Detection of a position of a wafer within a transfer robot vacuum chamber
A location detection system for detecting a location of a wafer within a transfer robot vacuum chamber (TRVC), the detection system may include (i) an illumination unit that is configured to direct a transmitted radiation pattern through a transparent window of the TRVC and towards one or more TRVS reflecting elements located below an upper side of a wafer holding element of the transfer robot; wherein the illumination unit is located outside the TRVC; (ii) a sensing unit that is configured to generate one or more detection signals indicative of a received radiation pattern that is reflected from the one or more TRVS reflecting elements; and (iii) a location processing circuit that is configured to detect a location of the wafer based on the one or more detection signals.
1 . A location detection system for detecting a location of a wafer within a transfer robot vacuum chamber (TRVC), the location detection system comprises:
an illumination unit that is configured to direct a transmitted radiation pattern, at an angle of incidence, through a transparent window of the TRVC and towards one or more TRVC reflecting elements located below an upper side of a wafer holding element of a transfer robot located within the TRVC; wherein the illumination unit is located outside the TRVC;
a sensing unit that is configured to generate one or more detection signals indicative of a received radiation pattern that is reflected from the one or more TRVC reflecting elements and is received at an angle of reflection that equals the angle of incidence; wherein the received radiation pattern is a two dimensional array of spaced apart spots when there is no wafer within the TRVC, (b) is a portion of the two dimensional array of spaced apart spots when the wafer partially blocks the transmitted radiation pattern, and (c) is null when the wafer completely blocks the transmitted radiation pattern;
and
a location processing circuit that is configured to detect the location of the wafer based on the one or more detection signals.
2 . The location detection system according to claim 1 wherein the transmitted radiation pattern comprises a two dimensional array of spaced apart radiation spots.
3 . The location detection system according to claim 1 wherein the transmitted radiation pattern comprises a radiation beam, and wherein the one or more TRVC reflecting elements comprise a two dimensional array of spaced apart TRVC reflecting elements.
4 . The location detection system according to claim 1 wherein the location processing circuit is configured to detect the location of the wafer while the wafer is static.
5 . The location detection system according to claim 1 wherein the transmitted radiation pattern propagates along a path that is normal to the transparent window.
6 . The location detection system according to claim 1 wherein the one or more TRVC reflecting elements comprises multiple TRVC reflecting elements that are spaced apart from each other.
7 . The location detection system according to claim 6 wherein the location processing circuit is configured to compare detection signals indicative of reflection from at least two TRVC reflecting elements of the multiple TRVC reflecting elements.
8 . The location detection system according to claim 1 wherein the location processing circuit is configured to detect a location of an edge of the wafer.
9 . The location detection system according to claim 1 wherein the one or more TRVC reflecting elements comprises (i) a first TRVC reflecting element that is configured to reflect radiation towards one or more first locations of the sensing unit, and (ii) a second TRVC reflecting element that is configured to reflect radiation towards one or more second locations of the sensing unit.
10 . The location detection system according to claim 1 wherein the location detection system comprises a mechanical adaptor for mechanically coupling at the sensing unit and the illuminating unit to the transparent window.
11 . A method for detecting a location of a wafer within a transfer robot vacuum chamber (TRVC), the method comprising:
directing, by an illumination unit that is located outside the TRVC, and at an angle of incidence, a transmitted radiation pattern through a transparent window of the TRVC and towards one or more TRVC reflecting elements located below an upper side of a wafer holding element of a transfer robot located within the TRVC;
generating, by a sensing unit, one or more detection signals indicative of a received radiation pattern that is reflected from the one or more TRVC reflecting elements; the received radiation pattern is received at an angle of reflection that equals the angle of incidence; wherein the received radiation pattern is a two dimensional array of spaced apart spots when there is no wafer within the TRVC, (b) is a portion of the two dimensional array of spaced apart spots when the wafer partially blocks the transmitted radiation pattern, and (c) is null when the wafer completely blocks the transmitted radiation pattern;
and
detecting, by a location processing circuit, the location of the wafer based on the one or more detection signals.
12 . The method according to claim 11 wherein the transmitted radiation pattern comprises a two dimensional array of spaced apart radiation spots.
13 . The method according to claim 11 wherein the transmitted radiation pattern comprises a radiation beam, and wherein the one or more TRVC reflecting elements comprise a two dimensional array of spaced apart TRVC reflecting elements.
14 . The method according to claim 11 comprising detecting a location of an edge of the wafer.
15 . The method according to claim 11 wherein the transmitted radiation pattern propagates along a path that is normal to the transparent window.
16 . The method according to claim 11 wherein the one or more TRVC reflecting elements comprises multiple TRVC reflecting elements that are spaced apart from each other.
17 . The method according to claim 16 comprising comparing detection signals indicative of reflection from at least two TRVC reflecting elements of the multiple TRVC reflecting elements.
18 . The method according to claim 11 comprising detecting the location of the wafer while the wafer is static.
19 . The method according to claim 11 comprising receiving, at one or more first locations of the sensing unit, reflected radiation from a first TRVC reflecting element;
and receiving, at one or more second locations of the sensing unit, reflected radiation from a second TRVC reflecting element.
20 . A non-transitory computer readable medium that stores instructions for:
directing, by an illumination unit and at an angle of incidence, a transmitted radiation pattern through a transparent window of a transfer robot vacuum chamber (TRVC) and towards one or more TRVC reflecting elements located below an upper side of a wafer holding element of the transfer robot; wherein the illumination unit that is located outside the TRVC;
generating, by a sensing unit, one or more detection signals indicative of a received radiation pattern that is reflected from the one or more TRVC reflecting elements; the received radiation pattern is received at an angle of reflection that equals the angle of incidence; wherein the received radiation pattern is a two dimensional array of spaced apart spots when there is no wafer within the TRVC, (b) is a portion of the two dimensional array of spaced apart spots when the wafer partially blocks the transmitted radiation pattern, and (c) is null when the wafer completely blocks the transmitted radiation pattern;
and
detecting, by a location processing circuit, a location of the wafer based on the one or more detection signals.