Light Reading

Infineon's Chip Sandwich

Light Reading
Out of the Lab
Light Reading
8/14/2002
50%
50%
Repost This

Yesterday, Infineon Technologies AG (NYSE/Frankfurt: IFX) announced what it claims is a breakthrough in chip packaging technology: a technique that allows two electronic ICs (integrated circuits) to be squeezed into the space formerly occupied by one (see Infineon Intros 'Sandwich' Chip System).

Put simply, the German chipmaker has come up with a way to solder two chips together, one above the other, using a layer of copper in which chip-to-chip interconnections can be formed.

Infineon claims that its technology offers "a way out of the wiring crisis" -- referring to the fact that the number of pin-outs on a chip, and the number of traces on a printed circuit board, are starting to limit the functionality that can be put inside the chip itself. Reducing those wires to short copper links inside a "sandwich" allows chips to run faster, take up less space, and could reduce costs by up to 30 percent, the company contends.

Clever though it is, the idea of using stacked chips is not unique to Infineon. Others, including Sharp Foundry Services (part of Japanese electronics giant Sharp Ltd.) and Intel Corp. (Nasdaq: INTC), have developed so-called chip scale packages (CSPs) with up to four chips stacked on top of each other.

The different lies in the interconnects, says Reiner Schönrock, spokesperson at Infineon's worldwide headquarters in Munich. Stacked CSPs from other companies make connections using standard wire-bonding around the edges of the silicon die, rather than the copper sandwich developed by Infineon. "This [copper sandwich] is true 3D integration," Schönrock claims.

All stacked CSPs save on space and the costs associated with packaging, an approach that has turned out to be a big hit with manufacturers of mobile handsets. But Infineon's approach has several additional advantages over technologies from the likes of Sharp and Intel, which will open up other applications, says Schönrock.

For starters, the connections between chips are much shorter, so they can support faster speeds. The company claims that clock speeds of up to 200 GHz should be possible with its chips -- roughly 100 times faster than the fastest microprocessor today. This figure is a little hard to believe, but clearly this process has implications for fast communications technologies, including mobile and broadband networking.

The other key advantage is in heat dissipation. Since 80 percent of the chip's surface is covered by copper, which is a good conductor, the chip maintains an even temperature and can dissipate excess heat more easily. Furthermore, since the chip-to-chip interconnects are so short, they generate less heat in the first place than their wirebond counterparts.

The above image, taken with a microscope, shows how the chips are melded together. Infineon uses a diffusion soldering process, called SOLID, for "solid liquid interdiffusion."

First, a layer of copper is applied to the two surfaces to be bonded. Patterns are created in the copper using standard photolithography techniques to define where the interconnections will go. Then a thin layer (3 microns) of solder is applied, and the surfaces are pressed together at 3 bar of pressure and 270 degrees C, creating a permanent bond. The backsides of the two silicon wafers have been pre-polished, so that when they are bonded together, their combined thickness is almost the same as an original single slice of silicon.

In the image, places where current is flowing appear bright. Copper, which shows up pink, forms a channel from the top chip to the bottom chip. The grey areas at the top and bottom of the image are cross-sections of plain silicon -- the electronics are only found in the surface layer of the wafer.

Infineon's first prototype 3D IC, produced for an unnamed smart-card vendor, integrates a memory chip with the smart-card controller, increasing the available memory from the usual maximum of 32 kbytes to 160 kbytes.

Proving that it works is the first step, says Schönrock, and now the company will look at partnering with other chipmakers to produce products that meet their needs. There is also an obvious opportunity to apply this technique to products that Infineon makes itself, such as VDSL gear. The company also "hasn't ruled out the possibility" of licensing its technology to other foundries, he adds.

— Pauline Rigby, Senior Editor, Light Reading
http://www.lightreading.com Want to know more? The big cheeses of the optical networking industry will be discussing this very topic at Opticon 2002, Light Reading’s annual conference, being held in San Jose, California, August 19-22. Check it out at Opticon 2002.

Register now and save $500 off the registration fee. Just use the VIP Code C2PT1LHT on your registration form, and deduct $500 from the published conference fee. It's that simple!

(0)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View
More Blogs from Out of the Lab
The US goverment has funded two projects to develop an optical packet router capable of scaling to 100 Tbit/s
BlazePhotonics has slashed losses in hollow fiber, according to research it presented at OFC
Intel's silicon modulator could turn out to be a bit of a letdown – because it's not all that fast
Xilinx is funding research that could lead to FPGAs replacing network processors in future optical networks
U. of Kansas researchers think they're close to multiwavelength all-optical clock recovery
Flash Poll
LRTV Documentaries
Cable Eyes Big Technology Shifts

4|16|14   |   03:02   |   (4) comments


US cable engineers are facing a lot of heavy lifting in the coming years, notes Light Reading Cable/Video Practice Leader Alan Breznick.
LRTV Custom TV
Maximizing Customer Experience & Assuring Service Delivery in an IP World

4|15|14   |   4:57   |   (0) comments


Steven Shalita, VP of Marketing, NetScout Systems, Inc., discusses the challenges cable/MSO operators face in assuring the delivery of new IP-based services. Key points include the value of proactively managing performance, and using rich analytics and operational intelligence to better understand service and usage trends, make smarter business decisions and ...
LRTV Documentaries
Bye-Bye DVD: Consumers Embrace Digital Video

4|10|14   |   04:17   |   (7) comments


Veteran video analyst Colin Dixon, founder and principal analyst of nScreenMedia, says research shows 56% are using digital video already.
LRTV Documentaries
Video: TW Cable Puts Multicast Gateways to the Test

4|8|14   |   04:13   |   (1) comment


Tom Gonder, a chief architect at Time Warner Cable, explains how its trial of multicast gateways is impacting IP-based video plans.
LRTV Custom TV
Managing & Monetizing Big Data in Operator Environments

4|7|14   |     |   (1) comment


At Mobile World Congress, Gigamon's Director of Service Provider Solutions, Andy Huckridge, and Heavy Reading Analyst Sarah Wallace discuss the 'big data' issues facing carriers and operators today.
LRTV Huawei Video Resource Center
Data Center Energy – Build Your Data Center in a Modular Way

4|7|14   |   2:13   |   (0) comments


Dr. Fang Liangzhou, VP Network Energy Product Line, shared his thoughts about the challenges for data centers during CeBIT 2014.
LRTV Huawei Video Resource Center
Agile Network Solution – An Overview of Huawei's Agile Network Solution

4|7|14   |   2:31   |   (0) comments


Ajay Gupta, Director of Product Marketing, Networking Product Line, gives an overview of the Agile Network Solutions during CeBIT 2014.
LRTV Huawei Video Resource Center
Huawei’s eLTE Voice Trunking, Video and Data Applied for Railways

4|7|14   |   1:38   |   (0) comments


Gottfried Winter is the Sales Director at Funkwerk, a German specialist in GSM-r terminals and a long-time partner of Huawei. At CeBIT 2014, Winter talks to Light Reading about this partnership and the integration of enhanced voice trunking, video and data functions.
LRTV Huawei Video Resource Center
LeaseWeb Speaks Highly of Huawei's Datacenter Products

4|7|14   |   1:37   |   (0) comments


Rene Olde Olthof, Operations Director LeaseWeb, talks about the next data center transformation during CeBIT 2014.
LRTV Documentaries
Comcast: Reshaping the Cable Network Architecture

4|3|14   |   07:11   |   (8) comments


Shamim Akhtar, Comcast's architect and senior director of network strategy, explains why the cable company is moving to a more distributed network architecture.
LRTV Custom TV
VMware CEO Pat Gelsinger at Mobile World Congress

4|1|14   |   3:41   |   (0) comments


VMware CEO Pat Gelsinger speaks to Heavy Reading about the value of virtualization spanning from the data center to service provider networks to mobile devices.
LRTV Huawei Video Resource Center
Analysts' Impressions of Huawei SoftCOM at ONS 2014

4|1|14   |   1:11   |   (0) comments


After visiting the Huawei booth at ONS, Lee Doyle of Doyle Research gives his appraisal of Huawei's SoftCOM solution.
Hot Topics
BlackBerry Invests in Healthcare IT Startup
Sarah Reedy, Senior Editor, 4/15/2014
Volvo: AT&T HSPA+ Can Drive My Car
Sarah Reedy, Senior Editor, 4/16/2014
T-Mobile Petitions Operators to Kill Overages
Sarah Reedy, Senior Editor, 4/14/2014
Cisco & VMware Are Apple & Google of SDN
Mitch Wagner, West Coast Bureau Chief, Light Reading, 4/14/2014
Mobile Apps Susceptible to Heartbleed, Too
Sarah Reedy, Senior Editor, 4/14/2014
Like Us on Facebook
Twitter Feed