Silicon Wafer Thinning to Reveal Cu TSV

2012 ◽  
Vol 2012 (DPC) ◽  
pp. 001673-001700 ◽  
Author(s):  
Laura Mauer ◽  
John Taddei ◽  
Ramey Youssef
Keyword(s):  
Silicon Wafer ◽  
Etch Rate ◽  
Cost Effective ◽  
Silicon Etching ◽  
3D Integration ◽  
Process Flow ◽  
Cost Effective Method ◽  
Etch Rates ◽  
Wet Etch ◽  
Wafer Thinning

3D Integration is becoming a reality in device manufacturing. The TSV Middle process is becoming the dominant integration scenario. For this process flow the silicon wafer needs to be thinned to reveal the Cu TSV. Grinding is used to remove the bulk of the silicon wafer. Currently a multistep sequence of processes that includes CMP and plasma have been used to complete the final thinning of the silicon. This paper will describe a simple, cost effective method to wet etch the remaining silicon to reveal the Cu TSVs. KOH is selected as the etchant since it will not attack the TSV materials and has a higher etch rate than TMAH. The development of processes with optimum etch rates and uniformity for silicon etching along with no attack of the Cu via or oxide liner and effective post cleaning to remove residual Potassium will be presented.

Process Control for Wet Etching for Silicon Wafer Thinning

2010 ◽  
Vol 2010 (DPC) ◽  
pp. 001030-001053
Author(s):  
Laura Mauer ◽  
Herman Itzkowitz ◽  
John Taddei
Keyword(s):  
Process Control ◽  
Silicon Wafer ◽  
Etch Rate ◽  
Wet Etching ◽  
Etching Solution ◽  
Control Techniques ◽  
Cost Of Ownership ◽  
The Cost ◽  
Wet Etch ◽  
Wafer Thinning

Thin wafers have become a basic need for a wide variety of new microelectronic products. Thinner die are being required to fit into thinner packages. Wafers that have been thinned using a final wet etch process on the backside have less stress compared with standard mechanical backgrinding. Isotropic wet etching of silicon is typically done with a mixture of nitric and hydrofluoric acids along with the addition of chemicals to adjust for viscosity and surface wettability for single wafer spin processing. As the silicon is etched and incorporated in the etching solution the etch rate will decrease with time. This variation has been modeled. The focus of this paper is to compare the process control techniques for maintaining a consistent etch rate as a function of time and wafers processed. The models allow for either the time to be extended, chemicals to be replenished or a combination of these. Results will be presented including the cost of ownership for each scenario.

Feasibility to Fabricate the 45° Slant with Anisotropic Silicon Etching in NaOH Solution

2012 ◽  
Vol 503-504 ◽  
pp. 615-619 ◽  
Author(s):  
Alonggot Limcharoen ◽  
Chupong Pakpum ◽  
Pichet Limsuwan
Keyword(s):  
Data Storage ◽  
Etch Rate ◽  
Silicon Etching ◽  
Naoh Solution ◽  
Conventional Photolithography ◽  
Sio2 Mask ◽  
P Type ◽  
Anisotropic Silicon Etching ◽  
Wet Etch ◽  
Laser Light Source

The experiments to study the feasibility to fabricate the 45 slant on p-type (100)-oriented silicon wafer were done. The various mask shapes, rectangular, cross, circle and boomerang, were patterned on the SiO2 mask by utilizing the conventional photolithography and dry etching process for investigating the anisotropic wet etch characteristic. The edge of masks were align in two crystal direction, 110 and 100 that is allowable to get a better understanding about the crystal orientation and the angle between planes in a crystal system. The very low etch rate,  50 nm/min, process regime was selected to fabricate the 45 slant with the concept is the lowest of an overall etch rate in the system to reach the level that is possible to detect the (110) plane. The etch recipe can be used for the next development work to built a housing of the laser light source for applying in a data storage technology.

Monitoring of Wet Etch for Wafer Thinning and Via Reveal Process

2013 ◽  
Vol 2013 (1) ◽  
pp. 000008-000012
Author(s):  
Chuannan Bai ◽  
Eugene Shalyt ◽  
Guang Liang ◽  
Peter Bratin
Keyword(s):  
Process Control ◽  
Etch Rate ◽  
Back Side ◽  
Reaction Products ◽  
Product Characteristics ◽  
Pros And Cons ◽  
Last Stage ◽  
Silicon Vias ◽  
Wet Etch ◽  
Wafer Thinning

TSV (Through Silicon Vias) are usually formed and deposited as blind vias. As a last stage, vias are opened by thinning of the back side of the wafer. While the bulk of the silicon can be removed by both wet and dry methods, the final step of the “Via Reveal” process is predominantly performed by wet etch. Two commonly used types of etching solutions are anisotropic alkaline etch (KOH, TMAH, etc.) and isotropic etch (HF/HNO3, etc.). Etch rate, uniformity, and product characteristics strongly depend on the composition of solution: both original compounds and reaction products. This presentation describes different approaches for process control of both alkaline and acidic etch solutions using advanced spectroscopic models and potentiometry. Pros and cons of different approaches are discussed. Specific emphasis is placed on the monitoring of reaction products.

Investigation of Choline Hydroxide for Selective Silicon Etch from a Gate Oxide Failure Analysis Standpoint

2002 ◽  
Author(s):  
Valentina Korchnoy
Keyword(s):  
Aqueous Solution ◽  
Oxide Film ◽  
Failure Analysis ◽  
Surface Quality ◽  
Etch Rate ◽  
Gate Oxide ◽  
Silicon Etching ◽  
Poly Silicon ◽  
Wet Etch

Abstract A robust procedure for poly-silicon wet etch selective to SiO2 is presented. The procedure is applicable for CMOS devices and maintains the integrity of the gate oxide film. The technique uses a 50% wt. choline hydroxide aqueous solution. The optimum etching conditions, which allow exposure of gate oxide to enable its further inspection using SEM or AFM were determined. An investigation of general silicon etching characteristics of choline hydroxide, as etch rate, selectivity and surface quality, has been carried out as well.

Optimization of Concentration and Temperature of KOH Etchant on Micromachining Process

2010 ◽  
Author(s):  
Mohsen Shayan ◽  
Behrooz Arezoo ◽  
Ali Amani
Keyword(s):  
Crystal Orientation ◽  
Etch Rate ◽  
Wet Etching ◽  
Etching Process ◽  
Structure Investigation ◽  
Optimal Amount ◽  
Etch Rates ◽  
Wet Etch

Due to vast application of silicon wet etching in Micromachining and MEMS structure, investigation about parameters that have more influence on wet etch rate is indispensable. Wet etch rate is dependent to several factor such as temperature, etchant concentration and crystal orientation. Because of temperature and concentration are more controllable therefore the etch rates R{hkl} depend mainly on concentration and temperature of the etchant. Understanding the relation between this parameters and wet etch rate can assist us in order to control and optimization of micromachining process. This paper present a relation between etchant concentration and temperature and wet etch rate on (100) plane, and then identify the etchant concentration in a certain range of temperature as the wet etch rate be in optimal amount. With optimization the etch rate of wafer (100), necessary time for etching process reduces and this reduction of time can lead to reduction of undercutting at convex and concave corners.

CAD Of Anticorrosive Protection Of Steel Structures

2019 ◽  
pp. 18-23
Keyword(s):  
Protective Coating ◽  
Computer Aided Design ◽  
Steel Structures ◽  
Cost Effective ◽  
Operating Conditions ◽  
Computational Tool ◽  
Protection Method ◽  
Cost Effective Method ◽  
The Cost ◽  
Aided Design

The choice of cost-effective method of anticorrosive protection of steel structures is an urgent and time consuming task, considering the significant number of protection ways, differing from each other in the complex of technological, physical, chemical and economic characteristics. To reduce the complexity of solving this problem, the author proposes a computational tool that can be considered as a subsystem of computer-aided design and used at the stage of variant and detailed design of steel structures. As a criterion of the effectiveness of the anti-corrosion protection method, the cost of the protective coating during the service life is accepted. The analysis of existing methods of steel protection against corrosion is performed, the possibility of their use for the protection of the most common steel structures is established, as well as the estimated period of effective operation of the coating. The developed computational tool makes it possible to choose the best method of protection of steel structures against corrosion, taking into account the operating conditions of the protected structure and the possibility of using a protective coating.

Application of KOH Electrochemical Etch and Passive Voltage Contrast Techniques for Deep Sub-Micron CMOS Leaky Gate Detection

2000 ◽  
Author(s):  
Fred Y. Chang ◽  
Victer Chan
Keyword(s):  
Case Studies ◽  
Detection Technique ◽  
Cobalt Silicide ◽  
Process Technology ◽  
Process Flow ◽  
Voltage Contrast ◽  
Emission Detection ◽  
Wet Etch ◽  
Direct Confirmation

Abstract This paper describes a novel de-process flow by combining cobalt silicide / nitride wet etch with KOH electrochemical wet etch (ECW) to identify leaky gate in silicided deep sub-micron process technology. Traditionally, leaky gate identification requires direct confirmation by gate level electrical or emission detection technique. Ohtani [1] used KOH electrochemical etch application to identify nonsilicided leaky gate capacitor in DRAM without using the above confirmation. The result of the case study demonstrates the expanded application of ECW etch to both silicided 0.18um logic and SRAM devices. Voltage contrast at metal 1 to assist leaky gate localization is also proposed. By combining both techniques, the possibility for isolating gate related defects are greatly enhanced. Case studies also show the advantages of the proposed technique over conventional poly level voltage contrast in leaky gate identification especially with devices that use local interconnect and nitride liner process.

Monitoring effluent quality in hypertrophic wastewater reservoirs using remote sensing

1996 ◽  
Vol 33 (8) ◽  
pp. 23-29 ◽  
Author(s):  
I. Dor ◽  
N. Ben-Yosef
Keyword(s):  
Water Quality ◽  
Theoretical Model ◽  
Principal Component ◽  
Cost Effective ◽  
Operational Parameters ◽  
Effluent Quality ◽  
Optical Images ◽  
Routine Monitoring ◽  
Cost Effective Method ◽  
Wastewater Quality

About one hundred and fifty wastewater reservoirs store effluents for irrigation in Israel. Effluent qualities differ according to the inflowing wastewater quality, the degree of pretreatment and the operational parameters. Certain aspects of water quality like concentration of organic matter, suspended solids and chlorophyll are significantly correlated with the water column transparency and colour. Accordingly optical images of the reservoirs obtained from the SPOT satellite demonstrate pronounced differences correlated with the water quality. The analysis of satellite multispectral images is based on a theoretical model. The model calculates, using the radiation transfer equation, the volume reflectance of the water body. Satellite images of 99 reservoirs were analyzed in the chromacity space in order to classify them according to water quality. Principal Component Analysis backed by the theoretical model increases the method sensitivity. Further elaboration of this approach will lead to the establishment of a time and cost effective method for the routine monitoring of these hypertrophic wastewater reservoirs.

A Cost-Effective Method to Prepare Pure Vildagliptin

2013 ◽  
Vol 10 (3) ◽  
pp. 159-163 ◽  
Author(s):  
Jun Peng ◽  
Yue Feng ◽  
Zhu Tao ◽  
Yingjie Chen ◽  
Xiangnan Hu
Keyword(s):  
Cost Effective ◽  
Cost Effective Method
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