Transcript
Page 1: Oblique-view Computed Tomography for 3D IC Package

This study has focused on the CUDA implementation to oblique-view CT(Computed Tomography) technique for non-destructive internal inspection of 3D IC chips. With 400 projected images from rotating phantom in an oblique direction, we executed 16 GUPS performance to reconstruct 5123 volume of phantom with NVIDIA Quadro K6000 GPU, showed that the GPU performed 100 times faster than the dual CPU processors in the CT reconstruction method.

I. Introduction of 3D IC Package

• 3D IC Package

Fig. 1. Multilayer chip

II. Chip-to-Chip Connection in 3D IC

• Chip-to-Chip Connection Techniques

(a) Conventional chip type (requirement: optical inspection)

(b) TSV packing chip type (requirement: 3D tomographic inspection)

TSV(Through Silicon Via) Packing

Fig. 2. Chip-to-Chip connection

- Long wire length- Pad area is needed

As advanced packing, offer size and performance.

Enable integration of several functional wafers

- Short wire length

- Packing size is smaller

III. 3D IC Inspection Method• CT Inspection System Based on X-ray

(d) close-to-focus(b) conventional (c) advanced(a) conical target detection scheme

Fig. 3. CT inspection system

!  Characteristics - Sample on table with rotating/tilting - Similiar with CBCT - Thin and slim wafer inspection

Enable oblique views at highest magnifications

* [Ref] http://www.qualitymag.com/articles/print/89082-x-ray-powers-up-complex-parts

III. 3D IC Inspection Method

• Nano CT Inspection in Oblique-view Geometry

Fig. 4. Schematic of Nano CT System

Nano-focus X-ray generator

Detector

Rotation table

Object(sample)

-  Open-type X-ray, FPD, rotational X-Y stage

-  Acquisition step

(1) Sample rotate in X-Y state.

(2) X-ray projection images are obtained

from various directions.

(3) X-ray projection images are transferred to the

host memory via an image grabber board.

(4) 3D image is obtained using GPU.

!  CT system : off-centered geometry

Tilt angle

III. 3D IC Inspection Method

Fig. 5. Off-centered geometry analysis

Fig. 6. Reconstructed image

Back-projection

IV. Experimental Results• Processing Hardware for 3D Volume Reconstruction

Fig. 7. Experimental hardware for image reconstruction

!  OS : Linux 3.2.0, 64 bits.

!  CPU : Intel Xeon X5520, 2.27GHz x 2

!  Memory : 48 GB

!  GPU : Quadro K6000

- CUDA core: 2880

- CUDA clock : 902Mhz

- Global memory size: 12288 MB

!  CUDA : Capability: 3.5

- Runtime Driver: 6.5

GPU

CPU CPU

FPGA

IV. Experimental Results

• Simulation of Shepp-Logan Phantom

Fig. 8. Projection images generated by forward projection

512 pixels

512 pixels

!  Input: 512x512, 400 projections, tilt angle: 0o

!  Output : 512x512x512, tilt angle: 0o

Fig. 9. Output by back- projection

(a) CPU (b) GPU

IV. Experimental Results

• Performance Comparison for Back-projection Processing

!  Correlation coefficient

Table 3. Correlation coefficient between reference and output

Table 1. Reconstruction performance by CPU

Input OutputRead/Write(s)

PreFilter(s)

RampFilter(s)

Back-projec=on(s)

TotalTime(s)

GUPS(BP)

256x256x400 256x256x256 0.15 0.19 1.58 51.21 53.13 0.13

512x512x400 512x512x512 4.88 0.69 5.85 426.38 437.80 0.13

Input OutputRead/Write(s)

PreFilter(s)

RampFilter(s)

Back-projec=on(s)

TotalTime(s)

GUPS(BP)

256x256x400 256x256x256 0.18 0.16 0.42 0.56 1.32 11.98

512x512x400 512x512x512 5.02 0.60 0.79 3.27 9.68 16.41

Table 2. Reconstruction performance by GPU

Reference(A) Output(B)Tiltangle

Correla=oncoefficient(r)

CPUprocessing

GPUprocessing

256x256x256 256x256x256

0o 0.982 0.977

10o 0.979 0.973

20o 0.969 0.963

30o 0.950 0.944

512x512x512 512x512x512

0o 0.984 0.979

10o 0.981 0.978

20o 0.970 0.964

30o 0.950 0.944

V. Conclusion

• Summary & Further Research!  Planning scheme to inspect TSV defect using

off-centered geometry CT - GPU-based back-projection method to enhance the speed of reconstruction. !  In 512x512x512 volume, back-projection time

was measured. - CPU case : 426.38 sec - GPU case : 3.27 sec - GPU is faster than CPU over 100 times!  In near future, the more adaptable filtering

scheme by missing wedge effect will be used in order to achieve wider adoption in inspection process.

Oblique-view Computed Tomography for 3D IC Package Inspection Using CUDA

Korea Institute of Industrial Technology1*, Korea Electronics and Telecommunication Research Institute2, SEC Co., LTD3Kyung-Chan Jin 1*, Yoon-Ho Song 2, Jung-Seok Yoon 3

• Reconstruction by Back-projection

Fig. 10. Reconstructed TSV image

ACKNOWLEDGEMENT:WewouldliketoacknowledgethefinancialsupportfromtheR&DConvergenceProgramofMSIP(MinistryofScience,ICTandFuturePlanning)andNST(NaHonalResearchCouncilofScience&Technology)ofRepublicofKorea(GrantB551179-12-04-00)andTSVphantomimageshavebeenkindlyprovidedcourtesybySECCo.,Ltd,SouthKorea. *Correspondingauthor:Kyung-ChanJin[E-mail:[email protected],TEL:+82-41-589-8439]

contact name

Kyung-Chan Jin: [email protected]

P6336

category: comPuter Vision & machine Vision - cVmV07

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