Workpiece treating method, temporary fixing composition, semiconductor device, and process for manufacturing the same

A temporary fixing composition comprising a polymer (A) including a structural unit represented by the following formula (A2):

• wherein in the formula (A2),
• Ar is a condensed polycyclic aromatic ring;
• —OR1 is a group bonded to the condensed polycyclic aromatic ring wherein R1 is a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms and when a plurality of —OR1 are present, the —OR1 groups may be the same as or different from one another;
• R2 is a group bonded to the condensed polycyclic aromatic ring and indicates a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms wherein when a plurality of R2 are present, the R2 groups may be the same as or different from one another;
• R3 groups are each a hydrogen atom or an organic group and the R3 groups may be the same as or different from one another;
• and
• a1 is an integer of 2 or greater and b is an integer of 0 or greater.

A semiconductor device manufacturing process comprising:

• a step (1) of forming a stack including a support, a temporary fixing material and a wiring layer wherein the temporary fixing material comprises a layer (I) that contains a polymer (A) including a structural unit represented by the formula (A2) below, and the wiring layer is formed on the temporary fixing material;
• a step (2) of arranging at least one selected from semiconductor wafers and semiconductor chips onto the wiring layer;
• a step (3) of applying light to the layer (I) through the support;
• and
• a step (4) of separating the support and the wiring layer from each other,
• wherein in the formula (A2),
• Ar is a condensed polycyclic aromatic ring;
• —OR1 is a group bonded to the condensed polycyclic aromatic ring wherein R1 is a hydrogen atom or a hydrocarbon group with 1 to 20 carbon atoms and when a plurality of —OR1 are present, the —OR1 groups may be the same as or different from one another;
• R2 is a group bonded to the condensed polycyclic aromatic ring and indicates a halogen atom or a hydrocarbon group with 1 to 20 carbon atoms wherein when a plurality of R2 are present, the R2 groups may be the same as or different from one another;
• R3 groups are each a hydrogen atom or an organic group and the R3 groups may be the same as or different from one another;
• and
• a1 is an integer of 2 or greater and b is an integer of 0 or greater.