Internet commentary

Citation

Ellis, B. (2005), "Internet commentary", Circuit World, Vol. 31 No. 3. https://doi.org/10.1108/cw.2005.21731cag.001

Internet commentary

He pattered with his keys at a great rate[1]

Keywords: Internet, Keyboards, Microvias

For a change, let me talk about a delightful piece of hardware that I've discovered. It is a keyboard and an ideal keyboard, at that, for use with the internet, be it for browsing or for e-mailing. It is called the Cherry CyMotion Master XPress and you can find details at http://www.cherry.de/english/cymotion-line/cymotion-line_master_xpress.htm (Plate 1).

Plate 1 Cherry CyMotion Master Xpress programmable keyboard, ideal for internet browsing. Some of the programmable keys can be seen on either side of the usual keyboard, over the number pad and in the silver-coloured areas above and below the traditional keys

Before describing it in detail, I must say that the “feel” of it is great, with a key pressure and movement that I find just right, at least for my clumsy fingers (have you thought that the keyboard is the only true digital computer peripheral?). As delivered, it is already internet-ready, with keys for starting up your browser and e-mail client and navigating within them. It does not stop there as there are specific keys for Back, Forward, Stop, Reload, Find, Favourites/ Bookmark and there is even an @ key (no Shift required). There is also a series of keys if you wish to play multimedia, including a very useful volume control. Further general functions include single keys for Scroll up, Scroll down, Scroll right, Scroll left, Cut, Paste, Copy, Undo and Redo, plus keys to bring up lists of My Files, Office Programs and Accessories, as well as a number of other ones. However, there's more to come. As technical guys, we often need special symbols when e-mailing or writing papers. This is where the best feature of all can be found. It comes with a software called Keym@n which allows you to programme any of nearly 30 of the keys to suit your own purposes. For example, I've keys on two out of three of my keyboards with symbols, such as °, ±, μ, ², ¼, ½, ¾, €, £ etc., but you can put in what you like. As I often e-mail in French, I've added à, â, c¸ and all the rest of the diacritical vowels used in that language and this on a standard US keyboard (there are also versions available for most countries, as well). I've also put in some text macros for my three most usual signatures for e-mails, such as:

Regards,   or     Best regards,Brian Ellis       Brian

This is a great time saver and other text macros of almost unlimited size can be put in. Keypress and chained program start-up macros are also possible with emulation of mouse movements. The possibilities are almost endless.

There is one problem that users may experience at first with this keyboard. There is an 81-page Operating Manual, which is in rather arcane language, probably written by the software developer who understood what it was all about. It took me a few hours to feel really at home with the niceties of programming it, but well worth the effort.

I should like to finish by saying that it costs very little more than a standard keyboard, so it is an excellent investment, of good quality. Needless to say, I have no vested interest in recommending this device.

My second news item of the day is the Firefox browser from http://www.mozilla.org/. I've been using the beta versions (formerly Firebird) of this and the Thunderbird e-mail client for about a year and have been impressed with both. Mozilla have now issued the full release version of Firefox 1.0 and I'm even more impressed. It is faster downloading pages than any other browser I've tried and is jam-packed with features, including multiple pages and tabs, multiple search engines on the standard toolbar, choice of sidebar function, configurable menus and so on.

One of the new features that I especially like is the new “Find in Page” function, which is brought up by Ctrl-F or from the menu. It opens a toolbar and menu at the foot of the page, as well as a text box with a white background. It starts the search as you type in the first letters of the word or phrase, so that you frequently don't even need to finish it. If there is nothing corresponding in the page, the background turns immediately to pink and a pink icon appears, along with a warning sound, so no time is lost in fruitless searches. The first match is highlighted in green. If you move onto a new page or tab, the toolbar stays put, until you decide to click it away, so that you can easily search on multiple pages. I grant you, this is only a small advance on the traditional Mozilla/Netscape/ Internet Explorer function but a very clever and useful one.

One of the most important features is that, by default, Firefox blocks the very dangerous pop-ups that sometimes harbour spyware functions. A banner strip warns you when a pop-up tries to be loaded and it gives you the choice to allow them or not from the particular site you are viewing. This is particularly useful for some net-banking sites that use pop-ups as an intermediary to printing out statements. Of course, you don't have to wait for the banner; if you have a list of trusted sites, you can easily enter them into a dialogue box. There are many other security features that you will not find elsewhere, making this one of the safest means of surfing, whether you use any one of the 32 bit Windows, Linux or Mac operating systems.

This browser is open-source, meaning that it can be downloaded free-of-charge and used by anyone, or even modified to suit your own needs, as the source code is also downloadable. It is easy to install and simple to operate. Individual configuration is equally simple, to suit your needs. It therefore offers anyone an alternative to the Microsoft Internet Explorer that, from the point of view of security, is as full of holes as a sieve and has become quite dated compared with a number of other browsers. At the same time, it offers its speed and advanced features, which are not to be found elsewhere and, unlike some others, it conforms rigidly to HTML coding without individual quirks. I strongly recommend it.

My screenshot in Figure 1 shows the appearance of Firefox, as I have it set up, as well as the content.

Finally on this subject, a humorous note: Microsoft recently published a screenshot of an MSN search page. It showed that the person who uploaded it was using Firefox! The screenshot was redistributed by the serious Associated Press agency. Amidst great embarrassment, Microsoft went so far as to deny that any of their employees would obtain permission to issue such a shot, but the evidence is there!

Figure 1 Screen shot of the Enthone Resources list. This also illustrates the new Mozilla Firefox 1.0 browser with two pages accessible from the Taskbar, two tabs, the toolbar Google search engine and the Find feature below the page display

A recent forum question on the IPC Technet list asked whether vias in pads were better than spur via connections from the pad. The answer can be summarised in the late Professor C.E.M. Joad's famous reply to almost any question: “it all depends what you mean by ...” via. Of course, a 0.5mm unfilled via in the middle of a pad for a small SMD would be asking for trouble, whereas a microvia may be relatively harmless. Then there is the question of filled or unfilled vias and, if filled, with what? There are so many “ifs” and “buts” that there is no possible answer to the question. It is obvious that a via-in- pad is the answer to a maiden's prayer for the designer, but it could equally be a Kafkaesque nightmare to the poor guy responsible for assembling the circuit. (Oh! That the designer and assembler could only speak the same language with each other; vive le concurrent engineering!) All this inspired me to search the Internet for guidance on this thorny subject and filling vias in general and here are a few websites to help.

http://www.honeywell.com/en/elecmat/announcement_details.jsp?rowID=2&docID=3624&catID=5

This is a news bulletin vaunting the idea of filled vias with high aspect ratios, from a PC Fab facility. Quite frankly, it left me wanting to know more, as the company has a proprietary process for filling, although it does give information where a technical paper can be obtained (would it not have been more convincing to have the paper available for downloading in PDF format?).

http://www.smta.org/files/pan_pac02-higashitani.pdf

This is a good paper, from Matsushita, describing a proprietary manufacturing process for filled through, buried and blind via, including microvia, holes using a conductive copper-loaded epoxy filling. It does not specifically deal with via-in-pad designs and I fear that it may not be entirely suitable, because of potential solderability problems with the filling.

http://www.smta.org/files/dallas_vias_presentation.pdf

Here we have another manufacturer's paper using non-conductive epoxy fillers in vias of all types, which are then capped with electroplated copper. Obviously, the solderability may be excellent, although the number of stages in the process is higher. The fact that the capping conceals the via is positive, up to a point, but it must place a greater burden on inspection and process control at earlier stages.

http://www.dupont.com/mcm/techpapr/imaps-9808.html

I'm a little puzzled at this reference. It is a succinct abstract of a technical paper, stating that metal-filled vias will reduce crosstalk between microstrips by “fencing” in the electromagnetic field, which may be logical in some conditions. It goes on to say that placing a metal strip across the vias will reduce the crosstalk by a further 8 to 10dB. This looks like a useful technique, but the abstract is insufficient for a good comprehension of what the authors are trying to tell us. Unfortunately, there is no link to give us more details, only a contact address.

http://www.circuitree.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2133,72451,00.html

This is an excellent magazine article entitled A Review of Filling High-Density, High Aspect Ratio Vias in a High-Volume Production Setting and is well worth reading, if you are in any way interested in the subject. I don't have to elaborate farther, because the title is explicit.

http://www.circuitsupply.com/emtech.htm

Although this is essentially publicity for a method to keep epoxy filling of a via to where you want it, this page does give a “newbies” guide to high density interconnect structures, albeit slightly on the nai¨ve side. Of course, this does not necessarily reflect on the quality of the product the company is selling.

http://www.photocircuits.com/technology_raod_map.htm

No, I didn't make a mistake with the spelling of the URL – I double- checked! Of course, Photocircuits has been a leading PCB Fab company since, well, it seems forever (actually, 54 years)! This particular page is not at all uninteresting, because it lists the company's current technical capabilities, the state-of-the-art possibilities and their future aims. In terms of via-in-pad and microvia technologies, the choice is quite wide, even to copper fill, as well as epoxy fill in the current technology.

http://en.wikipedia.org/wiki/Printed_circuit_board

I suppose that most readers have come across the Wikipedia online encyclopaedia. I don't want to sound patronising but this article is quite astonishing in the way it is complete and up-to-date, talking about blind and filled vias, considering it is designed for the general public. Furthermore, it has 11 links at the end of the article, some of which are to renowned references. One of these is to another Wikipedia article on waste from the electronics industry, this being even more astonishing.

http://www.enthone-omi.com/electronics/pdf/IM-UP-14.pdf

This is a short data sheet about plugging vias, but not via-in-pad technology. I found it in a useful page (Figure 1) at http://www.enthone-omi.com/electronics/pwb/resourcelist.cfm?HeadID=4&level=2, which gives a list of technical documents relating to a large number of processes offered by this supplier. The data sheet itself helpfully describes both the application of the fill material and its curing, to obtain the best results. I was slightly alarmed at the longish cure cycle at elevated temperatures, which may exceed the T_g of some laminates.

http://www.latticesemi.com/lit/docs/package/bgarecc.pdf?CFID=5259974&CFTOKEN=8594746

This is a design guide for interconnecting ball grid arrays, written by a semiconductor manufacturer. It is peculiar, because it makes no mention, whatsoever, of vias in pads. I would have thought that, if a large pin-out BGA were to be mounted on a high density interconnect structure PCB, this would have been an obvious solution. However, apart from this one, serious, omission, the article makes good sense.

http://www.marubeni-techno.com/english/Teflon.html

Now, here's an interesting thought. This is the site of a Japanese PCB Fab company, specialising in low cost polytetrafluoroethylene substrates. Obviously, microvias must be problematic, which is possibly why they state that the minimum diameter for filling is 0.3mm. I admit to speculation here and wonder what filling materials this company uses that preserve the RF integrity of the design.

Brian EllisCyprusb_ellis@protonique.com

Note1. As he drew near, he gazed upon the gateNe'er to be entered more by him or Sin,With such a glance of supernatural hate,As made Saint Peter wish himself within;He pattered with his keys at a great rate,And sweated through his apostolic skin:Of course his perspiration was but ichor,Or some such other spiritual liquor.George Gordon, Lord Byron,The Vision of Judgement (1822) st. 25