Memory Scramble Verification by Frontside and Backside FIB Modification

2013 ◽  
Author(s):  
Chun Ming Tsai ◽  
Yi Shiuan Huang ◽  
Ya Hui Lu ◽  
Jian Chang
Keyword(s):  
Flip Chip ◽  
Memory Cell ◽  
Bulk Silicon ◽  
Front Side ◽  
Test Program ◽  
Testing Data

Abstract Backside FIB circuit edit is an effective way to modify circuit on flip chip or stacked chips. Directly damaging memory cell through bulk silicon by FIB can be used to locate bit address to verify that the scramble test program coordinates correspond to the physical cell location. This paper presents the application of FIB for chip editing, discusses the limitation of the FIB approach and reports the scramble test experiments about the front-side and backside FIB technique to correct scramble testing data.

Simple and Effective Technique of Backside Deprocessing of Thin Flip Chip Package

2013 ◽  
Author(s):  
Suk Ho Lee ◽  
Chan Hee Park ◽  
Seung Joon Cha ◽  
Eun Cheol Lee ◽  
Kyu Shik Hong
Keyword(s):  
High Temperature ◽  
Flip Chip ◽  
Processing Technique ◽  
Wet Etching ◽  
Bulk Silicon ◽  
Front Side ◽  
Mechanical Grinding ◽  
Effective Technique ◽  
Processing Procedure ◽  
Silicon Thickness

Abstract This paper introduces a simple and effective technique of backside de-processing procedure. This technique reduces time and steps by simple wet etching. The front-side deprocessing requires many steps, such as wet and dry etching and parallel lapping, and also backside de-processing requires mechanical grinding to thin down the silicon thickness before wet etching. This paper introduces an effective way by skipping mechanical grinding and by etching at high temperature in case of thin flip chip. The backside silicon images are presented and compared after de-processing with TMAH and KOH which commonly have been used for bulk silicon etchant. The results show uniform backside images without any damage or residue. This backside de-processing technique was applied in two case studies to facilitate failure analysis.

FIB Micro-Surgery on Flip-Chips from the Backside

1998 ◽  
Author(s):  
Raymond Lee ◽  
Nicholas Antoniou
Keyword(s):  
Flip Chip ◽  
Focused Ion Beam ◽  
Ion Beam ◽  
Back Side ◽  
Bulk Silicon ◽  
Front Side ◽  
Large Hole ◽  
Area Of Interest ◽  
Flip Chip Packaging ◽  
Micro Surgery

Abstract The increasing use of flip-chip packaging is challenging the ability of conventional Focused Ion Beam (FIB) systems to perform even the most basic device modification and debug work. The inability to access the front side of the circuit has severely reduced the usefulness of tradhional micro-surgery. Advancements in FIB technology and its application now allow access to the circuitry from the backside through the bulk silicon. In order to overcome the problem of imaging through thick silicon, a microscope with Infra Red (IR) capability has been integrated into the FIB system. Navigation can now be achieved using the IR microscope in conjunction with CAD. The integration of a laser interferometer stage enables blind navigation and milling with sub-micron accuracy. To optimize the process, some sample preparation is recommended. Thinning the sample to a thickness of about 100 µm to 200 µm is ideal. Once the sample is thinned, it is then dated in the FIB and the area of interest is identified using the IR microscope. A large hole is milled using the FIB to remove most of the silicon covering the area of interest. At this point the application is very similar to more traditional FIB usage since there is a small amount of silicon to be removed in order to expose a node, cut it or reconnect it. The main differences from front-side applications are that the material being milled is conductive silicon (instead of dielectric) and its feature-less and therefore invisible to a scanned ion beam. In this paper we discuss in detail the method of back-side micro-surgery and its eflkcton device performance. Failure Analysis (FA) is another area that has been severely limited by flip-chip packaging. Localized thinning of the bulk silicon using FIB technology oflkrs access to diagnosing fdures in flip-chip assembled parts.

A Novel Deprocessing Technique for Revealing Transistor-Level Damage on 7nm FinFET Devices

2020 ◽  
Author(s):  
Fei Long Xu ◽  
Phoumra Tan ◽  
Dan Nuez
Keyword(s):  
High Resolution ◽  
Flip Chip ◽  
Fault Localization ◽  
Wet Etching ◽  
Efficient Technique ◽  
Solid Immersion Lens ◽  
Front Side ◽  
Flip Chip Packaging ◽  
Metal Layers

Abstract Physical FA innovations in advanced flip-chip devices are essential, especially for die-level defects. Given the increasing number of metal layers, traditional front-side deprocessing requires a lot of work on parallel lapping and wet etching before reaching the transistor level. Therefore, backside deprocessing is often preferred for checking transistor-level defects, such as subtle ESD damage. This paper presents an efficient technique that involves precise, automated die thinning (from 760µm to 5µm), high-resolution fault localization using a solid immersion lens, and rigorous KOH etch. Using this technique, transistor-level damage was revealed on advanced 7nm FinFET devices with flip-chip packaging.

Improvement of ELK Reliability in Flip Chip Packages using Bond-on-Lead (BOL) Interconnect Structure

2010 ◽  
Vol 2010 (1) ◽  
pp. 000197-000203 ◽  
Author(s):  
Eric Ouyang ◽  
MyoungSu Chae ◽  
Seng Guan Chow ◽  
Roger Emigh ◽  
Mukul Joshi ◽  
...  
Keyword(s):  
Finite Element ◽  
Flip Chip ◽  
Low Cost ◽  
Reliability Testing ◽  
Element Simulation ◽  
Testing Data ◽  
Flip Chip Packaging ◽  
Solder Mask ◽  
The Cost ◽  
Low K

In this paper, a novel flip chip interconnect structure called Bond-On-Lead (BOL) and its ability to reduce stress in the sensitive sub-surface ELK (Extra Low K) layers of the die is presented. BOL is a new low cost flip chip packaging solution which was developed by STATSChipPAC to dramatically reduce the cost of flip chip packaging. The BOL solution allows for efficient substrate routing by virtue of the use of narrow BOL pads and the removal of solder mask in the area of the BOL pads, which eliminates the limitations associated with solder mask opening sizes and positional tolerances. In addition to the compelling cost benefits, modeling results are confirmed with empirical reliability testing data to show that BOL is superior to the traditional Bond-on-Capture Pad (BOC) configuration from a mechanical stress and reliability perspective. The focus of this paper is on the theoretical analysis of the stress, strain, and warpage associated with the BOL configuration compared with the traditional BOC structure. For the package deformation, the global finite element method is used to simulate the package warpage. For the local bumping reliability, the focus is on the ELK layers which are the critical locations affecting the package's reliability. The local finite element simulation is conducted to compare the critical ELK layers stresses with BOL structure vs. with traditional BOC structure.

Development of a stress compensation layer for thin pixel modules 3D assembly

2014 ◽  
Vol 2014 (1) ◽  
pp. 000787-000793 ◽  
Author(s):  
G. Pares ◽  
T. McMullen ◽  
S. Tomé ◽  
L. Vignoud ◽  
R. Bates ◽  
...  
Keyword(s):  
Room Temperature ◽  
Flip Chip ◽  
Building Blocks ◽  
Back Side ◽  
Pixel Detector ◽  
Front Side ◽  
Radiation Length ◽  
Reflow Temperature ◽  
Solder Reflow ◽  
Deposition Conditions

The pixel modules are the fundamental building blocks of the ATLAS pixel detector system used in CERN LHC facility. They consist in their basic form of a silicon sensor that is flip-chipped bonded to a CMOS read-out integrated chip (ROIC). One of the main objectives for the ATLAS experiment is to develop an approach towards low mass modules and thus reducing radiation length. From the module perspective this can be achieved by using advanced 3D technology processes that includes the formation of copper and solder micro-bumps on top of the ROIC front-side, the thinning of both the sensor and the CMOS ROIC and finally the flip chip assembly of the 2 chips. The thinning of the silicon chips leads to low bump yield at the solder reflow stage due to bad co-planarity of the two chips creating dead zones within the pixel array. In the case of the ROIC, which is thinned to 100um, the chip bow varies from − 100 μm at room temperature to + 175 μm at reflow temperature resulting of CTE mismatch between materials in the CMOS stack and the silicon substrate. Our objective is to compensate dynamically the stress of the front side stack by adding a compensating layer to the back-side of the wafer. Utilising our material thermo-mechanical database coupled with a proprietary analytical simulator and measuring the bow of the ROIC at die level we are able to reduce the bow magnitude by approximately a factor of 3 by the introduction of the compensating layer. We show that it is possible to change the sign of the bow at room temperature after deposition of a SiN/Al:Si stack. This amplitude of the correction can be manipulated by the deposition conditions of the SiN/Al:Si stack. Further development of the backside deposition conditions are on-going where the target is to control the room temperature bow close to zero and reducing the bow magnitude throughout the full solder reflow temperature range hence conserving bump yield. In keeping with a 3D process the materials used are compatible with Through Silicon Via (TSV) technology with a TSV last approach in mind should we integrate this technology in the future.

Development of a Stress Compensation Layer for 3-D Assembly of Thin Pixel Modules

2015 ◽  
Vol 12 (1) ◽  
pp. 29-36
Author(s):  
G. Pares ◽  
T. McMullen ◽  
S. Tomé ◽  
L. Vignoud ◽  
R. Bates ◽  
...  
Keyword(s):  
Room Temperature ◽  
Flip Chip ◽  
Building Blocks ◽  
Back Side ◽  
Pixel Detector ◽  
Front Side ◽  
Radiation Length ◽  
Reflow Temperature ◽  
Solder Reflow ◽  
Deposition Conditions

Pixel modules are the fundamental building blocks of the ATLAS pixel detector system used in the CERN LHC facility. In their basic form, they consist of a silicon sensor that is flip-chip bonded to a CMOS read-out integrated chip (ROIC). One of the main objectives for the ATLAS experiment is to develop an approach toward low-mass modules, thus reducing radiation length. From the module perspective, this can be achieved by using advanced 3-D technology processes that include the formation of copper and solder microbumps on top of the ROIC front side, the thinning of both the sensor and the CMOS ROIC, and, finally, the flip-chip assembly of the two chips. The thinning of the silicon chips leads to low bump yield at the solder reflow stage, due to bad coplanarity of the two chips creating dead zones within the pixel array. In the case of the ROIC, which is thinned to 100 μm, the chip bow varies from −100 μm at room temperature to +175 μm at reflow temperature, resulting in CTE mismatch between materials in the CMOS stack and the silicon substrate. Our objective was to compensate dynamically for the stress of the front-side stack by adding a compensating layer to the back side of the wafer. Using our material thermomechanical database coupled with a proprietary analytical simulator, and measuring the bow of the ROIC at die level, we were able to reduce the bow magnitude by approximately a factor of 3 by introducing the compensating layer. We show that it is possible to change the sign of the bow at room temperature after deposition of a SiN/Al:Si stack. The amplitude of the correction can be manipulated by the deposition conditions of the SiN/Al:Si stack. Further development of the back-side deposition conditions are ongoing, where the target is to control the room temperature bow close to zero and reduce the bow magnitude throughout the full solder reflow temperature range, hence conserving bump yield. In keeping with a 3-D process, the materials used are compatible with through-silicon via (TSV) technology with a TSV-last approach in mind, should we integrate this technology in the future.

Design Features of Compliant Packages and Their Impact on Reliability

2001 ◽  
Author(s):  
Ilyas Mohammed ◽  
Young-Gon Kim
Keyword(s):  
Flip Chip ◽  
High Reliability ◽  
Electronic Packages ◽  
Detailed Design ◽  
Testing Data ◽  
Solder Balls ◽  
Cte Mismatch ◽  
The Difference ◽  
Electrical Connections ◽  
Package Reliability

Abstract It is well-known that the main cause of mechanical failure in electronic packages is due to the difference in the Coefficients of Thermal Expansion (CTE) of the silicon and the organic board. There are many packaging technologies that try to overcome this limitation; ranging from making curved connection pins (gull-wing leads) from the package to the board, as in the case of Thin Small Outline Package (TSOP), to using hard epoxy to rigidly adhere the die to the board as in the case of flip-chip packages. This paper illustrates a compliant packaging concept that minimizes the effect of the CTE mismatch between the silicon die and the board. A summary of different packaging techniques that address the CTE mismatch problem is presented. From this summary, it is apparent that many of these techniques do not provide as high reliability as the compliant packages do, especially when the electrical connections from the package to the board (solder balls) are present directly under the silicon die as in the case of chip scale packages. As the compliant package isolates the effect of the silicon die from the substrate, the silicon has some motion relative to the substrate. This means that the interconnections from the silicon to the substrate must be designed to withstand this motion. Hence the design of these interconnections is key to maximizing the reliability of the compliant packages. A detailed design and reliability analysis of compliant packages for different applications is presented. The design highlights the main parameters that have an effect on reliability of the package. Reliability simulation and analysis using finite element techniques is presented for different designs to highlight the key parameters that govern the reliability of compliant packages. Finally, reliability testing data is presented for different packages.

Continual learning classification method with single-label memory cells based on the intelligent mechanism of the biological immune system

2021 ◽  
pp. 1-17
Author(s):  
Dong Li ◽  
Lanlan Gong ◽  
Shulin Liu ◽  
Xin Sun ◽  
Ming Gu ◽  
...  
Keyword(s):  
Immune System ◽  
Memory Cell ◽  
Learning Ability ◽  
Classification Method ◽  
Memory Cells ◽  
Unique Type ◽  
Testing Data ◽  
Batch Learning ◽  
Biological Immune System ◽  
Continual Learning

The traditional batch learning classification methods need to obtain all kinds of data once before training. This makes them unable to recognize the data from the unseen types and cannot continuously enhance their classification ability through learning the testing data in the testing process, because they lack continual learning ability. Inspired by the continual learning mechanism of the biological immune system (BIS), this paper proposed a continual learning classification method with single-label memory cells (S-CLCM). The type of testing data is identified by memory cells, and the data type from unseen types is determined by an affinity threshold. New memory cells are cultivated continuously by learning the testing data to enhance S-CLCM’s classification ability gradually. Every memory cell has the same size and a unique type. It becomes a standard batch learning classification method or a standard clustering method under certain conditions. Take the experiments on twenty benchmark datasets to estimate its classification performance and possible superiority. Results show S-CLCM has good performance when it becomes a standard batch learning classification method, and S-CLCM is superior to the other classical classification algorithms when the data from unseen types or new labeled data appear during the testing process. It can improve the classification accuracy by up to 33%, and by at least 14%.

A Chip-Scale Cooling Scheme With Integrated Heat Sink and Thermal-Fluidic I/O Interconnects

2005 ◽  
Author(s):  
Bing Dang ◽  
Paul J. Joseph ◽  
Xiaojin Wei ◽  
Muhannad S. Bakir ◽  
Paul A. Kohl ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Sink ◽  
Flip Chip ◽  
Microchannel Heat Sink ◽  
Front Side ◽  
Thermal Interface ◽  
Fine Pitch ◽  
Solder Bumps ◽  
Cmos Compatible ◽  
Board Level

We demonstrate a prototype chip-scale microfluidic cooling scheme. CMOS compatible processes allow the monolithic integration of the microchannel heat sink into the backside of a Si chip at low temperature (≤260°C). At the front side of a chip, fine pitch area-array solder bumps are fabricated by electroplating for high-density electrical I/O interconnection, while a peripheral array of micro polymer pipes are fabricated as thermal-fluidic I/O interconnects. The resulting “microfluidic flip chip” can be bonded onto a liquid-cooled board substrate using conventional flip-chip assembly processes. The cooling liquid can, therefore, be transferred into a Si chip directly from the board-level manifolds to alleviate the thermal interface issues.   This paper was also originally published as part of the Proceedings of the ASME 2005 Heat Transfer Summer Conference.

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