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Multilevel Bond Wire Model (Arrays of User-defined N-segment Shapes): BWIRES3ARRAY

Symbol

Summary

BWIRES3ARRAY models a collection of metallic round bonding wires (bond wires) each made of linear segments and placed above a conducting ground plane. The actual smooth contour of a bonding wire is approximated by a user-specified number of linear segments, and parameters that define orientation of segments are Cartesian coordinates of the segment ends.

BWIRES3ARRAY provides a simpler way to specify arrays of bond wires for the BWIRES3 model.

This model allows specifying the X/Z cross section of one or more bonding profiles with the XProfile1, ZProfile1, XProfile2, ZProfile2... parameters. This is useful when modeling multiple couple bond wires with mixed bonding profiles, heights, and spacings.

Implementation Details

Internally, this model uses the BWIRES3 element. The BWIRES3ARRAY element provides a simpler interface for defining arrays of bond wires. See BWIRES3 for topology, equivalent circuit, and recommended usage.

Parameters

Name Description Unit Type Default
ID Element ID   IC1
N Number of wires   4
Nseg Number of segments   5
Dia Wire diameter Length 25.4
Rho Metal bulk resistivity relative to gold   1
*Er Relative dielectric constant of encasing material   1
*Tand Loss tangent of encasing material   0
*ZOffset Global Z Offset Length 0
*YOffsetBegin Y Offset at the start of the bond array Length 0
*YOffsetEnd Y Offset at the end of the bond array Length 0
YSpacBegin Spacing between wires at start of bond. Can be a single value or a vector (repeats until N wires if vector). Length {100}
YSpacEnd Spacing between wires at end of bond. Can be a single value or a vector (repeats until N wires if vector). Length {100}
NProfiles Number of bond wire profiles   2
Pattern Pattern to repeat bond wire profiles   {1,2,2,1}
XProfile1 X coordinates of wire bond profile 1 Length {0,200,400,600,800,1000}
ZProfile1 Z coordinates of wire bond profile 1 Length {0,77.131705,223.38425,223.38425,77.131705,0}
XProfile2 X coordinates of wire bond profile 2 Length {0,40,80,280,640,1000}
ZProfile2 Z coordinates of wire bond profile 2 Length {0,223.7847225,242.4828375,235.5260375,94.4133,0}

* indicates a secondary parameter

Parameter Details

N. Specifies the total number of bond wires in the array. The maximum is 512.

Nseg. Specifies the number of linear segments that make each wire. The number of segments is limited to 10. The recommended range is 3≤Nseg≤6.

NProfiles. Specifies the number of different bonding profiles that are used in the array. This parameter changes the number of XProfile_, ZProfile_ parameters.

XProfile1,ZProfile1,...XProfileN,ZProfileN. Each of these parameters is a vector of NSeg+1 length. Each pair of vectors defines one bonding profile. By default, XProfile1,ZProfile1 define a symmetric 'sinc' shape typical of a stitch-stitch bonding. XProfile2,ZProfile2 default to an asymmetric profile typical of a ball-stitch bonder.

Note that you can quickly modify the arrays with equations:

  • Adding/subtracting a value to the XProfile shifts the bond profile, for example, "100 + {0, 100, 200, 300, 400, 500}"

  • Adding/subtracting a value to the ZProfile raises and lower bond profile, for example, "100 + {0, 100, 200, 300, 200, 100}"

  • Multiplying the XProfile by a value stretches the length of the bond profile, for example, "1.5 * {0, 100, 200, 300, 400, 500}"

  • Multiplying the ZProfile by a value stretches the height of the bond profile, for example, "0.7*{0, 100, 200, 300, 200, 100}"

Pattern A vector that defines the order in which the N bond wires use the NProfiles specified profiles. This vector can be any length; the specified pattern is repeated out to N bond wires. For example:

  • There are N=10 bond wires, and NProfiles=2 profiles. Pattern={1,2,2,1}. Starting from the first wire, the profiles used are 1,2,2,1,1,2,2,1,1,2.

  • N=10 bond wires, and NProfiles=2. Pattern={1}. Starting from the first wire, the profiles used are 1,1,1,1,1,1,1,1,1,1,1 (not all profiles are required to be used.)

  • N=10 bond wires, and NProfiles=2. Pattern={0,1,2,3}. Starting from the first wire, the profiles used are 1,1,2,2,1,1,2,2,1,1 (profile #'s are automatically limited between 1 and NProfiles.)

YSpacBegin,YSpacEnd These parameters define the spacing between bond wires at the start and end of the bond. They can be scalar or vector parameters. Like the Profile parameter, the vectors can be any length, and the specified spacing is repeated out to N bond wires. For example:

  • YSpacBegin = {50,100,150}. YSpacEnd = {40,60}. If N = 10, the Y spacing between the start of adjacent wires is {50,100,150,50,100,150,50,100,150,50}. The spacing at the end of the wires is {40,60,40,60,40,60,40,60,40,60}.

  • YSpacBegin = {50,100,150}. YSpacEnd = {40,60}. If N = 10, the Y spacing between the start of adjacent wires is {50,100,150,50,100,150,50,100,150,50}. The spacing at the end of the wires is {40,60,40,60,40,60,40,60,40,60}.

YOffsetBegin,YOffsetEnd These scalar parameters add a constant YOffset to the beginning and end of the wires, respectively.

Er, Tand. Material used for optional encasing. The defaults are Er=1 and Tand=0.

Parameter Restrictions and Recommendations

  1. Number of segments is limited: 1≤Nseg≤10

  2. This model implies that the number of bond wires is less than or equal to 512.

  3. Dia>0.1 micron

We have compared our Bondwire model to other commercially available software which accounts for all loss and radiation, and found that we have a good match using 48 wires up to 1mm (roughly 40mils) long and up to 100GHz. A safe guideline to follow is Length of wire / Wavelength ratio should be less than 1/6.

Usage Examples

Example #1:

Three different bond profiles are used. The Pattern is 10 items long, so it repeats twice for N=20 bond wires. Note that the three profiles have the same vector values, but they are modified by adding and multiplying different constants to XProfileN, ZProfileN.

Example #2:

One bond profile is used with different YSpacBegin and YSpacEnd. YOffsetBegin is adjusted so that the wires are symmetrical about the center wires.

Example #3:

Two bond profiles are used with a pattern of {1,1,2,2}. The YSpacBegin, YSpacEnd parameters are also vectors, so that similar bonds are spaced closer together.

Layout

The layout for this cell has hard-coded model layers. When you first use this layout cell, a layer named "BondWires" is added to your drawing layer and model layer list (if they do not already exist). Using the model layer mapping, you can assign these layers to draw on any drawing layer.

This model has several layout-only parameters that control how the pad draws. You access these parameters by selecting the item in the layout, right-clicking and choosing Shape Properties to display the Cell Options dialog box, then clicking the Parameters tab.

Name Value Units Description
ShowNodeNum 0 Integer Show/hide node number
PointFaces 0 Integer Faces are points, not line segments
OrtTip 0 Integer 0 - Tip cut is horizontal, !=0 Tip cut orthogonal to segment axis

3D EM Layout

This model includes OrtTip, a layout-only parameter that controls how the tip of a wire is cut. If OrtTip=0 (default) then the tip is cut horizontally (this provides a smooth transition to some on-layer metal patch or strip); if OrtTip≠0 then the wire tip is cut orthogonally to the last/first segment axis. An orthogonal cut improves the transition to metal connectors if the last/first segments are horizontal or almost horizontal. To access this parameter, select the item in the layout, right-click and choose Shape Properties to display the Cell Options dialog box, then click the Parameters tab.

References

[1] Grover, F.W., Inductance Calculations, Mineola, New York: Dover Publishing, 2004

[2] Bahl, I.J., Lumped Elements for RF and Microwave Circuits, Norwood, MA: Artech House, 2003

[3] Balanis C.A., Antenna Theory: analysis and design, 2nd edition: Wiley, 1997

[4] Bond Wire Modeling Standard. EIA/JEDEC Standard EIA/JESD59: Electronics Industries Association, June 1997.

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