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EP-3893054-B1 - PATTERN FORMING METHOD, PHOTOSENSITIVE RESIN COMPOSITION, CURED FILM, LAMINATE, AND DEVICE

EP3893054B1EP 3893054 B1EP3893054 B1EP 3893054B1EP-3893054-B1

Inventors

  • YAMAZAKI KENTA
  • AOSHIMA TOSHIHIDE

Dates

Publication Date
20260506
Application Date
20191126

Claims (18)

  1. A pattern forming method comprising: an exposure step of exposing a photosensitive film to laser light; and a development step of developing the photosensitive film after the exposure to obtain a pattern, wherein the photosensitive film contains: at least one precursor selected from the group consisting of a polyimide precursor and a polybenzoxazole precursor, an onium salt, a Group 4 element-containing compound; a compound having a plurality of carboxy groups and having a molecular weight of 1,000 or less, wherein the compound having a plurality of carboxy groups is an unsaturated polyvalent carboxylic acid compound, characterised in that the photosensitive film further contains a compound having a sulfurous ester structure.
  2. The pattern forming method according to claim 1, wherein a wavelength of the laser light is 250 to 550 nm.
  3. The pattern forming method according to claim 1 or 2, wherein the compound having a plurality of carboxy groups is an unsaturated dicarboxylic acid compound.
  4. The pattern forming method according to claim 3, wherein the unsaturated dicarboxylic acid compound is a compound containing an unsaturated bond, which is conjugated with a carboxylic acid.
  5. The pattern forming method according to any one of claims 1 to 4, further comprising a curing step of heating the pattern to obtain a cured pattern, after the development step.
  6. The pattern forming method according to any one of claims 1 to 5, wherein a cation in the onium salt includes at least one cation selected from the group consisting of a tetraalkylammonium cation, a sulfonium cation, and an iodonium cation.
  7. The pattern forming method according to any one of claims 1 to 6, wherein the onium salt contains an ammonium cation as a cation, and the onium salt contains an anion of which a conjugate acid has a pKa of 1.8 or less, as an anion.
  8. The pattern forming method according to any one of claims 1 to 7, wherein the Group 4 element-containing compound is a photoradical generator.
  9. The pattern forming method according to any one of claims 1 to 8, wherein the Group 4 element-containing compound is an organic compound containing at least one selected from the group consisting of a titanium atom, a zirconium atom, and a hafnium atom.
  10. The pattern forming method according to any one of claims 1 to 9, wherein the Group 4 element-containing compound includes at least one selected from the group consisting of metallocene and a metallocene derivative.
  11. The pattern forming method according to any one of claims 1 to 10, wherein the photosensitive film is a photosensitive film formed by slit coating.
  12. The pattern forming method according to any one of claims 1 to 12, wherein the photosensitive film is formed on a rectangular base material.
  13. A photosensitive resin composition for forming a photosensitive film in a pattern forming method according to any one of claims 1 to 12, comprising: at least one precursor selected from the group consisting of a polyimide precursor and a polybenzoxazole precursor; an onium salt, a Group 4 element-containing compound, a compound having a plurality of carboxy groups and having a molecular weight of 1,000 or less, wherein the compound having a plurality of carboxy groups is an unsaturated polyvalent carboxylic acid compound, characterised in that the photosensitive film further contains a compound having a sulfurous ester structure.
  14. A cured film formed from the photosensitive resin composition according to claim 13.
  15. Use of a cured film according to claim 14 as an interlayer insulating film for a rewiring layer.
  16. A laminate comprising two or more layers of the cured film according to claim 14.
  17. The laminate according to claim 16, further comprising a metal layer between the cured films.
  18. A device comprising the cured film according to claim 15 or the laminate according to claim 16 or 17.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern forming method, a photosensitive resin composition, a cured film, a laminate, and a device. 2. Description of the Related Art In the related art, a polyimide resin, a polybenzoxazole resin, or the like, which has excellent heat resistance, electrical properties, mechanical properties, and the like has been used as a protective film and an interlayer insulating film of a semiconductor element. However, as the integration of semiconductor elements and the increase in the size of semiconductor elements progress in recent years, there is a demand for a thinner and smaller sealing resin package, and a method such as surface mounting using lead-on-chip (LOC) or a solder reflow method has been adopted. In recent years, demand for a material for semiconductor packaging is increased. There are various semiconductor packaging methods in semiconductor devices. For example, a semiconductor element is covered by a sealing member (a mold resin) except for one surface to form an element sealing member, and further, a rewiring layer is formed on the one surface of the semiconductor element which is not covered by the sealing member. Among the semiconductor packaging methods, in recent years, a semiconductor packaging method called Fan-Out packaging has become used mainly. Fig. 1 is a schematic cross-sectional view illustrating one example of a Fan-Out type semiconductor device. In Fig. 1, a semiconductor device 1 has a semiconductor chip 2, a sealing agent 3 that covers the semiconductor chip 2, and a rewiring layer 4 that is closely attached to the semiconductor chip 2 and the sealing agent 3. As shown in Fig. 1, the sealing agent 3 covers the surface of the semiconductor chip 2 and is formed in an area larger than the region of the semiconductor chip 2 in a case of being seen in a plan view (an arrow A). The rewiring layer 4 has a plurality of wires 5 that are electrically connected to a plurality of terminals 2a provided on the semiconductor chip 2, and an interlayer insulating film 6 with which the space between the wires 5 is filled. The plurality of terminals 2a provided on the semiconductor chip 2 and the plurality of wires 5 in the rewiring layer 4 are electrically connected. One end of the wire 5 is connected to the terminal 2a, and the other end is connected to an external connection terminal 7. The wire 5 between the terminal 2a and the external connection terminal 7 is entirely covered by an interlayer insulating film 6. In this manner, according to the Fan-Out type, an element sealing body can be formed by covering a semiconductor element (a semiconductor chip) with a sealing member so that the element sealing body is formed in a region larger than a size of a chip, and further, a rewiring layer that extends to the regions of the semiconductor chip and the sealing member can be formed. Since the rewiring layer is thin and even the region of the sealing member can be used as a region in which the rewiring layer is formed, the number of external connection terminals can be increased. Not only Fan-Out wafer level packaging (FOWLP) but also Fan-Out panel level packaging (FOPLP) is studied now. In addition, it is expected that the demand for materials for such semiconductor chips and semiconductor packaging increases with the expansion of the demand in the communication field and the in-vehicle field. In the manufacturing of such a semiconductor element, a photosensitive resin composition containing at least one precursor selected from the group consisting of a polyimide resin precursor (a polyimide precursor) and a polybenzoxazole resin precursor (a polybenzoxazole precursor) may be used. In a case where the photosensitive resin composition is used, merits such as simplification of the pattern forming step can be conceivable. For example, WO2018/025738A discloses a photosensitive resin composition containing a heterocyclic ring-containing polymer precursor, a thermal base generator, and an organic compound containing a Group 4 element. In addition, JP2010-039475A discloses a photosensitive resin composition for ultraviolet light laser exposure, containing (A) resin; (B) ethylenically unsaturated compound; (C) photopolymerization initiator; and (D) thiol compound. WO2017/038664A describes a composition containing a crosslinking agent and at least one type of resin comprising a polyimide precursor, a polyimide, a polybenzoxazole, and a polybenzoxazole precursor. US2018/079864A1 describes a photosensitive resin composition containing a polyimide precursor composition. WO2015/087830A describes a photosensitive resin composition which contains a polybenzoxazole precursor, a photoacid generator, a solvent, a crosslinking agent and a compound having a group in which an acid group is protected by an acid-degradable group, in the molecule. WO2015/087831A describes a photosensitive resin composition containing a polybenzoxazole