阅读说明：本技术 微型元件贴附方法 (Micro-device attaching method ) 是由 陈立宜 于 2019-02-01 设计创作，主要内容包括：一种微型元件贴附方法,其包含：局部地喷洒气体至基板的一部分上,其中气体的水蒸气压高于环境水蒸气压；以及在气体中的一部分水凝结并在基板的所述部分上形成液体层后,放置微型元件至基板的所述部分的上方并让微型元件接触液体层,使得液体层产生的毛细力抓住微型元件,并使得微型元件的位置保持在基板上的可控区域内。本发明所提出的方法,让用于贴附的湿度和温度有了更好的控制,使得贴附品质得以提升。(A method for attaching a micro-device includes locally spraying a gas onto a portion of a substrate, wherein the gas has a water vapor pressure above ambient water vapor pressure, and after portions of the gas condense and form a liquid layer on the portion of the substrate, placing the micro-device over the portion of the substrate and contacting the micro-device with the liquid layer such that capillary forces generated by the liquid layer grip the micro-device and maintain the position of the micro-device within a controlled area on the substrate.)

1, A method for attaching a micro device to a substrate, the method comprising:

locally spraying a gas onto the portion of the substrate, wherein the gas has a water vapor pressure higher than an ambient water vapor pressure;

after portions of the water in the gas condense and form a liquid layer on the portion of the substrate, the microelements are placed over the portion of the substrate and brought into contact with the liquid layer such that the capillary forces generated by the liquid layer grip the microelements and maintain the position of the microelements within a controlled area on the substrate.

2. The method of claim 1, further comprising adjusting the temperature of the substrate to a selected temperature point.

3. The method of claim 2, wherein the selected temperature point is the dew point.

4. The method of claim 2, wherein the adjustment is applied to the portion of the substrate.

5. The method of claim 2, wherein the adjustment is applied to the entire substrate.

6. The method of claim 1, wherein the gas consists essentially of nitrogen and water.

7. The method of claim 1, wherein the contacting is performed within 10 seconds after the liquid layer is formed on the portion of the substrate.

8. The method of claim 1, further comprising preparing the substrate having at least conductive pads.

9. The method of claim 8, wherein said locally spraying is spraying said gas onto said at least conductive pads of said portion of said substrate.

10. The method of claim 8, wherein the at least conductive pads are plural in number, and the locally spraying is spraying the gas onto at least two of the conductive pads of the portion of the substrate.

11. The method of claim 8, wherein the controllable regions are on the at least conductive pads.

Technical Field

The invention relates to methods for attaching a micro device to a substrate.

Background

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

In various aspects of the technology associated with microcomponents, the component transfer fabrication process is , the most challenging task in the commercialization of microcomponents, important issues with the component transfer process are the bonding of microcomponents to substrates.

Disclosure of Invention

The present invention is directed to overcoming the drawbacks of the prior art, and providing improved methods for attaching micro devices, which can control the humidity and temperature for attaching, so as to improve the attaching quality and make the attaching method more practical.

The purpose of the invention and the technical problem to be solved are realized by adopting the following technical scheme.

method of micro device attachment according to embodiments of the present invention includes locally spraying a gas onto portions of a substrate, wherein the gas has a water vapor pressure higher than the ambient water vapor pressure, and after portions of the gas partially condense and form a liquid layer on the portions of the substrate, placing the micro devices over the portions of the substrate and contacting the micro devices with the liquid layer such that capillary forces generated by the liquid layer grip the micro devices and maintain the positions of the micro devices within a controlled area on the substrate.

The object of the present invention and the technical problems can be further achieved by following technical means.

In the method above, the method further includes adjusting the temperature of the substrate to a selected temperature point.

In the foregoing method, the selected temperature point is the dew point.

In the foregoing method, the temperature of the substrate is adjusted to be applied to a portion of the substrate.

In the foregoing method, the temperature of the substrate is adjusted to be applied to the entire substrate.

In the foregoing method, the gas is mainly composed of nitrogen and water.

In the foregoing method, contacting the micro-device with the liquid layer is performed within about 10 seconds after the liquid layer is formed on the portion of the substrate.

In the above method, the method further includes preparing a substrate having at least conductive pads.

In the foregoing method, the locally spraying means spraying the gas onto the conductive pad of the portion of the substrate.

In the aforementioned method, the number of the at least conductive pads is plural, and the locally spraying means spraying the gas onto the at least two conductive pads of the portion of the substrate.

In the above method, the controllable region is on the conductive pad.

By the technical scheme, the micro-element attaching method can achieve considerable technical progress and practicability, has general utilization value in industry, and at least has the advantages of better controlling the humidity and temperature for attaching and improving the attaching quality.

The foregoing description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention may be implemented in accordance with the content of the description, and in order to make the above and other objects, features, and advantages of the present invention more clearly understood, the following preferred embodiments are described in detail with reference to the accompanying drawings.

Drawings

FIG. 1 is a flow chart illustrating a method for attaching a micro device according to embodiments of the present invention.

FIG. 2A is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 2B is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 2C is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 3 is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 4 is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 5A is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 5B is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 5C is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 6A is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 6B is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

FIG. 6C is a schematic cross-sectional view of illustrating intermediate stages of the method of FIG. 1 according to some embodiments of the invention.

[ description of main element symbols ]

100: micro-device attachment method 110: optional operations

120. 130, 130: operation 210: substrate

220: conductive pad 230: gas (es)

240: liquid layer 250: micro-element

P1, P2: parts LT1, LT 2: cooling device

Detailed Description

To further illustrate the technical means and effects of the present invention for achieving the intended purpose, the following detailed description of the method for attaching a micro device according to the present invention, its specific embodiments, structure, method, steps, features and effects will be given in conjunction with the accompanying drawings and preferred embodiments.

The foregoing and other technical and scientific aspects, features and advantages of the present invention will be apparent from the following detailed description of preferred embodiments, which is to be read in connection with the accompanying drawings. While the present invention has been described in connection with the preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but is intended to cover various modifications, equivalent arrangements, and specific embodiments thereof.

conventional structures and elements are shown in simplified schematic form in the drawings, and unless otherwise indicated, the same reference numerals may be used for corresponding elements in different drawings.

Referring to fig. 1-6C, fig. 1 is a schematic flow chart illustrating a method for attaching a micro device in embodiments of the invention, fig. 2A-6C are schematic cross-sectional views illustrating intermediate stages of the method of fig. 1 in embodiments of the invention.

The micro-component attachment method 100 begins with optional operations 110 and 120 of adjusting the temperature of the substrate 210 to a selected temperature point (optional operation shown with reference to figure 2A) and locally spraying gas 230 onto portion P1 of the substrate 210 (reference to figure 2B) followed by operation 130 of placing the micro-components 250 over the portion P1 of the substrate 210 after portions of the gas 230 partially condense and form the liquid layer 240 on the portion P1 of the substrate 210, with the micro-components 250 contacting the liquid layer 240 (reference to figure 2C) in the following paragraphs, where the disclosure of the invention is to be compared and simplified, various embodiments for performing similar operations will be presented in the same paragraph in which the order of optional operations 110 and 120 is not limited by the above description in the embodiments embodiments, the order of adjusting the temperature of the substrate 210 (optional operation 110) and spraying gas 230 (operation 120) may be interchanged in embodiments , the adjusting the temperature of the substrate 210 (optional operation 110) and the spraying gas 230 (operation 120) may be performed simultaneously for additional times, and the adjusting the optional operations may be performed separately for additional times in embodiments of the invention may be omitted, and the optional operations may be performed separately for additional times of the optional operations 110 and .

Referring to fig. 2A, 3, 5A, and 6a, which depict embodiments of optional operation 110, in embodiments, the temperature of substrate 210 is adjusted to a selected temperature point such that after gas 230 is sprayed over a portion (P1 or P2) or all of substrate 210 (portions of which are described in detail below), water in portion of gas 230 condenses on a portion (P1 or P2) or all of substrate 210 to form liquid layer 240. in embodiments, the selected temperature point is the dew point. in embodiments, the amount of adjusting the temperature of substrate 210 may be zero (i.e., not required to adjust the temperature of substrate 210) when the temperature and water vapor pressure (i.e., water vapor partial pressure) of gas 230 are sufficiently high, e.g., compared to the current ambient temperature (e., 23 degrees celsius) and the ambient water vapor pressure (e., 45% saturated vapor pressure), when gas 230 is 35 degrees celsius and 80% saturated (water) vapor pressure (but not limited thereto), because the temperature of substrate 210 has reached the condensation point at the current ambient temperature.

In embodiments, such as the embodiments described with reference to FIGS. 2A, 5A, and 6A, the temperature of the entire substrate 210 may be adjusted simultaneously, wherein the cooling apparatus LT1 may be used to lower the temperature of the entire substrate 210. the temperature of portions of the substrate 210 may also be adjusted. for example, the embodiment described with reference to FIG. 3. wherein the cooling apparatus LT2 may be used to lower the temperature of the portion P1 of the substrate 210. the cooling apparatuses LT1 and LT2 may be cooling plates, but are not limited thereto.

Referring to fig. 2B, 4, 5B, and 6B, these figures depict embodiments of operations 120. in some embodiments, gas 230 (shown in dashed lines) is sprayed locally and positively onto portion P1 of substrate 210. in some embodiments, the positive spray refers to spraying gas 230 onto portion P1 of substrate 210 in a direction perpendicular to the direction of extension of substrate 210. portion P1 of substrate 210 may have conductive pads 220 thereon, with conductive pads 220 serving as electrical contacts, but not limited to, the above-described local spray has the benefit of precisely controlling the vapor pressure and temperature of the sprayed gas 230. gas 230 may also be sprayed directly onto conductive pads 220 or substrate 210. in some embodiments, there may be multiple conductive pads 220, gas 230 may be sprayed onto at least two conductive pads 220 of portion P2 of substrate 210 (e.g., dashed lines shown in fig. 5B) in some embodiments, gas 230 may also be sprayed onto the entire substrate 210 or onto all portions P63220 of substrate 210. in some embodiments, gas 230 may be sprayed onto all of substrate 210, or may be sprayed onto all of the substrate 220, 5B 220, 120, 5B, 5 c.

The water vapor pressure and temperature of the gas 230 are selected to form the liquid layer 240 in a more efficient manner, embodiments are illustrated with the substrate 210 being in an environment having ambient temperature and ambient water vapor pressure conditions, but not limited thereto, the exemplary ambient temperature is 23 degrees celsius, the exemplary ambient water vapor pressure is 45% of the saturated vapor pressure, in other environmental conditions having different ambient water vapor pressures and ambient temperatures, the water vapor pressure of the gas 230 and the temperature of the modified gas 230 may be modified according to principles illustrated in embodiments of the invention, in embodiments, the water vapor pressure of the gas 230 sprayed locally to the portion P1, P2 of the substrate 210 (or sprayed to the entire substrate 210) is between about 65% and about 100% of the saturated vapor pressure, in embodiments, the water vapor pressure of the gas 230 sprayed locally to the portion P1, P2 of the substrate 210 (or sprayed to the entire substrate 210) is between about 80% and about 95% of the saturated vapor pressure, and the temperature of the portion P1, P2 (or the vapor pressure of the gas sprayed to the entire substrate 210) may be adjusted to be between about 80% of the saturated vapor pressure of the substrate 210, such that the temperature of the substrate 210 is less efficient than the temperature and the temperature of the substrate 210, and the ambient temperature of the substrate 230 is selected to be equal to the temperature of the substrate 210.

During The above operations (e.g., optional temperature regulation and gas spraying), The water vapor pressure and temperature of The sprayed gas 230, and The selected temperature point of The substrate 210, may be determined based on The detected ambient water vapor pressure and ambient temperature using The instantaneous temperature and instantaneous water vapor pressure controllers, i.e., The correlation between The water vapor pressure of The sprayed gas 230 plus The temperature of The sprayed gas 230 and The ambient water vapor pressure plus The ambient temperature as described in The various embodiments above, by The aforementioned controllers, may be used as a rule to determine The instantaneous water vapor pressure of The gas 230 and The instantaneous temperature of The gas 230, and to determine The selected temperature of The substrate 210. in embodiments, The Arden wick equation may be The liquid layer 240 forming The Arden wick equation is a set of empirical relationship relating The saturation vapor pressure to a given temperature, for example, The ambient temperature is first detected, then The ambient temperature is used as an input value, The saturation humidity is obtained by The Arden wick equation since water vapor may form when The relative condensation is greater than about 85% (e.g., see "humidity Control 240, The humidity map 240, The water vapor pressure table for example, The water vapor pressure as determined by The humidity map 11, humidity map for The humidity index for The substrate temperature, humidity map 2, The humidity map 2, The humidity map for example, The humidity map 11, The humidity map for example, The humidity map for The substrate 210, The water temperature of water temperature, humidity index, moisture point of water vapor pressure, moisture map for example, moisture map, moisture.

Referring to figures 2C, 5C, and 6C, in embodiments the microelements 250 are placed over the portion P1 of the substrate 210 and in contact with the liquid layer 240 such that the capillary force generated by the liquid layer 240 grips the microelements 250 and maintains the position of the microelements 250 within a controlled area on the substrate 210 in embodiments the contact of the microelements 250 with the liquid layer 240 is performed within about 10 seconds after the liquid layer 240 is formed on the portion P1 of the substrate 210, thereby avoiding evaporation of the liquid layer 240 prior to the aforementioned contact, hi addition, the quality of attachment of the microelements 250 to the substrate 210 is greatly enhanced due to the local control of the formation of the liquid layer 240 and the immediate contact (e.g., the aforementioned contact within 10 seconds) after the formation of the liquid layer 240 (see the four paragraphs that follow.) in embodiments , as shown in figures 5C and 6C, a plurality of microelements 250 are placed on the portion P2 or the entire substrate 210 and in contact with the liquid layer 240. similar contents have been mentioned in relation to the related embodiments of figure 2C.

In embodiments, the controllable region is on at least conductive pads 220. in embodiments, the microelement 250 is a micro light-emitting element, but not limited thereto. the microelement 250 comprises an active layer, a type semiconductor layer, and a second type semiconductor layer.the active layer is located between the type semiconductor layer and the second type semiconductor layer.the type semiconductor layer and the second type semiconductor layer can be a p-type semiconductor layer and an n-type semiconductor layer, respectively, and the active layer can be a quantum well or multiple quantum wells, but not limited thereto.in embodiments, the microelement 250 further comprises a bonding layer located on the type semiconductor layer or on the second type semiconductor layer.

Although various embodiments related to the same operations are described in the above paragraphs for convenience of comparison (e.g., the embodiments of fig. 2A, 3, 5A, and 6A are described in paragraph ), in some cases (e.g., the embodiment of the drawings mentioned immediately above), fig. 2A-2C can be considered as full embodiments for attaching microelements 250 to portion P1 of substrate 210, fig. 5A-5C can be considered as full embodiments for attaching a plurality of microelements 250 to portion P2 of substrate 210, and fig. 6A-6C can be considered as full embodiments for attaching a plurality of microelements 250 to the entire substrate 210.

After the microelements 250 are grasped by capillary force, the liquid layer 240 may be evaporated (e.g., by heating) such that the microelements 250 are in contact with the substrate 210 or the conductive pads 220. the aforementioned contact may occur between the th type semiconductor layer (or the second type semiconductor layer) and the substrate 210, between the th type semiconductor layer (or the second type semiconductor layer) and the conductive pads 220, between the bonding layer and the substrate 210, or between the bonding layer and the conductive pads 220.

In embodiments, at least of the lateral lengths and thicknesses of the microelements 250 are equal to or less than 50 microns, the lateral lengths described herein are the maximum lengths of the microelements 250 parallel to the direction of extension of the substrate 210, the thicknesses described herein are the maximum lengths of the microelements 250 perpendicular to the direction of extension of the substrate 210. microelements 250 having the above-described size ranges (i.e., at least of the lateral lengths and thicknesses are equal to or less than 50 microns) can achieve conditions that maintain the microelements 250 within a controlled area on the substrate 210 by capillary forces of the liquid layer 240. furthermore, the microelements 250 of the above-described size ranges form a firm contact with the substrate 210 or the conductive pad 220 after evaporation of the liquid layer 240.

In view of the foregoing, embodiments of the present invention provide methods of attaching microcomponents, wherein gas is locally sprayed onto a substrate and the sprayed gas forms a liquid layer for attaching the microcomponents to the substrate, because of the local control of the liquid formation and the immediate placement of the formed liquid, better control of the humidity and temperature for attachment is achieved, resulting in improved attachment quality.

Although the present invention has been described with reference to a preferred embodiment, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims.