US-12628482-B2 - Multi-layer release stack for light induced transfer of components

US12628482B2US 12628482 B2US12628482 B2US 12628482B2US-12628482-B2

Abstract

A method and system for light induced transfer of components ( 15 ) from a donor substrate ( 10 ) to an acceptor substrate ( 20 ). The donor substrate ( 10 ) comprises a transparent carrier ( 11 ) configured to carry the components ( 15 ) facing the acceptor substrate ( 20 ), and a release stack (S). The release stack (S) comprises a light-absorbing layer ( 12 ), a decomposition layer ( 16 ), a melt layer ( 13 ), and an adhesive layer ( 14 ). The light-absorbing layer ( 12 ) has a high absorption coefficient for absorbing the light beam (L) causing heat conduction to the melt layer ( 13 ). The light-absorbing layer ( 12 ) remains solid while the melt layer ( 13 ) is melted. The adhesive layer ( 14 ) adheres the components ( 15 ) to the melt layer ( 13 ) while the melt layer ( 13 ) is solid and releases adhesion when the melt layer ( 13 ) is melted (M). The decomposition layer ( 16 ) has an evaporation temperature above the melting temperature of the melt layer, and forms a bubble ( 17 ) stimulating the release and transfer when the melt layer 913 ) is liquid.

Inventors

Gari ARUTINOV
Rob Jacob Hendriks

Assignees

NEDERLANDSE ORGANISATIE VOOR TOEGEPAST-NATUURWETENSCHAPPELIJK ONDERZOEK TNO

Dates

Publication Date: 20260512
Application Date: 20220906

Claims (18)

1 . A method for light induced transfer of components from a donor substrate to an acceptor substrate, wherein the donor substrate comprises: a transparent carrier configured to carry the components facing the acceptor substrate, and a release stack disposed between the transparent carrier and the components for releasing one or more of the components from the donor substrate onto the acceptor substrate following illumination of the release stack by a light beam through the transparent carrier, wherein the release stack comprises: a melt layer having a melting temperature, a light-absorbing layer disposed between the transparent carrier and the melt layer, wherein the light-absorbing layer has an absorption coefficient for absorbing the light beam thereby causing the light-absorbing layer to be heated, wherein the heated light-absorbing layer is in thermal contact with the melt layer for conducting its heat to the melt layer thereby causing a temperature of the melt layer to rise above its melting temperature, wherein the light-absorbing layer has a melting temperature which is higher than the melting temperature of the melt layer such that the light-absorbing layer can remain solid while the melt layer is melted by the heat conducted from the light-absorbing layer, a decomposition layer, disposed between the melt layer and the light-absorbing layer, wherein the decomposition layer has an evaporation temperature which is higher than a melting temperature of the melt layer and which is lower than a melting temperature of the light-absorbing layer, and wherein a layer thickness of the decomposition layer is smaller than a layer thickness of the melt layer; and an adhesive layer adhering the components to the melt layer while the melt layer is solid and releasing adhesion when the melt layer is melted; the method comprising illuminating an area of the light-absorbing layer, forming a part of the release stack holding a respective component, with a light beam through the transparent carrier to heat a respective part of the light-absorbing layer, wherein the heat is conducted to the melt layer of the release stack via the decomposition layer thereby melting the melt layer and heating the decomposition layer while the respective part of the light-absorbing layer remains solid, wherein the melting of the melt layer causes a loss of adhesion between the melt layer and a respective part of the adhesive layer of the release stack adhering the respective components to the melt layer, wherein the loss of adhesion causes release and transfer of the respective component, and wherein the heating of the decomposition layer causes local gas production resulting in bubble-formation in the decomposition layer, thereby accelerating the loss of adhesion between the melt layer and a respective part of the adhesive layer.
2 . The method according to claim 1 , wherein the decomposition layer has a melting temperature which is higher than the melting temperature of the melt layer.
3 . The method according to claim 1 , wherein the layer thickness of the decomposition layer is smaller than 20% of the thickness of the melt layer.
4 . The method according to claim 3 , wherein the layer thickness of the decomposition layer is smaller than 20% of the thickness of the melt layer.
5 . The method according to claim 4 , wherein the layer thickness of the decomposition layer is smaller than 10% of the thickness of the melt layer.
6 . The method according to claim 1 , wherein the layer thickness of the decomposition layer is between 5 nanometers and 100 nanometers.
7 . The method according to claim 6 , wherein the layer thickness of the decomposition layer is between 5 nanometers and 50 nanometers.
8 . The method according to claim 1 , wherein one or more of: the melt layer comprises a first metal layer; the light-absorbing layer comprises a second metal layer; and/or the decomposition layer comprises a third metal layer.
9 . The method according to claim 1 , wherein at least one of: the decomposition layer has an evaporation temperature lower than an evaporation temperature of the melt layer; or the decomposition layer has an evaporation temperature of at most 15% higher than an evaporation temperature of the melt layer.
10 . The method according to claim 1 , wherein the light beam illuminating the release stack is configured to: cause a temperature of the melt layer to rise above its melting temperature but remain below its evaporation temperature, and further, after the temperature of the melt layer has risen above the melting temperature, to cause a temperature of the decomposition layer to rise above its evaporation temperature.
11 . The method according to claim 1 , wherein the adhesive layer has a disintegration temperature that is above the melting temperature of the melt layer, or higher than three hundred degrees Kelvin below the melting temperature of the melt layer.
12 . The method according to claim 1 , wherein at least one of the adhesive layer, the melt layer, the decomposition layer and the light-absorbing layer is segmented between the components.
13 . The method according to claim 1 , wherein an area of the melt layer holding a respective component is smaller than an area of the respective component by at least a factor of two.
14 . The method according to claim 1 , wherein a mask is aligned with the donor substrate, wherein the mask comprises a set of mask windows aligned with a subset of the components on the donor substrate, wherein, a set of light spots is used to sequentially or simultaneously illuminate the set of mask windows for release of respective components, wherein a respective light spot is larger than a respective mask window being illuminated, with a light spot FWHM diameter larger than a width of the mask window by a least a factor of two.
15 . The method according to claim 1 , wherein the light-absorbing layer is configured to absorb at least fifty percent of the light beam illuminating the release stack, wherein the light beam is configured to exclusively illuminate a subarea of the light-absorbing layer forming part of a selected release stack holding a selected component, without illuminating immediately adjacent areas of the light-absorbing layer, thereby exclusively releasing the selected component while adjacent components remain attached to the donor substrate.
16 . The method according to claim 1 , wherein the melting temperature of the melt layer is less than six hundred degrees Kelvin, wherein the melting temperature of the light-absorbing layer is higher than the melting temperature of the melt layer by at least one hundred degrees Kelvin.
17 . A donor substrate comprising a transparent carrier carrying components for light induced transfer with a release stack disposed between the transparent carrier and the components for releasing one or more of the components from the donor substrate following illumination of the release stack by a light beam through the transparent carrier, wherein the release stack comprises: a melt layer having a melting temperature, a light-absorbing layer disposed between the transparent carrier and the melt layer, wherein the light-absorbing layer has an absorption coefficient for absorbing at least fifty percent of a light beam in a wavelength range between 100-2000 nm and a pulse length less than ten nanoseconds, thereby causing the light-absorbing layer to be heated, wherein the light-absorbing layer is in thermal contact with the melt layer for conducting its heat to the melt layer thereby causing a temperature of the melt layer to rise above its melting temperature, wherein the light-absorbing layer has a melting temperature which is higher than the melting temperature of the melt layer such that the light-absorbing layer can remain solid while the melt layer is melted by the heat conducted from the light-absorbing layer, and a decomposition layer, disposed between the melt layer and the light-absorbing layer, wherein the decomposition layer has an evaporation temperature which is higher than a melting temperature of the melt layer and which is lower than a melting temperature of the light-absorbing layer, and wherein a layer thickness of the decomposition layer is smaller than a layer thickness of the melt layer; an adhesive layer adhering the components to the melt layer while the melt layer is solid and releasing adhesion when the melt layer is melted.
18 . A system for light induced transfer of components, the system comprising: the donor substrate according to claim 17 comprising the transparent carrier and the release stack with the light-absorbing layer, the melt layer, and the adhesive layer holding the components, wherein the adhesive layer is segmented between the components; an acceptor substrate; and a controller and a light source configured to generate a light beam illuminating an area of the light-absorbing layer, forming a part of the release stack holding a respective component, through the transparent carrier to heat a respective part of the light-absorbing layer, wherein the heat is conducted via a decomposition layer to a melt layer of the release stack thereby melting the melt layer and heating the decomposition layer while the respective part of the light-absorbing layer remains solid, wherein the melting of the melt layer causes a loss of adhesion between the melt layer and a respective part of the adhesive layer of the release stack adhering the respective components to the melt layer, wherein the loss of adhesion causes release and transfer of the respective component, and wherein the heating of the decomposition layer causes local gas production resulting in bubble-formation in the decomposition layer, thereby accelerating the loss of adhesion between the melt layer and a respective part of the adhesive layer.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a U.S. National Stage application under 35 U.S.C. § 371 of International Application PCT/NL2022/050502 (published as WO 2023/167582 A1), filed Sep. 6, 2022, which claims the benefit of priority to Application PCT/NL2022/050114, filed Mar. 1, 2022. Benefit of the filing date of these prior applications is hereby claimed. Each of these prior applications is hereby incorporated by reference in its entirety. TECHNICAL FIELD AND BACKGROUND The present disclosure relates to methods and systems for light induced transfer of components such as chips from a donor substrate to an acceptor substrate. The disclosure also relates to a donor substrate for use in such method or system. Controlled transfer of small components has various applications, e.g. in the placement of μLEDs. Light induced transfer can be used to selectively transfer components from a donor substrate to an acceptor substrate. To facilitate the transfer, a release stack can be provided between the donor substrate and the components. In one technique components are glued onto a carrier substrate, and released from the carrier due to rapid blister formation. In another technique a flat glass plate with a light absorbing layer is coated with a glue. The components can be released due to decomposition or melting of the glue when the light absorbing layer rapidly heats up by the light pulse. For each of the known methods, a trade-off is to be made between efficiency (i.e. speed), yield and level of control. None of these methods provide the desired level of control of the transfer process. The faster techniques provide lower yields There remains a need for further improvement in the controlled transfer and placement of components. SUMMARY Some aspects of the present disclosure relate to methods and systems for light induced transfer of components from a donor substrate to an acceptor substrate. Other or further aspects relate to the donor substrate for use in such methods or systems. Typically a transparent carrier is configured to carry the components facing the acceptor substrate, and a release stack is disposed between the transparent carrier and the components for releasing one or more of the components from the donor substrate onto the acceptor substrate following illumination of the release stack by a light beam through the transparent carrier. As described herein the release stack of the donor substrate comprises a light-absorbing layer, a decomposition layer, a melt layer, and an adhesive layer. The light-absorbing layer is disposed between the transparent carrier and the decomposition layer. By providing the light-absorbing layer with a relatively high absorption coefficient the light beam can be efficiently absorbed thereby causing the light-absorbing layer to be heated. By providing the heated light-absorbing layer in thermal contact with the melt layer via the decomposition layer, the absorbed heat can be conducted through the decomposition layer to the melt layer so the temperatures of the decomposition layer and the melt layer can rise. By providing the material of the melt layer with a relatively low melting temperature, this material can be easily melted. By providing the light-absorbing layer with a relatively high melting temperature (at least higher than the melting temperature of the melt layer), the light-absorbing layer can remain solid while the melt layer is melted by the heat conducted from the light-absorbing layer. By providing the adhesive layer between the components and the melt layer, the components can be easily adhered to the melt layer while the melt layer is solid. Furthermore, this adhesion can be released when the melt layer is melted. By providing the decomposition layer with an evaporation temperature in between the melting temperature of the melting layer and the melting temperature of the light-absorbing layer, the material of the decomposition layer will start to evaporate after melting of the melting layer. Within the decomposition layer, bubbles formation raises the pressure in the layer, which results in the decomposition layer to develop a convex shape underneath the molten melt layer. This stimulates release of the component by increasing the contact angle with the adhesive layer at a right moment. The release of the component is thereby accelerated over a situation wherein no decomposition layer would have been present. As a result, the total heat transfer to the component is limited due to the acceleration of the release, which in turn counteracts potential loss of components due to thermal damage. Furthermore, by segmenting at least the adhesive layer between the components, the components can be more easily transferred. For example, shear forces during transfer can be alleviated if part of the adhesive layer can be released together with the component without being connected to surrounding parts of the adhesive layer, e.g. holding adjacent (non-t