Thermal print head and method for manufacturing thermal print head

A method for manufacturing a thermal print head, the method comprising:

• preparing a substrate having a first surface and a second surface opposite to the first surface;
• forming, on the first surface, a raised portion protruding toward a side opposite to the second surface and extending along a first direction in a plan view;
• forming an insulating layer on the first surface;
• forming a wiring layer on the insulating layer with a resistor layer interposed therebetween;
• and
• forming a protective layer on the insulating layer to cover the wiring layer, wherein
• a constituent material of the wiring layer is aluminum or an aluminum alloy,
• the wiring layer has a bonding pad,
• an opening that exposes the bonding pad is formed in the protective layer,
• a width of the opening in the first direction is greater than a width of the bonding pad in the first direction,
• the bonding pad has an upper surface and a bottom surface opposite to the upper surface,
• a width of the bottom surface in a second direction is 1.1 times or more as great as a width of the upper surface in the second direction, and
• the second direction is orthogonal to the first direction in a plan view,
• in a cross-sectional view orthogonal to a second direction, the bonding pad has an upper surface, a bottom surface opposite to the upper surface, and a side surface continuous to the upper surface and the bottom surface,
• aluminum chloride is not detected at the side surface of the bonding pad when analyzed using energy dispersive X-ray spectroscopy, and
• the second direction is orthogonal to the first direction in a plan view, and
• the forming of the wiring layer includes:
• depositing the constituent material of the wiring layer, and
• patterning the deposited constituent material of the wiring layer by wet etching using a resist pattern as a mask.