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DE-102018214337-B4 - Methods for processing a substrate

DE102018214337B4DE 102018214337 B4DE102018214337 B4DE 102018214337B4DE-102018214337-B4

Abstract

Method for processing a substrate (W), wherein the substrate (W) has a side (1) and a side (6) opposite the one side (1), the substrate (W) has at least one recess (7) on one side (1) or on the side (6) opposite one side (1), and The procedure includes: Provide a protective film (4); Applying the protective film (4) to the side of the substrate (W) which has the at least one recess (7), such that at least a central area of a front surface (4a) of the protective film (4) is in direct contact with the side of the substrate (W) which has the at least one recess (7), so that no adhesive is present between at least the central area of the front surface (4a) of the protective film (4) and the side of the substrate (W) which has the at least one recess (7); Applying pressure to the protective film (4) such that the protective film (4) enters the at least one recess (7) along at least part of a depth of the recess (7); Heating the protective film (4), wherein the pressure is applied to the protective film (4) during and/or after heating the protective film (4); and Processing one side (1) of the substrate (W) and/or the side (6) of the substrate (W) opposite one side (1).

Inventors

  • Karl Heinz Priewasser
  • Kensuke Nagaoka

Assignees

  • DISCO CORPORATION

Dates

Publication Date
20260513
Application Date
20180824

Claims (14)

  1. A method for processing a substrate (W), wherein the substrate (W) has a side (1) and a side (6) opposite the first side (1), the substrate (W) has at least one recess (7) on the first side (1) or on the side (6) opposite the first side (1), and the method comprises: providing a protective film (4); applying the protective film (4) to the side of the substrate (W) having the at least one recess (7), such that at least a central region of a front surface (4a) of the protective film (4) is in direct contact with the side of the substrate (W) having the at least one recess (7), such that no adhesive is present between at least the central region of the front surface (4a) of the protective film (4) and the side of the substrate (W) having the at least one recess (7); Applying pressure to the protective film (4) such that the protective film (4) enters the at least one recess (7) along at least part of a depth of the recess (7); Heating the protective film (4), wherein the pressure is applied to the protective film (4) during and/or after heating the protective film (4); and Working on one side (1) of the substrate (W) and/or the side (6) of the substrate (W) opposite that side (1).
  2. Procedure according to Claim 1 , wherein the application of the pressure to the protective film (4) comprises or consists of, during and/or after the application of the protective film (4) to the side of the Substrates (W) which have at least one recess (7) to apply a vacuum to the protective film (4).
  3. Procedure according to Claim 1 or 2 , in which the substrate (W) is a wafer which has on one side (1) a component area (2) with several components (27).
  4. Method according to one of the preceding claims, wherein at least one dividing line (11) is formed on one side (1) of the substrate (W) and the at least one recess (7) extends along the at least one dividing line (11).
  5. Method according to one of the preceding claims, wherein the pressure is applied to the protective film (4) such that the protective film (4) enters at least one recess (7) to a depth of 3 to 500 µm, preferably 5 to 300 µm, in particular 5 to 50 pm.
  6. Method according to one of the preceding claims, further comprising removing substrate material from one side (1) of the substrate (W) or from the side (6) of the substrate (W) opposite one side (1) in order to form at least one recess (7).
  7. Method according to one of the preceding claims, wherein the method comprises machining the side (6) of the substrate (W) opposite one side (1), and machining the side (6) of the substrate (W) opposite one side (1) comprises grinding the side (6) of the substrate (W) opposite one side (1) to adjust the substrate thickness.
  8. A method according to any of the preceding claims, wherein the protective film (4) is provided with an adhesive layer (9), the adhesive layer (9) is provided only in a circumferential region of the front surface (4a) of the protective film (4), the circumferential region surrounding the central region of the front surface (4a) of the protective film (4), and the protective film (4) is applied to the side of the substrate (W) having the at least one recess (7) in such a way that the adhesive layer (9) comes into contact only with a circumferential section of the side of the substrate (W) having the at least one recess (7).
  9. Method according to one of the preceding claims, wherein a damping layer is applied to a rear surface (4b) of the protective film (4) which is opposite its front surface (4a).
  10. Procedure according to Claim 9 , in which a base layer is applied to a rear surface of the damping layer.
  11. A method according to any of the preceding claims, further comprising: dividing the substrate (W) into several separate elements (30), and receiving the separate elements (30) from the protective film (4).
  12. Method according to one of the preceding claims, wherein the protective film (4) consists of a polymer, in particular a polyolefin.
  13. Method according to one of the preceding claims, further comprising attaching a circumferential section of the protective film (4) to an annular frame (25), in particular an annular frame of semiconductor size.
  14. Method according to one of the preceding claims, wherein the protective film (4) remains continuously attached to the substrate (W) during the processing of the substrate (W).

Description

Technical field The present invention relates to a method for processing a substrate, such as a wafer, for example a semiconductor wafer, which has at least one recess on one of its sides. Technical background When processing a substrate, such as a semiconductor wafer, it is important to protect the substrate's sides from damage and contamination. This requirement is particularly critical if components, such as semiconductor devices, are located on one side of the substrate. For example, in a semiconductor device manufacturing process, a wafer, which contains a component area with multiple components typically separated by several parting lines, serves as the substrate. This wafer is processed to divide the wafer into individual chips. This manufacturing process typically includes a grinding step to adjust the wafer thickness and a cutting step to cut the wafer along the parting lines to obtain the individual chips. The grinding step is performed from the back side of the wafer, which is opposite the front side where the component area is formed. Other processing steps, such as polishing and/or etching, can also be performed on the back side of the wafer. The wafer can be cut along the parting lines from either its front or back side. Protection of one side of the substrate can be provided by attaching a protective film or cover. In particular, to protect components formed on a wafer during processing of the wafer, for example from breakage, deformation and/or contamination by dirt particles, grinding water or cutting water, such a protective film or protective cover can be applied to the front of the wafer before processing. Such protection of one side of the substrate is particularly important if there is a recess on the side, such as a groove, a slot, a cut, or the like. Firstly, such recesses are susceptible to contamination, for example, by dirt particles or water that can accumulate in them. Secondly, the presence of the recess can lead to an uneven distribution of pressure during processing, such as grinding, polishing, or cutting, thereby increasing the risk of mechanical damage to the substrate, such as substrate breakage. Therefore, the use of a protective film or cover is of particular importance when working with substrates that have one or more cutouts on one side. However, the side of the substrate to which the protective film or cover is applied can be damaged by the adhesive force of an adhesive layer formed on the protective film or cover, or contaminated by adhesive residue when the film or cover is removed from the substrate. In particular, such residue can remain in a recess formed on the substrate side. This is especially problematic if sensitive components, such as MEMS, are located on the side of the substrate to which the protective film or cover is applied. In this case, the component structure can be significantly compromised. Consequently, there remains a need for a reliable and efficient method for processing a substrate with a recess on one of its sides, which makes it possible to minimize the risk of contamination and damage to the substrate. EP 2 631 938 A1 discloses a foil bonding process in which an adhesive foil is applied to a surface of a wafer. JP 2004 - 217 757 A teaches a multi-layered adhesive film. WO 2018 / 002 035 A2 Disclosing a method for processing a wafer with a first side having a component area and a second side opposite the first side having several projections. In this method, a protective film is applied to the second side of the wafer. Summary of the invention Accordingly, an objective of the present invention is to provide a reliable and efficient method for processing a substrate with a recess on one of its sides, which makes it possible to minimize the risk of contamination and damage to the substrate. This objective is achieved by a substrate processing method with the technical features of claim 1. Preferred Embodiments of the invention follow from the dependent claims. The invention provides a method for processing a substrate. The substrate has one side, for example a front, and a side opposite that side, for example a back. The substrate has at least one recess on that side or on the side opposite that side. The method comprises providing a protective film or layer and applying the protective film or layer to the side of the substrate that has the at least one recess, such that at least a central region of a front surface of the protective film or layer is in direct contact with the side of the substrate that has the at least one recess, so that no adhesive is present between at least the central region of the front surface of the protective film and the side of the substrate that has the at least one recess. Furthermore, the method comprises applying pressure to the protective film or protective layer such that the protective film or protective layer enters the at least one recess along at least part of a depth of the recess, heating the protecti