Sensor usable in ultra pure and highly corrosive environments
First Claim
1. A sensor having a non-porous outer surface, said sensor comprising:
- a backing plate that includes apertures extending therethrough;
a diaphragm;
a sensing element disposed over an inner surface of the diaphragm;
at least one electrical lead extending through at least one aperture and coupled to the sensing element on the diaphragm, the electrical lead having a coil head adapted for brazing over the inner surface of the diaphragm with a high temperature braze composition; and
a glass layer adapted to be bonded by glassing to the backing plate and the diaphragm, the glass layer having both a high bond strength and a high melt temperature that is at or above 700°
C., wherein the glass layer bonds the backing plate to the diaphragm and the coil head is brazed to the sensing element.
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Accused Products
Abstract
The electrical pin lead structure and brazing technique of the present invention provide a brazed lead in a sensor that adheres well to a semiconductor substrate while facilitating lateral flexibility without joint fatigue or breakage. In one example embodiment, the pin lead includes a coil head that is brazed to a silicon layer on a sapphire substrate using a silver-copper-palladium braze material. An advantage to this approach is the ability to both braze the pin lead to the diaphragm and seal the diaphragm to the ceramic backing plate with a high temperature glass in a single process step. Further, the palladium in the braze composition is a factor in reducing surface tension between the metal lead and semiconductor substrate during cooling to avoid stress fractures in the substrate.
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Citations
18 Claims
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1. A sensor having a non-porous outer surface, said sensor comprising:
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a backing plate that includes apertures extending therethrough;
a diaphragm;
a sensing element disposed over an inner surface of the diaphragm;
at least one electrical lead extending through at least one aperture and coupled to the sensing element on the diaphragm, the electrical lead having a coil head adapted for brazing over the inner surface of the diaphragm with a high temperature braze composition; and
a glass layer adapted to be bonded by glassing to the backing plate and the diaphragm, the glass layer having both a high bond strength and a high melt temperature that is at or above 700°
C., wherein the glass layer bonds the backing plate to the diaphragm and the coil head is brazed to the sensing element. - View Dependent Claims (2, 3, 4, 5, 6)
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- 7. An electrical lead member configured for use in connection with a semiconductor element disposed on an insulating substrate, the electrical lead comprising a coiled lead member, a portion of the coiled member adapted to be brazed to the semiconductor element on the substrate.
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11. A method of bonding an electrical lead to a semiconductor device comprising the steps of:
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forming an electrical lead comprised of a coiled member;
applying a braze composite material on the substrate surface;
locating a portion of the coiled member on the braze material and on a substrate surface such that a shaft of the lead is substantially perpendicular to the surface of the substrate; and
heating the braze composite material to a sufficiently high temperature such that the braze material melts and the coiled member adheres to the substrate surface as the braze material cools. - View Dependent Claims (12, 13, 14, 15)
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16. A method for bonding an electrical lead to a semiconductor device comprising the steps of:
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forming an electrical lead comprised of a coiled member;
providing a backing plate that includes apertures extending therethrough;
providing a substrate having a semiconductor element thereon and adapted to be coupled with the backing plate;
providing a glass layer adapted to be bonded by glassing to the backing plate and the substrate, the glass layer comprised of a high bond strength and high melt temperature material;
applying a braze composite material in the apertures of the backing plate; and
locating the coiled member of the electrical lead through at least one aperture in the backing plate and adjacent the braze material, such that a portion of the lead is protruding from the backing plate; and
heating the braze composite material and the glass layer to a sufficiently high temperature such that the coiled member is brazed to the substrate and the backing plate and the substrate are glassed together. - View Dependent Claims (17, 18)
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Specification