Variable Gradient Thickness Coating
A coating device comprising a sample carrier, a source, shadow mask and coating driver. The source comprises a plurality of targets such as a first target and second target. The source is arranged to coat at least one sample housed in the sample carrier. The shadow mask is disposed in a line-of-sight between the sample carrier and source. The shadow mask is arranged such that the first target provides a first coating contribution. The shadow mask is further arranged such that the second target provides a second coating contribution. The second coating contribution is different to the first coating contribution. At least one of the first and second coating contributions is non-uniform in a first dimension of the sample. The coating driver is arranged to independently control the first coating contribution and second coating contribution such that a thickness gradient of the coating in the first direction is variable.
1 . A coating device comprising:
a sample carrier;
a source comprising a first target and a second target, wherein the source is arranged to coat a sample housed in the sample carrier;
a shadow mask disposed between the sample carrier and source, wherein the shadow mask is arranged such that the first target provides a first coating contribution and the second target provides a second coating contribution different to the first coating contribution, wherein at least one of the first and second coating contributions is non-uniform in a first dimension of the sample; and
a coating driver arranged to independently control the first coating contribution and second coating contribution such that a thickness gradient of the coating in the first direction is variable.
2 . A coating device as claimed in claim 1 , wherein the source is arranged to coat a plurality of samples housed in the sample carrier.
3 . A coating device as claimed in claim 1 , wherein the shadow mask comprises a first shadow mask component aligned with the first target to provide the first coating contribution and/or a second shadow mask component aligned with the second target to provide the second coating contribution.
4 . A coating device as claimed in claim 3 , wherein the first shadow mask component defines a first coating aperture that varies in size in the first dimension of the sample and/or the second shadow mask component defines a second coating aperture that varies in size in the first dimension of the sample.
5 . A coating device as claimed in claim 4 , wherein the first coating aperture comprises alternating first and second sections, wherein each first section comprises an increase in aperture size and each second section comprises a decrease in aperture size.
6 . A coating device as claimed in claim 5 , wherein the increase in aperture size of the first section is equal and opposite to the decrease in aperture size of the second section.
7 . A coating device as claimed in claim 5 , wherein the source is arranged to coat a plurality of samples housed in the sample carrier, and wherein each first and second section corresponds to a respective sample of the plurality of samples.
8 . A coating device as claimed in claim 1 , wherein the coating driver comprises at least one selected from the group comprising: a magnetic bar controller arranged to change the magnitude of a magnetic field at a plurality of positions of the source, a pressure controller arranged to change the pressure of a gas of the coating device; and a magnet rotator arranged to control a direction of deposition (in a plane perpendicular to the vertical direction.
9 . A coating device as claimed in claim 1 , wherein the coating driver is arranged to change the first coating contribution and/or second coating contribution by no more than 20%.
10 . A coating device as claimed in claim 1 , wherein a material of the first target is different to a material of the second target such that the coating is a blended target comprising material of the first target and the second target.
11 . A coating device as claimed in claim 1 , wherein a material of the first target is the same as a material of the second target.
12 . A coating device as claimed in claim 1 , wherein the first target and second target are spatially separated.
13 . A coating device as claimed in claim 1 , wherein a coating direction of the coating device is substantially perpendicular to the first dimension of the sample.
14 . A coating device as claimed in claim 1 , wherein coating of the sample comprises sputtering the target material.
15 . A coating device as claimed in claim 1 , wherein the source is arranged to rotate about an axis parallel to the first dimension.
16 . A method of changing the thickness gradient of a coating formed by source comprising a first target and second target, the method comprising:
shadow masking by arranging or disposing a shadow mask in a line-of-sight between the source and sample carrier such that the first target provides a first coating contribution and the second target provides a second coating contribution different to the first coating contribution, wherein at least one of the first and second coating contributions is non-uniform in a first dimension of the sample or samples housed in the sampled carrier;
depositing material from the first target and coating material from the second target towards the sample carrier via the shadow mask; and
software-controlling the first coating contribution and/or second coating contribution by changing an operating condition or parameter of a coating driver of the coating device such that a thickness gradient of the coating in the first direction is continuously variable.