Method and apparatus for thermal conductivity measurements

Claim 1

A method for measuring the thermal conductivity of a material comprising: (a) preparing a first sample of the material in the form of a thin wafer having a known thickness, known dimensions and known weight; (b) encapsulating the first sample of the material in a thin layer of conforming high thermal conductivity material, the mass of said thin layer of high thermal conductivity material having a first value; (c) preparing a second sample of the material as a right angle cylinder having flat and parallel top and bottom surfaces, the height of said cylinder being greater than the thickness of the first sample of the material; (d) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (e) placing the first sample in the sample position of the differential scanning calorimeter; (f) placing a thin wafer of the high thermal conductivity material on the reference position of the differential scanning calorimeter, the mass of said thin wafer of high thermal conductivity material having the first value; (g) measuring the effective heat capacity of the first sample by: (α) selecting a modulation angular frequency and a modulation amplitude, (β) varying the temperature of the sample position and the reference position according to the selected modulation amplitude and modulation angular frequency, and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; (h) removing the first sample from the sample position; (i) removing the thin wafer of high thermal conductivity material from the reference position; (j) placing the second sample on the sample position of the differential scanning calorimeter; (k) measuring the effective heat capacity of the second sample by: (α) selecting a modulation angular frequency and a modulation amplitude, (β) varying the temperature of the sample position and the reference position according to the selected modulation amplitude and modulation angular frequency, and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; and (l) calculating the thermal conductivity of the material from the measured heat capacities of the first sample and of the second sample, from the dimensions and weights of the first sample and of the second sample, and from the modulation angular frequency.

Claim 2

A method for measuring the thermal conductivity of a material comprising: (a) preparing a first sample of the material in the form of a thin wafer having a known thickness, known dimensions and known weight; (b) encapsulating the first sample of the material in a thin layer of conforming high thermal conductivity material, the mass of said thin layer of high thermal conductivity material having a first value; (c) preparing a second sample of the material as a right angle cylinder having flat and parallel top and bottom surfaces, the height of said cylinder being greater than the thickness of the first sample of the material; (d) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (e) placing the first sample in the sample position of the differential scanning calorimeter; (f) placing a thin wafer of the high thermal conductivity material on the reference position of the differential scanning calorimeter, the mass of said thin wafer of high thermal conductivity material having the first value; (g) measuring the effective heat capacity of the first sample by: (α) selecting a modulation angular frequency and a modulation amplitude, (β) varying the temperature of the sample position and the reference position according to the selected modulation amplitude and modulation angular frequency, and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; (h) removing the first sample from the sample position; (i) removing the thin wafer of high thermal conductivity material from the reference position; (j) placing the second sample on the sample position of the differential scanning calorimeter; (k) measuring the effective heat capacity of the second sample by: (α) selecting a modulation angular frequency and a modulation amplitude, (β) varying the temperature of the sample position and the reference position according to the selected modulation amplitude and modulation angular frequency, and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; and (l) calculating the thermal conductivity of the material from the measured heat capacities of the first sample and of the second sample, from the dimensions and weights of the first sample and of the second sample, and from the modulation angular frequency.

Claim 17

A method for measuring the thermal conductivity of a thin film material comprising: (a) preparing a right angle cylinder of a material having a known heat capacity, said cylinder having flat and parallel top and bottom surfaces and having a known cross-sectional area; (b) preparing two wafers of the thin film material, said wafers having similar dimensions and thicknesses, and measuring the thickness of the two wafers; (c) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (d) placing a layer of high thermal conductivity compound uniformly over the sample position of the differential scanning calorimeter; (e) placing an amount of the high thermal conductivity material over the reference position of the differential scanning calorimeter equal to the amount placed over the reference position; (f) mounting the cylinder on the same position of the differential scanning calorimeter; (g) selecting a modulation angular frequency and a modulation amplitude; (h) measuring the true heat capacity of the cylinder, using the selected modulation angular frequency and the selected modulation amplitude; (i) removing the cylinder from the sample position; (j) mounting one wafer of the thin film material onto the sample position, and the other wafer of the thin film material to the reference position; (k) mounting the cylinder of the known heat capacity material over the wafer on the sample position; (l) measuring the effective heat capacity of the cylinder using the selected modulation angular frequency and the selected modulation amplitude; and (m) calculating the thermal conductivity of the film from the true heat capacity of the cylinder measured in step (h), the effective heat capacity of the cylinder measured in step (l), the thickness of the thin films, the selected modulation angular frequency and the cross-sectional area of the cylinder.

Claim 18

A method for measuring the thermal conductivity of a thin film material comprising: (a) preparing a right angle cylinder of a material having a known heat capacity, said cylinder having flat and parallel top and bottom surfaces and having a known cross-sectional area; (b) preparing two wafers of the thin film material, said wafers having similar dimensions and thicknesses, and measuring the thickness of the two wafers; (c) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (d) placing a layer of high thermal conductivity compound uniformly over the sample position of the differential scanning calorimeter; (e) placing an amount of the high thermal conductivity material over the reference position of the differential scanning calorimeter equal to the amount placed over the reference position; (f) mounting the cylinder on the same position of the differential scanning calorimeter; (g) selecting a modulation angular frequency and a modulation amplitude; (h) measuring the true heat capacity of the cylinder, using the selected modulation angular frequency and the selected modulation amplitude; (i) removing the cylinder from the sample position; (j) mounting one wafer of the thin film material onto the sample position, and the other wafer of the thin film material to the reference position; (k) mounting the cylinder of the known heat capacity material over the wafer on the sample position; (l) measuring the effective heat capacity of the cylinder using the selected modulation angular frequency and the selected modulation amplitude; and (m) calculating the thermal conductivity of the film from the true heat capacity of the cylinder measured in step (h), the effective heat capacity of the cylinder measured in step (l), the thickness of the thin films, the selected modulation angular frequency and the cross-sectional area of the cylinder.

Claim 24

A method for measuring the thermal conductivity of a material comprising: (a) preparing a sample of the material as a right angle cylinder having flat and parallel top and bottom surfaces, the height of said cylinder being greater than 1 mm; (b) measuring the height of the cylinder, the dimensions of its cross-section, and the weight of the cylinder; (c) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation frequencies and modulation amplitudes; (d) placing the sample of the material on the sample position of the differential scanning calorimeter; (e) measuring a first effective heat capacity of the sample by: (α) selecting a first modulation angular frequency and a first modulation amplitude; (β) varying the temperature of the sample position and the reference position according to the selected first modulation amplitude and first modulation angular frequency; and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; (f) measuring a second effective heat capacity of the sample by: (α) selecting a second modulation angular frequency differing from the first modulation angular frequency by at least a factor of two, (β) selecting a second modulation amplitude, (γ) varying the temperature of the sample position and the reference position according to the selected second modulation amplitude and second modulation angular frequency, and (δ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; and (g) calculating the thermal conductivity of the material from the first and second effective measured heat capacities of the sample, from the height and cross-sectional dimensions of the cylinder, from the weight of the sample, and from the first and second angular modulation frequencies.

Claim 25

A method for measuring the thermal conductivity of a material comprising: (a) preparing a sample of the material as a right angle cylinder having flat and parallel top and bottom surfaces, the height of said cylinder being greater than 1 mm; (b) measuring the height of the cylinder, the dimensions of its cross-section, and the weight of the cylinder; (c) providing a differential scanning calorimeter having a sample position and a reference position, said differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation frequencies and modulation amplitudes; (d) placing the sample of the material on the sample position of the differential scanning calorimeter; (e) measuring a first effective heat capacity of the sample by: (α) selecting a first modulation angular frequency and a first modulation amplitude; (β) varying the temperature of the sample position and the reference position according to the selected first modulation amplitude and first modulation angular frequency; and (γ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; (f) measuring a second effective heat capacity of the sample by: (α) selecting a second modulation angular frequency differing from the first modulation angular frequency by at least a factor of two, (β) selecting a second modulation amplitude, (γ) varying the temperature of the sample position and the reference position according to the selected second modulation amplitude and second modulation angular frequency, and (δ) recording a differential signal representative of differential changes in the heat flow to and from the sample position with respect to the heat flow to and from the reference position; and (g) calculating the thermal conductivity of the material from the first and second effective measured heat capacities of the sample, from the height and cross-sectional dimensions of the cylinder, from the weight of the sample, and from the first and second angular modulation frequencies.

Claim 29

A method for measuring the thermal conductivity of a material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) measuring the heat capacity of a sample of the material placed in the sample position in the modulated differential scanning calorimeter by measuring the differential heat flow to the sample position with respect to the reference position under quasi-ideal conditions; (c) measuring the effective heat capacity of a sample of the material in the modulated differential scanning calorimeter by measuring the differential heat flow to the sample position with respect to the reference position under non-ideal conditions; and (d) calculating the thermal conductivity of the material from the sample dimensions, sample weights, heat capacity measured under quasi-ideal conditions, and effective heat capacity measured under non-ideal conditions.

Claim 30

A method for measuring the thermal conductivity of a material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) measuring the heat capacity of a sample of the material placed in the sample position in the modulated differential scanning calorimeter by measuring the differential heat flow to the sample position with respect to the reference position under quasi-ideal conditions; (c) measuring the effective heat capacity of a sample of the material in the modulated differential scanning calorimeter by measuring the differential heat flow to the sample position with respect to the reference position under non-ideal conditions; and (d) calculating the thermal conductivity of the material from the sample dimensions, sample weights, heat capacity measured under quasi-ideal conditions, and effective heat capacity measured under non-ideal conditions.

Claim 36

A method for measuring the thermal conductivity of a thin film material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a sample of the thin film material on the sample position, and a matching sample of the thin film material on the reference position; (c) placing a specimen having a known heat capacity on top of the sample of the thin film on the sample position; (d) measuring the effective heat capacity of the specimen; and (e) calculating the thermal conductivity of the material from the dimensions and thickness of the sample of thin film material, from the dimensions and weight of the specimen, from the known heat capacity of the specimen, and from the effective heat capacity of the specimen measured in step (d).

Claim 37

A method for measuring the thermal conductivity of a thin film material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a sample of the thin film material on the sample position, and a matching sample of the thin film material on the reference position; (c) placing a specimen having a known heat capacity on top of the sample of the thin film on the sample position; (d) measuring the effective heat capacity of the specimen; and (e) calculating the thermal conductivity of the material from the dimensions and thickness of the sample of thin film material, from the dimensions and weight of the specimen, from the known heat capacity of the specimen, and from the effective heat capacity of the specimen measured in step (d).

Claim 38

A method for measuring the thermal conductivity of a thin film material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a specimen on the sample position of the modulated differential scanning calorimeter; (c) measuring the true heat capacity of the specimen in the modulated differential scanning calorimeter under quasi-ideal conditions; (d) removing the specimen from the sample position; (e) placing a sample of the thin film material on the sample position, and a matching sample of the thin film material on the reference position; (f) placing the specimen on top of the sample of the thin film on the sample position; (g) measuring the effective heat capacity of the specimen; and (h) calculating the thermal conductivity of the material from the dimensions and thickness of the sample of thin film material, from the dimensions and weight of the specimen, from the true heat capacity measured in step (c), and from the effective heat capacity measured in step (g).

Claim 39

A method for measuring the thermal conductivity of a thin film material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a specimen on the sample position of the modulated differential scanning calorimeter; (c) measuring the true heat capacity of the specimen in the modulated differential scanning calorimeter under quasi-ideal conditions; (d) removing the specimen from the sample position; (e) placing a sample of the thin film material on the sample position, and a matching sample of the thin film material on the reference position; (f) placing the specimen on top of the sample of the thin film on the sample position; (g) measuring the effective heat capacity of the specimen; and (h) calculating the thermal conductivity of the material from the dimensions and thickness of the sample of thin film material, from the dimensions and weight of the specimen, from the true heat capacity measured in step (c), and from the effective heat capacity measured in step (g).

Claim 40

A method for measuring the thermal conductivity of a liquid material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a crucible containing a sample of the liquid material on the sample position, and a matching crucible containing a matching sample of the liquid material on the reference position; (c) placing a specimen having a known heat capacity on top of the sample of the liquid material at the sample position, said specimen being supported by a plurality of low-conductivity rods; (d) measuring the effective heat capacity of the specimen; and (e) calculating the thermal conductivity of the material from the depth of the liquid material in the crucible, the dimensions of the crucible, from the dimensions and weight of the specimen, from the known heat capacity of the specimen, and from the effective heat capacity of the specimen measured in step (d).

Claim 41

A method for measuring the thermal conductivity of a liquid material comprising: (a) providing a modulated differential scanning calorimeter having a sample position and a reference position, said modulated differential scanning calorimeter comprising means for modulating the temperature of the sample and reference positions at selected modulation angular frequencies and modulation amplitudes; (b) placing a crucible containing a sample of the liquid material on the sample position, and a matching crucible containing a matching sample of the liquid material on the reference position; (c) placing a specimen having a known heat capacity on top of the sample of the liquid material at the sample position, said specimen being supported by a plurality of low-conductivity rods; (d) measuring the effective heat capacity of the specimen; and (e) calculating the thermal conductivity of the material from the depth of the liquid material in the crucible, the dimensions of the crucible, from the dimensions and weight of the specimen, from the known heat capacity of the specimen, and from the effective heat capacity of the specimen measured in step (d).