CN102412500A - Packaging method of semiconductor laser - Google Patents

Abstract

The invention belongs to a manufacturing technique of semiconductor photoelectric devices, and relates to a packaging method for an 850nmVCSEL (vertical cavity surface emitting laser) semiconductor laser. The packaging method of the semiconductor laser comprises: a. pasting a VCSEL chip on a heat sink the surface of which is coated with gold, educing the positive electrode and negative electrode of the chip by virtue of a golden wire bonding technology, then turning the chip over for 90 degrees and fixing the chip; b. keeping the working temperature of the chip of the laser always at the range of 24 DEG C +/-1 DEG C by utilizing the working principle of a refrigerator; c. monitoring the working current of the refrigerator time to time by using a thermistor with a negative temperature coefficient; d. coupling a metallic optical fiber and the chip directly; e. fixing an optical fiber by using a laser welding technology; f. storing a coupling device at high temperature for 8 hours firstly, and then ensuring the release of welding stress through high and low temperature cycling for 24 hours; and g. sealing a device by using a parallel sealing and welding machine. The packaging method provided by the invention has the advantages of high chip light-emitting efficiency, high fiber output power, high production throughout yield, good stability and long service life.

Description

The method for packing of semiconductor laser

Technical field

The invention belongs to the manufacturing technology of semiconductor photoelectric device, relate to the semiconductor laser method for packing that 850nm VCSEL semiconductor laser is carried out encapsulation type.

Background technology

Because the zlasing mode of 850nm VCSEL chip of laser has positive luminous, makes the application of 850nm VCSEL chip of laser be confined to the encapsulation pattern of coaxial laser device for a long time.Because it is little that these characteristics make in the luminous power of monomode fiber coupling, for the fiber power that improves device just becomes one of technological difficulties.

The factor that influences device fiber power has the following aspects:

1, chip of laser is attached on the coaxial base, adds electric current to chip and make it luminous.Increase in time, the heat that chip produces is also along with increase makes the working temperature of chip uprise.The chip operation temperature uprises the luminous efficient in back and will reduce, thus the light intensity decreasing of chip.Because the volume of coaxial base is little. heat conductivility is poor, reduces the chip operation temperature so the heat of chip can not in time distribute.At high temperature work for a long time like fruit chip, and will influence the stability and the useful life of chip light emitting.

2, chip of laser is attached on the coaxial base, can causes the luminous meeting of chip to squint with axis direction by the influence of paster precision.At present automatic placement machine can precision be controlled at ± 5um in, the precision of artificial paster can be controlled at ± 25um in.After chip light emitting squints with axis direction, when carrying out the encapsulation of lens again some light will take place blocked by lens, the luminous part of will losing of chip makes the luminous power that of chip diminish like this.

3, when carrying out lens packages, the pipe cap and the base of band lens are not that absolute vertical also can squint on axis, the bias effect of the paster that adds up again, and bigger skew will take place in the bright dipping optical track of last chip.Use the method for artificial paster at present, every batch of bad ratio that all can occur about 5%.When these bad devices carried out the optical fiber coupling, fiber power was just very little.Even being coupled of having is big, but because the skew of axis makes device when welding, rosin joint can occur, the suffered unbalanced stress of device is spared and is caused the luminous power instability like this.

Summary of the invention

Technical problem to be solved by this invention is; A kind of coupling luminous power that can guarantee 850nm VCSEL laser at monomode fiber is provided, guarantees device stability that works long hours and the semiconductor laser method for packing that improves product first-pass yield in process of production simultaneously.

For realizing above-mentioned purpose, semiconductor laser method for packing of the present invention is:

A. the VCSEL chip is attached on surface gold-plating heat sink, the chip both positive and negative polarity is drawn with the technology of gold wire bonding, fixing 90 ° of chip upsets again;

B. utilize the refrigerator operation principle, make the temperature of chip of laser work remain at 24 ℃ ± 1 ℃ scope;

C. use the thermistor of negative temperature coefficient that the operating current of refrigerator is monitored constantly, ensure that the chip of laser bright dipping is stable;

D. the direct and chip coupling with metallization optical fiber reduces luminous decay and the loss of chip of laser, improves coupling efficiency greatly;

E. with laser welding process optical fiber is fixed;

F. coupled apparatus is carried out 8 hours high temperature storage earlier, carry out the release that laser welding stress was guaranteed in high low temperature circulation in 24 hours again;

G. with parallel welder device is sealed.

The present invention is owing to take above technical scheme, and it has the following advantages:

1, the VCSEL chip is attached to thermal conductivity and does substrate on well heat sink, again substrate is attached on the refrigerator, add that simultaneously thermistor monitors the working temperature of chip.Refrigerator makes the scope of chip operation temperature in the best through the feedback of thermistor like this, thereby it is most effective and stable to reach chip light emitting.

2, directly adopt metallization optical fiber and chip to be coupled, with laser welding process optical fiber is fixed again.Save the loss of the optical efficiency that the pipe cap encapsulation of chip through the band lens bring; Such method has not only improved the fiber power of device; Simultaneously also solved the bad ratio of bringing because of chip paster precision in the production process, thereby made the window of production technology become the big production first-pass yield that improved.

3, components and parts that laser assembly is all are integrated in a housing the inside, drop to minimumly with vacuumizing the moisture content of baking with the housing the inside again, utilize parallel soldering and sealing with housing seal at last.Such method can make chip in a good environment, work, the stability of the chip operation of assurance and the useful life that prolongs chip.

Embodiment

Practical implementation step of the present invention is following:

1, elder generation puts into shell 1 with refrigerator 2, again shell is placed on to heat on the heating platform scolder of refrigerator upper and lower surfaces is dissolved.Then metal heat sink 6 is placed on the refrigerator upper surface, stirs the heat sink even nitrogen blowing of scolder that makes gently, shell is taken off from heating station refrigerator and heat sink and shell are fixed, at last the refrigerator pin is linked to each other with the pin of shell with the metal tweezers.

2, VCSEL chip 4 is attached on the chip heat sink 9 of surface gold-plating, the chip both positive and negative polarity is drawn, be fixed on the chip upset on the metal heat sink for 90 ° again with the technology of gold wire bonding.

3, with thermistor 7 be attached to thermistor heat sink 8 on, sintering is accomplished the connection of each element then with the technology of gold wire bonding with reference to circuit diagram on metal heat sink 6 together.

4, metal optical fiber 5 is penetrated in the shell, use the metallic sheath of high-precision three-dimensional coupling table fiber clamping again, the other end interface of optical fiber links to each other with light power meter.Be inserted in power line on the pin of shell to the chip energising then, then slowly regulate the X of three-dimensional coupling table, Y, the reading of Z axle observation light power meter stops X, Y, the adjusting of Z axle when the reading on the light power meter reaches desirable value.

5, regulate the position of laser welding machine welding gun, make pad carry out laser welding the nickel support 3 of metalloid optical fiber both sides.The reading of observing simultaneously on the light power meter changes, and exceeds required value like variation and then carries out laser and beat the correction of carrying out luminous power and make it to meet the demands.Device after welding is accomplished will be at the test under microscope solder joint, and solder joint can not have rosin joint or leak the weldering phenomenon.

6, the device of passed examination is put into 85 ℃ of baking oven bakings after 8 hours, put into-40 ℃～85 ℃ high-low temperature chamber circulations 24 hours again.

7, device is put into the feeding warehouse of parallel welder, vacuumize earlier again inflated with nitrogen so circulation 3 times carry out 100 ℃ of heating in vacuum after having arranged the aqueous vapor in the feed bin, toasted 12 hours.When treating the vapor content of capping warehouse＜100PPM after baking finishes, the feed hopper inflated with nitrogen is opened door and device is put into the capping storehouse is carried out the capping program.

Claims (1)

1. semiconductor laser method for packing is characterized in that:

A. the VCSEL chip is attached on surface gold-plating heat sink, the chip both positive and negative polarity is drawn with the technology of gold wire bonding, fixing 90 ° of chip upsets again;

B. utilize the refrigerator operation principle, make the temperature of chip of laser work remain at 24 ℃ ± 1 ℃ scope;

C. use the thermistor of negative temperature coefficient that the operating current of refrigerator is monitored constantly;

D. the direct and chip coupling with metallization optical fiber;

E. with laser welding process optical fiber is fixed;

F. coupled apparatus is carried out 8 hours high temperature storage earlier, carry out the release that laser welding stress was guaranteed in high low temperature circulation in 24 hours again;

G. with parallel welder device is sealed.