Device for separating two substrates

Abstract

This disclosure relates to a device for separating two substrates to be utilized in electronics, optics, optoelectronics and/or photovoltaics. The device separates the substrates at an interface, the device comprising a holder; a member for retaining the structure, the member being mounted on the holder; a tool for separating the two substrates, also mounted on the holder; and means for moving the separating tool and/or means for moving the retaining member relative to the holder so as to bring them closer together or move them farther apart from each other, preferably over a limited range of travel. This device is noteworthy in that the separating tool comprises a leading edge that has, in cross-section, in succession from its tip or its front edge to its back, a tapered portion that is extended by a flared portion.

Claims

1. A device for separating two substrates at a separation interface, at least one of the two substrates being intended to be used in electronics, optics, optoelectronics and/or photovoltaics, the two substrates together forming a structure, the device comprising: a holder; a member for retaining the structure, the member being mounted on the holder; a separating tool for separating the two substrates, the separating tool also mounted on the holder, the separating tool comprising a leading edge having, in cross-section, in succession from a tip or a front edge thereof to a back thereof, a tapered portion that is extended by a flared portion that is extended by a back portion; and moving means for providing relative movement between the separating tool and the retaining member, the moving means making it possible to move the tool and/or member relative to the holder so as to bring the separating tool and the retaining member closer together or move the separating tool and the retaining member farther apart from each other; wherein: the tapered portion of the separating tool has an isosceles-triangle-shaped cross-section having two sides, an angle at a tip of the isosceles-triangle-shaped cross-section having a non-zero angle that is lower than 30, a height of the isosceles-triangle-shaped cross-section of the tapered portion being between 2 mm and 20 mm; the flared portion has an isosceles-trapezium-shaped cross-section having two sides adjacent to and extending away from the two sides of the tapered portion, an angle between the two sides at a tip of the isosceles-trapezium-shaped cross-section being larger than 30, a height of the isosceles-trapezium-shaped cross-section of the flared portion being between 10 mm and 100 mm; the back portion has a rectangular parallelepiped-shaped cross-section having two sides adjacent to and extending away from the two sides of the flared portion, the border between the flared portion and the back portion being configured to support the two substrates without the two substrates contacting the tapered portion once the separating tool penetrates a distance therebetween; and the separating tool has a longitudinal, vertical plane of symmetry passing through the tip or the front edge to the back of the separating tool, each of the two sides of the tapered portion, the flared portion and the back portion is symmetric with respect to the longitudinal, vertical plane of symmetry.

2. The device of claim 1, wherein a thickness of the separating tool measured level with a base of the isosceles-trapezium-shaped cross-section of the flared portion is larger than two times the product of the tangent of half the angle at the tip of the isosceles-triangle-shaped cross-section of the tapered portion and the height of the isosceles-triangle-shaped cross-section of the tapered portion.

3. The device of claim 1, wherein the leading edge of the separating tool is an elongate rectilinear element.

4. The device of claim 1, wherein the separating tool comprises a fluoropolymer or a material covered with a lubricant.

5. The device of claim 4, wherein the separating tool comprises polytetrafluoroethylene.

6. The device of claim 4, wherein the separating tool comprises a material covered with a lubricant.

7. The device of claim 1, wherein the retaining member comprises a vertical retaining groove, the groove having a bottom and two lateral walls inclined upward and toward an exterior of the groove, the groove allowing the structure or the two substrates to be retained in an at least substantially vertical position, and wherein the moving means are configured to move the separating tool and/or the retaining member in a vertical plane.

8. The device of claim 7, wherein an angle between the two lateral walls is larger than or equal to 8.

9. The device of claim 7, wherein the vertical retaining groove is circularly arcuate in shape.

10. The device of claim 7, wherein: the retaining groove has a longitudinal, vertical plane of symmetry passing through the bottom of the groove; and the retaining member and the separating tool are mounted on the holder so that the separating tool is located above the retaining member and so that their respective vertical planes of symmetry are coincident.

11. The device of claim 7, wherein the bottom of the vertical retaining groove has a width between about 1.5 mm and 4 mm.

12. The device of claim 7, wherein a depth of the vertical retaining groove is at least 10 mm.

13. The device of claim 7, further comprising a central rest protruding vertically from the bottom of the vertical retaining groove.

14. The device of claim 13, wherein the rest has a height between 50 m and 600 m and a width between 50 m and 300 m.

15. The device of claim 13, further comprising a spring housed in a void in the bottom of the groove, the rest mounted on the spring so as to be vertically movable.

16. The device of claim 1, wherein the separating tool further includes a spray nozzle in a central portion of the separating tool, the spray nozzle connected to a source for supplying a liquid to the spray nozzle.

17. The device of claim 16, wherein the liquid has a composition promoting the separation of the two substrates at the separation interface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other features and advantages of the disclosure will become apparent from the description that will now be given thereof, with reference to the accompanying drawings, that show, by way of nonlimiting indication, one possible embodiment thereof. In these drawings:

(2) FIG. 1 is a schematic showing the method used by Maszara to determine the bonding energy between two substrates;

(3) FIGS. 2 and 4 are schematic cross-sectional views of two embodiments of the separating tool of the device according to the disclosure, two substrates having furthermore been schematically shown in FIG. 2;

(4) FIGS. 3 and 5 are perspective views of two other embodiments of the separating tool;

(5) FIGS. 6 and 7 are schematics showing vertical cross-sections through two variant embodiments of the retaining member of the separating device according to the disclosure; and

(6) FIGS. 8 and 9 are a front and side view, respectively, of one embodiment of the separating device according to the disclosure.

DETAILED DESCRIPTION

(7) One possible embodiment of the device for separating two substrates according to the disclosure will now be described with reference to FIGS. 8 and 9.

(8) Generally, this device comprises a holder 1, a member 2 for retaining the structure to be separated, a separating tool 3, and means 4 and 5 for moving the separating tool 3 and the retaining member 2, respectively, relative to the holder 1.

(9) However, it will be noted that the device could comprise only one of the two moving means 4 or 5.

(10) The holder 1 is a flat rectangular plate. It could have another shape provided that it allows the member 2 and the tool 3 to be mounted and operated as described below.

(11) The separating device, shown in FIGS. 8 and 9, is intended to receive a structure to be separated that is arranged vertically and it allows the separation to be carried out in a vertical plane. Therefore, the plate of the holder 1 is erected vertically and, in the rest of the description and in the claims, the terms vertical, horizontal, upper, lower, top and bottom are to be taken into consideration relative to the position of the separating device shown in FIGS. 8 and 9.

(12) However, this separating device could be used horizontally.

(13) A first embodiment of the separating tool 3 will now be described with reference to FIG. 3.

(14) The separating tool 3 comprises a front portion 30 or leading edge that is extended by a back portion 31.

(15) The back portion 31 preferably has the shape of a rectangular parallelepiped and serves for fastening to the holder 1.

(16) The leading edge 30 itself comprises, in succession from front to back (i.e., from right to left in FIG. 3), a tapered portion 32 and a flared portion 33.

(17) The tapered portion 32 has the shape of a triangular prism, the base of which is an isosceles triangle. The two isosceles triangle-shaped end faces are referenced 321, whereas the two longitudinal rectangular faces located in the extension of the sides of the same length of the two isosceles triangles 321 are referenced 322. The free edge or front edge of the prism, located at the junction of the two faces 322, has been given the reference 323.

(18) The angle between the two lateral faces 322, designated the angle at the tip below, is smaller than 30 and preferably equal to 10.

(19) The height H1 of the end face 321 is advantageously between 2 mm and 20 mm and preferably equal to 10 mm.

(20) The flared portion 33 has the shape of a six-faced polyhedron, the two end faces 331 of which are isosceles-trapezium shaped. The two longitudinal rectangular faces located in the extension of the sides of the same length of the two isosceles trapeziums 331 are referenced 332.

(21) The angle between the two longitudinal faces 332 is larger than 30 and preferably equal to 60.

(22) The height H2 of the end face 331 is advantageously between 10 mm and 100 mm and is preferably equal to 50 mm.

(23) Lastly, the thickness e of the separating tool 3 measured level with the base of the trapezoidal face 331 is advantageously larger than two times the product of the tangent of half the angle at the tip of the tapered portion 32 and the height H1 of the same portion, and is preferably equal to 50 mm.

(24) Moreover, it will be noted that the leading edge 30 has a longitudinal plane of symmetry P1 that includes the front edge 323.

(25) The leading edge 30 has the general shape of an elongate rectilinear element.

(26) A variant embodiment of the separating tool (referenced 3) will now be described with reference to FIG. 2.

(27) The separating tool 3 differs from the tool 3 described above in that the tapered portion 32 of its leading edge 30 has the shape of a cone of angle at the tip (tip referenced 320) and in that the flared portion 33 has the shape of a truncated cone of angle . The back portion 31 preferably has a cylindrical shape.

(28) The other dimensions remain identical.

(29) The separating tool 3 has a multitude of planes of symmetry passing through its axis of revolution X-X. Only one, referenced P2, has been depicted in FIG. 2.

(30) The gradient of the exterior wall of the leading edge of the tools 3 and 3 therefore changes abruptly.

(31) A second embodiment of the separating tool (referenced 3) will now be described with regard to FIG. 5.

(32) It differs from the tool 3 in that its leading edge 30 has the general shape of a prism, the base of which has the shape of an isosceles triangle but the two equal sides of which are concave. The back portion 31 preferably has the shape of a rectangular parallelepiped.

(33) The two end faces are referenced 301, the two concave faces 302 and the edge that joins them 303.

(34) Also, preferably, each face 302 has the profile of a half parabola, the tip of the parabola being located level with the intersection of the back portion 31.

(35) The leading edge 30, therefore, again has a tapered portion 32 and a flared portion 33, but its gradient does not change abruptly. Furthermore, it has the general shape of an elongate rectilinear element.

(36) The height H3 of the face 301 is preferably between 10 mm and 120 mm and, even more preferably, is equal to 60 mm. Its thickness e1 is preferably larger than 1 mm, more preferably between 1 mm and 65 mm or, even more preferably, is equal to 50 mm.

(37) Lastly, the leading edge 30 has a longitudinal plane of symmetry P3 that includes the front edge 303.

(38) The concave shape of the faces 302 (and all the more so, the semi-parabolic shape of the latter) is particularly advantageous, because it makes it possible to make the advance of the separating tool proportional to the advance of the separating wave that separates the two substrates of the structure to be separated.

(39) Specifically, it is known that the length L of the separating wave between the two substrates is proportional to the square root of the distance by which the two substrates are parted.

(40) A variant embodiment of the separating tool, referenced 3, is described below with reference to FIG. 4.

(41) The tool 3 differs from the tool 3 in that its leading edge 30, which is made up of a tapered portion 32 and a flared portion 33, has the shape of a cone, the peripheral wall of which is concave and preferably parabolic. The back portion 31 is preferably cylindrical. The tip of the cone is referenced 320.

(42) One of its planes of symmetry P4 passing through its axis of revolution X1-X1 has been shown in FIG. 4.

(43) The separating tool 3, 3, 3, 3 or, at the very least, its leading edge 30, 30, 30, 30 is preferably made of a material having a low coefficient of friction, such as polytetrafluoroethylene (PTFE), or of a material covered with a lubricant.

(44) A first embodiment of the retaining member 2 will now be described with reference to FIGS. 6, 8 and 9.

(45) The member 2 for retaining the structure to be separated has the general shape of a rectangular parallelepiped, the upper longitudinal face 20 of which is curved into a circular arc, preferably of about 70. Seen from the front, this retaining member, therefore, has a concave shape, the concavity of which is oriented upward.

(46) The upper face 20 contains over its entire length a longitudinal groove 21 that is open upward.

(47) As is more clearly shown in the detail view in FIG. 6, this groove 21 has a bottom 210, bordered by two inclined walls 211 and 212.

(48) These inclined lateral walls 211 and 212 make an angle between them, this angle preferably being larger than or equal to 8.

(49) The width L1 of the bottom 210 is preferably between 1.5 mm and 4 mm. Below 1.5 mm, it would be difficult to insert therein a structure composed of two substrates, such as those that are commonly found on the market.

(50) Moreover, the height H4 of the groove 21 is preferably at least 10 mm in order to correctly retain the edge of the structure, the diameter of which may be as much as 300 mm.

(51) The groove 21 furthermore has a vertical longitudinal plane of symmetry P5 that follows the bottom 210.

(52) A variant embodiment of the retaining member will now be described with reference to FIG. 7.

(53) This retaining member is referenced 2. It differs from the retaining member 2 only in the shape of its groove 21.

(54) The latter has a bottom 210, bordered by two longitudinal lateral walls 211, 212, that are inclined upward and toward the exterior, and that make between them an angle that is preferably larger than or equal to 8. The bottom 210 follows the circularly arcuate contour of the upper face 20.

(55) Preferably, the width L2 of the bottom 210 is between 1.5 mm and 4 mm and its height H5 is at least 10 mm.

(56) Furthermore, and contrary to the preceding embodiment, the bottom 210 is equipped with a central rest 213 advantageously having, in vertical cross-section, the shape of an isosceles triangle, the tip 216 of which is directed upward. Preferably, the height H6 of the rest 213 is between 50 m and 600 m and its width L3 is between 50 m and 300 m. It will be noted, that for this reason, the rest 213 has been shown at a larger scale than that of the rest of the groove 21.

(57) This rest 213 has, in longitudinal vertical cross-section, the shape of a portion of a circular arc that follows the contour of the upper face 20 of the retaining member 2.

(58) Advantageously, the rest 213 is mounted on a spring 214 housed in a void 215 provided in the bottom 210.

(59) The spring 214 permanently tends to repel the rest 213 upward.

(60) Lastly, the groove 21 has a longitudinal vertical plane of symmetry referenced P6.

(61) As may be seen in FIGS. 8 and 9, the separating tool 3 and the retaining member 2 are mounted on the holder 1 so that the tool 3 is above the member 2 and so that their respective planes of symmetry P1 and P5 are coincident and oriented vertically. The same is likewise true if the retaining member 2 is replaced by the retaining member 2 of plane of symmetry P6 and/or if the separating tool 3 is replaced by the separating tool 3, 3 or 3 of respective planes of symmetry P2, P3, P4.

(62) Advantageously, the separating tool 3, 3, 3, 3 is equipped with moving means 4 that allow it to be moved vertically relative to the holder 1, in order to bring it closer to or, in contrast, move it farther away from the retaining member 2, 2, preferably over a limited range of travel.

(63) In the embodiment shown in FIGS. 8 and 9, means 4 are manual means consisting of a crank 40, a threaded rod 42 of which moves inside a tapped longitudinal orifice produced vertically in a part 41 that is securely fastened to the holder 1. Rotating the crank 40 causes the separating tool 3, 3, 3 or 3 to move in the vertical plane of symmetry P1, P2, P3 or P4 in a direction illustrated by the axis Z-Z and the arrow F (see FIG. 8).

(64) In an industrial version of the device, means 4 could, for example, consist of a hydraulic cylinder.

(65) The retaining member 2, 2 may also be equipped with moving means 5 that allow it to be moved vertically relative to the holder 1, in order to bring it closer to or, in contrast, move it farther away from the separating tool 3, 3, 3, 3, preferably over a limited range of travel. This movement occurs in the vertical plane of symmetry P5 or P6, in a direction illustrated by the axis Z-Z and the arrow G (see FIG. 8). The range of travel is limited to about several centimeters.

(66) Means 5 are only schematically shown in FIGS. 8 and 9. They may be identical to the moving means 4.

(67) Lastly, the device advantageously also comprises a spray nozzle 6 of axis Z-Z, arranged within the separating tool 3, 3, 3 or 3 so as to open level with the front edge 323, 303 or with the tip of the cone 320, 320.

(68) Spray nozzle 6 is connected to a source for supplying a liquid promoting the separation of the substrates, such as deionized water, this source not being shown in the figures.

(69) The separating device operates in the following way.

(70) The structure to be separated comprising the two substrates is inserted into the separating device so that a portion of its edge rests in the groove 21 of the retaining member 2, the groove 21 of the retaining member 2, respectively. The circularly arcuate shape of the retaining member 2, 2 closely follows the outline of the edge of the disc-shaped structure to be separated.

(71) Temporary retaining means 7, shown only schematically in FIG. 8, allow the structure to be separated to be held in a vertical plane that is coincident with the planes P1, P2, P3, P4, P5 and/or P6. It is, for example, a question of retractable fingers that are movable laterally toward the interior or exterior (arrows H).

(72) Once the retaining member 2, 2 and the separating tool 3, 3, 3, 3 have been brought sufficiently close to each other that the front edge 323, 303 or the tip 320, 320 of the separating tool 3 or 3, respectively, has made contact with the chamfers bordering the two substrates making up the structure to be separated, temporary retaining means 7 are withdrawn.

(73) The movement of the retaining member 2, 2 and/or the separating tool 3, 3, 3, 3 is continued until the separating tool, which penetrates between the two substrates, exerts a corner effect and causes the structure to separate along a separating interface, as described above.

(74) By virtue of the features of the disclosure, and especially by virtue of the shape of the leading edge of the separating tool 3, 3, 3, 3, the separating process is improved.

(75) The tapered portion 32, 32, 32, 32 makes it possible to ensure better control of the progression of the tool at the start of its insertion between the two substrates, since its penetration distance corresponds to the two substrates being parted a small amount. Furthermore, the resultant of the forces J exerted by the tapered portion on the edge of the substrates S (see FIG. 2) is almost perpendicular to the plane of separation of the two substrates, thereby improving the effectiveness of the separation.

(76) The flared portion 33, 33, 33, 33 for its part makes it possible to propagate the separating wave, to reinforce the corner effect during the separation and to limit the risk of scratching the faces of the substrates located on either side of the separating interface. Specifically, once the separating tool 3, 3, 3, 3 penetrates a little farther between the two substrates, the latter only now rest by their border on the faces of the flared portion 33, 33, 33, 33 and no longer make contact with the tapered portion 32, 32, 32, 32.

(77) Moreover, by virtue of the preferentially vertical arrangement of the separating device, combined with the shape of the groove 21, 21 equipped with inclined lateral walls 211, 211 and 212, 212, the structure to be separated is not subjected to any external stresses during the separation (except for the action of the tool 3, 3, 3, 3). Thus, the two substrates part freely from each other, under the effect of their own weight, once the separation has been initiated, and each comes to rest against one of the inclined walls 211, 211 and 212, 212. This was not the case with the prior art device described in the aforementioned U.S. Pat. No. 7,406,994.

(78) The two substrates are then in positions that are sufficiently far apart from each other for them not to accidentally remake contact.

(79) When the retaining member 2 is used, it will be noted that the rest 213 tends to be pressed into the void 215, against the force of the spring 214, under the action of the weight of the structure. Once the separation has been carried out, the rest 213 tends to return to its original position, in which it also participates in preventing the two previously separated substrates from remaking contact with each other.

(80) Lastly, it will be noted that the beneficial effect on the separation, this effect being obtained by virtue of the shape of the separating tool, would also be obtained even if the separating device were arranged horizontally.

(81) The spray nozzle 6 is used to inject a separating liquid once the separation of the two substrates has been initiated, this promoting the propagation of the separating wave.