Pixel Detector Module using MCM-D Technology for the B-layer of the ATLAS Pixel Detector DETECTOR CHIP Pixel 2000 Workshop BUMP ELECTRONIC CHIP Christian Grah grah@whep.uni-wuppertal.de University of Wuppertal www.atlas.uni-wuppertal.de O. Bäsken O.Ehrmann K.H.Becks M.Töpper P.Gerlach J.Wolf Ch. Grah June 2000, Genova
DETECTOR CHIP Overview BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal ➤ The concept of building modules in MCM-D technology ➤ MCM-D modules for the ATLAS Pixel Detector ➤ Measurements on Prototypes ➢ Lab measurements on full scale module and single chip devices ➢ Testbeam measurements on single chip devices ➤ Conclusion and Outlook Pixel 2000, Genova 2
DETECTOR CHIP ATLAS Pixel Detector BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal ➤ 2200 modules ➤ 2.2 m 2 active Si ➤ 1 x 10 8 channels Pixel 2000, Genova 3
The basic structure of modules for DETECTOR CHIP BUMP the ATLAS Pixel Detector ELECTRONIC CHIP Ch.Grah University of Wuppertal ➤ Sensor tile (16.4 mm x 60.4 mm active area) Main components which need to be contacted: ➤ 16 read out IC ´ s, each providing 18 x 160 pixel unit cells (preamplifier, discriminator, digital readout; pixel cell size: 400 x 50 µm 2 ) 46080 connections in the pixel cell array per module with bump- bonding and flip-chipping as interconnection technique ➤ one module controller chip ➤ Idea of using a Thin Film technology to perform the signal interconnections and power distribution on the active sensor Pixel 2000, Genova 4
MCM-D, a Thin Film DETECTOR CHIP BUMP Technology ELECTRONIC CHIP Ch.Grah University of Wuppertal M ulti C hip M odule D eposited conductor layers dielectric layers ➤ Up to 5 copper layers: ➤ “ Spin-on ” polymer: BCB (Benzocyclobutene / DOW:CYCLOTENE ™ ) ➢ magnetron sputtered up to 2 µ m Ti/Cu/Ti ➤ Photosensitive 10 m Ω / � ➤ Specific dielectric constant ε r = 2.7 ➢ additive electroplating up to 5 µ m Ti/Cu ➤ Process temperatures : ➤ Minimal width and spacing 1h 220 ° C per layer 10 and 20 µ m last layer 1h 250 ° C ➤ Final metallisation: ➤ Thickness / layer 4 - 10 µ m ➢ electroless ∅ >20 µ m, Pad 30µm ➤ Via ∅ ∅ ∅ ➢ 5 µ m Ni:P/ 200nm Au Pixel 2000, Genova 5
DETECTOR CHIP MCM-D Module BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal Pixeldetector Module Module Controller Chip Temperature Sensor Opto Package (VCSEL & PIN diode) with 3 optical fibres 16 Frontend Readout Chips Connections to DORICp VDCp outer world 78,6 mm 24,4 mm Sensor Pixel 2000, Genova 6
Advantages of modules in DETECTOR CHIP BUMP MCM-D technology ELECTRONIC CHIP Ch.Grah University of Wuppertal ➤ A robust, “ easy-to-handle ” module with bump-bonding as the only interconnection technique ➤ Signal lines in µ-strip configuration, so with low crosstalk and well defined impedance ➤ Allows routing in the pixel cell array to contact sensor and electronic cells which are not facing each other Pixel 2000, Genova 7
Schematic Cross-Section of a DETECTOR CHIP BUMP Bus System ELECTRONIC CHIP Ch.Grah University of Wuppertal Pixel 2000, Genova 8
Some pictures of the MCM-D DETECTOR CHIP BUMP structures ELECTRONIC CHIP Ch.Grah University of Wuppertal Feed-throughs 50 µ m power contact signal bus Pixel 2000, Genova 9
DETECTOR CHIP Feasibility Studies BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal Voltage [V] ➤ Just two -260 -240 -220 -200 -180 -160 -140 -120 -100 -80 -60 -40 -20 0 20 1 exemplary 0 -1 plots -2 ➤ The sensor -3 Current [µA] -4 properties are -5 not affected by -6 the MCM-D -7 -8 technology IZM01 t1 -01 -9 IZM09 t1 -01 -10 IZM01 t1 -01 (after processing) IZM09 t1 -01 (after processing) -11 -12 -13 Pixel 2000, Genova 10 10
DETECTOR CHIP Yield Test - Thin Film BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal Feed-through structures ➤ Daisy-Chain interconnection ➤ Four copper layers ➤ 1.1 . 10 6 monitored vias with a diameter of 25µm ➤ Measured defect rate 8.13 . 10 -6 (9 defects of 1 105 920 vias) ➤ We expect 1.5 unconnected BCB etched for better visualisation pixel/module Pixel 2000, Genova 11
DETECTOR CHIP Full Scale Prototype Module BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal MCC Frontend Chips Additional test pads contacted by wire bonding Pixel 2000, Genova 12
Threshold and Noise DETECTOR CHIP BUMP (Untuned Full Scale Module) ELECTRONIC CHIP Ch.Grah University of Wuppertal The MCM-D Module shows encouraging performance regarding Threshold distribution and Noise performance Module: MCM-D T1/Frontend B Pixel 2000, Genova 13
DETECTOR CHIP Single Chip Module BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal A Single Chip Module consists of: Sensor cell array + MCM-D interconnections + Frontend chip ➤ Investigation of different Feed-through layouts, especially routing Picture: Frontend C on Single Chip PCB Pixel 2000, Genova 14
Feed-throughs in different DETECTOR CHIP BUMP layouts ELECTRONIC CHIP Ch.Grah University of Wuppertal Class R 1 (to neighbouring pixel Class U 400/600 (two columns at the cell) border of the hybrid) Class R 2 (skipping one cell) Class R 3 (skipping two cells) Class U (most common class) Pixel 2000, Genova 15
Threshold distribution DETECTOR CHIP BUMP (Single Chip) ELECTRONIC CHIP Ch.Grah University of Wuppertal 2000 adjusted threshold: 400 - ] standard settings: all TDAC´s = 4 mean value: 825 [e - ] standard deviation: 45 [e - ] threshold adjusted to 825 [e 1600 300 - ] Threshold [e 1200 entries/bin 200 800 not adjusted threshold: - ] mean value: 825 [e - ] standard deviation: 225 [e 100 400 0 0 320 640 960 1280 1600 1920 2240 2560 2880 400 600 800 1000 1200 1400 1600 Pixel number - ] Threshold [e Hybrid: MCM-D ST1/Frontend C Pixel 2000, Genova 16
Noise distribution DETECTOR CHIP BUMP (Single Chip) ELECTRONIC CHIP Ch.Grah University of Wuppertal 350 600 300 500 250 400 200 - ] - ] Noise [e entries/bin mean value: 86 [e 300 - ] standard deviation: 11 [e 150 200 100 50 100 0 0 320 640 960 1280 1600 1920 2240 2560 2880 0 20 40 60 80 100 120 140 160 180 200 Pixel number - ] Noise [e Hybrid: MCM-D ST1/Frontend C Pixel 2000, Genova 17
Summary of Noise DETECTOR CHIP BUMP measurements ELECTRONIC CHIP Ch.Grah University of Wuppertal hy brid MCMD FeC- St 1 MCMD FeC- St 2 mean v alue ± st andard dev iat ion [ e - ] c lass U 4 0 0 79 ± 10 130 ± 12 n/ a U 6 0 0 88 ± 12 U 80 ± 10 126 ± 12 R1 93 ± 10 136 ± 12 R2 96 ± 8 142 ± 13 R3 94 ± 8 151 ± 15 There is no influence on the performance, due to Feed-throughs in MCM-D. As expected, the crossing of copper lines in different layers (classes Ri) increases the Noise, due to the higher interpixel capacitance. Pixel 2000, Genova 18
DETECTOR CHIP Crosstalk Measurements BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal Crosstalk = fraction of charge that couples into the neighbouring pixel through the interpixel capacitance Q Pixel N (masked to read out) hits Pixel N+1 (with threshold T) Crosstalk = T / Q For Pixel N+i similar Pixel 2000, Genova 19
Crosstalk distribution DETECTOR CHIP BUMP (Single Chip) ELECTRONIC CHIP Ch.Grah University of Wuppertal 25 Ri U 600 20 to neighbouring pixel Crosstalk [%] skipping one pixel 15 skipping two pixel 10 “ganged” Pixel: These electronic cells are connected 5 to two sensor cells (by design). 0 0 320 640 960 1280 1600 1920 2240 2560 2880 Pixel number Pixel 2000, Genova 20
Summary of crosstalk DETECTOR CHIP BUMP measurements ELECTRONIC CHIP Ch.Grah University of Wuppertal hy brid FeC- St 1 FeC- St 2 t o pixel N + 1 N + 2 N + 3 N + 1 N + 2 N + 3 c lass mean v alue ± st andard dev iat ion [ % ] U 4 0 0 6, 9 ± 0,3 2, 6 ± 0, 2 < 1 2,8 ± 0, 8 1, 6 ± 0,4 1, 1 ± 0, 2 n/ a n/ a n/ a U 6 0 0 8 ,6 ± 0 ,5 3 ,9 ± 0 ,2 < 1 U 7 ,0 ± 0 ,3 2 ,5 ± 0 ,1 < 1 3 ,0 ± 0 ,7 1 ,3 ± 0 ,3 < 1 R1 8 ,2 ± 0 ,5 2 ,7 ± 0 ,1 < 1 4,6 ± 0, 9 1, 6 ± 0,3 < 1 R2 8 ,9 ± 0 ,5 4 ,3 ± 0 ,2 < 1 5,1 ± 1, 1 2, 4 ± 0,4 < 1 R3 8, 6 ± 0,4 5, 7 ± 0, 2 2,8 ± 0, 1 5,0 ± 0, 8 3, 7 ± 0,5 2, 0 ± 0, 3 Note 1: There is no influence on the crosstalk, due to the Feed-throughs in MCM-D. Note 2: The performance of class R1 and R2 layouts is comparable to the 600µm long sensor cells (U 600 ). Pixel 2000, Genova 21
DETECTOR CHIP Source measurement BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal Upper 3 cells not connected (by design) The MCM-D nr of hits hybrid shows a uniform functionality. Defects were recognized as bad bump connections. Am 241 : Gamma-rays Pixel 2000, Genova 22
DETECTOR CHIP Testbeam data BUMP ELECTRONIC CHIP Ch.Grah University of Wuppertal ➤ H8 Testbeam at SPS (CERN) ➢ primary: 450 GeV protons ➤ Data was mainly taken with: 180 GeV pions ➤ Telescope with 4 layers of strip-detectors (Resolution: 3 µm) H8 Telescope system All presented measurements: (MCM-D) SSG/Frontend B Pixel 2000, Genova 23
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