Area-Selective Adhesive Bonding Using Photosensitive BCB for WL CSP Applications

2005 ◽  
Vol 127 (1) ◽  
pp. 7-11 ◽  
Author(s):  
A. Polyakov ◽  
M. Bartek ◽  
J. N. Burghartz
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Wafer Bonding ◽  
Potential Application ◽  
Adhesive Bonding ◽  
Wafer Level ◽  
Chip Scale Package ◽  
Rf Applications

This paper reports on an area-selective adhesive wafer bonding, using photosensitive BCB from Dow Co. The strength of the fabricated bonds is characterized using the wedge-opening and tensile methods. The measured fracture toughness is 53.5±3.9J/m2 with tensile strength up to 71 MPa. The potential application of BCB bonding is demonstrated on a concept of wafer-level chip-scale package for RF applications and microfilter array for microfluidic applications.

Wafer-Level Strength and Fracture Toughness Testing of Surface-Micromachined MEMS Devices

1999 ◽  
Vol 605 ◽  
Author(s):  
H. Kahn ◽  
N. Tayebi ◽  
R. Ballarini ◽  
R.L. Mullen ◽  
A.H. Heuer
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Microelectromechanical Systems ◽  
Reliability Prediction ◽  
Bend Strength ◽  
Mems Devices ◽  
Wafer Level ◽  
Toughness Testing ◽  
Loading Devices

AbstractDetermination of the mechanical properties of MEMS (microelectromechanical systems) materials is necessary for accurate device design and reliability prediction. This is most unambiguously performed using MEMS-fabricated test specimens and MEMS loading devices. We describe here a wafer-level technique for measuring the bend strength, fracture toughness, and tensile strength of MEMS materials. The bend strengths of surface-micromachined polysilicon, amorphous silicon, and polycrystalline 3C SiC are 5.1±1.0, 10.1±2.0, and 9.0±1.0 GPa, respectively. The fracture toughness of undoped and P-doped polysilicon is 1.2±0.2 MPa√m, and the tensile strength of polycrystalline 3C SiC is 3.2±1.2 GPa. These results include the first report of the mechanical strength of micromachined polycrystalline 3C SiC.

Laser Direct Patterning of Dry Etch BCB Adhesive Layers for Low Temperature Permanent Wafer-to-Wafer Bonding

2016 ◽  
Vol 2016 (DPC) ◽  
pp. 001222-001254
Author(s):  
Kai Zoschke ◽  
J.-U. Kim ◽  
M. Wegner ◽  
M. Gallagher ◽  
R. Barr ◽  
...  
Keyword(s):  
Low Temperature ◽  
Wafer Bonding ◽  
Adhesive Bonding ◽  
Special Focus ◽  
Transfer Printing ◽  
Wafer Level ◽  
Optical Elements ◽  
Flat Surfaces ◽  
Laser Ablation Process ◽  
Bond Layer

To enable advanced wafer level packaging approaches for devices like MEMS, image sensors or optical elements, wafer-to-wafer bonding processes using structured low temperature curable adhesives are required. A lot of Benzocyclobutene (BCB)-based wafer bonding works have been reported in the past showing a broad range of applications and good performance, but also some limitations such as long bond cycles and high cure temperature of 250 °C. In 2013 new process concepts were demonstrated [1], showing that wafer bond cycle time can be reduced to less than 10 min and a post bond batch cure at temperatures below 200 °C can be used to significantly shrink the overall cost of a BCB-based adhesive wafer bonding process. In order to create a patterned BCB bond layer, photo structuring of CYCLOTENE ® 4000 Resin is one solution. However, due to the decreased flow capability of that material after exposure, high bond forces and extended bonding times during wafer bonding as well as nearly flat surfaces with low topography are required for void-free bonding. To overcome these limitations, an increased material flow capability during wafer bonding is required. In this context non-photo sensitive CYCLOTENE ® 3000 Resin is suitable, since it has excellent flow capability in non-cured state. However, non-cured CYCLOTENE ® 3000 Resin cannot be structured with standard dry etching processes using a photo resist layer as mask. In order to enable patterned adhesive bonding based on CYCLOTENE ® 3000 Resin, alternative structuring methods have to be evaluated. One method was presented in [1] which is transfer printing of CYCLOTENE ® 3000 Resin from a help wafer to topography features of the device wafer. Although very good results were obtained, the method is restricted to applications with significant topography to enable the transfer printing. In this work we focus on a new structuring method for non-cured BCB layers formed from CYCLOTENE ® 3000 Resin. The layers were spin coated, baked and subsequently patterned using a 248 nm excimer laser stepper. The system features a 2.5× mask projection with a resulting exposure field of 6.5 × 6.5 mm2 and allows a direct ablation patterning of polymers. By using this method bond frame structures were patterned into 5 μm thick BCB layers at 200 mm silicon wafers. The wafers with the structured adhesive were bonded at 80 °C and 0.2 MPa for 5 minutes with 200 mm glass wafers. The bonded wafer stacks were subsequently post bond batch cured at 190 °C. Wafer dicing and shear tests of the bonded structures revealed excellent mechanical robustness of the BCB bond frames. The paper will review the new BCB wafer bond processes for supporting short cycle times with special focus on the new patterning approach by laser ablation. Process flow description as well as systematical analysis of pattern reproducibility of the new structuring method is part of the discussion.

MEMS on LSI by Adhesive Bonding and Wafer Level Packaging

2012 ◽  
Vol 1427 ◽  
Author(s):  
Masayoshi Esashi ◽  
Shuji Tanaka
Keyword(s):  
Wafer Bonding ◽  
Communication Systems ◽  
Adhesive Bonding ◽  
Wireless Communication Systems ◽  
Surface Micromachining ◽  
Wafer Level ◽  
Open Collaboration ◽  
Wafer Level Packaging ◽  
Hands On ◽  
Mems Process

ABSTRACTResonators and switches are fabricated on LSI for advance wireless communication systems. In addition to surface micromachining, adhesive bonding has been applied for the fabrication. Lamb wave resonators are fabricated for multi-frequency oscillators by surface micromachining. Multi-band filters are formed by a MEMS process after bonding a Si wafer to a LSI wafer (wafer bonding first approach). SAW filters are made by bonding a MEMS wafer to a LSI wafer (wafer bonding last approach). Variable capacitors are fabricated on a piezoelectric LiNbO3 wafer. Wafer level packaging techniques are developed to encapsulate the MEMS on LSI. Open collaboration as shared wafer, prototyping facility and hands-on access fabrication facility are discussed to reduce a cost and a risk in the development of the MEMS on LSI.

UNIFLUX 70

Alloy Digest ◽  
1978 ◽  
Vol 27 (9) ◽  
Keyword(s):  
Carbon Dioxide ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Carbon Steel ◽  
Physical Properties ◽  
Heat Treating ◽  
Shielding Gas ◽  
Electrode Wire ◽  
Welding Electrode

Abstract UNIFLUX 70 is a continuous flux-cored welding electrode (wire) for welding in carbon dioxide shielding gas in the flat groove and horizontal fillet positions. It is used widely in shipbuilding and other fabricating industries to weld carbon steel and provides around 82,000 psi tensile strength and around 50 foot-pounds Charpy V-notch impact at 0 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as heat treating, machining, and joining. Filing Code: CS-74. Producer or source: Unicore Inc., United Nuclear Corporation.

KAISER ALUMINUM ALLOY 7050

Alloy Digest ◽  
2000 ◽  
Vol 49 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
Fracture Toughness ◽  
Tensile Strength ◽  
Aluminum Alloy ◽  
Heat Treating ◽  
High Fracture Toughness ◽  
High Fracture ◽  
Kaiser Aluminum ◽  
Structural Parts ◽  
Very High

Abstract Kaiser Aluminum Alloy 7050 has very high mechanical properties including tensile strength, high fracture toughness, and a high resistance to exfoliation and stress-corrosion cracking. The alloy is typically used in aircraft structural parts. This datasheet provides information on composition, physical properties, hardness, tensile properties, and shear strength as well as fracture toughness and fatigue. It also includes information on forming, heat treating, machining, and joining. Filing Code: AL-366. Producer or source: Tennalum, A Division of Kaiser Aluminum.

LESCALLOY 300M VAC ARC

Alloy Digest ◽  
1993 ◽  
Vol 42 (2) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
High Strength ◽  
Melting Process ◽  
Heat Treating ◽  
Pressure Vessels ◽  
Low Alloy Steel ◽  
Steel Company ◽  
High Hardenability ◽  
Ingot Structure

Abstract LESCALLOY 300M VAC ARC is a low-alloy steel with an excellent combination of high hardenability and high strength coupled with good ductility and good toughness. Its tensile strength ranges from 280,000 to 300,000 psi. It is produced by the vacuum consumable electrode melting process to provide optimum cleanliness and preferred ingot structure. Its applications include aircraft components, pressure vessels and fasteners. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: SA-321. Producer or source: Latrobe Steel Company. Originally published March 1976, revised February 1993.

CORONA 5 Alloy

Alloy Digest ◽  
1978 ◽  
Vol 27 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Density Ratio ◽  
Heat Treating ◽  
Steel Company ◽  
Specific Strength ◽  
Strain Fracture ◽  
Crucible Steel ◽  
Chloride Stress Corrosion Cracking

Abstract CORONA 5 is a titanium alloy developed for applications in fracture-controlled aircraft components. Plane strain fracture toughnesses of 110,000 to 150,000 psi sq.rt. in. (120 to 165 MPa sq.rt. m) have been produced in this alloy at 135,00 psi (930 MPa) tensile strength through a variety of different process histories. The specific strength (strength/density ratio) is superior to that of the Ti-6A1-4V alloy. Resistance to fatigue crack propagation and resistance to chloride-stress-corrosion cracking are comparable to those of Ti-6A1-4V. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-70. Producer or source: Crucible Steel Company of America, Titanium Division.

INLAND DURASPRING

Alloy Digest ◽  
1998 ◽  
Vol 47 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Tensile Properties ◽  
High Stress ◽  
High Strength ◽  
Spring Steel ◽  
Fatigue Properties ◽  
Light Truck ◽  
Suspension Systems ◽  
Spring Steels

Abstract Inland DuraSpring is a high-strength microalloyed spring steel for use in high stress coil springs for automobile and light truck suspension systems. This bar product offers significant improvements in tensile strength, fatigue properties, and fracture toughness compared to conventional spring steels. This datasheet provides information on composition, hardness, and tensile properties as well asfracture toughness and fatigue. Filing Code: SA-496. Producer or source: Ispat Inland Inc.

VASCO 9-4-20

Alloy Digest ◽  
1997 ◽  
Vol 46 (10) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
High Temperature ◽  
Ultimate Tensile Strength ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
High Tensile Strength ◽  
Temperature Performance

Abstract Vasco 9-4-20 (0.20 wt% C) is a premium quality aircraft steel that combines high tensile strength with good fracture toughness. It is a heat-treatable alloy capable of developing an ultimate tensile strength greater than 190 ksi. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance as well as heat treating, machining, and joining. Filing Code: SA-489. Producer or source: Vasco, An Allegheny Teledyne Company.

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