Lithography system, sensor, converter element and method of manufacture

Abstract

Charged particle beamlet lithography system for transferring a pattern to a surface of a target comprising a sensor for determining one or more characteristics of one or more charged particle beamlets. The sensor comprises a converter element for receiving charged particles and generating photons in response. The converter element comprises a surface for receiving one or more charged particle beamlets, the surface being provided with one or more cells for evaluating one or more individual beamlets. Each cell comprises a predetermined blocking pattern of one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface. The converter element surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light. An electrically conductive layer is located between the coating layer and the blocking structures.

The invention claimed is: 
     
       1. Charged particle beamlet lithography system for transferring a pattern to a surface of a target comprising a sensor for determining one or more characteristics of one or more charged particle beamlets, the sensor comprising a converter element for receiving charged particles and generating photons in response, the converter element comprising a surface for receiving one or more charged particle beamlets, the surface being provided with one or more cells for evaluating one or more individual beamlets, each cell comprising a predetermined blocking pattern of one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, the surface being provided with a pattern comprising charged particle blocking regions and charged particle non-blocking regions, the charged particle blocking regions comprising one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, wherein the converter element surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light, and an electrically conductive layer is located between the coating layer converter element surface and the blocking structures, the electrically conductive layer being located underneath the blocking structures, the electrically conductive layer being located only within the blocking regions. 
     
     
       2. System according to  claim 1 , wherein the sensor is adapted for determining one or more characteristics of a plurality of charged particle beamlets for each of the beamlets in parallel by simultaneously generating a signal in response to receiving each of the plurality of charged particles beamlets. 
     
     
       3. System according to  claim 1 , wherein the conductive layer is substantially similar in shape and size as the dimensions of the blocking structures in a plane substantially parallel to the converter element surface. 
     
     
       4. System according to  claim 1 , wherein the conductive layer comprises chromium. 
     
     
       5. System according to  claim 1 , wherein the blocking structures comprise tungsten. 
     
     
       6. System according to  claim 1 , wherein the converter element comprises a scintillating material. 
     
     
       7. System according to  claim 6 , wherein the scintillating material comprises an yttrium aluminum garnet. 
     
     
       8. System according to  claim 1 , wherein the coating layer comprises titanium. 
     
     
       9. System according to  claim 1 , wherein the charged particle beamlets are electron beamlets. 
     
     
       10. System according to  claim 1 , wherein the sensor further comprises:
 a photon receptor for receiving photons generated by said converter element; and 
 a control unit for receiving signals from the photon receptor and for determining one or more characteristics of one or more beamlets based on said signals. 
 
     
     
       11. System according to  claim 1 , further comprising:
 a beamlet generator for generating a plurality of charged particle beamlets; 
 a modulation system for modulating the charged particle beamlets in accordance with a pattern to be transferred; 
 an electron-optical system for focusing the modulated beamlets onto the surface of the target; 
 a deflecting system for deflecting the focused beamlets over the surface of either the target or the sensor. 
 
     
     
       12. Sensor for generating a signal in response to exposure thereof by a charged particle beam, the sensor comprising a converter element for receiving charged particles and generating photons in response, the converter element comprising a surface for receiving one or more charged particle beamlets, the surface being provided with one or more cells for evaluating one or more individual beamlets, each cell comprising a predetermined blocking pattern of one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, the surface being provided with a pattern comprising charged particle blocking regions and charged particle non-blocking regions, the charged particle blocking regions comprising one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, wherein said converter surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light, and an electrically conductive layer is located between the coating layer converter element surface and the blocking structures, the electrically conductive layer being located underneath the blocking structures, the electrically conductive layer being located only within the blocking regions, and wherein the sensor further comprises a photon receptor associated with the converter element for generating a signal on the basis of photons generated by the converter element. 
     
     
       13. Sensor according to  claim 12 , wherein the photon receptor is arranged for forming reception information based on photons generated by the converter element, the sensor further comprising a control unit for receiving the reception information from the photon receptor and determining a characteristic of the plurality of charged particle beams based on the reception information. 
     
     
       14. Converter element for receiving charged particles and generating photons in response for use in a sensor for sensing a characteristic of a plurality of charged particles beamlets, the converter element comprising a surface for receiving one or more charged particle beamlets, the surface being provided with one or more cells for evaluating one or more individual beamlets, each cell comprising a predetermined blocking pattern of one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, the surface being provided with a pattern comprising charged particle blocking regions and charged particle non-blocking regions, the charged particle blocking regions comprising one or more charged particle blocking structures forming multiple knife edges at transitions between blocking and non-blocking regions along a predetermined beamlet scan trajectory over the converter element surface, wherein the converter element surface is covered with a coating layer substantially permeable for charged particles and substantially impermeable for ambient light, and an electrically conductive layer is located between the coating layer converter element surface and the blocking structures, the electrically conductive layer being located underneath the blocking structures, the electrically conductive layer being located only within the blocking regions. 
     
     
       15. Method of manufacturing a converter element arranged for selectively converting impinging charged particles into photons, the method comprising:
 providing a substrate comprising a conversion material for converting charged particles into photons; 
 subsequently coating the substrate with a first layer comprising an electrically conductive material, a second layer comprising an etch stop material and a third layer comprising a third material; 
 providing a resist layer on top of said third layer; 
 patterning, and developing the resist layer so as to form a first predetermined pattern, and etching the developed resist layer until the third layer is exposed; 
 coating the exposed third layer with a fourth layer comprising a further etch stop material; 
 lifting of the developed resist such that the third layer is exposed in accordance with a second predetermined pattern, the second predetermined pattern being an inversion of the first predetermined pattern; 
 etching the third layer in accordance with the second predetermined pattern until the second layer is exposed; 
 etching the fourth layer as well as the second layer in accordance with the second predetermined pattern until the first layer is exposed. 
 
     
     
       16. The method according to  claim 15 , wherein said first layer is substantially impermeable for ambient light and substantially permeable for charged particle beamlets. 
     
     
       17. The method according to  claim 15 , wherein the etch stop material of the second layer and the further etch stop material of the fourth layer are the same. 
     
     
       18. The method according to  claim 15 , wherein at least one of the etch stop material and the further etch stop material comprises chrome chromium. 
     
     
       19. The method according to  claim 15 , wherein the electrically conductive material of the first layer comprises at least one of titanium and aluminum. 
     
     
       20. The method according to  claim 15 , wherein the third layer material has a high selectivity to both wet and dry etching. 
     
     
       21. The method according to  claim 15 , wherein the third material comprises tungsten. 
     
     
       22. The method according to  claim 15 , wherein the conversion material of the substrate comprises a scintillating material. 
     
     
       23. The method according to  claim 22 , wherein the scintillating material comprises an yttrium aluminum garnet. 
     
     
       24. System according to claim 1, wherein the converter element surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light, and the electrically conductive layer is located between the coating layer and the blocking structures. 
     
     
       25. System according to claim 24, wherein the coating layer comprises titanium. 
     
     
       26. Sensor according to claim 12, wherein the electrically conductive layer comprises chromium. 
     
     
       27. Sensor according to claim 12, wherein the blocking structures comprise tungsten. 
     
     
       28. Sensor according to claim 12, wherein the converter element comprises a scintillating material. 
     
     
       29. Sensor according to claim 28, wherein the scintillating material comprises an yttrium aluminum garnet. 
     
     
       30. Sensor according to claim 12, wherein the converter element surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light, and the electrically conductive layer is located between the coating layer and the blocking structures. 
     
     
       31. Sensor according to claim 30, wherein the coating layer comprises titanium. 
     
     
       32. Converter element according to claim 14, wherein the converter element comprises a scintillating material. 
     
     
       33. Converter element according to claim 14, wherein the electrically conductive layer comprises chromium. 
     
     
       34. Converter element according to claim 14, wherein said converter element surface is covered with a coating layer substantially permeable for said charged particles and substantially impermeable for ambient light, and the electrically conductive layer is located between the coating layer and the blocking structures.