(12) United States Patent (10) Patent N0.: US 8,794,072 B2

USOO8794072B2

(12) United States Patent (10) Patent N0.: US 8,794,072 B2 Kessler et a1. (45) Date of Patent: Aug. 5, 2014

(54) SCANNING ACOUSTIC MICROSCOPE WITH 4,503,708 A * 3/1985 Kino et a1. .................... .. 73/628 PROFILOMETER FUNCTION 4,513,384 A * 4/1985 Rosencwaig .... .. 702/170

4,768,155 A * 8/1988 Takishita et al. 702/39 4,781,067 A * 11/1988 Cichanski . . . . . . . . . . . . . .. 73/620

(75) Inventors: Lawrence W. Kessler, Buffalo Grove, IL 5,029,476 A * 7/1991 Metala et al‘ N 73/620 (Us); Michael G- OraveCZ, Lombard, IL 5,241,287 A * 8/1993 Jen ................... .. .. 333/143 (US); Zhiqi Guo, Palatine, IL (US) 5,331,855 A * 7/1994 Takashita et a1. .. 73/602

5,475,613 A * 12/1995 Itoga et a1. . . . . . . . . . . . . .. 702/39

(73) Assignee: Sonoscan, Inc., Elk Grove Village, IL 5,602,336 A : 2/1997 TakeuChl et al' 73/624 Us) 5,641,706 A 6/1997 Tjaden et al. . . . . . . . . . .. 438/20

( 6,880,387 B2* 4/2005 Kessler et al. . . . . . . . . .. 73/105

_ _ _ _ _ 6,890,302 B2 * 5/2005 Oravecz et a1. .. 600/443

( * ) Notice: SubJeCI to any disclaimer, the term of this 6,981,417 B1 * 1/2006 OravecZ . . . . . . . . . . . . .. 73/619

patent is extended or adjusted under 35 7,132,617 B2* 11/2006 Lee et a1. ..... .. 219/109 U_S_C_ 154(b) by 697 day, 2003/0089171 A1* 5/2003 Kene?ck et a1. 73/597

2007/0180914 A1 * 8/2007 Kessler ......................... .. 73/607

(21) APP1-N0-I 12/2441460 OTHER PUBLICATIONS

(22) Filed: Oct, 2, 2008 DiStefano et 31., “Acoustic Contour Mapping”, IBM Technical Dis closure Bulletin, vol. 25, Issue 10, pp. 5103-5108, Mar. 1983*

(65) Prior Publication Data * cited by examiner

US 2009/0095086 A1 Apr. 16, 2009 Primary Examiner * Peter Macchiarolo

Related U-s- Application Data Assistant Examiner * Rose M Miller

(60) Provisional application No. 60/979,021, ?led on Oct. (74) Attorney) Agent) 0" Firm * MCCFaCken & Frank LLC 10, 2007, provisional application No. 61/038,460, ?led on Mar. 21, 2008. (57) ABSTRACT

A seaming acoustic microscope, includes an ultrasonic trans (51) Int- Cl- ducer, a data storage memory, a display, a scanner assembly,

G01N29/06 (2006-01) and a controller. The controller is adapted to cause the motor (52) U-s- CI- to move the transducer along a path With respect to a sample,

USPC ............................................. .. 73/634; 73/633 and cause the ultrasonic transducer to emit a pulse of acoustic

(58) Field of Classi?cation Search energy towards the sample at each point in a plurality of USPC .................................................. .. 73/ 633, 634 points along the path. In addition, the controller is adapted to See application ?le for complete search history. cause the ultrasonic transducer to receive a set of re?ection

signals that correspond to each of the pulses emitted there (56) References Cited from. The sets of re?ection signals are used to generate an

US. PATENT DOCUMENTS image of a pro?le of the sample and an image representative of acoustic impedance features in the interior of the sample. The image of the pro?le of the sample shows a variation in

DEPTH

GATE SELECTION

DETECTOR

SIGNAL SIGNAL 1 N

SIGMA AMPLITUDE PEAK

DETECTION DATA

238 1

AMPLITUDE PEAK

DETECTION ACQUISITION ALGORITHM

2,937,522 A * 5/1960 McGaughey ................. .. 73/633 _ 3,792,613 A * 2/1974 Couture ,,,,,,,, u 73/629 height across a surface ofthe sample. 4,021,771 A * 5/1977 Collins et a1. .... .. 367/8

4,455,872 A * 6/1984 Kossoffet a1. ................ .. 73/618 22 Claims, 18 Drawing Sheets

11 PHI

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TRIGGER——_I r 210 V f— 2“ comm" WAVEFORM

ZAXIS 108‘ l l ACQUISITIOFN d ACTUATOR “'“I‘ " 226

PULSERI r 218 RECEIVER PROFILE

ECHO TIME WAVEFORM m, —I DETECTION M X l V AXIS 224 ALGORITHM

ACTUATOR SIGN“ WAVEFDRMa momma DISPLAY

INTERNAL IMAGE N DATA

INTERNAL IMAGE 1 DATA

142 ’— COMPUTER NETWORK OR OTHER STORAGE

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CONTROLLER <-—--—-—--> ROLL MOTOR

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US. Patent Au .5 2014 Sheet 11 0f 18


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Profile Tilt Adjust

- 3-Pt-PIane Based Tilt Adjust

I PM I | P12 II I Pt-3 II TiItAdjust

Row: I II I II I II Column: I II I II I II Und"

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FIG. 12 F m

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POSlTION ( 704 PIXEL TRIGGER

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END RASTER SCAN

SURFACE CURVATU '

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CALCULATE SURFACE CURVATURE

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GET INPUT OF BOUNDS

SURFACE CURVATU '

OUTSIDE BOUNDS?

728

732 r 734 REJECT END

ACCEPT END

US. Patent IAug.5,2014 Sheetl60f18

FIG. 12A

738

AMPLITUDE PEAK ACQUISITION BEGINS

REFLECTION AND/OR

i r' 740 TRANSMISSION ECHO RECEIVED

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AMF’LITUDE PEAK ACQUISITION ENDS

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US. Patent Aug. 5,2014 Sheet 18 0f 18 US 8,794,072 B2

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GATHER PROFILE AND INTERNAL DATA

REQUENCY DOMAI REPRESENTATION?

GET USER SELECTED DATA

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FOURIER TRANSFORM WITH USER DATA

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DISPLAY FREQUENCY DOMAIN SIGNAL

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TIME DOMAIN REPRESENTATION?

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DISPLAY PROFILE?

GENERATE PROFILE AND DISPLAY

END

US 8,794,072 B2 1

SCANNING ACOUSTIC MICROSCOPE WITH PROFILOMETER FUNCTION

CROSS-REFERENCE TO RELATED APPLICATION

The content of US. provisional application Ser. No. 60/979,021, ?led Oct. 10, 2007 and 61/038,460, ?led Mar. 21, 2008 is incorporated by reference into this application as if fully set forth herein. The following US patents and applica tions are assigned to Sonoscan, and generally relate to various aspects of scanning acoustic microscopy: US. Pat. Nos. 4,518,992, 4,781,067, 4,866,986, 5,351,544, 5,684,252, 6,357,136, 6,460,414, 6,880,387, 6,890,302, 6,895,820, 6,981,417, and 7,000,475, as well as Ser. No. 11/626,177 ?led Jan. 23, 2007. All such patents and applications are incorpo rated by reference as if fully set forth herein.

DESCRIPTION OF RELATED ART

As is well known in the art a scanning acoustic microscope typically comprises a transducer which is driven by voltage pulses which may have amplitudes of, for example, 100 volts or more and are typically in the frequency range of tens of megahertz to 100 megahertz or higher.

The pulsed acoustic beam penetrates the target, which may be an IC package, for example. A fraction of the energy passes through the target, and the remainder is absorbed, scattered, or re?ected. In many applications su?icient energy is returned to the transducer (after a delay) to be sensed. Acoustic energy is almost totally re?ected by an air gap. Thus acoustic micro scopes have proven to be extremely useful in locating dis bonds (air gaps) between internal layers of a device such as an IC package.

The return signal is an echo composed of a range of fre quencies centered around the transducer’ s resonant fre quency. As described further in US. Pat. No. 6,981 ,417, the return signal is commonly known as the “A” waveform or “A-scan”, and in practice contains a great deal of information about acoustic impedance perturbations or features in the body of the IC package. As is well known in the art, a time domain signal received

by the acoustic microscope during a scanning session is con ventionally gated by a gating process. During the gating pro cess, a gate isolates a pixel-representative signal segment associated with a single pixel.

Gating of the signal permits a user to examine any chosen level in the target simply by selecting an appropriate delay time for the gate. For example, a single pixel segment might be captured with a gate 100 nanoseconds wide set at a delay of 384-484 nanoseconds. If a deeper level were to be visual ized, a longer delay would be employed.

SUMMARY OF THE DISCLOSURE

In accordance with the invention, there is provided a scan ning acoustic microscope capable of collecting and display ing any pro?le image of a sample including a surface pro?le, an internal pro?le or any combination of the two.

In accordance with another aspect of the invention, the scanning acoustic microscope may also be capable of simul taneously collecting and displaying an internal acoustic image of a sample.

In accordance with yet another aspect of the invention, the scanning acoustic microscope may be con?gured to simulta neously display a surface pro?le, a time domain signal rep

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2 resentation, a frequency domain signal representation, or any representation of features on or within a sample.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an acoustic imaging microscope.

FIG. 2 is a schematic illustration of an alternative acoustic imaging microscope.

FIGS. 3A and 3B illustrates alternative transducer assem blies which may be implemented in certain applications of the present invention.

FIG. 4A is an illustration of a pro?le scan of an integrated chip useful in understanding an aspect of the present inven tion.

FIG. 4B is a 3-dimensional illustration of an integrated chip.

FIG. 5A illustrates a side view of an ultrasonic pulse that is directed towards a tilted part.

FIG. 5B is a schematic diagram showing how an exemplary tilt ?xture can be rotated about two different axes.

FIG. 5C is an annotated perspective view of an exemplary tilt ?xture shown with exemplary roll and pitch axes.

FIG. 6 is a ?owchart showing the steps of manually adjust ing a tilt ?xture.

FIG. 7 is a schematic block diagram of a system that allows a scanning acoustic microscope to perform tilt adjustment measurements under automatic control.

FIG. 8 is a normalized pro?le scan of the IC illustrated in FIG. 4A.

FIG. 9 is an illustration of a pro?le tilt adjust screen used to manually normalize a pro?le image.

FIGS. 10A and 10B is an illustration of excessive warpage of a part.

FIG. 11 illustrates a graphical user interface allowing a user to specify warpage information.

FIG. 12 is a ?owchart that shows program steps that are followed to allow a scanning acoustic microscope to collect acoustic pro?le information.

FIG. 12A is a ?ow chart used in conjunction with FIG. 12 to allow a scanning acoustic microscope to simultaneously collect internal and pro?le acoustic information.

FIG. 13A-13C is an illustration of a pro?le image, time domain image, and frequency domain image capable of being displayed simultaneously.

FIG. 14 is a ?ow chart illustrating how a user can cause visual indication of surface pro?le data to be simultaneously displayed with a time domain signal representation and/or a frequency domain signal representation.

DETAILED DESCRIPTION

FIG. 1 illustrates in highly schematic form an acoustic imaging microscope, shown as being adapted to inspect a sample, for example, an integrated circuit (“IC”) package 94 submerged in a coupling medium 96. Although an IC is used in the example, the sample may be any of a variety of tangible objects and is not restricted to an IC. A sample may be, for example, a ceramic plate, a diamond, a medical device, a machine plate, or an electrical component such as a capacitor or a transistor. A pulser 98, under the control of a motion controller 100 excites a transducer 102 to generate a pulsed ultrasonic probe 104, typically at frequencies ranging from 10 MHz or lower to 230 MHz or higher. The transducer 102 is scanned in X, Y, and Z coordinates by an X-Y-Z stage 106 through an X-Y-Z stage driver 108 under the control of motion controller 100.

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(12) United States Patent (10) Patent N0.: US 8,794,072 B2