Solid state fingerprint sensor packaging apparatus and method

A packaging apparatus for providing a closed cavity that physically surrounds a capacitance type object sensor, comprising:

• a rigid substrate assembly having a base area, having a generally centrally located dome that extends upward from said base area so as to be encircled by said base area, and having a topmost located dome area that contains a capacitance type object sensor, to thereby support said object sensor at a given distance above said base area;
• a rigid and continuous wall member defining encircling cavity walls providing a through-hole having a top surface and a bottom surface, said top surface being located generally at said given distance above said bottom surface;
• first mounting means mounting said through-hole bottom surface on said base area to thereby locate said substrate assembly within said wall member;
• a flexible membrane member having a low dielectric constant;
• and
• second mounting means mounting said membrane member on said through-hole top surface to thereby provide a closed cavity having a top surface that comprises a low dielectric constant downward deflectable surface for physical association with an object whose presence is to be sensed.

An apparatus for providing a closed cavity that physically surrounds, seals and protects a capacitance fingerprint pattern determining array, comprising:

• a rigid substrate assembly having a base area that occupies a first horizontal plane;
• said substrate assembly having a dome that extends vertically upward generally from a center of said substrate assembly so as to surrounded said dome with said base area;
• said dome having a top dome area that contains said array and occupies a second horizontal plane that is generally parallel to said first horizontal plane;
• said second plan being located a given distance vertically above said first plane;
• a continuous wall member defining vertical cavity walls that encircle a vertically extending through-hole having a top planar and horizontal surface and a bottom planar and horizontal surface;
• said top through-hole surface being generally parallel to said bottom through-hole surface;
• said top through-hole surface being located vertically above said bottom through-hole surface by a distance that is generally equal to said given distance;
• first sealing means mounting said bottom through-hole surface on said base area to thereby encircle said substrate assembly with said vertical cavity walls;
• a flexible membrane member having a low dielectric constant;
• and
• second sealing means mounting said membrane member on said top through-hole surface to thereby cover said substrate assembly and provide a low dielectric constant flexible surface for physical association with a fingertip whose fingerprint pattern is to be determined.

An apparatus for providing an internal cavity that physically protects a capacitance type object sensor, comprising:

• a planar support member having a top horizontal surface of a first size;
• a semiconductor substrate having a bottom horizontal surface of a second size that is less than said first size;
• first mounting means mounting said bottom horizontal surface of said substrate generally centered upon said top horizontal surface of said support member, to thereby provide an exposed edge portion of said top horizontal surface of said support member;
• said substrate having a top surface topography providing a horizontal and planar edge surface, and an upwardly tapered surface that terminates at a generally center disposed, planar, and top horizontal dome surface that contains a capacitance type object sensor;
• said planar dome surface being located a given distance above said exposed edge portion of said top horizontal surface of said support member;
• a vertically extending and continuous wall member defining an encircling cavity wall providing a through-hole having a top horizontal surface and a bottom horizontal surface, said top surface being located generally at said given distance above said bottom surface;
• second mounting means mounting said through-hole bottom surface on said edge exposed portion of said top horizontal surface of said support member, to thereby locate said substrate and said object sensor within said through-hole;
• a flexible membrane member having a low dielectric constant;
• and
• third mounting means mounting said membrane member on said through-hole top surface to thereby provide a low dielectric constant downward flexible surface that closely overlies said capacitance type object sensor.

An apparatus for providing a cavity that physically surrounds and protects a solid-state capacitance fingerprint pattern determining array, comprising:

• a rigid support member having a base surface that occupies a first horizontal plane;
• a flat-top dome extending vertically upward generally from a center of said base surface;
• said flat-top dome containing said solid-state array and occupying a second horizontal plane that is generally parallel to said first horizontal plane and is located a given distance vertically above said first horizontal plane;
• an encircling wall member providing a vertically extending through-hole having a top horizontal and planar surface and a bottom horizontal and planar surface;
• said top through-hole surface being generally parallel to said bottom through-hole surface, and said top through-hole surface being located vertically above said bottom through-hole surface by a distance that is generally equal to said given distance;
• first sealing means mounting said bottom through-hole surface on said base area to thereby encircle said flat-top dome;
• a flexible membrane member having a low dielectric constant;
• second sealing means mounting said membrane member on said top through-hole surface to thereby cover said flat-top dome and provide a low dielectric constant flexible surface for physical association with a fingertip whose fingerprint pattern is to be determined;
• a first electrical conductor path associated with said base member and said flat-top dome and connected to said solid-state array;
• a dielectric passivation layer covering said first electrical conductor path and said solid-state array;
• a via formed in said dielectric passivation layer so as to physically expose a portion of said first electrical conductor path;
• a second electrical conductor path extending through said encircling wall member;
• said second electrical conductor path having a portion that terminates adjacent to said base member;
• and
• electrical connection means extending from said portion of said first electrical path to said portion of said second electrical path.