Laminate substrate thermal warpage prediction for designing a laminate substrate

Patent metadata

Field	Value
Publication number	US-10108753-B2
Application number	US-201615176101-A
Country	US
Kind code	B2
Filing date	Jun 7, 2016
Priority date	Jun 7, 2016
Publication date	Oct 23, 2018
Grant date	Oct 23, 2018

Abstract

Method of designing a laminate substrate having upper laminate layers and an equal plurality of lower laminate layers including: dividing the laminate substrate into regions having corresponding laminate layer pairs consisting of an upper laminate layer and a lower laminate layer; calculating a net stretching value for each corresponding laminate layer pair in each region to result in net stretching values in each region; summing the net stretching values in each region to result in a net stretching value for each region proportional to a curvature of each local region; calculating a relative out-of-plane displacement for the laminate substrate from the curvature of each local region; calculating a predicted thermal warpage for the laminate substrate; and finalizing a design of the laminate substrate when the predicted thermal warpage is within a predetermined acceptable range.

First claim

What is claimed is:

1. A computer-implemented method of designing a laminate substrate having a core, a plurality of laminate layers above the core and a plurality of laminate layers below the core, the method comprising:
dividing the laminate substrate into a plurality of regions, each region having a plurality of corresponding laminate layer pairs consisting of a laminate layer above the core and a laminate layer below the core;
calculating a net stretching value for each corresponding laminate layer pair in each region to result in a plurality of net stretching values in each region;
summing the plurality of net stretching values in each region to result in a net stretching value for each region wherein the net stretching value in each region is proportional to a curvature of each local region;
calculating a relative out-of-plane displacement for the laminate substrate from the curvature of each local region;
calculating a predicted thermal warpage for the laminate substrate such that the predicted thermal warpage is proportional to the relative out-of-plane displacement divided by a thickness of the core raised to an exponent; and
finalizing a design of the laminate substrate when the predicted thermal warpage is within a predetermined acceptable range.

2. The computer-implemented method of claim 1 further comprising instantiating the design of the laminate substrate into a physical laminate substrate.

3. The computer-implemented method of claim 1 further comprising revising the design of the laminate substrate when the predicted thermal warpage is not within the predetermined acceptable range followed by:
calculating a predicted thermal warpage for the laminate substrate such that the predicted thermal warpage is proportional to the relative out-of-plane displacement divided by the thickness of the core raised to an exponent; and
finalizing the design of the laminate substrate when the predicted thermal warpage is within the predetermined acceptable range.

4. The computer-implemented method of claim 1 wherein the laminate substrate includes a chip site and the predicted thermal warpage is applicable to the entire laminate substrate including the chip site.

5. The computer implemented method of claim 1 wherein the net stretching value in each region is calculated according to the equation

Δ
⁢

⁢

S
Net

⁡

(

x
,
y

)

=

Σ
⁢

⁢

weights
i

×
Δ
⁢

⁢

S

Layer
⁢

⁢

Pair
i

⁡

(

x
,
y

)

Σ
⁢

⁢

weights
i

where ΔS Layer Pair i (x,y) is a difference in stretching between a layer above the core and a corresponding layer below the core and the weights i is a value proportional to a squared distance of a layer i from a center of the core where i is from 1 to the number of corresponding laminate layer pairs.

6. The computer implemented method of claim 1 wherein the relative out-of-plane displacement, z′, is calculated according to the equation

∂
2

⁢

z
′

∂

y
2

+

∂
2

⁢

z
′

∂

x
2

≈

(

∑

i
=
1

#
⁢
Layers

⁢

weights
i

×

Metal

Layer
⁢

⁢
Pair

⁡

(

x
,
y

)

⁢

∑

i
=
1

#
⁢
Layers

⁢

weights

Assignees

• IBM

Inventors

• Call Anson J
• Khanna Vijayeshwar D
• Russell David J
• Tunga Krishna R

Classifications

• G06F2113/26

  Composites · CPC title

• G06F2119/08

  Thermal analysis or thermal optimisation · CPC title

• G06F17/50 Primary

  Physics · mapped topic

• G06F30/20 Primary

  Design optimisation, verification or simulation (optimisation, verification or simulation of circuit designs G06F30/30) · CPC title

• H05K1/0271 Primary

  Arrangements for reducing stress or warp in rigid printed circuit boards, e.g. caused by loads, vibrations or differences in thermal expansion · CPC title