CN101872828A

CN101872828A - Packaging method for flip LED chips

Info

Publication number: CN101872828A
Application number: CN 201010204860
Authority: CN
Inventors: 李漫铁; 李志新; 扶韩伟
Original assignee: Ledman Optoelectronic Co Ltd
Current assignee: Ledman Optoelectronic Co Ltd
Priority date: 2010-06-21
Filing date: 2010-06-21
Publication date: 2010-10-27
Anticipated expiration: 2030-06-21
Also published as: CN101872828B

Abstract

The invention relates to a packaging method for flip LED chips, which belongs to the field of LED fabrication. The packaging method at least includes the following steps that: (a) phosphor is coated on the surface of an LED chip by screen printing, and is baked to become solidified; (b) the LED chip is fixed on a chip substrate, so that the electrodes of the LED chip are bonded with the electrodes of the chip substrate; (c) the LED chip and the chip substrate are fixed on a support and the bottom of a reflective cup; (d) wires are utilized to respectively connect the positive and the negative electrodes of the fixed chip substrate with the positive and the negative electrodes of the support; (e) a sealing mould or a lens covers on the support on which the LED chip and the chip substrate are fixed, and silica gel is filled; and (f) the whole structure is backed to become solidified. Since the used LED chip is a flip chip and the phosphor is coated on the surface of the LED chip before the wires are soldered, the product yield can be increased, and the screen printing technique can ensure that the thickness of the coated phosphor is more uniform, so the distribution of phosphor powder particles is more uniform.

Description

A kind of method for packing of flip LED chips

Technical field

The present invention relates to a kind of method for packing of flip LED chips, belong to LED and make the field.

Background technology

The conventional coated technique of fluorescent material mainly contains two kinds on the led chip at present, and first kind of technology is for filling full fluorophor, as shown in Figure 1 in the support bowl cup that will be fixed with led chip, this kind technical maturity is stable, easy to operate, but the fluorophor shape that makes is difficult to control, and consistency is poor, it is yellow dizzy to cause product to present obvious hot spot, divide the distribution of the chromaticity coordinates point between the light time product more diffusing, stepping is more, and product warehousing and sale are brought very big difficulty, and the large usage quantity of fluorophor, waste is serious; Second kind of technology is coating fluorescent powder on led chip only, and as shown in Figure 2, the consumption of the product fluorophor that this kind technology is made is few, fluorescent material launching efficiency height, hot spot improves, but operation inconvenience, surface covered is low, but because led chip is positive cartridge chip, must connect lead earlier, carry out coating fluorescent powder again, otherwise can't welding lead, behind the welding lead again coating fluorescent powder cause lead to cave in easily, cause damage of product, bigger to the influence of the fine ratio of product of product.

Summary of the invention

The technical problem that the present invention mainly solves provides a kind of packaging efficiency height, fluorescent material launching efficiency height, and look district discreteness is little, the method for packing of the uniform flip LED chips of hot spot.

For solving the problems of the technologies described above, the technical solution used in the present invention is: a kind of method for packing of flip LED chips is provided, may further comprise the steps at least:

(a) by silk screen printing fluorophor is coated on the surface of led chip light-emitting area, and fluorophor is carried out baking-curing;

(b) led chip is fixed on the chip substrate, and makes the electrode and the chip substrate electrode bonding at the led chip back side;

(c) led chip and chip substrate are fixed on the cup end of support reflector;

(d) utilize the positive and negative electrode of the chip substrate that lead will fix to be connected with the positive and negative electrode of support respectively;

(e) will seal die cap on the support that is fixed with led chip and chip substrate, be full of the space of sealing between mould and the support with silica gel then, perhaps with lens cover on the support that is fixed with led chip and chip substrate, be full of space between lens and the support with silica gel then;

(f) overall structure is carried out baking-curing.

Wherein, silk screen is to be tightened in the screen printing forme that makes on the screen frame by silk fabrics, synthetic fabrics or woven wire in the described step (a), by the extruding of scraper plate, makes fluorophor transfer to the surface of led chip light-emitting area by mesh during printing.

Wherein, described fluorophor is the mixture of silica gel and fluorescent material.

Wherein, the baking temperature of fluorophor is 40～150 ℃ in the described step (a), and stoving time is 0.5～2 hour.

Wherein, be to utilize gluing mode led chip and chip substrate to be fixed on the cup end of support reflector in the described step (c), and the primer that is arranged on the chip substrate back side carried out baking-curing, described primer is 1/4～1/3 of a chip substrate height, baking temperature is 100～180 ℃, and stoving time is 0.5～5 hour.

Wherein, being the mode of utilizing soldering in the described step (c) is fixed on the cup end of support reflector to led chip and chip substrate, and to or to the curing that refluxes of the tin cream at the chip substrate back side, the thickness of tin cream is 1/4～1/3 of chip substrate height.

Wherein, baking divides secondary to carry out in the described step (f), and baking temperature is 40～150 ℃ for the first time, and stoving time is 0.5～1 hour, and baking temperature is 150 ℃ for the second time, and stoving time is 2～5 hours.

The invention has the beneficial effects as follows: because the led chip that the present invention uses is flip-chip, earlier at led chip surface applied fluorophor, again led chip is fixed on the chip substrate, and the electrode of led chip and chip substrate top electrode bonding, and then welding lead, electrode on the chip substrate is connected with the electrode of support, so can realize applying earlier fluorophor welding lead again, thereby guarantee the bonding point of chip electrode and lead effectively and prevent that lead from caving in, improve the product yield, and the technology that adopts silk screen printing is coated in fluorophor on the surface of led chip, the technology of silk screen printing can make the fluorophor applied thickness more even, so fluorescent powder grain is more evenly distributed, look district delivery rate promotes, and hot spot can well be improved.

Description of drawings

The present invention is described in detail below in conjunction with drawings and Examples.

Fig. 1 is the encapsulating structure schematic diagram of a kind of led chip in the prior art, and Fig. 1 a is the vertical view of encapsulating products, and Fig. 1 b is the front view of encapsulating products;

Fig. 2 is the encapsulating structure schematic diagram of another kind of led chip in the prior art, and Fig. 2 a is the vertical view of encapsulating products, and Fig. 2 b is the front view of encapsulating products;

Fig. 3 is the encapsulating structure schematic diagram of flip LED chips of the present invention, and Fig. 3 a is the vertical view of encapsulating products, and Fig. 3 b is the front view of encapsulating products.

Wherein, 1, support; 11, reflector; 2, led chip; 3, lead; 4, fluorophor; 5, envelope mould; 6, chip substrate; 61, electrode.

Embodiment

By describing technology contents of the present invention, structural feature in detail, realized purpose and effect, give explanation below in conjunction with execution mode and conjunction with figs. are detailed.

Because the concrete structure of flip LED chips has been prior art, publication number is that CN100380694C, denomination of invention have detailed introduction in the Chinese invention patent of " a kind of flip LED method for packing ", so the specific embodiment of the invention only is introduced at the improvement part of flip LED chips method for packing.

Embodiment as the method for packing of flip LED chips of the present invention sees also Fig. 3, may further comprise the steps at least:

(a) by silk screen printing fluorophor 4 is coated on the surface of led chip 2 light-emitting areas, and fluorophor 4 is carried out baking-curing;

(b) led chip 2 is fixed on the chip substrate 6, and makes the electrode and the chip substrate 6 electrode bondings at led chip 2 back sides;

(c) led chip 2 and chip substrate 6 are fixed on the cup end of support 1 reflector 11;

(d) utilize the positive and negative electrode 61 of the chip substrate 6 that lead 3 will fix to be connected with the positive and negative electrode of support 1 respectively;

(e) will seal mould 5 covers on the support 1 that is fixed with led chip 2 and chip substrate 6, be full of the space of sealing between mould 5 and the support 1 with silica gel then, perhaps with lens cover on the support 1 that is fixed with led chip 2 and chip substrate 6, be full of space between lens and the support with silica gel then;

(f) overall structure is carried out baking-curing.

Because the led chip that the present invention uses is flip-chip, earlier at led chip surface applied fluorophor, again led chip is fixed on the chip substrate, and the electrode of led chip and chip substrate top electrode bonding, and then welding lead, electrode on the chip substrate is connected with the electrode of support, so can realize applying earlier fluorophor welding lead again, thereby guarantee the bonding point of chip electrode and lead effectively and prevent that lead from caving in, improve the product yield, and the technology that adopts silk screen printing is coated in fluorophor on the surface of led chip, the technology of silk screen printing can make the fluorophor applied thickness more even, so fluorescent powder grain is more evenly distributed, look district delivery rate promotes, and hot spot can well be improved.

If flip-chip is the surface light emitting device, then the size in the hole on the silk screen led chip size of should just coincideing only needs apply fluorophor, if flip-chip is five surface light-emitting devices on light-emitting area, chip sides also can be installed silk screen, and the method for the coating fluorophor of ipsilateral light-emitting area is basic identical.The silk screen printing fluorophor is more convenient than the method that adopts special mould and utilize the stainless steel scraper at the uniform velocity to scrape, and applies more even.

As second embodiment of the method for packing of flip LED chips of the present invention, the described fluorophor 4 of present embodiment is the mixture of silica gel and fluorescent material, and fluorophor 4 baking temperature preferred values are 40～150 ℃ in the step (a), and stoving time is 0.5～2 hour; Be to utilize gluing mode led chip 2 and chip substrate 6 to be fixed on the cup end of support reflector 11 in the step (c), and the primer that is arranged on chip substrate 6 back sides carried out baking-curing, described primer is 1/4～1/3 of chip substrate 6 height, when primer be chip substrate 6 height 3/10 the time, can well fixed L ED chip 2, and guarantee that led chip 2 and chip substrate 6 well combine with support reflector 11, simultaneously primer can too much not overflow when the expanded by heating because amount and cause the both positive and negative polarity short circuit to led chip 2 surfaces and bright dipping is caused damage, the baking temperature preferred value is 100～180 ℃, and stoving time is 0.5～5 hour; Or the mode of utilizing soldering is fixed on led chip 2 and chip substrate 6 at the cup end of support reflector 11, and to the curing that refluxes of the tin cream at chip substrate 6 back sides, the thickness of tin cream is 1/4～1/3 of chip substrate 6 height, when primer be chip substrate 6 height 3/10 the time, can well fixed L ED chip 2, make led chip 2 and chip substrate 6 well combine with support reflector 11, and guaranteeing that thrust is qualified, tin cream can too much not cause the both positive and negative polarity short circuit and bright dipping is caused damage refluxing to overflow when solidifying because amount to led chip 2 surfaces simultaneously; Baking divides secondary to carry out in the step (f), the baking temperature preferred value is 40～150 ℃ for the first time, stoving time is 0.5～1 hour, the baking temperature preferred value is 150 ℃ for the second time, and stoving time is 2～5 hours, and low temperature advances to bake the bubble that can glue be produced in solidification process for the first time an outside discharging process, thereby minimizing bubble, reduce the silica gel internal stress simultaneously, the long roasting silica gel energy full solidification that makes of the high temperature second time, colloid cohesive force and hardness all can reach desired requirement.

The above only is embodiments of the invention; be not so limit claim of the present invention; every equivalent structure or equivalent flow process of utilizing specification of the present invention and accompanying drawing content to be done; or directly or indirectly be used in other relevant technical fields, all in like manner be included in the scope of patent protection of the present invention.

Claims

1. the method for packing of a flip LED chips is characterized in that: may further comprise the steps at least:

(c) led chip and chip substrate are fixed on the cup end of support reflector;

(f) overall structure is carried out baking-curing.

2. the method for packing of flip LED chips according to claim 1, it is characterized in that: silk screen is to be tightened in the screen printing forme that makes on the screen frame by silk fabrics, synthetic fabrics or woven wire in the described step (a), by the extruding of scraper plate, make fluorophor transfer to the surface of led chip light-emitting area by mesh during printing.

3. the method for packing of flip LED chips according to claim 1, it is characterized in that: described fluorophor is the mixture of silica gel and fluorescent material.

4. the method for packing of flip LED chips according to claim 1 is characterized in that: the baking temperature of fluorophor is 40～150 ℃ in the described step (a), and stoving time is 0.5～2 hour.

5. the method for packing of flip LED chips according to claim 1, it is characterized in that: be to utilize gluing mode led chip and chip substrate to be fixed on the cup end of support reflector in the described step (c), and the primer that is arranged on the chip substrate back side carried out baking-curing, described primer is 1/4～1/3 of a chip substrate height, baking temperature is 100～180 ℃, and stoving time is 0.5～5 hour.

6. the method for packing of flip LED chips according to claim 1, it is characterized in that: be the cup end that the mode of utilizing soldering is fixed on led chip and chip substrate the support reflector in the described step (c), and to or to the curing that refluxes of the tin cream at the chip substrate back side, the thickness of tin cream is 1/4～1/3 of chip substrate height.

7. the method for packing of flip LED chips according to claim 1, it is characterized in that: baking divides secondary to carry out in the described step (f), and baking temperature is 40～150 ℃ for the first time, and stoving time is 0.5～1 hour, baking temperature is 150 ℃ for the second time, and stoving time is 2～5 hours.