Metal contact systems for semiconductor-based pressure sensors exposed to harsh chemical and thermal environments
First Claim
1. A metal electrical contact system for a piezoresistive pressure sensor for use in harsh chemical and thermal environments comprising:
- a semiconductor substrate, an electrically conductive impurity doped region formed in a portion of the substrate, a passivation layer formed on the said surface of the substrate including the impurity doped region, an opening formed in the passivation layer exposing a portion of the impurity doped region, an ohmic contact formed in a portion of the impurity doped region aligned with the opening, and a layer of one of tantalum and a tantalum alloy formed in the opening on the ohmic contact.
4 Assignments
0 Petitions
Accused Products
Abstract
Highly corrosion resistant electrically conductive contact systems suitable for semiconductor pressure sensor devices exposed to acidic, elevated temperature environments, such as automotive exhaust gas environments, are disclosed. The preferred embodiment (10) comprises a platinum top layer (26), and a tantalum lower layer (24). Both are highly electrically conductive layers and exhibit corrosion resistance to acidic environments. The top layer of the metallization also provides a suitable material for the external connectivity (e.g., wire bonding, solder bumping, chip-chip fusion). The lower layer of the metallization also serves as an adhesion layer between the top metal and lower layers, typically silicon based glasses and in some cases serves as a diffusion barrier.
21 Citations
20 Claims
-
1. A metal electrical contact system for a piezoresistive pressure sensor for use in harsh chemical and thermal environments comprising:
a semiconductor substrate, an electrically conductive impurity doped region formed in a portion of the substrate, a passivation layer formed on the said surface of the substrate including the impurity doped region, an opening formed in the passivation layer exposing a portion of the impurity doped region, an ohmic contact formed in a portion of the impurity doped region aligned with the opening, and a layer of one of tantalum and a tantalum alloy formed in the opening on the ohmic contact. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
11. A metal electrical contact system for a semiconductor pressure sensor for use in harsh chemical and thermal environments comprising:
a semiconductor substrate, an electrically conductive impurity doped region formed in a portion of the substrate, a passivation layer formed on the said surface of the substrate including the impurity doped region, an opening formed in the passivation layer exposing a portion of the impurity doped region, an ohmic contact formed in at least a portion of the impurity doped region aligned with the opening, and a layer of one of niobium and a niobium alloy formed in the opening on the ohmic contact. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
Specification