Method and apparatus for depositing atomic layers on a substrate

1. A method of depositing an atomic layer on a substrate, the method comprising:

supplying a precursor gas from a precursor-gas supply comprised in a drum; the drum being rotatable with respect to a sealing piece that receives gas from a gas source, wherein one of the drum and sealing piece comprises one or more gas feed channels in fluid connection with the precursor-gas supply, wherein the other of the drum and sealing piece comprises one or more circumferential grooves in its surface sealed by the one of the drum and sealing piece thereby preventing a fluid flowpath in a radial direction and leaving a fluid flow path in a circumferential direction, wherein during the supplying the precursor gas from the precursor-gas supply towards the substrate, the gas feed channels abut the sealed grooves, wherein a part of the gas flow path is formed by the sealed grooves, and wherein at least one sealed groove is provided with one or more separations separating adjacent zones of process gas feeds in the sealed groove, thus allowing zones to provide for mutually differing process gas compositions; and

providing a relative motion between the precursor-gas supply and the substrate to have the precursor gas react on the substrate so as to form an atomic layer by rotating the drum along a rotation trajectory while supplying the precursor gas; thus depositing a stack of atomic layers of a gradient composition,

wherein the at least one groove is formed by an upstanding wall that is sealed by an abutting face of one of the sealing piece or the drum, and

wherein the separations are recessed relative to the upstanding wall thereby forming a flow restriction relative the abutting face in order to provide a controlled cross flow between adjacent zones.

2. The method according to claim 1 , wherein the separations are provided with a wall thickness that is smaller than a corresponding feed channel diameter in order to provide a controlled cross flow between adjacent zones.

3. The method according to claim 2 , wherein the gas supply is comprised in drum that receives gas from a stationary gas source via a gas flow path comprising relative rotating parts; wherein a leakage of the precursor gas through an opening between the relative moving parts is prevented by a purge gas provided around said opening having a higher pressure than the precursor gas.

4. The method according to claim 1 , further comprising switching between:

supplying the precursor gas from the precursor-gas supply towards the substrate over a first part of the rotation trajectory; and

interrupting supplying the precursor gas from said precursor-gas supply over a second part of the rotation trajectory.

5. The method according to claim 4 , wherein

over the first part of the rotation trajectory the substrate is in proximity to an output face, which is supplying the precursor gas, for the depositing the atomic layer,

over the second part of the rotation trajectory the substrate is removed or away from the output face; and

said interrupting is provided by redirecting or switching off a precursor gas flow through the precursor gas supply to prevent a leakage of the precursor gas over the second part of the rotation trajectory.

6. The method according to claim 4 , wherein the circumferential sealed grooves extend along the first part of the rotation trajectory, ending between the first and second part of the rotation trajectory in such a way that during interrupting supplying the precursor gas from said precursor-gas supply over the second part of the rotation trajectory, the gas flow path is interrupted by a surface of the other of the drum and sealing piece.

7. An apparatus for depositing an atomic layer on a substrate, the apparatus comprising:

a drum comprising a deposition head and a sealing piece that seals at least part of the drum's surface;

wherein the drum is rotatable with respect to the sealing piece that receives gas from a gas source,

wherein one of the drum and sealing piece comprises one or more gas feed channels in fluid connection with the precursor-gas supply,

wherein the other of the drum and sealing piece comprising one or more circumferential grooves in its surface sealed by the one of the drum and sealing piece thereby preventing a fluid flowpath in a radial direction and leaving a fluid flow path in a circumferential direction,

wherein in use, during the supplying the precursor gas from the precursor-gas supply towards the substrate the gas feed channels abut the sealed grooves wherein a part of the gas flow path is formed by the sealed grooves;

wherein at least one sealed groove is provided with one or more separations separating adjacent zones of process gas feeds in the sealed groove, thus allowing zones to provide for mutually differing process gas compositions;

wherein the deposition head is constructed for realizing a relative motion between the precursor-gas supply and the substrate to have the supplied precursor gas react on the substrate so as to form an atomic layer by rotating the drum along a rotation trajectory while supplying the precursor gas; thus depositing a stack of atomic layers of a gradient composition,

wherein the at least one groove is formed by an upstanding wall that is sealed by an abutting face of one of the sealing piece or the drum, and

wherein the separations are recessed relative to the upstanding wall thereby forming a flow restriction relative the abutting face to provide a controlled cross flow between adjacent zones.

8. The apparatus according to claim 7 , wherein the separations are provided with a wall thickness that is smaller than a corresponding feed channel diameter thereby forming a flow restriction in order to provide a controlled cross flow between adjacent zones.

9. The apparatus according to claim 7 , further comprising a gas switching structure arranged and constructed for switching between:

supplying the precursor gas from the precursor-gas supply towards the substrate over a first part of the rotation trajectory; and

interrupting supplying the precursor gas from said precursor-gas supply over a second part of the rotation trajectory.

10. The apparatus according to claim 9 , wherein the circumferential sealed grooves extend along the first part of the rotation trajectory comprising an end wall, ending the groove between the first and second part of the rotation trajectory by an end wall in such a way that during interrupting supplying the precursor gas from said precursor-gas supply over the second part of the rotation trajectory, the gas flow path is interrupted by a surface of the other of the drum and sealing piece.

11. The apparatus according to claim 7 , wherein the circumferential sealed grooves extend along end faces of the rotatable drum.