Pin for brazing to a substrate and improved package resulting therefrom
AssigneeInternational Business Machines Corporation
InventorsArmando S. Cammarano, Giulio DiGiacomo
Life of this patent
Estimating the term…
Abstract
A pin designed to be attached to a solid state module for making connection between the module and other parts of a metallurgical system. The end of the pin that is to be brazed to the module has a sloping (e.g., conical or wedge) shaped head so that gas bubbles can readily escape during brazing, thus reducing voids in the braze.
Claims2
As an article of manufacture, a substrate and a pin, one end of said pin being brazed to said substrate by a brazing material having a brazing temperature significantly below the melting point of said pin,
- said one end of said pin having a substantial portion of its surface at an angle with respect to a plane perpendicular to the axis of the pin;
- said angle being equal to or larger than an angle .theta. which satisfies the relationship ##EQU3## where:
- r=the radius of the smallest void for which escape is desired to be reasonably certain,
- .mu.=viscosity of the molten braze,
- .rho.=density of the braze,
- g=acceleration due to gravity,
- t=time during which the braze will remain in a molten state, and
- S=maximum distance of travel by a void in order for it to escape from the braze between the end of the pin and the substrate;
- whereby it is reasonably certain that the brazing material which joins said pin to said substrate will contain no voids having a radius equal to or greater than r.
A pin, one end of which will be fixed to a substrate by a braze, at a temperature significantly below the melting point of said pin,
- said one end having a substantial portion of its surface at an angle with respect to a plane perpendicular to the axis of the pin;
- said angle being equal to or larger than an angle .theta. which satisfies the relationship ##EQU4## where:
- r=the radius of the smallest void for which escape is desired to be reasonably certain,
- .mu.=viscosity of the molten braze,
- .rho.=density of the braze,
- g=acceleration due to gravity,
- t=time during which the braze will remain in a molten state, and
- S=maximum distance of travel by a void in order for it to escape from the braze between the end of the pin and the substrate;
- whereby it is reasonably certain that the braze which will fix said pin to a substrate will contain no voids having a radius equal to or larger than r.
Dependencies are inferred from the claim text.