Semiconductor Manufacturing Process

Hello Folks!!!

   Long time since I have blogged, this is some non-IT stuff that I am sharing today. It would be helping freshers working in supply chain solution providing firm in a semiconductor manufacturing company. All electronic gadgets that you use these days contain semiconductor devices like ICs, Transistor, Diodes, Resistors and blah blah. This article all about the semiconductors like how a semiconductor chip is manufactured n kinda stuff. What exactly i am gonna cover are some semiconductor manufacturing terms like ASSEMBLY, BUMP, BURN IN, DIE, DIFFUSION, ETCH,EPITAXY, FAB, INGOT, PROBE, LITHOGRAPHY, LEAD FRAME, LEAD FINISH, MOLD, SORT, SUBSTRATE, WAFER, TURN KEY, ASN, GRN, WAFER MANUFACTURING PROCESS, and SEMICONDUCTOR MANUFACTURING PROCESS. hope you find this interesting.

ASSEMBLY

A step in semiconductor manufacturing in which the chip (die) is either encased in a plastic, ceramic or other package or assembled directly on a printed circuit board or a fully processed semiconductor device/circuit in the form of a chip is mechanically and electrically connected to the package.

BUMP

The process of forming solder or gold bumps on bond pads of a die. The bumps maybe formed by electroplating and evaporation.

BURN IN

Burn-in mirrors the worst-case bias that the device will be subjected to in the course of its useable life by testing their electrical characteristics and functions at room temperature and below.

DIE

A small block of semiconducting material, on which a given functional circuit is fabricated. A wafer is sliced into pieces, each containing one copy of the circuit, called die.

DIFFUSION

Diffusion and Ion implant are the two major processes by which chemical species or   dopants are introduced into a semiconductor such as silicon to form the electronic structures that make integrated circuits useful.

ETCH

Etching is the process of removing regions of the underlying material that are no longer protected by photoresist after development. 

EPITAXY

Epitaxy is the process of depositing a thin layer of single crystal material over a single crystal substrate, usually through chemical vapour deposition (CVD) in order to improve the performance of bipolar devices.

 FAB

 Fabrication(Fab) is a manufacturing process in which an item is made out of raw or semi-finished materials, on which a given functional circuit is fabricated.

INGOT

A Semi-finished solid metal form produced in a non-continuous casting process by pouring liquid metal into large molds.

LOT BASED MANUFACTURING

Lot based manufacturing is generally order based Manufacturing process where products are generally varying in nature more or less order by order / lot by lot you can say. 

PROBE

Process of probing/testing die in wafer form.

LEAD FRAME

The 'skeleton' of the IC package, providing mechanical support to the die during its assembly into a finished product.  It consists of a die paddle, to which the die is attached, and leads, which serve as the means for external electrical connection to the outside world. You may know exactly if you look at the picture showing what a lead frame is.

LITHOGRAPHY

Lithography is transferring a pattern from a photo mask to the surface of the wafer.

LEAD FINISH

Lead finish is the process of applying a   coat   of metal over the leads of an IC to:

·       protect the leads against corrosion

·       protect the leads against abrasion

·       improve the solder-ability of the leads

·       improve the appearance of the leads

MOLDING

Molding is the process of encapsulating the device in plastic material.  Transfer molding is one of the most widely used molding processes in the semiconductor industry because of its capability to mold small parts with complex features.

SORT

A test step where each individual die on a wafer surface is tested and bad wafers are marked as bad and hence a wafer map is created. 'Wafer mapping' is a process in which the performance of semiconductor devices on a substrate is represented by a map showing the performance as a color-coded grid. The map is a convenient representation of the variation in performance across the substrate, since the distribution of those variations may be a clue as to their cause.

SUBSTRATES

Substrates are parts that provide the package with mechanical base support and a form of electrical interface that would allow the external world to access the device housed within the package.

WAFER
A thin slice, typically sawed from a cylindrical ingot of extremely pure, crystalline silicon.

WAFER MANUFACTURING PROCESS

You yet might not be clear about the term ‘wafer’, wafer manufacturing itself is a complex set of processes. Let’s take a look.

Note: Each wafer lot essentially contains 25 wafers.

SEMICONDUCTOR MANUFACTURING PROCESS

The semiconductor production process can be divided into two sequential sub-processes commonly referred to as front-end and back-end production, both of which contain many steps.

Front-end refers to the fabrication from a blank wafer to a completed wafer (i.e. the microchips are created but they are still on the wafer). 

Back-end refers to dicing the wafer into individual chips and all the processes thereafter; such as test, assembly and packaging.

END TO END TURNKEY AND WAFER SHIPMENT PROCESS

Now what is a turnkey?

Yet another term."Turnkey" means that you only provide documentation to someone else to build something. They then source all the parts, get other parts modified or made, etc. Basically you send them specs and money and they send you fully built units.

But in the world of semiconductors turnkey is when the assembly and the test is done by the same vender organization.

Few more things to learn in the process ASN (Advanced Ship Notice, issued by the supplier before shipment), and GRN (Goods Receipt Notice, issued by the company receiving contract for the intermediate wafer processing).