NEWS 2005

Double-sided in a single day!

Reduction of turn-around time may be needed for LHC finalisation

Price is the same

19 October 2005. After having reduced the urgent delivery times already considerably in June 2005, we feel confident enough to publish that for urgent cases TS-DEM is able to deliver double-sided boards in just 24 hours from reception of the design files.

With only a single day the improved organisation in the workshop can handle urgent jobs much faster than the three days we had before as goal for this type of circuits! The table of delivery times is adapted accordingly. Note that we can handle maximum two urgent jobs per week.

Robert Aymar and Walter Lecroy: electronics plays an important role

The first large size GEMs produced in the PMT workshop for HERA-B.
(left to right: Angelo Gandi, Rui De Oliveira and Jean-Claude Labbé)

27 September 2005. When CERN received the Milestone from IEEE in recognition of the invention of electronic particle detectors at CERN, Walter Lecroy and CERN's Director General Robert Aymar both made speeches in which they confirmed the growing importance of electronics for physics. Mr. Lecroy said: "The advent of electronic particle detectors, brought the need to store, transmit and analyse data faster than ever before."

"CERN's reputation is based on fundamental research," said the Laboratory's Director General, Robert Aymar, "but the Organization is also an important source of new technologies. In our work we need instruments based more and more on electronics, so that a tight collaboration worldwide in this field is beneficial to science.

From the start of CERN, the circuit fabrication workshop in building 102 has been involved in the development of particle detectors based on electronics technologies. Recent examples are GEM, Micromega and HMPID detectors, Pixel detector interconnection carriers, and the development of the fabrication process of a new, patented detector called FGLD. The workshop, often known under the names of their renowned leaders, such as "Atelier Goddet" and "Atelier Gandi", is now lead by Mr. de Oliveira.

We are happy to note that Mrs. Wauquier, chief technician in the TS-DEM assembly workshop, was part of the team that developed the very first wire-chambers for Nobel-prize winner Mr. Charpak.

No-clean? or Yes, clean!

Question

Betty,

We are in the last discussions with a contractor for the assembly of our boards.

In our specification we have asked to clean the boards after assembly with an "aquaous cleaning".

The contractor tells us that they use exclusively a "no-clean" solder-paste, which is more modern and as reliable as the solder pastes that need cleaning. Their clients deploy telecommunication modules in polar and tropical climatic conditions. They have received no complaints about corrosion or reliability of the solder joints.

What do you think about using "no-clean" solder paste for our cards?

When we ask them, they can change the process but this requires a recalibration of the temperature profile of their ovens; I'm afraid this will reduce the reliability of our cards.

Regards,

Answer

Hi,

The so-called no-clean processes are effectively often used in industry, even for telecom and other critical applications.

It's not only the flux used in the solder paste for the SMD components that is important, but one has also to take into account the flux used in the wave-soldering process and in the solder wires used for manual soldering.

However, there are not only the flux residues on the printed circuit boards, but also pollutions related to the components, the PCB and the handling. Therefore, in certain cases (e.g. high-impedance, high-speed, very low-level signals) these residues and also those of the no-clean flux can disturb the functioning of the circuit. In addition, we have no assurance of the correct long-term functioning without cleaning.

That's the reason why we ask that all productions that are made for CERN are done with a cleaning step, even if the subcontractors push us to skip this. In general this request does not impose the company to change the soldering products because the no-clean solder may be cleaned anyway if needed.
One should not impose a cleaning method though, but should insist on a cleaning that is compatible with the flux used.

I hope this answers your question.

Best regards,
Betty


Before cleaning	After cleaning

Lower prices of PCBs made by the PMT workshop

Productivity and yield increased by automated verifications

23 August 2005. Since over 12 months the DEM-PMT workshop is using systematically the flying-probe tester to verify every produced PCB for fabrication errors. In addtion, the Orbotech automated visual inspection machine is now being used for the verification of the inner layers before stacking and pressing them together. Those measures resulted in an increase of the productivity and yield which makes that we will be able to lower the price of standard PCBs by 12%.

3 weeks turn-around for urgent modification and production of prototypes

I would like to express my appreciation for the fast and excellent job performed by the design office and the assembly workshop and coordinated by Mme Betty Magnin.

Thanks to their efforts and to the extra support of Mr. Claude Millerin and Mr. Rui De Oliveira we were able to fit our very tight schedule in producing and testing prototypes of the new Cards for the Barrel.

The fully succesful first tests show that the re-design of this cards solved our technical problems and increased the overall system reliability.

Thanks again and best regards,

3 August 2005. After having tested the prototypes and even having built a series, one of the LHC experiments found a problem with the I2C bus on their cards. To make matters worse, this problem appeared on four different types of cards. A workaround was quickly found, but needed a re-design of the PCB. To test this modification before launching the production of another 3000 cards, DEM was asked to do the re-design, production and the assembly as quickly as possible.

This request came on 30 June and we managed to deliver just three weeks later six cards of two types. Just one week later we delivered the prototypes of the remaining types of boards.

This example shows that, although the standard turn-around time of DEM is ten weeks, in extreme cases we are able to react much faster which is exactly one of the roles of DEM at CERN:

competencies not available from industry
prototyping facilities to assist research
flexibility as needed to face emergency situations

DEM will present at LECC workshop

2 August 2005. The organisers of the 11th Workshop on Electronics for LHC and future Experiments (LECC) have asked Rui de Oliveira to make a presentation in the session on hybrids and assembly issues. Rui will present several technologies used in industry and in the DEM-PMT workshop, ranging from standard PCBs to MultiChip Modules Deposited (MCM-D). The explanation of the production processes will be followed by an overview of the main technical problems and the limitations related to each of these technologies.

This workshop will be a good occasion to have discussions with the many users of the DEM-PMT workshop, notably in view of the future upgrades of the detectors and technical choices to be made.

Job offer for electronics technicien

You

want to help build anti-matter?

want to work in one of the most advanced laboratories in the world?

know about electronics production methods and machines?

Then go for it apply!

1 August 2005. The assembly of electronics components requires more and more complex machines and processes. Examples of this are the assembly and inspection of components on which the soldered pins are not visible anymore, computer controlled machines to deposit solder-paste or to semi-automatically place components and computer controlled microscopes. Furthermore there are changes in soldering processes because of new requirements such as lead-free solders and the need for connections to be made by conductive glues.

In order to follow the progress in technology, the assembly workshop will therefore have to buy several new machines over the coming years. This will give a higher load to the electronics assembly workshop that cannot be handled by the current staff. For this reason TS-DEM has opened a vacancy for an Electronics Technician who will have the role of Assistant to the manager of the electronics assembly workshop

Free measurement booklets gone in 2 days

4 July 2005. DEM has delivered 70 booklets that explain how to make high-precision electrical measurements to over 30 engineers at CERN. DEM had requested these highly practical booklets were from a company specialised in this type of measurements. No more booklets are available, but as we have given a few to the CERN central library, you can still borrow them from there.

Reinforcement of the DEM subcontracting office

Change will improve:

follow-up of orders
shorten feedback path from assembly to the design office
productivity in assembly workshop as components are ordered by the subcontracting office

17 June 2005. Over the last two years the TS-DEM group has enlarged its service from only prototype production to small and medium scale productions. This was asked for by CERN's management and is a logical step forward in view of the construction of LHC for which sometimes several thousands of circuits have to be built. In general TS-DEM subcontracts these productions to industry.

To adapt the functioning of the TS-DEM group to this higher demand for subcontracting services, Claude Millerin will reinforce the team that is handling it. As Claude will leave the assembly workshop that he lead for over 20 years, Betty Magnin will become responsible for it as from July 2005. Betty, who has a large industrial experience in the domain of electronics assembly, will continue to lead the electronics design office as well.

For you as a client there will be the following changes:

for the layout or assembly of your boards: contact Betty Magnin (tel: 70688, e-mail: Betty.Magnin@cern.ch)
for small modifications on cards you may go directly to the assembly workshop (Bld.1/1-005) or call 72694

La structure organique du groupe TS-DEM a été réorganisée avec le mutation de Claude Millerin vers l’activité de sous-traitance au sein de TS-DEM. Betty Magnin sera responsable de la section WS (atelier de câblage) ainsi de la section BE incluant le Planning Office, le bureau d'études et l’unité de sous-traitance (passation des commandes, recherche et suivi des composants).

8-layer and halogen-free in just 6 working days!

Improved organisation halved production time for urgent work

10 June 2005. Friday last week we got the request to produce urgently an 8-layer board for the group PH/ED. To complicate matters, it even had to be made with halogen-free materials. Industrial companies could at best offer a four weeks delivery time as they don't yet stock halogen-free materials. This Friday we delivered the boards on the desk of the client, i.e. it has taken less than 6 working days from the moment the client gave his design files until the board landed on his desk.

As we have seen now, with only 6 days the improved organisation in the workshop can handle urgent jobs much faster than the 12 days we had before as goal! The table of delivery times is adapted accordingly. Note that we can handle maximum two urgent jobs per week.

DEM Presentations

TS Workshop 2005
24-26 May 2005	Archamps

	27 May 2005. DEM has made three presentations on issues varying from the role of DEM to CERN, quality procedures and a highly technical paper on circuits that allow detectors to become much more precise at the TS Workshop 2005. The papers and the transparencies of these talks are available on the web.
The role of DEM at CERN	The DEM group in the Technical Support department provides services for the fabrication of special printed circuits that are invaluable for the whole particle physics community. The capability is based around a core technology that is developed by using skills to etch and process materials that are not commonly used in industry, combined with production methods used in PCB manufacturing. The role of the prototyping facilities is to assist engineers and physicists and to offer them easy access to competencies often not available from industry. At the same time, with the expertise and production capacity available, it makes that CERN is always geared up to handle emergency situations. The design office and the assembly workshop that are also part of DEM have similar roles that lower the cost and improve the quality and maintainability of electronics developed at CERN.
Introduction de procédures qualité au BE électronique	Le bureau d’études TS/DEM-BE est issu de la fusion en 2002 de deux sections distinctes. Celles-ci avaient des outils et des méthodes de travail différents que nous nous sommes attachés à unifier au cours de l’année 2004. Ce document présente les deux axes sur lesquels nous avons travaillé. D’une part, nous avons défini les bases techniques pour les études de circuits imprimes et créé les procédures et dessins de référence pour que tous les travaux soient réalisés selon les mêmes règles satisfaisant aux exigences de fabrication et d’assemblage. D’autre part, nous avons développé un outil simple et fiable, en attendant la mise en place du projet JMT2, pour gérer les quelques 800 demandes reçues au cours de l’année, que ce soit la seule étude de circuit imprimé, la réalisation de nouveaux produits complets, ou la relance de pièces déjà fabriquées.
The development of the fabrication process of "low mass" circuits	To improve the precision of particle detection measurements, there is a growing interest in the physics community for circuits built with low mass materials that are more transparent to particles. We have been working for two years in setting up a new process to build those high-density, low mass multilayer circuits based on aluminium instead of copper that is commonly used in industry. The ALICE Silicon Pixel Detector project has initiated the development and its flex bus circuit is the first one that has been created with this new technology. We have seen that the success and the best ways to find solutions did not only come from new technical ideas but also from the way the project was managed.

Building 102 finally on twisted pair Ethernet

Consolidation of service will continue with fire detection

20 April 2005. Over the last week some 25 machines (PCs, printers and special machines) in building 102 have been moved from the shared 10 Mbps coax network to a modern switched 100 Mbps network. For undocumented reasons the building had been forgotten in the structured cabling project. The actual changeover has given only a very short interuption thanks to the scrupulous preparation by IT and its contractors. With the new network the operation of the PCB fabrication workshop will be more reliable than before. To furthermore consolidate the service the installation of a fire detector system is foreseen.

Industrial excellence is rewarded by CMS Gold Award

Awarded company learned
tricks of the trade from DEM

TIB Barrel module of the CMS Tracker with pitch adapter

15 April 2005. As written in the Weekly Bulletin 16-17/2005, as part of the sixth annual ceremony to honour its top suppliers, the CMS collaboration presented awards to nine firms. The Swiss firm Reinhardt Microtech received the Gold Award for producing over 15000 aluminium-on-glass pitch adapters, perfectly fulfilling the stringent quality requirements and conforming to the schedule.

It is very interesting to see how the company got involved in this project. Reinhardt Microtech was first only a provider of base material to the DEM fabrication workshop: on request they deposited thin aluminium layers on glass, without knowing what we used it for. Later they understood that DEM used it to make very fine circuits which they wanted to learn to make as well. As CERN is always open to transfer technology, Rui de Oliveira from DEM therefore had paid several visits to explain them how to make those circuits with photolithographic processes and with special chemistries to etch the aluminium. After this knowledge transfer, Reinhard Microtech was able to make its first pitch adapters for the ATLAS experiment. This in turn made that when CMS needed a large quantity of these circuits on glass for the Tracker detector, the company was able to offer the best price of all companies requested. It is nice to see how the company looks back to the first steps of the project as Dieter Kägi writes to us:

From: Dieter Kägi/Reinhardt-Microtech
Sent: Wednesday, April 13, 2005
To: A.Honma; M.Mannelli; R. De Oliveira; E.Focardi; C.Vdvelde
Subject: CMS Gold Award

I like to say in the name of Reinhardt Microtech to your team behind you at CERN and to you thanks for the honour to award us with this "price of excellence". It is a big pleasure for our staff too, to hear - or to be awarded - for doing an excellent job. This feedback of estimation is normally rarely, because all our customers are expecting a high quality service at limits of feasibilities for volume production.

If I look back to first discussions of patterning such Pitch Adapters with Rui de Oliveira and today's product I like to say it was/is a challenging job and we were happy to have all over the time a very close and fruitful collaboration with all your team members to get this products under control - from specification - over CAD files and design rules - till the finished product (with removing them from blue tape). ...

CERN Academic training showed DEM products

12 April 2005. In the Academic Training program for postgraduate students a series of lectures is given on "Particle Detectors - Principles and Techniques". The lecture on "Tracking" given by Mr. Ropelewski from the PH department has shown images of gas detectors that have been co-developed and produced by the DEM workshop.

Examples shown were GEMs and read-out structures for the experiments Compass, Totem, LHCb and MICE, but also HMPID for ALICE, the ATLAS TRD straws (see also article below) and Resistive Plate Chambers.

TRT of ATLAS: DEM (hidden) on frontpage of the CERN Bulletin

7 April 2005. The CERN Bulletin no 14/2005 of 4 April describes in the article "The detector with the golden wires!" the ATLAS Transition Radiation Tracker. "Its barrel comprises 96 modules crossed by 52 544 straw tubes, each with a 30 micron diameter tungsten wire running through its center". All those tubes and wires are tensioned in a special circuit developed in collaboration with TS-DEM. Christoph Rembser has made a report with photos on the manufacturing of the ATLAS TRT WEBs. Also some series of photos are available of the construction of the first prototype and the insertion of the wires.

The "Daisy" design (as it's tenderly called by insiders) has been developed by the DEM design office which was at the time led by Alain Monfort. Also for the fabrication innovative means were invented by the PMT section led at the time by Angelo Gandhi. It was the technician Rui de Oliveira who invented (and even patented) the right chemistries to etch the kapton sheets. After the transfer of know-how, the large scale production has been made by a British company. To date for the process step where the kapton is chemically etched (see image on the left) the DEM workshop is still involved in the production of the TRT. The ATLAS TRT detector could not have worked without the involvement of TS-DEM.

1000 designs entered in EDMS in just 2 years

Color plot used for manual assembly

31 March 2005. The electronics design office enters systematically all design information in the CERN Electronic Data Management System called EDMS. All those items have a name of the type EDA-xxxxx. All design data (schematics, PCB layout, PCB fabrication files and assembly information) is stored in a standardised way. The companies with whom DEM works know how to work with this: the EDMS item number suffices to produce or assemble cards. The EDMS number is made visible on the fabricated PCBs and on front-panels.

In March we have entered the 1000-th design, EDA-01000. We've reached this number in just over two years. You can see all designs on the examples page.

2004 in 4 images

2004 was a great year for DEM...

to aid the the Experiments,

the Accelerators...

and others who were in trouble!

ELEC-2005: DEM gives lecture in CERN training program

31 January 2005. The CERN Technical Training service organises a full training program on modern electronics, given by CERN physicists and engineers. DEM participates in this so-called ELEC-2005 program by giving on 3 February a lecture called printed circuit boards (PCBs) and hybrids. Rui de Oliveira will describe fabrication technologies of PCBs and detectors based on PCB technology and Betty Magnin will describe design methods and tools and the assembly of components. For people who could not be present, the transparencies and videos of this training are made available on the ELEC-2005 website.
Design and Assembly (pdf), Betty Magnin, PCB production at CERN (pdf), Rui de Oliveira