Abstract
A method for forming a device coupon (100) includes providing a source wafer (1) with a source substrate (10); a sacrificial layer (11); and a film (12). At least one device coupon (100) is formed in the film (12). One or more designed breakable tethers is designed to secure the device coupon (100) to the film (12). The method includes etching one or more recesses (111) extending through the device coupon (100), thereby exposing the sacrificial layer (11); and etching the sacrificial layer (11) away at least partially through one or more of the recesses (111), thereby forming one or more sacrificial recesses (121) in the sacrificial layer (11). At least some pairs of recesses (111) and sacrificial recesses (121) are filled with a support material (200), thereby forming support structures (220) for device coupon (100).
Claims
1. A method for forming a device coupon for heterogeneous integration through micro-transfer printing for integrated photonics systems and/or integrated electronics systems, said method comprising the steps of: providing a source wafer comprising: a source substrate ; a sacrificial layer on top of said source substrate; and a film on top of said sacrificial layer; forming at least one device coupon in said film, wherein a device coupon is delimited by a periphery; designing one or more designed breakable tethers at said periphery, said designed breakable tethers being configured to secure said device coupon to said film; etching one or more recesses in said device coupon, said recesses extending through said device coupon, thereby exposing said sacrificial layer; partially etching said sacrificial layer away at least through one or more of said recesses, thereby forming one or more sacrificial recesses in said sacrificial layer between said device coupon and said source substrate; and filling at least some pairs of recesses and sacrificial recesses with a support material, thereby forming support structures for said device coupon (100) in said device coupon and in said sacrificial layer.
2. The method according to claim 1, wherein a distance from any point of said device coupon to an edge of a recess and a distance from any point of said device coupon to said periphery of said device coupon are smaller than ten times a collapsing length for said film.
3. The method according to claim 2, wherein said collapsing length is determined by the following method steps: providing said film on top of said sacrificial layer on top of a test substrate; defining a test device coupon in said film with a fixed predetermined width and extending over a length; etching said sacrificial layer away between said test device coupon and said test substrate, thereby suspending said test device coupon above said test substrate and forming a cavity extending between said test device coupon and said test substrate; and repeating said providing and said defining and said etching for different test device coupons of said fixed predetermined width and for increasing predetermined lengths for said test device coupons until a length for which a test device coupon first touches said test substrate along said fixed predetermined width, thereby determining said collapsing length.
4. The method according to claim 1, wherein said method further comprises the steps of etching said sacrificial layer away: at least partially between said designed breakable tethers and said source substrate, thereby forming breakable tethers; and at least partially between said device coupon and said source substrate, thereby at least partially suspending said device coupon above said source substrate and forming a cavity extending at least partially between said device coupon and said source substrate and at least partially around said device coupon; and wherein said breakable tethers bridge said cavity, thereby securing said device coupon to said film.
5. The method according to claim 1, wherein said support material is further provided on top of said device coupon.
6. A method for heterogeneously integrating a device coupon onto a target wafer via micro-transfer printing using the source wafer according to claim 4, wherein said method comprising the steps of: adhering said device coupon onto a stamp; lifting said device coupon adhered onto said stamp away from said source substrate, thereby breaking one or more of said breakable tethers; and pressing said device coupon onto said target wafer, thereby printing said device coupon onto said target wafer.
7. A method for heterogeneously integrating a device coupon onto a target wafer via micro-transfer printing using the source wafer according to claim 4, wherein said method comprising the steps of: adhering said support material onto a stamp; lifting said support material adhered onto said stamp and said device coupon away from said source substrate, thereby breaking one or more of said breakable tethers; and pressing said device coupon onto said target wafer, thereby printing said device coupon onto said target wafer.
8. The method according to claim 6, wherein said support structures formed in said sacrificial recesses are lifted together with said device coupon away from said source substrate; and wherein said method further comprises the step of forming target recesses on said target wafer configured to host said support structures when said device coupon is pressed onto said target wafer.
9. The method according to claim 6, wherein said support structures formed in said sacrificial recesses remain on said source substrate when said device coupon is lifted away from said source substrate.
10. The method according to claim 6, wherein said target wafer comprises one or more integrated optical structures.
11. A device manufactured using the method of claim 6.
12. A source wafer for heterogeneous integration through micro-transfer printing for integrated photonics systems and/or integrated electronics systems, said source wafer comprising: a source substrate; a film; wherein said film comprises at least one device coupon delimited by a periphery, wherein said device coupon comprises one or more recesses extending through said device coupon; one or more designed breakable tethers at said periphery and configured to secure said device coupon to said film; a sacrificial layer between said source substrate and said film, wherein said sacrificial layer comprises a sacrificial recess below one or more said recesses; a support material filling at least some pairs of recesses and sacrificial recesses, thereby forming support structures for said device coupon in said device coupon and in said sacrificial layer; and wherein a distance from any point of said device coupon to an edge of a recess and a distance from any point of said device coupon to said periphery of said device coupon are smaller than ten times a collapsing length for said film, wherein said collapsing length is determined by the following method steps: providing said film on top of said sacrificial layer on top of a test substrate; defining a test device coupon in said film with a fixed predetermined width and extending over a predetermined length; etching said sacrificial layer away between said test device coupon and said test substrate, thereby suspending said test device coupon above said test substrate and forming a cavity extending between said test device coupon and said test substrate; and repeating said defining and said etching for different test device coupons of said fixed predetermined width and for increasing predetermined lengths for said test device coupons until a predetermined length for which a test device coupon first touches said test substrate along said fixed predetermined width, thereby determining said collapsing length.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
[0138] Some example embodiments will now be described with reference to the accompanying drawings. The drawings depict cross-sections of source wafers and target wafers according to the present disclosure for clarity reasons. It is clear that the source wafers and the target wafers depicted in the accompanying drawings can have any shape and extend along any direction along the longitudinal direction 3 and/or the traverse direction 4, and/or a third direction 5 traverse to the longitudinal direction 3 and traverse to the traverse direction 4. The above directions are not repeated on all the accompanying drawings to keep the drawings simple.
[0139] FIGS. 1A and 1B schematically depict example embodiments of a source wafer according to the present disclosure.
[0140] FIG. 2A schematically depicts an example embodiment of a device coupon according to the present disclosure and comprising two recesses. FIGS. 2B and 2C schematically depict an example embodiment of a flexibility test for a film according to the present disclosure.
[0141] FIG. 3 schematically depicts an example embodiment of a source wafer according to the present disclosure.
[0142] FIG. 4 schematically depicts an example embodiment of a source wafer according to the present disclosure, wherein the sacrificial layer has been etched away and a device coupon is at least partially suspended above the source substrate.
[0143] FIG. 5 schematically depicts an example embodiment of a device coupon according to the present disclosure being lifted away from the source wafer.
[0144] FIG. 6 schematically depicts an example embodiment of a device coupon according to the present disclosure being printed onto a target wafer.
[0145] FIG. 7 schematically depicts an example embodiment of a device coupon according to the present disclosure being printed onto a target wafer.
[0146] FIG. 8 schematically depicts an example embodiment of a device coupon according to the present disclosure being printed onto a target wafer comprising one or more target recesses.
[0147] FIG. 9 schematically depicts an example embodiment of a device coupon according to the present disclosure being printed onto a target wafer comprising one or more target recesses.
[0148] FIG. 10 schematically depicts an example embodiment of a device coupon according to the present disclosure printed onto a target wafer comprising one or more target recesses.
[0149] FIG. 11 schematically depicts an example embodiment of a device coupon according to the present disclosure printed onto a target wafer comprising one or more target recesses.
[0150] FIG. 12 schematically depicts an example embodiment of a device coupon according to the present disclosure printed onto a target wafer.
[0151] FIG. 13 schematically depicts an example embodiment of a device coupon according to the present disclosure printed onto a target wafer.
detailed description of embodiment(s)
[0152] FIG. 1A schematically depicts an example embodiment of a source wafer 1 according to the present disclosure. A source wafer 1 comprises a source substrate 10, a sacrificial layer 11 on top of the source substrate 10, and a film 12 on top of the sacrificial layer 11. At least one device coupon 100 is formed in the film 12. One or more breakable tethers secure the device coupon 100 to the source substrate 10. The device coupon 100 comprises one or more recesses 111 extending through the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. The sacrificial layer 11 is etched away at least partially through one or more of the recesses 111, thereby forming one or more sacrificial recesses 121 in the sacrificial layer 11 between the device coupon 100 and the source substrate 10. A support material 200 is provided in at least some pairs of recesses 111 and sacrificial recesses 121, thereby forming support structures 220 for the device coupon 100 in the sacrificial layer 11.
[0153] FIG. 1B schematically depicts an example embodiment of a source wafer 1 according to the present disclosure. A source wafer 1 comprises a source substrate 10, a sacrificial layer 11 on top of the source substrate 10, and a film 12 on top of the sacrificial layer 11. At least one device coupon 100 is formed in the film 12. One or more breakable tethers secure the device coupon 100 to the source substrate 10. The device coupon 100 comprises one or more recesses 111 extending through the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. The sacrificial layer 11 is etched away at least partially through one or more of the recesses 111, thereby forming one or more sacrificial recesses 121 in the sacrificial layer 11 between the device coupon 100 and the source substrate 10. A support material 200 is provided in at least some pairs of recesses 111 and sacrificial recesses 121, thereby forming support structures 220 for the device coupon 100 in the sacrificial layer 11. The support material 200 is further provided on top of the device coupon 100.
[0154] FIG. 2A schematically depicts an example embodiment of a design limitation for the support structures according to the present disclosure. A device coupon 100 is depicted in top view. The device coupon 100 comprises one or more recesses 111 which are etched completely through a thickness of the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. For each recess 111, a sacrificial recess is etched in the sacrificial layer 11. Point P in the device coupon 100 can be any point at the top surface of the device coupon 100. Alternatively, point P in the device coupon 100 can be any point defined through the thickness of the device coupon 100. Support structures 220 are formed out of a support material 200 in the pairs of recesses 111 and sacrificial recesses. A distance 21 from point P to a periphery 25 of the device coupon 100 is smaller than 10 times a collapsing length for the film in which the device coupon 100 is formed. A distance 22 from point P to an edge of a recess 111 of the device coupon 100 is smaller than 10 times a collapsing length for the film in which the device coupon 100 is formed.
[0155] FIG. 2B schematically depicts a top view of an example embodiment of a test device coupon 400 for a flexibility test for the film in which a device coupon is formed. FIG. 2C schematically depicts a side view of an example embodiment of a test device coupon 400 for a flexibility test for the film in which a device coupon is formed. For the flexibility test for a film, the film is provided on top of the sacrificial layer 11 on top of a test substrate 50. A test device coupon 400 is formed in the film 12 with a fixed predetermined width 24 and extends over a length 23. The sacrificial layer 11 is etched away between the test device coupon 400 and the test substrate 50, thereby suspending the test device coupon 400 above the test substrate 50 and forming a cavity 52 extending between the test device coupon 400 and the test substrate 50. This test is repeated for different test device coupons 400 with the fixed predetermined width and for increasing lengths for the test device coupons 400 until a length for which a test device coupon 400 first touches the test substrate 50 along the fixed predetermined width, thereby determining a collapsing length for the film.
[0156] FIG. 3 schematically depicts an example embodiment of a source wafer 1 according to the present disclosure. FIG. 3 depicts a first step of a method for micro-transfer printing according to the present disclosure. A source wafer 1 comprises a source substrate 10, a sacrificial layer 11 on top of the source substrate 10, and a film 12 on top of the sacrificial layer 11. At least one device coupon 100 is formed in the film 12. One or more breakable tethers secure the device coupon 100 to the source substrate 10. The device coupon 100 comprises one or more recesses 111 extending through the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. The following method step is depicted in FIG. 1A or FIG. 1B and consists in etching the sacrificial layer 11 away through the recesses 111, thereby forming one or more sacrificial recesses 121 in the sacrificial layer 11.
[0157] FIG. 4 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A source wafer 1 comprises a source substrate 10, a sacrificial layer 11 on top of the source substrate 10, and a film 12 on top of the sacrificial layer 11. At least one device coupon 100 is formed in the film 12. One or more breakable tethers 110 secure the device coupon 100 to the source substrate 10 when the sacrificial layer 11 is etched away at least partially between designed breakable tethers 110 and the source substrate 10. The device coupon 100 comprises one or more recesses 111 extending through the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. The sacrificial layer 11 is etched away at least partially through one or more of the recesses 111, thereby forming one or more sacrificial recesses 121 in the sacrificial layer 11 between the device coupon 100 and the source substrate 10. A support material 200 is provided in at least some pairs of recesses 111 and sacrificial recesses 121, thereby forming support structures 220 for the device coupon 100 in the sacrificial layer 11. The sacrificial layer 11 is etched at least partially between the device coupon 100 and the source substrate 10, thereby suspending the device coupon 100 at least partially above the source substrate 10 and forming a cavity 51 extending at least partially between the device coupon 100 and the source substrate 10 and at least partially around the device coupon 100. The breakable tethers 110 bridge the cavity 51.
[0158] FIG. 5 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A source wafer 1 comprises a source substrate 10, a sacrificial layer 11 on top of the source substrate 10, and a film 12 on top of the sacrificial layer 11. At least one device coupon 100 is formed in the film 12. One or more breakable tethers 110 secure the device coupon 100 to the source substrate 10 when the sacrificial layer 11 is etched away at least partially between designed breakable tethers 110 and the source substrate 10. The device coupon 100 comprises one or more recesses 111 extending through the device coupon 100, thereby exposing the sacrificial layer 11 through the recesses 111. The sacrificial layer 11 is etched away at least partially through one or more of the recesses 111, thereby forming one or more sacrificial recesses 121 in the sacrificial layer 11 between the device coupon 100 and the source substrate 10. A support material 200 is provided in at least some pairs of recesses 111 and sacrificial recesses 121, thereby forming support structures 220 for the device coupon 100 in the sacrificial layer 11. The sacrificial layer 11 is etched at least partially between the device coupon 100 and the source substrate 10, thereby suspending the device coupon 100 at least partially above the source substrate 10 and forming a cavity 51 extending at least partially between the device coupon 100 and the source substrate 10 and at least partially around the device coupon 100. The breakable tethers 110 bridge the cavity 51. A stamp 40 is adhered onto the support material 200 provided on top of the device coupon 100. The support material 200 adhered onto the stamp 40 and the device coupon 100 are lifted away from the source substrate 10, thereby breaking one or more of the breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film 12. According to an alternative embodiment, no support material 200 is provided on top of the device coupon 100. A stamp 40 is adhered onto the device coupon 100. The device coupon 100 is lifted away from the source substrate 10, thereby breaking one or more of the breakable tethers 110. As depicted on FIG. 5, the support structures 220 formed in the sacrificial recesses 121 are lifted together with the device coupon 100 away from the source substrate 10. According to an alternative embodiment, the support structures 220 formed in the sacrificial recesses 121 remain on the source substrate 10 when the device coupon 100 is lifted away from the source substrate 10.
[0159] FIG. 6 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A stamp 40 is adhered onto the device coupon 100. The device coupon 100 has been lifted away from a source substrate, thereby breaking one or more breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses remain on the source substrate when the device coupon 100 is lifted away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31.
[0160] FIG. 7 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A stamp 40 is adhered onto the support material 200 provided on top of the device coupon 100. The support material 200 adhered onto the stamp 40 and the device coupon 100 are lifted away from the source substrate, thereby breaking one or more of the breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses remain on the source substrate when the device coupon 100 is lifted away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31.
[0161] FIG. 8 schematically depicts an alternative embodiment of a method step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A stamp 40 is adhered onto the device coupon 100. The device coupon 100 has been lifted away from a source substrate, thereby breaking one or more breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses are lifted together with the device coupon 100 away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31. The target wafer 30 further comprises one or more target recesses 310 formed to host the support structures 220 when the device coupon 100 is pressed onto the target wafer 30.
[0162] FIG. 9 schematically depicts an alternative embodiment of a method step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. A stamp 40 is adhered onto the support material 200 provided on top of the device coupon 100. The support material 200 adhered onto the stamp 40 and the device coupon 100 are lifted away from the source substrate, thereby breaking one or more of the breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses are lifted together with the device coupon 100 away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31. The target wafer 30 further comprises one or more target recesses 310 formed to host the support structures 220 when the device coupon 100 is pressed onto the target wafer 30.
[0163] FIG. 10 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. Support material 200 is provided on top of the device coupon 100. The support material 200 adhered onto a stamp and the device coupon 100 are lifted away from the source substrate, thereby breaking one or more of the breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses are lifted together with the device coupon 100 away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31. The target wafer 30 further comprises one or more target recesses 310 formed to host the support structures 220 when the device coupon 100 is pressed onto the target wafer 30.
[0164] FIG. 11 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. The support material 200 of FIG. 10 is stripped away from the assembly formed by the device coupon 100 and the target wafer 30, i.e. is stripped away from the recesses 111, from the target recesses 310 and optionally from above the device coupon 100.
[0165] FIG. 12 schematically depicts an alternative embodiment of a method step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. Support material 200 is provided on top of the device coupon 100. The support material 200 adhered onto a stamp and the device coupon 100 are lifted away from the source substrate, thereby breaking one or more of the breakable tethers 110. A broken breakable tether 110 comprises a first portion remaining coupled to the device coupon 100 and a second portion remaining coupled to the film on the source wafer. The support structures 220 formed in the sacrificial recesses remain on the source substrate when the device coupon 100 is lifted away from the source substrate. The device coupon 100 is pressed onto a target wafer 30, thereby printing the device coupon 100 onto the target wafer 30. The target wafer 30 for example comprises several layers and for example a target substrate. The target wafer 30 for example comprises one or more integrated optical structures 31.
[0166] FIG. 13 schematically depicts the following step of a method for micro-transfer printing according to the present disclosure. Components having identical reference numbers than on previous figures fulfill the same function. The support material 200 of FIG. 10 is stripped away from the assembly formed by the device coupon 100 and the target wafer 30, i.e. is stripped away from the recesses 111 and optionally from above the device coupon 100.
[0167] Although the present invention has been illustrated by reference to specific embodiments, it will be apparent to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied with various changes and modifications without departing from the scope thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the scope of the claims are therefore intended to be embraced therein.
[0168] It will furthermore be understood by the reader of this patent application that the words comprising or comprise do not exclude other elements or steps, that the words a or an do not exclude a plurality, and that a single element, such as a computer system, a processor, or another integrated unit may fulfil the functions of several means recited in the claims. Any reference signs in the claims shall not be construed as limiting the respective claims concerned. The terms first, second, third, a, b, c, and the like, when used in the description or in the claims are introduced to distinguish between similar elements or steps and are not necessarily describing a sequential or chronological order. Similarly, the terms top, bottom, over, under, and the like are introduced for descriptive purposes and not necessarily to denote relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances and embodiments of the invention can operate according to the present invention in other sequences, or in orientations different from the one(s) described or illustrated above.
