From: Michal Koziel Date: Sun, 16 Feb 2014 18:28:03 +0000 (+0100) Subject: Update 16.02 X-Git-Url: https://jspc29.x-matter.uni-frankfurt.de/git/?a=commitdiff_plain;h=fbcc255acb0de37a4372b3fa22fa8689707fe5c2;p=reports.git Update 16.02 --- diff --git a/GSI_2014_MK_ProbeTests/MK_ProbeTests.tex b/GSI_2014_MK_ProbeTests/MK_ProbeTests.tex index 4e8a5c1..f50f373 100644 --- a/GSI_2014_MK_ProbeTests/MK_ProbeTests.tex +++ b/GSI_2014_MK_ProbeTests/MK_ProbeTests.tex @@ -25,44 +25,42 @@ -The Compressed Baryonic Matter experiment installed at the future FAIR facility will be equipped with a high-precision micro-vertex detector aiming at an outstanding primary and secondary vertex resolution. Highly granular, ultra-low material budget sensors, so-called Monolithic Active Pixel Sensors, manufactured at standard CMOS process, will be employed. Imperfections in CMOS process as well as further dicing and thinning procedures affect the yield of sensors to be mounted in the detector stations. To select sensors with the best characteristics, probe testing prior to integration is mandatory. However, handling and testing of 50~$\upmu$m thin CMOS pixel sensors is non-standard. - -\begin{itemize}[noitemsep,nolistsep] - \item Email from Marc about yield after thinning. - \item Total amount of sensors. - \item Observation during the prototyping phase. - \item Information about the probecard itself : No tungsten pins, redundant pads. - \item Chack adapter for standard station => take pictire on white background. - \item Adaptation to DAQ prototype version , TRBv2 based => migration to TRBv3 in progress. - \item First test. - \item Interest in this activity from the side of PLUME experiment and NE-61 experiment. - \item Future plans: S-curves. Probe test several sensors then bond them and compare results. -\end{itemize} +The Compressed Baryonic Matter experiment installed at the future FAIR facility will be equipped with a high-precision micro-vertex detector aiming at an outstanding primary and secondary vertex resolution. Highly granular, ultra-low material budget sensors, so-called Monolithic Active Pixel Sensors, manufactured at standard CMOS process, will be employed. Imperfections in CMOS process as well as further dicing and thinning procedures may reduce the final yield of sensors to be mounted in the detector stations to about 60-70$\%$. To select sensors with the best characteristics, probe testing prior to integration is mandatory. -Overall, 18 ultra-thin MIMOSA-26 sensors were assembled and different supports (12 used in the beam setup , plus backup core single-sided modules). One sensors was not operational due to the internal short circuit, two others exhibited a broken line (high noise) or column. In one of the sensors assembled into the double-sided module one out of four internal sub-matrices was broken. It is important to stress that due to the lack of infrastructure we did not perform sensor check before assembly. The total achieved yield after assembly was observed to agree with the yield claimed by the sensor provider, that is IPHC-Strasbourg. Therefore, it can be concluded that most likely the sensor integration process does not affect the yield. Nevertheless, for the sensor integration into the final CBM-MVD, the sensor cross-check will be addressed by the means of probe test prior to assembly. +A standard way of checking CMOS circuits before packaging is testing them with tiny needles serving as interconnection (instead of wire bonds) between CMOS circuitry and readout/test boards. Such a probe tests were addresed at IKF with CMOS sensor MIMOSA-26. The motivation to use this sensor is that the readout system \cite{1} for MIMOSA-26 already exists and it can be easily adapted to work with probe card. Moreover, the thicknes of MIMOSA-26 of 50~$\upmu$m reproduces well expected mechanical properites of final MVD device: where mechanical stability is of concern w.r.t. probe testing. +The IKF probe test bench shown in figure \ref{fig:setup} was located at clean room. The probcard hots 65 tungsten needles with minimum pitch of 120 $\upmu$m. The needles are assembled into a PCB (figure \ref{fig:card_chuckadapter}a), serving as an electrical adapter between a sensor and the previously developped DAQ system. Signals from sensors are oruted through the probe card PCB to so called adapter card. The use of additional PCB was motivated by the fact that the probcard is made by an external company (HTT-Dresden) and any changes into that probe card are expensive, while an adpater card we can design ourselve and implemented any kind of useful electronics and logic if needed. In addition. we manufactured a test board hosting a wire-bonded working MIMOSA-26 sensor. This board is used to debug all readout chain including probe card but not sensors connected with needles, where problem with contact is of concern. To hold an ultra thin sensor, a probe station chuck adapter with vacuum channels was manufactured, see figure \ref{fig:card_chuckadapter}b. +\begin{itemize} + \item First test. + \item Interest in this activity from the side of PLUME experiment and NE-61 experiment. + \item Future plans: S-curves. Probe test several sensors then bond them and compare results. TRB3 +\end{itemize} \begin{figure}[htb] \centering %\includegraphics*[width=65mm]{gsisr1} -\includegraphics*[width=82mm]{setup.eps} -\caption{Probe station setup: (1) Microscope lens, (2) Adapter card, (3) Connectivity to DAQ, (4) Probe card, (5) Test board hosting reference sensor and (6) chuck adapter with one Mimosa-26 sensor. .} -\label{l2ea4-f1} +\includegraphics*[width=82mm]{card_chuckadapter.eps} +\caption{Detailed view on selected probe setup components: a) probe card needles b) chuck adapter/sensor vacuum holder.} +\label{card_chuckadapter} \end{figure} + + \begin{figure}[htb] \centering %\includegraphics*[width=65mm]{gsisr1} -\includegraphics*[width=82mm]{card_chuckadapter.eps} -\caption{Detailed view on selected probe setup components: a) probe card needles b) chuck adapter/sensor vacuum holder.} -\label{l2ea4-f1} +\includegraphics*[width=82mm]{setup.eps} +\caption{Probe station setup: (1) Microscope lens, (2) Adapter card, (3) Connectivity to DAQ, (4) Probe card, (5) Test board hosting reference sensor and (6) chuck adapter with one Mimosa-26 sensor. .} +\label{setup} \end{figure} + + %\begin{figure*}[tb] %\centering %\includegraphics*[width=145mm]{gsisr2}