasted diode of one kind provided in an embodiment of the present invention；

Fig. 5 is the main view of the diode in Fig. 4；

Fig. 6 is the bottom view of the diode in Fig. 4.

In figure: 1 conductive sheet, 2 metal connecting columns, 3 base of ceramic, 4 molybdenum sheets, 5 routing pieces, 6 becket frames, 7 metal cover boards, 8 second connecting holes, 9 side metal layers, 10 pits, 11 chips, 12 solders, 13 bonding wires.

Specific embodiment

In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is A part of the embodiments of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, ordinary skill people Member's every other embodiment obtained without making creative work, shall fall within the protection scope of the present invention.

In the description of the present invention, it is to be understood that, term " center ", " axial direction ", " radial direction ", " longitudinal direction ", " transverse direction ", " length ", " width ", "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outside", " clockwise ", " inverse The orientation or positional relationship of the instructions such as hour hands ", "vertical", "horizontal" is to be based on the orientation or positional relationship shown in the drawings, and is only For the convenience of describing the present invention and simplifying the description, rather than the device or element of indication or suggestion meaning must have specific side Position is constructed and operated in a specific orientation, therefore is not considered as limiting the invention.

In the present invention unless specifically defined or limited otherwise, fisrt feature second feature "upper" or "lower", It may include that the first and second features directly contact, also may include that the first and second features are not direct contacts but pass through it Between other characterisation contact.Moreover, fisrt feature includes the first spy above the second feature " above ", " above " and " above " Sign is in the surface and oblique upper of second feature, or is merely representative of first feature horizontal height higher than second feature.First is special Sign includes fisrt feature in the underface and obliquely downward of second feature under the second feature " below ", " below " and " below ", or only Only indicate that first feature horizontal height is less than second feature.

Referring to Fig.1~Fig. 6, Fig. 1 are the structural schematic diagram of surface pasted plastic packaged device in the prior art；Fig. 2 is the present invention The decomposition texture schematic diagram of the shell for the highly reliable surface-pasted diode of one kind that embodiment provides；Fig. 3 is the shell in Fig. 2 The structural schematic diagram of base of ceramic and becket frame after removing cover board；Fig. 4 is that one kind provided in an embodiment of the present invention is highly reliable The schematic cross-sectional view of surface-pasted diode；Fig. 5 is the main view of the diode in Fig. 4；Fig. 6 is two poles in Fig. 4 The bottom view of pipe.

This application provides a kind of highly reliable surface-pasted diode, including for encapsulation shell, chip 11, be used for By solder 12 that the chip 11 is fixed on the shell and it is used to connect at the electrode of the electrode of the chip 11 and shell The bonding wire 13 connect；

The shell includes two pieces of conductive sheets 1, metal connecting column 2, base of ceramic 3, molybdenum sheet 4, routing piece 5, becket frame 6 And metal cover board 7；

The pit 10 for placing the chip 11, the pit are offered on the portion of upper surface of the base of ceramic 3 The first connecting hole is offered on 10 inner bottom surface, and the second connecting hole 8, institute are offered on the remaining upper surface of the base of ceramic 3 It states and is provided with side metal layer 9 on the surrounding side of base of ceramic 3；

The molybdenum sheet 4 is fixed in the pit 10 on the base of ceramic 3 and is covered in the pit 10 by soldering First connecting hole；

The routing piece 5, which is fixed on the remaining upper surface of the base of ceramic 3 by soldering and covers described second, to be connected Connect hole 8；

The conductive sheet 1 is fixed on the bottom surface of the base of ceramic 3 by soldering；

Metal connecting column 2 is provided in first connecting hole, and the metal connecting column 2 in first connecting hole is upper End and the lower surface soldering connection of the molybdenum sheet 4, the lower end of the metal connecting column 2 in first connecting hole with led described in one piece The upper surface soldering connection of electric piece 1；

It is provided with metal connecting column 2 in second connecting hole 8, and the metal connecting column 2 in second connecting hole 8 The lower surface soldering connection of upper end and the routing piece 5, the lower end of the metal connecting column 2 in second connecting hole 8 with it is another The upper surface soldering connection of conductive sheet 1 described in block；

The becket frame 6 is fixed at the surrounding edge on the upper surface of the base of ceramic 3 by soldering；

The metal cover board 7 is fixed on the upper surface of the becket frame 6 opening by parallel seam welding sealing；

The chip 11 is sintered to fix on the molybdenum sheet 4 by solder 12；

One end of the bonding wire 13 is connect with the bonding region of the chip 11, and the other end of the bonding wire 13 and institute The routing piece 5 stated in shell connects.

In one embodiment of the invention, the back side of the chip 11 is provided with three layers composite metal layer, from it is interior to Successively titanium-nickel-silver, the front of the chip 11 are aluminium layer outside, and the thickness of the aluminium layer is greater than 2 microns.

In one embodiment of the invention, the solder 12 is slicker solder silver solder.

In one embodiment of the invention, the bonding wire 13 is aluminium wire, and diameter is 250 μm.

1) chip is sintered:

Then welding wire is picked up, makes the molybdenum sheet 4 of wire tip contact shell, wire tip melted by heat is at solder droplets in shell Molybdenum sheet 4 on, then chip 11 is lain on solder 12, moving chip 11 is until the outside of surrounding edge of chip 11 can See solder 12；

Then bluff piece of going bail for is lain on chip 11, and the shell with chip 11 is then placed on nitrogen nozzle and is carried out It is cooling, screening glass 2s~3s is then pushed, removes screening glass after cooling 10min；

2) ultrasonic bond

It first passes through ultrasonic bond processing to connect one end of the bonding wire 13 with the routing piece 5 in the shell, then leads to It crosses ultrasonic bond processing to connect the other end of the bonding wire 13 with the bonding region of the chip 11, control ultrasonic bond processing In opposite ultrasonic power be 100~150W, opposite ultrasonic time is 150~300ms, and opposite ultrasonic pressure is 20~26gf；

3) parallel seam welding

The metal cover board 7 sealing is fixed on the upper surface of the becket frame 6 opening, control point by parallel seam welding Weldering power is 1400W~1600W, and seam weld power is 1600W~1800W, and seam weld pressure is 0.98N~1.176N, pulse period For 90ms~110ms, pulse width is 6ms~10ms, and speed is 2.0mm/s~3.0mm/s；So far diode preparation is completed.

In one embodiment of the invention, the welding wire is slicker solder silver wire, and ingredient is Pb92.5%-Sn5%- Ag2.5%.

In one embodiment of the invention, the bonding wire 13 is aluminium wire, and diameter is 250 μm, and purity is more than or equal to 99.99%.

It is highly reliable surface-pasted to one kind provided by the invention below with reference to embodiment for a further understanding of the present invention The preparation method of diode is described in detail, and protection scope of the present invention is not limited by the following examples.

Embodiment 1

A kind of preparation method of highly reliable surface-pasted diode, comprising the following steps:

1) chip is sintered:

Then shell is taken out from nitrogen cabinet, is then started to supply hydrogen and nitrogen into sintering furnace, is controlled hydrogen flowing quantity For 600mL/min, nitrogen flow 6L/min；

It takes a shell to put to preheating zone and carries out the pre-heat treatment, control preheating zone surface temperature is 200 DEG C, and preheating time is 5min；

Then shell is put to sintering zone and is sintered, control sintering zone surface temperature is 410 DEG C, and sintering time is 1.5min；

The welding wire is slicker solder silver wire, and ingredient is Pb92.5%-Sn5%-Ag2.5%.

Then bluff piece of going bail for is lain on chip 11, and the shell with chip 11 is then placed on nitrogen nozzle and is carried out It is cooling, screening glass 3s is then pushed, removes screening glass after cooling 10min；

2) ultrasonic bond

It first passes through ultrasonic bond processing to connect one end of the bonding wire 13 with the routing piece 5 in the shell, then leads to It crosses ultrasonic bond processing to connect the other end of the bonding wire 13 with the bonding region of the chip 11, control ultrasonic bond processing In opposite ultrasonic power be 135W, opposite ultrasonic time is 250ms, and opposite ultrasonic pressure is 25gf；

The bonding wire 13 is aluminium wire, and diameter is 250 μm, purity 99.99%；

3) parallel seam welding

The metal cover board 7 sealing is fixed on the upper surface of the becket frame 6 opening, control point by parallel seam welding Weldering power is 1500W, and seam weld power is 1700W, and seam weld pressure is 1.1N, pulse period 100ms, pulse width 8ms, speed Degree is 2.6mm/s；So far diode preparation is completed.

The method and apparatus of the not detailed description of the present invention are the prior art, are repeated no more.

Principle and implementation of the present invention are described for specific embodiment used herein, above embodiments Illustrate to be merely used to help understand method and its core concept of the invention.It should be pointed out that for the common skill of the art , without departing from the principle of the present invention, can be with several improvements and modifications are made to the present invention for art personnel, these change It is also fallen within the protection scope of the claims of the present invention into modification.

Claims

1. A method for preparing a highly reliable surface-mounted diode, wherein the diode comprises a casing for packaging, a chip, a solder for fixing the chip on the casing, and a solder for fixing the chip on the casing. the bonding wire connecting the electrode of the chip and the electrode of the shell;

The shell includes two conductive sheets, metal connecting posts, ceramic bases, molybdenum sheets, wire-bonding sheets, metal ring frames and metal cover plates;

Part of the upper surface of the ceramic base is provided with a pit for placing the chip, the inner bottom surface of the pit is provided with a first connection hole, and the remaining upper surface of the ceramic base is provided with a second connection hole. a connection hole, and a side metallization layer is provided on the surrounding sides of the ceramic base;

The molybdenum sheet is fixed in the cavity on the ceramic base by brazing and covers the first connection hole in the cavity;

The wire bonding sheet is fixed on the remaining upper surface of the ceramic base by brazing and covers the second connection hole;

The conductive sheet is fixed on the lower bottom surface of the ceramic base by brazing;

The first connection hole is provided with a metal connection post, and the upper end of the metal connection post in the first connection hole is brazed and connected to the lower surface of the molybdenum sheet, and the metal connection post in the first connection hole The lower end of the conductive sheet is brazed and connected to the upper surface of a piece of said conductive sheet;

The second connection hole is provided with a metal connection post, and the upper end of the metal connection post in the second connection hole is brazed and connected to the lower surface of the wire bonding sheet, and the metal connection in the second connection hole is connected. The lower end of the column is connected with the upper surface of the other conductive sheet by soldering;

The metal ring frame is fixed on the four peripheral edges on the upper surface of the ceramic base by brazing;

The metal cover plate is sealed and fixed at the upper opening of the metal ring frame by parallel seam welding;

The chip is fixed on the molybdenum sheet by solder sintering;

One end of the bonding wire is connected with the bonding area of the chip, and the other end of the bonding wire is connected with the wire bonding sheet in the housing;

The preparation method of the diode includes the following steps:

1) Chip sintering:

After the temperature of the bonding machine is stable, use the temperature measuring head of the spot thermometer to fully contact the preheating zone and the sintering zone of the sintering furnace respectively, and control the surface temperature of the preheating zone and the sintering zone to be within the specified range of process conditions;

Then take out the shell from the nitrogen cabinet, and then start to supply hydrogen and nitrogen into the sintering furnace, control the hydrogen flow to be 600mL/min±100mL/min, and the nitrogen flow to be 5L/min±1L/min;

Take a shell and put it in the preheating zone for preheating treatment, control the surface temperature of the preheating zone to be 200℃±5℃, and the preheating time to be 4min-6min;

Then put the shell into the sintering zone for sintering treatment, control the surface temperature of the sintering zone to be 400℃±10℃, and the sintering time is not more than 2min;

Then pick up the welding wire so that the end of the welding wire touches the molybdenum sheet of the shell, and the end of the welding wire is heated and melted into a drop of solder on the molybdenum sheet of the shell, and then the chip is placed flat on the solder, and the chip is moved until the outer edge of the chip can see the solder;

Then take the protective sheet and lay it flat on the chip, then place the shell with the chip at the nitrogen nozzle for cooling, then press down the protective sheet for 2s to 3s, and remove the protective sheet after cooling for 10 minutes;

2) Ultrasonic bonding

First, one end of the bonding wire is connected to the wire bonding sheet in the housing by ultrasonic bonding, and then the other end of the bonding wire is connected to the bonding area of the chip by ultrasonic bonding. Control the relative ultrasonic power in the ultrasonic bonding process to be 100-150W, the relative ultrasonic time to be 150-300ms, and the relative ultrasonic pressure to be 20-26gf;

3) Parallel seam welding

The metal cover plate is sealed and fixed at the upper opening of the metal ring frame by parallel seam welding. The pulse period is 90ms～110ms, the pulse width is 6ms～10ms, and the speed is 2.0mm/s～3.0mm/s; so far, the diode preparation is completed.

2 . The preparation method according to claim 1 , wherein the welding wire is a lead-tin-silver welding wire, and the composition is Pb92.5%-Sn5%-Ag2.5%. 3 .

3 . The preparation method according to claim 1 , wherein the bonding wire is an aluminum wire, the diameter is 250 μm, and the purity is greater than or equal to 99.99%. 4 .

4. The preparation method according to claim 1, wherein the back of the chip is provided with three layers of composite metallization layers, titanium-nickel-silver sequentially from inside to outside, the front side of the chip is an aluminum layer, so the The thickness of the aluminum layer is greater than 2 microns.

5 . The preparation method according to claim 1 , wherein the solder is lead-tin-silver solder. 6 .