Different type of Ram Modules

Process of Memory IC Manufacturing Full Specification IC

1. Wafer fabrication. - Wafer are fabricated by the Big makers, like Hynix, Samsung, Micron, Elpida, Nanya, Promos, Powerchip.

2. Wafer probe test -Test are done to check which Dies are rejected, they will mark with Ink, so we call Ink Dies

3. Packaging - Pack into plastic.

4. Testing - Testing with full test, including temperature test, - Full specification test. using specialise state of the art tester, like Advantest.

This will be sold out as IC with their own marking like Hynix, Samsung mark on the ICs itself. We call this Full Specification IC, it can be used without further testing, sold to meet most of the applications in the market.

Utt - Due to loss, some wafer manufacturers are selling the wafer out without testing. Testing is done by those buyer themselves. Yield is normally 95%.

Ett - Electrical tested, this is something which, because of Too many rejected due to complaints by Buyer of UTT, manuafacturer decided to do a simple  test to satisfy the buyer. The yield improved after this test. Normally promise at 99%. But that depends on the luck of the buyer. They are not put throught Burn in test, temperature cycling and etc.

Rejected  Dies (Downgrade) - This are rejected dies and they are sold in $/Kg. Buyer will buy and retested to lower specification. This has the highest rejection rate, and due the testing method, normally on motherboards only the test is not complete to detect failure, failures can come anytime even after 1 year of operation.

Typical Failure Rate of Modules

1st party - Modules manufactured by Hynix, Samsung, Micron itself using Full Specification IC and their own design Jedec compliant PCB, - less than 0.025% Some of modules - Crucial, Micron, Hynix, Samsung Original

3rd party - Modules manufactured by 3rd party vendor like Us, using Full Specification Ic like Hynix, Samsung, Micron using Taiwan Generic PCB design according to Jedec Specification, tested on motherboard - less than 0.035%. Some of the modules that use this type of IC ( Kingston, Transcend, Memory Power, Crucial and many more)

Oem modules - Modules manufactured using UTT or ETT ic, tested using motherboards, due to different type of motherboard this type of testing is not accurate, as different motherboards has different noise level - generally guaranteed to be less than 1%. Some of the modules that use this type of IC ( Kingston Value Ram, Patriot, Cosair, PQI, Apacer, Twinmos closed shop already, Transcend Jet Ram.)

Downgrade Oem modules - Modules manufactured using Ink Dies, tested using motherboards, due to different type of motherboard this type of testing is not accurate, as different motherboards has different noise level - generally guaranteed to be less than 3%-50%. Some brand that are using this type of IC are plenty,  TA close, LD close,Dynet, RC, Ramos, Elixir. Blitz They are too many to name. Buy at your own risk.

Pricing Different

1. Top price normally for Big customer like Compaq, Dell, Apple, IBM, Lenovo, Toshiba, Fujitsu.

2 Downgrade modules lowest price 10%-30% different from Original.