High Change Rate Temperature Cycling Tests for Printed Circuit Boards.

 

                            CTE mismatch (above) leads to elongation and contraction ;

     Over time, this mismatch will lead to crack and intermittent or catastrophic failure. 

This is the basis for High Change Rate Temperature Cycling Tests, which are typically conducted in a chamber called, Environmental Stress Screening Chamber. Stress Screening Chambers come either in Single Zone or Two Zone type. 

QRA is proud to market these ESS chambers under our brand name, and also under our principal from S Korea, ETSP. 

Lets go straight to the facts. Below is a diagram of a typical PCB board, which can be used in a myriad of applications from latest smart phones, notebooks, IPads and EV cars. The top part is the silicon chip (think Nvidia, Lenovo and Intel) which does all the microprocessing, and the bottom part connects the chip to the Printed Circuit Board. The connections are provided by solder bumps or balls and the point of contact is called the solder joints.

To improve transmission speed, the area in yellow is called the underfill and the solder bump sits on a contact pad.

The issue with reliability of PCB Boards, is that owing to cost pressures, the silicon chip is typically of a certain Coefficient of Thermal Expansion (CTE) and is normally on the low side, ranging from 2.5 - 4 ppm / C. The organic base substrate for cost reasons has a high CTE something like 20 - 30 ppm / C. 

When the device is powered up (smartphone, car or laptop), the underfill expands very fast and longer, while the silicon chip expands slower and at a smaller overall length.

When the device is powered down or switched off, the rate of contraction between the Organic Base Substrate and the Silicon Chip again is very wide, leading to the solder bumps positioning from the top picture to the bottom fixture. With repeated switch on and switch off, the solder bumps will crack over thousands of cycles. 

Therein lies the CTE Mismatch. Over time, this mismatch of elongation and contraction will lead to crack on the solder bump and the chip will be non - functioning. 

Its like a loose tooth, if you move it regularly, over time the gum base will give way and the tooth will fall out.  

The ESS chamber is simulating the power on and off for anything ranging from 100 cycles to up to 1000 cycles. There are standards which typify the environment which the boards are typically subjected to, to replicate the actual functioning. 

Set points can range from below 0 (-20 C) to about 100 C and the change rates vary from 1 C / min up to 20 C / min. 

                                       2  Zone ESS Chamber or Thermal Shock Chamber 

Why Do the Temperature Cycle Tests ? 

1. To ensure that the solder bump CTE is not too far off from the silicon chip, as well as the organic base substrate chosen (its all a matter of costs), is also not too high compared to the silicon chip.

2. If after 1000 cycles, the PCB Board is subjected to 

a) functional tests to ensure board functionality with a 'Pass / Fail' checking

b) High magnification Visual Inspection to determine microscopic cracks.

The reliability of PCB Boards, is critical to the high end brand's overall good name.

If after all the ESS tests are done, and the checks give a 95% yield (5% failure rate), then the batch of PCB Boards can be considered good for production and the assembly can proceed.

If the yields are far higher, (say 20 % upwards), the manufacturing manager1  may conduct an internal audit to review the selection choices of 

 

> Organic Base Substrate

> Solder Ball Materials.

Reliability is essentially Quality and Performance of a Product over the entire Life Time of the Product ( 2, 3 up to 10 years for EV cars).

Top manufacturers cannot compromise on poor out field reliability. 

It is better to recall and rework the new product in the factory before even a single batch is sent out. 

Manufacturers who have to conduct a product recall face a huge loss of brand confidence leading to huge revenue dips and profit  losses from a (perceived) poor reliability product. 

ESS Temperature Cycle Tests save millions if done properly. 

For more information ;

E :    mark@qra.com.sg

        qrasales@qra.com.sg

W :  https:\\www.qra.com.sg

2026 QRA International Products - High Quality and Reliability for the New Millenium.

 

                                        2026 QRA International Equipment  

Designed by QRA International, our very own Temperature and Humidity Chambers are suitable for all kinds of testing under various temperature and humidity extremes. Our installed base of hundreds of chambers regionally establishes QRA as one of the region’s best in class brands.

                                        1. QRA  Stability Chambers

 

Stability Chambers are essentially chambers which control temperature, and humidity with various ranges for various applications. Below are some ranges and size of the chambers which QRA can provide for very competitive prices and 1 to 2 year warranty ranges.

Temperature and Humidity tests are designed specifically to accelerate the aging of the products subjected to the tests. Higher temperatures (50 C and above) and higher humidity settings (60 – 98%) can be programmed and achieved as standard performance settings of QRA Stability Chambers.

 

Stability Chamber at Global Multi National Beverage Group

                    2. QRA Bench Top Temperature and Humidity Chamber

 

 

Bench Top Temperature and Humidity Chamber at Global Nutritional Group 

Temperature and Humidity tests are essential in simulating environments and also stimulating by high temperatures, high and low humidity, fast change rates to screen out infant mortalities on poorly made components, assemblies and completed products.

Biomedical and Pharmaceutical in particular use temperature and humidity chambers to perform accelerated aging and shelf life testing of the new products and stress test the effectiveness of their barrier systems rigorously.

 

Many advanced manufacturing industries utilize our equipment. Here are the industries we support :

1. Biomedical

2. Pharmaceutical

3. Electronics

4. Semiconductor

5. EV Automotive

6. Aerospace

7. Defence

 

3. Walk In Temperature and Humidity Chamber

Temperature Range

- 70 C to 180 C

Humidity Range

20 to 98 % RH

 

Change Rate

0.5 to 3 C / min heating

0.5 to 1 C / min cooling

Chamber Sizes (Small to Large)

2 m  x 2  m   x  2.3 m  - Smallest

W    x  D      x   H

25 m x  10 m x  4.5 m  - Largest (Cold Room) 

W    x    D    x     H 

 

 

 QRA Walk In Cold Room Chamber

 

Temp Range : 0 to 8 C

Temp Stability : +/- 1 C

Temp Uniformity : +/-  3 C

Enquire Now :

E  : mark@qra.com.sg

      qrasales@qra.com.sg

Website :  www.qra.com.sg  

 

How to Grow Business Revenue - the Key Steps

 

Nurturing Entrepreneurship - Is this a major contradiction in terms ?

I read with some amusement recently that a Minister of State, in a recent interview with Channel News Asia,  made comments that Singapore(ans) should start youth on entrepreneurship earlier.

The optics of this is hilarious. Its as if you have a General who all throughout his career, has risen through the ranks to reach the pinnacle (on paper) in rank. He is probably an expert in  engaging war strategy, best practises, soldier discipline, equipment specifications and availabilty etc etc. 

Everything on paper to protect his country, and its interests.

He then goes to tell the many youth out there to go and 'Chiong' where he has never engaged in firefight, dogfight or skirmish, let alone engage with the enemy in the battlefield.

When we look from the sidelines, we see the Government leaders telling people go. Its yours to win, I read it all in books, we have the means to support you !  This is typical of our leaders in Government, they are good cheerleaders, provide grants yet in their past resumes, no one (with very few exceptions) has literally 'walked the talk' as far as starting, managing and growing a business from scratch to (say) S$ 10 million revenue in size.

Fact of the matter in entrepreneurship, 70% of businesses fail in the year, 90 - 95% fail within 3 years and only a tiny fraction (0.01%) make it to $10 Million within say 10 years upon startup.

Entrepreneurs for the most part are born not made. Their stories are filled with grit, failure, lots of late nights, tough decisions and heartbreak time and again. They need to have the stomach to take sizeable risks and go 'all in' or sell the house type of risk to achieve the ultimate reward.

Olivia Lum was a successful businesswoman at the listed company Hyflux. She started here entrepreneurial jpurney when she was in Primary school selling eggs from her hometown in Ipon to her classmates to make some pocket money.

Sim Wong Hoo (Creative Tech Chairman) did the near impossible. He realised that the Singapore market was too small a market to scale up on his flagship Soundcard, so he ventured to the US market in the late 1980s and took a good 5 years to establish a foothold, gain loyal following and develop his brand, and then and only then, the fastidious Singapore market was broken into.

His Chinese PC was ahead of its time, and failed.

His Zen Patent Music Organizer, was in contention with Apple's own version, and they fought a costly lawsuit which Creative subsequently won for USD 100 million.

Who Dares Wins. For a small fraction, this is a handsome payout, and to my recollection, only the 2 companies above, Creative Tech and Hyflux have come from private sector without any big Government money at key stages in their growth. 

Who Loses will lose his house, and shirt on this back big time. 

So Mr. Minister, standing from the sidelines, you have the spectators, you have the running shoes, maybe even provide the coaching.... (I believe and I may be wrong)...but there are strings attached.  

I have had my share of grants disbursed from the Enterprise SG and boy its full of bureaucratic rigmarole designed at 'helping SMEs' but at the end of the day, its essentially an extra administration burden required with endless submissions, approvals and assessments to get the money. 

It was really not worth the effort and time to get the grants, in my opinion. 

The best runners will be running barefeet, training with their own parents' money and slowly working their way up. Many will fail, will suffer breakdowns and injuries. Heartache and mental duress is all part of the athletes game.

When they do suceed.

And boy they will one day.

The scent and taste of success will be so sweet.  

 

Parties with Cousins in the 1970s at our Parents' place.

 

Wynne Leong and Johnathon Mun

My mother is the eldest sister amongst 4 sisters and 2 brothers (one half). The 2nd sister Aunty Dona married a doctor Dr. Leong Chai Mun and they have 2 children.

> Winston Leong Ah Pan

> Wynne Leong Chee Whye

Papa with Angela Lau

The third sister Mina Lau married Mr. Lau - a police man, later he became an inspector.

They have 4 children, namely :

May Lay

Clifford Lau

Wendy Lau 

Angela Lau 

May Lau wedding with my Mum and her colleagues 

There are 2 more sister and brothers, who children I will name here :

The youngest sister (Mona) was married to a school teacher, Mr. Phoon He later became a school principal and the President of the Orchid Society. I recall spending many days at the Phoon family residence as we (my Mum and Aunty Mona) were especially close and our families were both members of the Singapore Swimming Club.

Back in the day, after our morning swim, we had to proceed to school However, every Sunday was a treat as all the swimmers (the boys at least) went to the open area (Cabana is now built here).

The Boys would then proceed to play football with a soft ball replicating Star Soccer. 

I was famously known as Stiff Legs. I firmly believed my legs were metallic just like the 6 Million Dollar Man - Steve Austin/

I recall once when we were playing and my shoes, gave way. I continued to play barefeet and had made a swipe of the ball aimed at the goal.

I missed it pathetically, and my meet grazed the 100 year old tree and the bark actually flew out.

I was a terrible ruffian and could take and give punishment. LOL. 

True Story.

 

One Last Video of the 1960s

 

Childhood Video1968 Family and Parties

 

This Video uploaded by me is probably taken in 1968. My father had a Cine Camera and probably had the maid or my Mum to take the film.

I was 6 and Johnny was 3 years old. In the video, we had a swing at the side of the house.

The lady in the video wearing a saree was probably my father's mother, or grandmother. 

The black dog in the video is Trixie, a mixed Cocker Spaniel.