Die having coefficient of thermal expansion graded layer

A semiconductor die, comprising:

• a substrate including a topside and a bottomside, wherein said topside includes circuit elements configured to provide a circuit function including a plurality of through-substrate-vias (TSVs) that extend through said substrate from said topside to be electrically accessible from said bottomside, wherein said plurality of TSVs include:
• a coefficient of thermal expansion (CTE) graded liner comprising at least a dielectric portion that lines vias in said substrate, said CTE graded liner including an inner portion that contacts said substrate and an outer portion that extends outward from said substrate having a thickness in a thickness direction;
• a diffusion barrier metal layer on said outer portion of said CTE graded liner, and
• a metal filler on said diffusion barrier metal layer,
• wherein said CTE graded liner includes a non-constant composition profile across said thickness direction that provides a graded CTE which increases in said CTE from said inner portion to said outer portion.

A method of fabricating a semiconductor die including circuit elements configured to provide a circuit function, comprising:

• providing a substrate including a bottomside and a topside, and
• forming at least one multi-layer structure, including:
• depositing a coefficient of thermal expansion (CTE) graded layer comprising at least a dielectric portion on a first material having a first CTE to provide a first side facing said first material and a second side opposite said first side, said depositing including (i) flowing a first reactive component and at least a second reactive component, and (ii) automatically changing a gas flow ratio of said first reactive component relative to said second reactive component during a deposition time to provide a non-constant composition profile which has a graded CTE that increases from said first side to said second side, and
• forming a metal layer comprising a second material having a second CTE on said second side, wherein said second CTE is higher than said first CTE.