CN104465965B - A kind of fluorescent powder film preparation method for white light LEDs wafer-level packaging - Google Patents

Abstract

The invention discloses a method for preparing a phosphor film for white LED wafer-level packaging. First, a polymer film layer is prepared, and a film with uniform thickness is prepared through a casting process, and then micro-nano structures are manufactured on the polymer film; A mixture of different phosphors, organic colloids and additives that change the flow characteristics of the colloids is evenly coated on the polymer film in a vacuum environment to form a multi-layer phosphor layer structure; then it is cured, semi-cured or fluid state after being irradiated with different ultraviolet light Phosphor film for white LED wafer-level packaging. The present invention is conducive to greatly improving the packaging efficiency of LEDs, and because this method realizes the conformal coating of phosphor powder, and the thickness of the phosphor powder layer on the wafer is consistent, it will obtain good spatial color uniformity and overall color temperature consistency. LED white light chips will greatly promote the development and innovation of LED packaging technology.

Description

A preparation method of phosphor film for white LED wafer level packaging

technical field

The invention belongs to the technical field of LED encapsulation, and relates to a method for preparing a phosphor film in the LED encapsulation for realizing the phosphor powder coating process of the LED encapsulation, and is particularly applied to realizing high-power LED wafer-level encapsulation.

Background technique

LED (Light Emitting Diode) is a semiconductor light-emitting device based on the principle of P-N junction electroluminescence. It has the advantages of high electro-optical conversion efficiency, long service life, environmental protection and energy saving, and small size. It is known as the green lighting source in the 21st century. If it can be applied to the field of traditional lighting, it will have a very significant energy-saving effect, which is of great significance in today's increasingly tense global energy sources. With the breakthrough of the third-generation semiconductor material technology represented by nitrides, the semiconductor lighting industry based on high-power and high-brightness light-emitting diodes (LEDs) is rapidly emerging in the world, and is becoming a new economic growth point for the semiconductor optoelectronics industry. There has been a revolution in lighting. Due to its unique advantages, LED has been widely used in many fields. It is considered by the industry to be the main development direction of future lighting technology and has huge market potential.

High-power white LEDs are usually mixed with two-wavelength light (blue light + yellow light) or three-wavelength light (blue light + green light + red light). Currently widely used white LEDs are composed of blue LED chips (GaN) and yellow phosphors (YAG or TAG). In the LED package, parameters such as the geometric shape, concentration and thickness of the phosphor layer seriously affect the important optical properties of the LED such as light extraction efficiency, color temperature, and spatial color uniformity; in order to obtain LED products with good optical properties, the realization process of the phosphor layer is very critical.

The current LED packaging process is to fix the chip cut from the LED wafer on the substrate or bracket, first realize the electrical connection, and then coat the mixture of phosphor powder and epoxy resin or silica gel around the LED chip to form phosphor powder. Floor. Due to the high viscosity of the phosphor powder, the amount of phosphor powder varies greatly between different packaging modules during the process of coating the phosphor powder, resulting in a large change in the light color of the packaged LED product, which affects the consistency of the product. Because when the color temperature exceeds a certain range, the LED product cannot be used, so it also affects the yield of the LED and increases the cost of the product. Moreover, in domestic packaging companies, phosphor glue is generally applied around the LED by dots to form a spherical cap-shaped phosphor shape. This shape will lead to uneven spatial colors of LED products, which will affect the lighting of LED product users. comfortability. At the same time, the efficiency of this single package form is often not ideal. To this end, a new LED phosphor coating process must be developed to overcome the shortcomings of the current packaging process, such as low color temperature consistency, low yield, low spatial color uniformity, and low packaging efficiency.

Contents of the invention

In order to solve the above technical problems, the present invention provides a method for preparing a phosphor film for white LED wafer-level packaging.

The technical solution adopted in the present invention is: a method for preparing a phosphor film for white LED wafer-level packaging, which is characterized in that it includes the following steps:

Step 1: First prepare the polymer film layer, prepare a film of uniform thickness by casting process, and then fabricate micro-nano structures on the polymer film;

Step 2: Apply a mixture of different phosphors, organic colloids and additives that change the flow characteristics of the colloids evenly on the polymer film layer in a vacuum environment to form a two-layer or multi-layer phosphor layer structure;

Step 3: Subsequent to different ultraviolet light irradiation or heating to form a phosphor film in a cured, semi-cured or fluid state for realizing white LED wafer-level packaging.

Preferably, the material of the polymer film layer is polyethylene or polyester resin, and the thickness of the film is 20-100 microns.

As a preference, the manufacturing method of the micro-nano structure on the polymer film adopts a micro-nano processing method, including nanoimprinting method and inkjet printing method.

Preferably, the additive for changing colloidal flow properties is hexachloroplatinic acid.

As a preference, in the two-layer or multi-layer phosphor layer structure, the phosphor layer materials include phosphor materials and colloidal materials; the phosphor materials are photoluminescent materials, specifically YAG, TAG or quantum dot materials ; The colloidal material is epoxy resin, silica gel or spin-on glass; the phosphor layer material is solid, semi-solid or liquid when coated, and the concentration is 0.01g/ml-3g/ml.

As a preference, the mixture of different fluorescent powders, organic colloids and additives that change the flow characteristics of the colloids is uniformly coated on the polymer film layer in a vacuum environment, and the process adopted is a roll-to-roll process, a screen printing process or spin coating process.

Preferably, the thickness of the two or more phosphor layers is 50-250 microns.

The present invention is conducive to greatly improving the packaging efficiency of LEDs, and because this method realizes the conformal coating of phosphor powder, and the thickness of the phosphor powder layer on the wafer is consistent, it will obtain good spatial color uniformity and overall color temperature consistency. LED white light chips will greatly promote the development and innovation of LED packaging technology.

Description of drawings

Accompanying drawing 1: is the schematic diagram of the first embodiment of the present invention;

Accompanying drawing 2: is the schematic diagram of the second embodiment of the present invention;

Accompanying drawing 3: is the schematic diagram of the third embodiment of the present invention;

Accompanying drawing 4: is the schematic diagram of the fourth embodiment of the present invention;

Explanation of symbols in the figure

11. Polyethylene film; 12. Phosphor layer; 21. Polyethylene film; 22. Phosphor layer; 31. Polyester resin film; 32. First phosphor layer; 33. Second phosphor layer; 41. Polyester resin film; 42, the first phosphor layer; 43, the second phosphor layer.

Detailed ways

In order to facilitate those of ordinary skill in the art to understand and implement the present invention, the present invention will be described in further detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the implementation examples described here are only used to illustrate and explain the present invention, and are not intended to limit this invention.

Example 1:

Referring to Fig. 1, in this embodiment, a uniform polyethylene film 11 with a thickness of 35 microns is first prepared by a casting process, and a triangular pyramid structure with a size of 25 microns manufactured by nanoimprinting on the polymer film; 1. The phosphor layer 12 of a mixture of organic colloid and hexachloroplatinic acid is evenly coated on the polyethylene film by a roll-to-roll process in a vacuum environment, wherein the phosphor concentration is 1.0g/ml, and the thickness of the phosphor layer 12 is 150 microns; Finally, a single-layer, liquid-state phosphor film for wafer-level packaging of white LEDs is formed.

Example 2

Referring to Fig. 2, the present embodiment first prepares a uniform polyethylene film 21 with a thickness of 40 microns through a casting process, and a hemispherical structure with a size of 30 microns manufactured by inkjet printing on the polymer film; , the phosphor layer 22 of the mixture of organic colloid and hexachloroplatinic acid is evenly coated on the polyethylene film by screen printing in a vacuum environment, wherein the phosphor concentration is 1.0g/ml, and the thickness of the phosphor layer 22 is 150 microns; finally Form a single-layer, liquid-state phosphor film for wafer-level packaging of white LEDs.

Example 3

Referring to Fig. 3, the present embodiment firstly prepares uniform polyester resin film 31 with a thickness of 40 microns by casting process, and adopts inkjet printing on the polymer film to make a hemispherical structure with a size of 30 microns; The first fluorescent powder layer 32 of the mixture of fluorescent powder, organic colloid and hexachloroplatinic acid is uniformly coated on the polyethylene film by screen printing in a vacuum environment, wherein the phosphor powder concentration is 1.0g/ml, and the thickness of the phosphor powder layer is 50 micron; then use a power of 10W ultraviolet light to achieve complete curing of the first phosphor layer 32; then coat red quantum dot phosphor powder, organic colloid and hexachloroplatinum on the surface of the first phosphor layer 32 by a roll-to-roll process acid mixture to form the second phosphor layer 33, wherein the phosphor concentration is 0.5g/ml, and the thickness of the phosphor layer is 200 microns; the final effect is to prepare a double layer, containing two states of solid and liquid for realizing white light Phosphor film for LED wafer level packaging.

Example 4

Referring to Fig. 4, the present embodiment first prepares uniformly by tape casting process, and the polyester resin film 41 that thickness is 40 microns, adopts the method for ink-jet printing on the macromolecule film to be the triangular cone-shaped structure of 30 microns in size; The first phosphor layer 42 of yellow phosphor, organic colloid and hexachloroplatinic acid mixture is uniformly coated on the polyethylene film by screen printing in a vacuum environment, wherein the phosphor concentration is 1.0g/ml, and the thickness of the phosphor layer is 50 microns; then use a power of 10W ultraviolet lamp to irradiate for 1 minute to realize the complete semi-curing of the first phosphor layer 42; then coat red phosphor powder, organic colloid and six phosphors on the surface of the first phosphor layer 42 by roll-to-roll process. Chloroplatinic acid mixture to form the second phosphor layer 43, wherein the phosphor concentration is 0.5g/ml, the thickness of the phosphor layer is 200 microns, and the power is 10W ultraviolet lamp for 1 minute to realize that the second phosphor layer 43 is completely half Curing; the final effect is to prepare a double-layer, semi-cured phosphor film for wafer-level packaging of white LEDs.

Although this description uses more polyethylene film 11, phosphor layer 12, polyethylene film 21, phosphor layer 22, polyester resin film 31, first phosphor layer 32, second phosphor layer 33, polyester resin film 41. Terms such as the first phosphor layer 42 and the second phosphor layer 43, but the possibility of using other terms is not excluded. These terms are only used to describe the essence of the present invention more conveniently, and it is against the spirit of the present invention to interpret them as any additional limitation.

It should be understood that the parts not described in detail in this specification belong to the prior art.

It should be understood that the above-mentioned descriptions for the preferred embodiments are relatively detailed, and should not therefore be considered as limiting the scope of the patent protection of the present invention. Within the scope of protection, replacements or modifications can also be made, all of which fall within the protection scope of the present invention, and the scope of protection of the present invention should be based on the appended claims.

Claims (6)

1. a kind of fluorescent powder film preparation method for white light LEDs wafer-level packaging, which is characterized in that include the following steps：

Step 1：Macromolecule membrane layer is prepared first, and the film of uniform thickness is prepared by casting technique, it is then thin in macromolecule Micro nano structure is manufactured on film；

Step 2：By the mixture of the additive of different fluorescent powders, organic colloid and change colloid flow behavior under vacuum conditions It is coated uniformly on macromolecule membrane layer, forms two or more layers phosphor powder layer structure；

The two or more layers phosphor powder layer structure, phosphor powder layer material include phosphor material powder and colloidal materials；It is described Phosphor material powder for embedded photoluminescent material, specially YAG, TAG or quanta point material；The colloidal materials are asphalt mixtures modified by epoxy resin Fat, silica gel or spin-coating glass；The phosphor powder layer material is solid-state, semisolid or liquid, a concentration of 0.01g/ in coating ml-3g/ml；

Step 3：It then passes through different ultraviolet lights or is thermally formed being used to implement under curing, semi-solid preparation or fluid state The fluorescent powder film of white light LEDs wafer-level packaging.

2. the fluorescent powder film preparation method according to claim 1 for white light LEDs wafer-level packaging, feature exists In：The material of the macromolecule membrane layer is polyethylene or polyester resin, and the thickness of film is 20-100 microns.

3. the fluorescent powder film preparation method according to claim 1 for white light LEDs wafer-level packaging, feature exists In：Described manufactures micro nano structure on macromolecule membrane, and manufacturing method is using micro-nano processing method, including nanometer Stamped method, ink-jet printing.

4. the fluorescent powder film preparation method according to claim 1 for white light LEDs wafer-level packaging, feature exists In：The additive of the change colloid flow behavior is chloroplatinic acid.

5. the fluorescent powder film preparation method according to claim 1 for white light LEDs wafer-level packaging, feature exists In：The mixture by different fluorescent powders, organic colloid and the additive for changing colloid flow behavior is under vacuum conditions It is coated uniformly on macromolecule membrane layer, adopts the technology that roll-to-roll process, silk-screen printing technique or spin coating proceeding.

6. the fluorescent powder film preparation method according to claim 1 for white light LEDs wafer-level packaging, feature exists In：The two or more layers phosphor powder layer, thickness are 50-250 microns.