Hand book for use of library : Start_cmiV4

Transcription

1 Hand book for use of library : Start_cmiV4 The library of CMI for layout design has been up-dated, changes are : - V4.3 (27. Feb. 2008) o add cell ELECTRODEP_CIRCLE for electro-plating deposition o add cell EBEAM_WAF for E-Beam lithography o modifications of cell WAFER_ROUTE - V4.4 (9. Feb. 2009) o Splitting of the CMI library for: Single mask process without alignment (1layer) Alignment up to 3 masks on topside + 1 backside mask (3layers_optical) Multi-layer template for single level e-beam lithography (EBEAM) o Update exclusion area top and backside o Add inverted (darkfield) symbols for inverted mode mask fabrication FILES: This library is available under the file name: 1. Start_cmi_1layer_V4_4 for single mask process 2. Start_cmi_3layers_optical_only_V4_4 for multilevel process 3. Start_cmi_Electrodep_V4_4 special multilevel with ED 4. Start_cmi_DWL_align_V4_4 specific for use with laser direct writing 5. Start_cmi_EBEAM_V4_4 specific for ebeam writing (die level) Choose one of the above library in function of the process complexity. Import the library in your preferred CAD software, both format CIF (.cif extension) or GDSII (.gds file extension) are equivalent. Use the Wafer_ROUTE symbol to create the mapping of your dies at wafer level. A summary table of the layers used in the CMI libraries can be found at the end of this document. When the design is finished, export it as a GDSII (.gds file extension) or CIF (.cif extension). Some restrictions can appear while trying to export in CIF. Exported file under CIF or GDSII can be converted for direct writing or mask fabrication with DWL200. LIBRARY CONTENT A library is composed of several cells which we make an instance into a top cell. The interest of using a hierarchical design is to repeat the same structure many times, and if necessary, change all the structures by only changing the initial cell. For the libraries Start_cmi_xx_V4, the top cell i.e. the cell that contains all the others, is «WAFER_ROUTE». 3 cells are included in WAFER_ROUTE : WAF_CONTOUR define the exclusion area and make your design centred with respect to the wafer. Additional exclusion are available in case of electrodeposition. JB, SC, GAR/CMI 1 / 11

2 Guide_tests are optional guide to find alignment targets and tests structures for lithography controls DECOUP_CROSS contain the alignment cross for the final wafer dicing and repetition properties of the dies (=mapping) You include your dies using the following rules: 1. Open DECOUP_CROSS as the die main cell. 2. Include your die as an instance in this cell 3. Open WAFER_ROUTE and select DECOUP_CROSS array 4. Move array and edit the repetition parameters of the array according to you die dimension. 5. Edit the cross marker layer to change the layer target (recommended is a metal layer to enhance optical contrast). 6. Guide and tests structures may be moved according to your mapping. Specific library may contain alignment marks and help for die mapping LEFT3NIV ; RIGHT3NIV ; BSREF ; DWL_GLOBAL, ELECTRODEP_CIRCLE Note: For some CAD (clewin) the top cell is named main symbol. PLOTS OF LIBRARY WITH COMMENTS Following pages are commented plots of the fabrication cell (top cell) for the above mentioned library files. 1. WAFER_ROUTE for single mask process p WAFER_ROUTE for 3 level topside + 1 backside alignment p Die level E_BEAM p. 5 JB, SC, GAR/CMI 2 / 11

3 WAFER_ROUTE (Single mask process)

4 WAFER_ROUTE (3layers_optical)

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6 COMPONENTS OF THE LIBRARIES - a ring in layer Exclusion (layer #30). The ring delimits the drawing zone where you should not put any drawing, and the rectangles represent the openings in the chuck of mask-aligners for back-side alignment. It is in these zones where you put your alignment marks. Cell : «WAF_CONTOUR» (0,0) Layer : Exclusion (#30) - 3 areas in layer Exclusion BSA (layer #31). These areas delimit the drawing zone where you should not put any drawing in wafer backside. 3 ovals delimits the landing zone of the EVG150 vacuum suckers. The rectangles represent the openings in the chuck of maskaligners for back-side alignment. It is in these zones where you put your alignment marks (both top and backside). - alignment marks : Cell : «WAF_CONTOUR» (0,0) Layer : Exclusion BSA (#31) «back-side» alignment marks Alignment marks permit to place correctly each layers of your design to the other ones. Hence, you have to put these marks on ALL the layers of your design, and on the left and right side of the wafer. The arrows permit to find the marks quickly but you can remove it if you want. In Start_cmiv4, marks are implemented in layers 1, 2 and 3 only. Cell : «RIGHT3NIV (42000;0)», «LEFT3NIV (-42000;0)», «BSREF ( ;0) (40000;0)» Layer : on all the layers For contrast inverted masks alternate alignment targets are available (dark field) for larger field of view around alignment targets (replace instance in array properties). Cell : «RIGHT_INV_LAYER2 (42000;0)», «LEFT_INV_LAYER2 ( ;0)», «BSREF_INV (-40000;0) (40000;0)» Layer : from second layer level JB, SC, GAR/CMI 6 / 11

7 - photolithography test patterns Many test patterns permit to check if the photolithography is well defined (resolution test to find the good exposure dose for example). Users may place these structures on each layers and in different places. Cell : «LITHO_TEST», «LITHO_TEST2», «LITHO_TEST3», Layer : recommended on all the layers having critical dimensions - Laser writer alignment cross Alignment cross for the laser writer are imperatives for those who want to use direct writing with DWL with alignment. The centre of the middle-cross (the one which is in a frame) must be placed on the origin points (0,0) of the design. These patterns must be on the first layer of photolithography, which is made with DWL himself. Cell : «DWL_GLOBAL» (0,0) Layer : exclusively on the first layer - Dicing cross a a b b JB, SC, GAR/CMI 7 / 11

8 Dicing cross allows guiding the saw. These should be placed near the corners of your design like on the example. To make the wafer dicing easier, the distance between two cross should be the same (but a can be different as b). The simpliest solution is to include your design as a die using the following rules: 7. Open DECOUP_CROSS as the die main cell. 8. Include your die as an instance in this cell 9. Open WAFER_ROUTE and select DECOUP_CROSS array 10. Move array and edit the repetition parameters of the array according to you die dimension. 11. Edit the cross marker layer to change the layer target (recommended is a metal layer to enhance optical contrast). 12. Guide and tests structures may be moved according to your mapping. Cell : «DECOUP_CROSS» -> Define as array with repetition n a, m b Layer : on the first layer or a metal layer - ring for electro-platting For electroplating deposition of metal, you should use the layer Metal (# 15) for you drawing and add the ring of the cell named «ELECTRODEP_CIRCLE». You have to create an instance of this cell because the inner diameter of the exclusion layer is smaller than the one of «WAF_CONTOUR» cell. Remark: the layer Metal can be used for other kind of metallization without the ring. Cell : «ELECTRODEP_CIRCLE» Layer : Metal (# 15) DESIGN WITH LITHOGRAPHIE E-BEAM For E-Beam lithography, special cells will be used. The first step of a fabrication process that use E-Beam lithography, is the patterning of alignment marks on the surface of the wafer. JB, SC, GAR/CMI 8 / 11

9 These marks are on different layers depending on on which are required (layer #21 to #24) of the cell «EBEAM_WAF». Don t use these layers as design layers. This cell which covers all the surface of the wafer contains elements which are essential for e- beam writing. Thus, you must not erase ANY element of this cell nor put patterns at less than 150 um away from those. The wafer is divided into 36 square cells of 1 cm long. These cells will contain your e-beam designs. It is thus possible to write up to 36 designs different on a 4 inches wafer. The only requirement is to make an instance of the cell EBEAM_frame, which contains a frame on the layer Text (#32), in your design cell (the structures has to be inside the frame). This frame allows to the software to easily find the centre of your design and then, align it on the wafer. 6 Cell 1, 6 Cell 2, 6 Cell 3, 6 Cell 4, 6 Cell 5, 6 Cell 6, 6 5 Cell 1, 5 Cell 2, 5 Cell 3, 5 Cell 4, 5 Cell 5, 5 Cell 6, 5 4 Cell 1, 4 Cell 2, 4 Cell 3, 4 Cell 4, 4 Cell 5, 4 Cell 6, 4 3 Cell 1, 3 Cell 2, 3 Cell 3, 3 Cell 4, 3 Cell 5, 3 Cell 6, 3 2 Cell 1, 2 Cell 2, 2 Cell 3, 2 Cell 4, 2 Cell 5, 2 Cell 6, 2 1 Cell 1, 1 Cell 2, 1 Cell 3, 1 Cell 4, 1 Cell 5, 1 Cell 6, 1 Y/X Each corner of each cell is made of 4 squares of 20 um long edges that constitute alignment markers. That s why the number of e-beam writing is limited to 4, for the whole process. JB, SC, GAR/CMI 9 / 11

10 DWL center cross and the 4 alignement marks. If you start your process with UV lithography, you must combine the first photolitho layer with reserved e-beam layers (e-beam_xxx) of the cell EBEAM_WAF during the conversion of the design to.lic files (in BM 1.135) If you start with e-beam writing, a Cr-mask (bright field and dark field) has already been done to make the alignment marks. Ask the staff to use it. A key point for e-beam lithography is to have a lot of contrast on the alignement marks. Different ways to define these markers are possible (conductive layer deposition and etching, insulating layer etching trough the whole thickness to get a conductive layer, ). In all the case, contact the person in charge of the e-beam machine to choose the best strategy. Summary for E-Beam : - Cell «EBEAM_WAF» is the wafer level cell (top cell of the hierarchy) used to define markers - Cell «EBEAM_FRAME» that contain the frame to use to do your designs. JB, SC, GAR/CMI 10 / 11

11 LAYERS Name GDS number CIF number Exclusion 30 L20 Exclusion BSA 31 L19 Text 32 L22 Lay1 1 L1 Lay2 2 L2 Lay3 3 L3 Metal 15 L15 e-beam_pam 21 L21 Reserved e-beam_die 22 L22 e-beam_dash 23 L23 e-beam_waf 24 L24 Add as many layers as you need!! LAST RECOMMENDATION!! For all the names you are going to use (cells, layers, design) do NOT use special characters like &, %, $, Use only alpha-numerical characters and replace all the spaces by underscore ( _ ). JB, SC, GAR/CMI 11 / 11