System and method for performing bulge testing of films, coatings and/or layers

A method of bulge testing a thin film at a plurality of locations, the method comprising the steps of:

• providing a bulge testing membrane structure including a plurality of freestanding membrane portions located on a single substrate, each of said freestanding membrane portions being disposed adjacent a corresponding cavity having a corresponding fluid outlet, so that a plurality of discrete cavities and corresponding cavity fluid outlets are provided adjacent said freestanding membrane portions;
• providing a thin film on the membrane structure, over top of the plurality of freestanding membrane portions;
• evacuating a plurality of cavities via said fluid outlets, either simultaneously or separately, so as to cause the plurality of freestanding membrane portions to deflect or bulge inwardly along with the corresponding overlying thin film portions provided thereon and without causing said overlying film or coating to peel from said membrane;
• and
• measuring the deflection of a plurality of the freestanding membrane portions and corresponding overlying thin film portions caused by said evacuating, and based upon said measuring determining modulus and stress properties of the overlying the film portions at a plurality of different locations.

A method of bulge testing a film at a plurality of different locations, the method comprising the steps of:

• providing a bulge testing apparatus including a major surface and a cavity defined therein;
• providing a film on the major surface over top of the cavity;
• evacuating the cavity by applying a vacuum thereto so as to cause the film to deflect inwardly and without causing said film to peel from said major surface;
• and
• measuring the deflection of the film caused by said evacuating at a plurality of different locations, and based upon said measuring determining modulus and stress properties of the film.

A method of bulge testing a film, the method comprising the steps of:

• providing a bulge testing apparatus including a major surface and a cavity defined therein;
• providing a film on the major surface over top of the cavity;
• locating a center point on the film, the center point overlying approximately the center of the cavity;
• locating first and second points spaced from the center point so that the first and second points are located in positions not susceptible to bulging, and wherein a line connecting the first and second points, and the center point, crosses a portion of the film overlying the cavity;
• and
• optically measuring bulging or deflection of the film, by measuring deflection of the center point relative to the first and second points which are positioned at undeflected locations.

A method of bulge testing a film, the method comprising the steps of:

• providing a bulge testing apparatus including a major surface and a cavity defined therein;
• providing a film having a compressive residual stress on the major surface over top of said cavity;
• allowing said film to bulge, either inwardly or outwardly, as a result of said compressive residual stress present in the film, without pressurizing or evacuating the cavity;
• and
• measuring bulging or deflection of the film caused by said stress, so that it is necessary to either pressurize or evacuate the cavity.

A method of bulge testing a film, the method comprising the steps of:

• providing a bulge testing apparatus including a major surface and a cavity defined therein;
• providing a film on the major surface over top of the cavity;
• measuring a deflection or bulge of the film proximate the cavity;
• storing a predetermined lookup table which enables determination of residual stress in the film based upon the film's material, thickness, and measured deflection;
• and
• using the lookup table to determine residual stress of the film indicated by the measured deflection, the determined residual stress being a function of the film's thickness, material, deflection, and of pressure applied in the cavity.