Method and device for coating a product substrate

Abstract

A method and device for coating projecting surfaces of discrete projections of a product substrate that has functional units arranged at least partially in recesses. The method includes the steps of: bringing the projecting surfaces into contact with a coating material that is applied on a carrier substrate, and separating the carrier substrate from the projecting surfaces in such a way that the coating material remains partially on the product substrate. In addition, this invention relates to a corresponding device.

Claims

1. A method for coating a substrate surface, the method comprising: providing a product substrate including (i) a plurality of projections having respective projecting surfaces and (ii) a plurality of recesses that are located between the plurality of projections, wherein functional units are at least partially arranged in the plurality of recesses, said functional units including at least one of a microelectronic system or a micromechanical system, providing a carrier substrate with a coating material applied to a surface thereof, contacting the projecting surfaces of the product substrate with the coating material applied to the surface of the carrier substrate, applying a force load to transfer a portion of the coating material from the surface of the carrier substrate to the projecting surfaces of the product substrate, wherein said force load includes a first force applied to a side of the carrier substrate facing away from the projecting surfaces, said force load applied after and/or during the contacting of the projecting surfaces with the coating material, and separating the carrier substrate from the product substrate such that the portion of the coating material transferred to the product substrate remains at least partially on the projecting surfaces, wherein separating the carrier substrate from the product substrate includes successively stripping the carrier substrate from the plurality of projections.

2. The method according to claim 1, wherein, after separating the carrier substrate from the product substrate, the portion of the coating material transferred to the product substrate remains predominantly on the projecting surfaces.

3. The method according to claim 1, wherein, after separating the carrier substrate from the product substrate, the portion of the coating material transferred to the product substrate remains exclusively on the projecting surfaces.

4. The method according to claim 1, wherein portions of each of the functional units arranged in the plurality of recesses are not exposed to the coating material.

5. The method according to claim 1, wherein the carrier substrate is a flexible carrier film.

6. The method according to claim 1, wherein the force load includes a second force that is applied in a direction opposite to a direction of the first force.

7. The method according to claim 1, wherein the method further comprises encapsulating the functional units after separating the carrier substrate from the product substrate, said encapsulating including bonding at least one cover to the coating material on the projecting surfaces of the plurality of projections.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1a a diagrammatic side view, not to scale, of a first embodiment of a structured product substrate according to the invention,

(2) FIG. 1b a diagrammatic side view, not to scale, of a second embodiment of the structured product substrate,

(3) FIGS. 2a to 2g diagrammatic side views, not to scale, of process steps of an embodiment of a method according to the invention,

(4) FIG. 3a a diagrammatic side view, not to scale, of a first end product (packaging of functional units),

(5) FIG. 3b a diagrammatic side view, not to scale, of a second end product (packaging of functional units), and

(6) FIG. 4 a diagrammatic sketch of an embodiment of a device according to the invention.

(7) In the figures, the same components and components with the same function or components in different processing states are identified with the same reference numbers.

DETAILED DESCRIPTION OF THE INVENTION

(8) FIG. 1a shows a diagrammatic side view, not to scale, of a product substrate 3, comprising: A wafer 4, on which several projections 5 are formed, Functional units 6, which are to be encapsulated, are arranged between the projections 5.

(9) The wafer 4 has a mean thickness t1. The entire thickness of the structured product substrate 3 is consequently greater than t1.

(10) FIG. 1b shows a diagrammatic side view, not to scale, of a structured product substrate 3, comprising: A wafer 4, produced in particular by etching, with multiple projections 5, which are created by the etching of recesses 7, The functional units 6, which are to be encapsulated, are arranged between the projections 5, i.e., in the recesses 7.

(11) The wafer 4 has a mean thickness t1. In this embodiment, the total thickness of the structured product substrate 3 is in particular equal to the thickness t1.

(12) The first process step of the carrier substrate preparation according to the invention is depicted in FIG. 2a. In this case, a carrier substrate 1 is laid down on or attached to a specimen holder 10 with a side that faces away from a carrier substrate surface 1o. The attachment is made by attaching means 11, in particular vacuum strips, on which a vacuum can be applied. Also conceivable are electrostatic, electric, adhesive, magnetic or mechanical attachments, which ensure that the carrier substrate 1 is attached relative to the specimen holder 10 and remains attached.

(13) In this case, the carrier substrate 1 is a carrier film. In the first process step, cleaning of the carrier substrate surface 1o can be carried out. This is primarily necessary when the carrier substrate surface 1o was already coated in a preceding process step with a coating material 2 and is now to be reused.

(14) FIG. 2b shows a second process step according to the invention, in which a coating material 2 is deposited on the carrier substrate surface 1o. The deposition is carried out preferably in a centrifugal enameling unit, as an alternative in a spray-enameling unit. A material layer thickness t3 can be set very precisely and lies preferably in the micrometer range or even more preferably in the nanometer range.

(15) In a third process step according to the invention in accordance with FIG. 2c, a rough adjustment of the structured product substrate 3 is carried out, including the wafer 4 with ridges 5 in relation to the carrier substrate 1 that is prepared with the coating material 2. In this case, the structured product substrate 3 is also attached by attaching means 11 from a specimen holder 10. An exact adjustment of the structured specimen holder 3 relative to the carrier substrate 1 is not necessary, since projecting surfaces 5o of the projections 5 are located at each position via a part of the coating material 2 and come into contact with the latter in the case of subsequent contact.

(16) In the subsequent figures, the carrier substrate 1 is always shown on the bottom on its specimen holder 10, although in the implementation of the process according to the invention, a laying-down or lamination of the carrier substrate 1, in particular a carrier film, on the structured product substrate 3 is preferable. In addition, it is disclosed that the specimen holder 10, to which the carrier substrate 1 is attached, is in particular an attaching system of a laminating device, which attaches, in particular tensions, the carrier substrate 1, in particular a carrier film, so that it can be laminated on the structured product substrate 3 that is to be coated. Thus, the carrier substrate 1 does not rest on the full surface.

(17) in a fourth process step according to the invention in accordance with FIG. 2d, the projecting surfaces 5o make contact with the coating material 2. In this process step, the structured product substrate 3 can be considered as a type of stamp. The transfer of the coating material 2 to the projecting surfaces 5o is preferably promoted, enhanced, or even first made possible by a force, in particular a surface force F.

(18) In a special, in particular alternative or additional, process step according to the invention in accordance with FIG. 2e, a more optimal material transfer is carried out by the application of a moving force transfer means 12, in particular a roller. The force transfer means 12 in this case exerts a force F, in particular a line force, on a rear side of the carrier substrate 1, in particular a carrier film, and thus promotes the material transfer from the carrier substrate 1 to the projecting surfaces 5o. The process step according to the invention in accordance with FIG. 2e can be combined with the process step according to the invention in accordance with FIG. 2d if the specimen holder 10, which is attached to the carrier substrate 1, is elastic enough to allow the force transfer of the force transfer means 12.

(19) In a first separation step according to the invention in accordance with FIG. 2f, the carrier substrate 1, in particular a carrier film, is stripped from the projecting surfaces 5o. The stripping begins with one or more, in particular peripherally placed, spots. The stripping is therefore in particular not full-surface.

(20) In a second alternative separation step according to the invention in accordance with FIG. 2g, the carrier substrate 1 and the structured product substrate 3 are removed from one another by normal forces, in particular surface forces.

(21) FIGS. 3a and 3b show two possible encapulations of the structured product substrates 3, 3 in end products 9, 9 (packaging of functional units).

(22) In the embodiment according to FIG. 3a, the encapsulation is carried out by the bonding of a cover 8 in the form of a wafer to the coating material 2 that is transferred according to the invention.

(23) In the embodiment according to FIG. 3b, an end product 9 is shown, in which the encapsulation is carried out by individual covers 8. The individual covers 8 can be positioned and bonded by, for example, a chip-to-wafer bonder.

(24) FIG. 4 shows a diagrammatic sketch of a unit 16 according to the invention, which comprises a coating device 13, a laminating device 14 (contacting means), and a delaminating device 15 (separating means), A laminating device 14 is understood in this connection as any device that is able to perform a layer transfer according to the invention of the coating material 2, 2 from a carrier substrate 1 to the projecting surfaces 5o. In particular, this refers to a conventional laminating device. The use of a bonder, in particular a wafer bonder, which brings the carrier substrate 1 up by approaching the structured product substrate 3, would also be conceivable, however.

(25) A delaminating device 15 is understood in this connection to be any device that is able to perform a removal, according to the invention, of the carrier substrate 2 from the structured product substrate 3, in particular the projecting surfaces 5o. In particular, this refers to a conventional delaminating, device.

(26) Some laminating devices 14 can also be used at the same time as delaminating devices 15.

(27) A robot system, wafer cassettes, in particular FOUPS or all other necessary components that are required for handling, manipulation, or for loading or unloading the necessary substrates are not depicted.

LIST OF REFERENCE SYMBOLS

(28) 1 Carrier substrate

(29) 2, 2 Coating material

(30) 3, 3 Product substrate

(31) 4, 4 Wafer

(32) 5, 5 Projections

(33) 5o, 5o Projecting surfaces

(34) 6 Functional units

(35) 7 Recesses

(36) 8, 8 Cover

(37) 9 End product

(38) 10, 10 Specimen holder

(39) 11, 11 Attaching means

(40) 12 Force transfer means

(41) 13 Coating device

(42) 14 Laminating device

(43) 15 Delaminating device

(44) 16 Unit