RU2594958C2 - Sealing of oled hardware and oled micro display built around silicon substrate with help of vitreous paste - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to sealing of micro displays built around the organic electroluminescent materials and can be used in production of OLED micro displays on silicon substrate. Claimed process proceeds from application of vitreous paste for sealing the OLED hardware on silicon substrate composed by 3-5 mcm deep SiO_x ply and from laser soldering at the 60 W output power and output radiation wavelength of 810 nm.

EFFECT: production of dense-vacuum glass seam, higher quality of sealing, longer life.

6 cl, 6 dwg

Description

The invention relates to a method for sealing microdisplays based on organic electroluminescent materials and can be used in the manufacture of OLED microdisplays on a silicon substrate.

In the known method for protecting OLED devices from the negative effects of oxygen and water vapor, an adhesive structure based on epoxy resins was used [1].

In some cases, protection is also used in the form of multilayer organic and inorganic films, known as Vitex, in combination with the use of UV curable adhesive [2].

Note that, in general, the known sealing methods have achieved results that ensure the operability of OLED devices for several thousand hours.

Until recently, these sealing methods were dominant. However, a more effective protection is sealing using a glassy paste (frit paste) as the connecting layer between the glass cover and the base [3]. In this case, the sealing is carried out by laser welding (non-adhesive construction). Apparently, this method of sealing is promising, since glass is an ideal barrier against the penetration of moisture vapor and oxygen.

In FIG. 1 shows the construction of an OLED device including a light-emitting structure 3, a transparent glass cover 1 and a glass base 4, the sealing of which is made using frit paste 2. Sealing is carried out by laser irradiation, schematically shown in FIG. 1 in the form of two parallel arrows.

The disadvantage of this method of sealing is that it is applicable for a substrate of insulating material, for example glass 4. For this reason, a sealing method using frit paste for OLED microdisplays on a silicon substrate 6 is not implemented, because the thermal conductivity of glass and silicon are very different and equal respectively: ~ 2 W / m · K and ~ 150 W / m · K. This leads to the fact that the thermal power supplied to the frit paste due to the absorption of laser radiation will be insufficient to melt the doped glass with the formation of a reliable junction.

The present invention solves this problem as follows:

- the introduction of an additional layer 5 with low thermal conductivity SiO _x at the periphery of the structure. to reduce heat sink to the silicon substrate. 6 of FIG. 2, or

- the formation in the silicon substrate of the implanted regions 7 with a strongly broken crystal lattice and low thermal conductivity under the designed area of the weld, FIG. 3, or

- using an additional layer 5 along the periphery of the structure with low thermal conductivity in combination with creating in the silicon substrate regions 7 with a strongly broken crystal lattice with low thermal conductivity under the projected area of the weld, FIG. four.

Modern information display systems use the technology of thin organic electroluminescent films in the manufacture of devices having a silicon substrate as the base. In the silicon substrate, VLSI is formed to control the matrix of light-emitting elements based on organic electroluminescent films.

An important task in the manufacturing technology of such devices is the creation of high-quality sealing, which protects organic films from the negative effects of vapors and oxygen due to their extreme sensitivity. The developed sealing should ensure leakage of ≤10 ^-10 Pa · m ³ / s and allow to increase the working time to several tens of thousands of hours.

The indicated technical result for OLED and OLED microdisplays is achieved by the fact that the method of sealing OLED on a silicon substrate using a glassy paste based on the use of a paste, a 3-5 μm thick SiO _x layer and laser welding at 60 W output power mode and output radiation wavelength λ = 810 nm consists in the fact that before the sealing process under the designed area of the weld using the frit paste, an implanted region with a strongly broken crystal lattice is created in silicon, while before the process The sealing system creates an implanted region with a strongly broken crystal lattice in silicon, and a layer of low-temperature silicon oxide SiO _x 3-5 μm thick is deposited over the implanted region.

The method of sealing an OLED microdisplay on a silicon substrate has the following operational sequence: deposit a silicon oxide layer of 3-5 μm thick 6.1.1 onto a silicon wafer with chips 6.1, form a silicon oxide layer 6.1.2 on each chip of the silicon wafer along its periphery by photolithography, spray organic and inorganic layers 6.1.5 are sequentially prepared on it, a glass plate 6.2 is prepared for sealing in the technological sequence: on a glass plate of the same size as a silicon plate, at the periphery of an individual chip, there is a layer of glassy paste 6.2.2 containing vanadium oxide VO <35% by mass, antimony trioxide Sb ₂ O ₃ <6% by mass, iron oxide Fe ₂ O ₃ <6%, phosphorus pentoxide P ₂ O ₅ <16%, silicon oxide SiO _x 7%, terpineol C ₁₀ H ₁₈ O 3%, ethyl cellulose [C ₆ H ₇ O ₂ (OH) _3-x (OS ₂ H ₅ ) _x ] _n <4%, butyl carbitol acetate C ₁₀ H ₂₀ O ₄ <23%, they perform special heat treatment of a layer of glassy paste in the mode shown in FIG. 5, glue is applied around the periphery of the plate 6.2.3, after combining and gluing the silicon and glass plates along the perimeter 6.0, laser welding is performed on 6.0.1 silicon chip chips with a glass plate in the output power mode of 60 W and a radiation wavelength of λ = 810 nm, produce low-temperature annealing of the obtained billet and cutting the billet with diamond disks with a rotation speed of 3000 rpm, cooled by water 6.02, make welding of the contacts 6.03 and protect the area of contact joints with epoxy glue 6.04. Before transferring the silicon wafer for deposition to the KU installation, operations related to the creation of a heavily doped implanted layer in the silicon substrate along the periphery of the chip are performed on it. In this case, before transferring the silicon wafer for deposition to the KU installation, it performs operations of creating a heavily doped implanted layer in silicon with the formation of an SiO _x layer 0.15-0.17 μm thick at the sites of the implanted layer over it.

The complexity of the problem lies in the fact that the sealing based on the frit paste is directly unsuitable for use in OLED devices with a silicon substrate.

The essence of the invention consists in introducing additional technological operations that provide a vacuum-tight glass joint without pores and cracks in the route for manufacturing OLED devices with a silicon substrate. They include operations on processing a silicon substrate to obtain regions with a strongly broken crystal lattice and reduced heat conductivity, selecting the composition of the glassy (frit) paste and its heat treatment, and determining the laser welding mode.

In this description of the invention, a preferred embodiment of the invention is presented and illustrated, in which various modifications and changes may be made without affecting the essence and scope of the invention defined by the claims.

On a silicon substrate (with a strongly broken region of the crystal lattice and untreated) with a light-emitting OLED matrix, a 3-5-μm thick SiO _x layer is deposited at the periphery by a low-temperature method and photolithography is used to leave portions of the SiO _x layer, which subsequently overlap with frit sections pastes on the glass lid;

- an even layer of Frit paste is applied on the glass plate by the screen printing method according to the specified pattern, the composition of which is: vanadium oxide VO <35% by mass, antimony trioxide Sb ₂ O ₃ <6% by mass, iron oxide Fe ₂ O ₃ <6%, phosphorus pentoxide P ₂ O ₅ <16%, silicon dioxide SiO ₂ 7%, terpineol C ₁₀ H ₁₈ O 3%, ethyl cellulose [C ₆ H ₇ O ₂ (OH) _3-x (OS ₂ H ₅ ) _x ] _n < 4%, butylcarbitol acetate C ₁₀ H ₂₀ O ₄ <23%; The frit paste in the form of a seam is annealed in a special heat treatment mode: temperature 370 ° С exposure for 30 minutes (decarbonization and decarburization process), sintered at 420 ° С and maintained for 30 minutes according to FIG. 5.

- two components of the body (glass cover and silicon substrate) combine along a glassy seam with portions of the SiO _x layer;

- vitrification of heat-treated frit paste is carried out on a laser melting unit for glass junction LTS-2R by an IR laser in an output power mode of 60 W and an output radiation wavelength λ = 810 nm;

- the resulting billet is subjected to low-temperature annealing and subsequent cutting is carried out using diamond disks.

Brief Description of the Drawings

In FIG. 1 shows a well-known construction using a glass-paste sealant. This design does not involve the use of a silicon substrate as a base.

In FIG. 2-4 show the proposed design, working according to the claimed method. The differences in them consist in the structure of the areas in contact when combined with a glassy seam.

In FIG. 5 shows a graph of the temperature of the annealing of the glassy seam from time to time according to the claimed method.

In FIG. 6 shows a block diagram of an embodiment of the invention along a microdisplay route.

The compatibility of innovations in the claimed method of sealing was tested in the technological route for the manufacture of OLED microdisplays on a silicon substrate.

In FIG. 6 shows the places for introducing additional operations into the technological route for the manufacture of microdisplays. In the technological chain, the substrate with silicon chips (pos. 6.1) includes additional operations of low-temperature deposition of SiO _x (pos. 6.1.1), photolithography along the SiO _x layer (pos. 6.1.2). After typical washing and heat treatment operations, the silicon wafer goes through a cycle to a vacuum cluster unit (KU) for spraying organic and inorganic layers (item 6.1.3). In the technological chain there is a glass cover with light filters (pos. 6.2), operations of applying frit paste (pos. 6.2.1) and special heat treatment (pos. 6.2.2) are added, after which the cap enters the KU installation for further passage along the technological route .

Studies of OLED and OLED microdisplays showed that when using this invention, the leakage rate in OLED is reduced to 2 × 10 ^-10 Pa · m ³ / s and the service life of OLED microdisplays is increased to 20-30 thousand hours.

Information sources

1. Ewald Guenther. Encapsulation for OLED devices. Patent USA 7255823. 2007 (option).

2. Maizen, Vincent. Method of sealing OLED with liquid adhesive. Patent USA 7452258. 2008 (option).

3. Bruce G. Aitken, Joel P. Carberry. Glass package, that is hermetically sealed with a frit and method of fabrication. Patent USA 6,998,776. 2006.

Claims (6)

1. The method of sealing OLED on a silicon substrate using a glassy paste, based on the use of paste, a layer of SiO _x 3-5 microns thick and laser welding in the mode of output power of 60 W and a wavelength of output radiation of λ = 810 nm. 2. The sealing method according to claim 1, characterized in that before the sealing process under the projected area of the weld using the frit paste, an implanted region with a strongly broken crystal lattice is created in silicon. 3. The sealing method according to claim 1 or 2, characterized in that before the sealing process an implanted region with a strongly broken crystal lattice is created in silicon and a layer of low-temperature silicon oxide SiO _{x is} deposited over the implanted region _. 3-5 microns thick. 4. A method for sealing an OLED microdisplay on a silicon substrate, having the following operational sequence: a silicon oxide layer 3-5 microns thick is deposited on a silicon wafer with chips, a silicon oxide layer is formed on each silicon wafer chip along its periphery by photolithography, and organic and inorganic layers, prepare a glass plate for sealing in the technological sequence: on a glass plate of the same size as the silicon plate, apply along of the individual chip, a layer of a glassy paste containing vanadium oxide VO <35% by mass, antimony trioxide Sb ₂ O ₃ <6% by mass, iron oxide Fe ₂ O ₃ <6%, phosphorus pentoxide P ₂ O ₅ <16%, oxide silicon SiO _x 7%, terpineol C ₁₀ H ₁₈ O 3%, ethyl cellulose [C ₆ H ₇ O ₂ (OH) _3-x (OS ₂ H ₅ ) _x ] _n <4%, butyl carbitol acetate C ₁₀ H ₂₀ O ₄ <23%, a special heat treatment of a layer of glassy paste is carried out in the following mode: temperature 370 ° C, holding for 30 minutes (decarbonization and decarburization process), then sintered at a temperature of 420 ° C and held for 30 minutes, then apply glue on the periphery of the pla stins, after combining and gluing the silicon and glass plates around the perimeter, laser welding the silicon plate chips with a glass plate in an output power mode of 60 W and a radiation wavelength of λ = 810 nm, low-temperature annealing of the obtained workpiece and cutting the workpiece with diamond disks with a rotation speed 3000 rpm, cooled by water, make the welding of the contacts and protect the area of the contact joints with epoxy glue. 5. The method of sealing the microdisplay according to claim 4, characterized in that before transferring the silicon wafer for sputtering into a vacuum cluster unit (KU), operations are performed on it related to the creation of a highly alloyed implanted layer in the silicon substrate along the periphery of the chip. 6. The microdisplay sealing method according to claim 4 or 5, characterized in that before transferring the silicon wafer to sputtering in a vacuum KU, it performs operations to create a heavily doped implanted layer in silicon with the formation of a 0.15 SiO _x layer on top of the implanted layer on top of it -0.17 microns.

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