CN1247982C - Six shaft mechanical performance measurer for micro samples - Google Patents

Abstract

The present invention relates to a six-axle mechanical property measuring device for tiny samples by aiming at that a traditional mechanical testing machine can not satisfy the testing requirements of the tiny samples, such as micro machines (MEMS), etc. The present invention comprises a precise six-axle numerical control table, a six-axle force testing sensor, a heating box and a computer control system, wherein the six-axle numerical control table is driven by a permanent magnet linear motor and five direct current motors. The device can finish testing the mechanical properties, the mechanical behaviors and the heating machine characteristics of the tiny samples. The device uses a PZT working table or an electromagnetic vibration exciter to match with a linear motor in a Z direction, and dynamic loading frequency from 10 to 500Hz can be realized. An optical opposite phase scattering method is adopted to measure the three-dimensional deformation of the inner parts of the surfaces and the left surfaces of the tiny samples directly so as to eliminate errors caused by the rigidity of the working table.

Description

A kind of six mechanical property measurement mechanisms that are used for tiny sampler

Technical field

The invention belongs to mechanical property micrometering amount technical field, be specifically related to a kind of six mechanical property measurement mechanisms that are used for tiny sampler.

Background technology

In order better to study manufacturing process, development of new MEMS device and the system of MEMS and to expand its application in industry member, need to understand mechanics and the physical characteristicss such as constitutive relation, coefficient of thermal expansion, yang type modulus, viscoelasticity and visco-plasticity of material under these process conditions, and the inefficacy that causes of the fracture strength of solder joint and encapsulating structure, fatigue (comprising heat fatigue, mechanical fatigue).Mechanical test usually is used to determine properties of materials and mechanical behavior thereof, but traditional mechanical test machine generally is by the feed screw nut or the system drive of surging, usually can produce the driving force of 500～100000N, be widely used in the part mechanical test in fields such as automobile, aviation.For small electron package structure, microelectronic component, the test mechanism of macroscopic view can not be applied to microscopic fields, and continuum theory is no longer valid, and size effect is more remarkable, and this testing machine is no longer suitable.Therefore, need the new method of testing of research, set up the new theory of testing, the formation feature under qualitative, quantitative examination different process (processing and the packaging technology) condition, for MEMS designs, technology provides parameters optimization, be used for instructing and improving process conditions and design parameter.

Because the MEMS device size is little, and is fine strip shape, and some be hard brittle material, traditional mechanical test machine, and first machine construction is big, is difficult to install on machine little MEMS sample like this; It two is that the measuring unit lack of resolution is to measure small power and distortion; It three is to lack that sample is aimed at and regulatory function.When sample is installed because bad alignment can cause the error of experimental result to strengthen, sometimes even cause the damage of sample.In order to satisfy above requirement, need six Micro-force sensor technology of research, and accurate six worktable technology, and relevant loading technique.For this reason, people such as Liu Sheng of U.S. Wayne State University (Wayne State University) developed the heat-machine testing machine of six inferior μ m orders of magnitude in 1999.The worktable that they adopt six direct current generators to drive constitutes the testing machine of six-freedom degree numerical control, and power and moment when adopting six force cells monitoring samples to install, eliminates the preload of little sample installation process as feedback information.Its precision of rectilinear motion is 0.1 μ m, and the rotational motion precision is 0.001 °.Also thermal fatigue test has increased warm change system to this device at encapsulating material, and range temperature changes-60 ℃～400 ℃, changes 1 ℃ of precision.And MEMS encapsulating materials such as scolder, filler have been carried out testing mechanical characteristic, and the differentiation of encapsulation (solder joint) structural failure crackle is studied.But because the worktable that drives with direct current generator and feed screw nut is as driver, so the frequency when having reversing of motion gap and torture test is on the low side.

Above-mentioned proving installation has adopted high-resolution six force cells and loading system at the little force measurement requirement of tiny sampler; And control six axial adjustment worktable, the predeformation that produces when eliminating the sample clamping by force feedback; And, introduced warm change control system for the hot machine characteristic of study sample.But two problems do not have to solve: one is owing to use direct current generator and the worktable of feed screw nut's driving, and the frequency when having reversing of motion gap and torture test is on the low side; It two is that measurement to sample distortion is secondhand by the displacement of worktable, and the rigidity error of worktable can cause the error of test result.

Summary of the invention

The purpose of this invention is to provide a kind of six mechanical property measurement mechanisms that are used for tiny sampler that can overcome above-mentioned defective; This measurement mechanism can be eliminated backlass, improves test frequency, its mechanical stiffness height, and can eliminate the error that the worktable rigidity causes.

A kind of six mechanical property measurement mechanisms that are used for tiny sampler provided by the invention, comprise computing machine, six Shaft and NC Machining Test worktable, six force cells, heating box and jaw, it is characterized in that: described six Shaft and NC Machining Test worktable are driven by a permanent-magnet linear motor and a direct current generator, wherein, the Ry worktable that rotates around Y-axis is assemblied in Z on worktable, Rz worktable around the rotation of Z axle is fixed on the Ry worktable by counter flange, Y is assemblied in X to worktable by flange and constitutes two-dimentional work bench on worktable, X to stationary table on base plate, the Rx stationary table of rotating around X-axis at Y on worktable, six force cell flanges are installed on the Rx worktable, and Z links to each other with base plate by accurate line slideway to worktable; One end of left and right jaw makes multidiameter shape flange, link to each other with six force cells and Rz worktable respectively, its other end is positioned at heating box, be used for fixing tested tiny sampler, the temperature of heating box is by computer control, and six Shaft and NC Machining Test worktable and six force cells link to each other with computing machine by digital signal processor respectively.

Above-mentioned measurement mechanism can be set up optics anti-phase scattering deformation measuring system and high frequency charger.The high frequency charger can be PZT worktable or electromagnetic exciter.

The present invention can be used for the high frequency mechanical property testing of MEMS device and encapsulation, can be implemented in six loadings and six power and torgue measurement under 25-250 ℃ the condition, comprise that one dimension loads and multidimensional loads simultaneously, mechanical and hot CYCLIC LOADING is tested, and the torture test under the high, medium and low frequency.Wherein the Z axle adopts the permanent-magnet linear motor to eliminate backlass fully, and its mechanical stiffness is 10 times of direct current generator, and the torture test frequency rises to 11Hz.

The present invention adopts PZT worktable or electromagnetic exciter can realize the loading frequency of 10～500Hz.The PZT worktable is mainly used in the precision measurement of tiny sampler, can realize the displacement resolution of 5nm; Electromagnetic exciter is mainly used in the high cycles fatigue test of sample, and the highest loading frequency can reach 500Hz, amplitude ± 5mm.Also can utilize optics anti-phase scattering method, directly measure in the tiny sampler face and 3 D deformation, replace the distortion of the displacement of worktable, to eliminate the error that the worktable rigidity causes as sample from face.

Description of drawings

Fig. 1 is a kind of structural representation that is used for six mechanical property measurement mechanisms of tiny sampler;

Fig. 2 is six worktable synoptic diagram;

Fig. 3 is the heating box synoptic diagram;

Fig. 4 is an optics anti-phase scattering deformation measuring system schematic diagram;

Fig. 5 is the structural representation of measurement mechanism control system;

Fig. 6 is small solder joint sample clamping synoptic diagram;

Fig. 7 is 5.5 * 10 for the solder joint of the sample of corresponding diagram 6 in room temperature, rate of strain ^-4Fatigue properties test under the condition of/s;

Fig. 7 (a) is the crack progress Damage Evolution; Fig. 7 (b) is cyclic softening/progressive damage; Fig. 7 (c) is for causing the crack propagation of solder joint failure;

Fig. 8 be in the microelectronics Packaging process typical filler in the viscoplasticity test result of different temperatures;

Fig. 9 is typical scolder 63Sn37Pb mechanical property testing result under different loading speed conditions;

Figure 10 is the test result of 63Sn37Pb solder creep.

Embodiment

Below in conjunction with drawings and Examples to further detailed explanation of the present invention.

As shown in Figure 1, this measurement mechanism comprises left jaw 11 and the right jaw 12 and the computer control system of the six Shaft and NC Machining Test closed- loop control worktable 1,2,3,4,5,6 that driven by a permanent-magnet linear motor and 5 direct current generators, six force cells 7 realizing small power and torgue measurement, heating box 8, clamping sample.For realizing accurate measurement, this device can also comprise in the measuring samples face/the optics anti-phase scattering deformation measuring system 9 of surface deformation; In order to realize high-frequency test, also can adopt high frequency charger 10.High frequency charger 10 can be piezoelectric ceramics worktable (being called for short the PZT worktable) 10.1 or electromagnetic exciter 10.2.

The structure of six Shaft and NC Machining Test worktable as shown in Figure 2.X is translation worktable to worktable 2 and Z to worktable 3 to worktable 1, Y, and is vertical mutually between the three.Rx worktable 4, Ry worktable 5 and Rz worktable 6 are respectively the worktable that rotates around X-axis, Y-axis and Z axle.5 axle systems that worktable 1,2,4,5,6 constitutes adopt the DC servo motor that can select Netec company for use to drive precise ball screw and gear reduction box, computer control system is by the controller (each controller can drive 3 DC servo motor) of two Nutec companies of serial ports control, utilize the photoelectric coded disk FEEDBACK CONTROL, realization is to the closed-loop control of above 5 direction of motion, straight-line displacement resolution can reach 0.1 μ m, and angular resolution can reach 0.001 °.In order to improve the loading frequency of torture test, Z adopts the linear motor driving of ACS company to motion, cooperates noncontact linear grating FEEDBACK CONTROL, and displacement accuracy can reach 0.1 μ m, and stroke reaches 100mm, and frequency response can reach 11Hz.Ry worktable 5 is assemblied in Z on worktable 3, Rz worktable 6 links together by counter flange 14 and Ry worktable 5, Y constitutes two-dimentional work bench with X to worktable 1 by flange 15 to worktable 2, Rx worktable 4 is assembled together to worktable 1,2 with X, Y, force cell 7 is installed on the Rx worktable by flange 16, on base plate 17, Z's X links to each other with base plate 17 by accurate line slideway 18 to worktable to stationary table.

Six force cells realizing small power and torgue measurement can be with six force cells of U.S. JR3 company, its range: Fx, Fy:18N, Fz:10N, Mx, My, Mz:1.4Nm; Power resolution: Fx, Fy:6mN, Fz:10mN, Mx, My:0.3mNm, Mz:0.4mNm.

As shown in Figure 3, heating box 8 is by computer control, its shell is made of stainless sheet steel, inner foundation uses the thick alumina layer 19 of 15mm as insulation course, resistance wire 20 is imbedded alumina layer, adopt accurate thermopair (ACEZ 328 Type K) 21 to measure, come the FEEDBACK CONTROL heating system, can realize 25 ℃～250 ℃ of heating-up temperature scopes, accuracy of temperature control can reach 1 ℃.When heating cabinet is installed, at first take off jaw, after being fixed, the window by heating cabinet is fixed on jaw on the worktable again.The window of heating box can be with 22 sealings of high quartz glass, to guarantee utilizing optics anti-phase scattering method directly to obtain the distortion of sample in the test process.

Two jaws 11,12 adopt low-expansion stainless steel material to make.One end of jaw 11 is made multidiameter shape flange, this end links to each other with six force cells 7, to increase area of dissipation, can prevent effectively that heat transferred is to sensor, jaw 12 links to each other with Rz worktable 6 (if carry out high-frequency test by multidiameter shape flange, need to use high frequency charger 10, at this moment jaw 12 links to each other with device 10, and 10 link to each other with Rz worktable 6).Sample 13 is not by fastening board (drawing among the figure), is fixed on two jaws with the screw lock of M3.

Optics anti-phase scattering deformation measuring system 9 as shown in Figure 4.By the Ar laser instrument 23 of a 160mw, wavelength is 488nm, through beam collimation device 24, through Transflective spectroscope 25, with the hot spot vertical irradiation of 100 μ m diameters on sample 13 surfaces, through the complex field f (x of sample reflection, y) phase place contains sample surfaces pattern h (x, information y).(x y) detects fourier transform lens 26 through one to complex field f, the ccd array sensor 27 at the focus place of lens, receive complex field not bright Hough diffracted intensity I (u, v), promptly there are relation of equal quantity I (u in the amplitude of Fourier transform and this diffracted intensity, v)=| F (u, v) | ²In addition, (u v) can obtain by the weakened phase restoring algorithm phase theta of Fourier transform.Then by inverse Fourier transform, just found complex field f (x, y), also promptly obtained sample surfaces little profile pattern h (x, y).Measuring process is as follows: computing machine 28 control loaded systems (as worktable or high frequency charger) motion, make sample produce distortion, distortion by optics anti-phase scattering deformation measuring system 9 record samples, utilize six force cell record magnitudes of load simultaneously, to realize test to the sample mechanical characteristic.

In order further to improve the test loading frequency, can use high frequency charger 10, it can be a PZT worktable 10.1, can realize accurate the loading, and displacement resolution can reach 5nm, and its open-loop response time, the closed loop response time was less than 50ms less than 20ms; Also can adopt electromagnetic exciter 10.2, under the excitation of signal generator 29, can produce and import the signal with frequently,, can realize frequency from 10～500Hz by adjusting amplifier current, amplitude from 0～± fatigue of 5mm loads.In the use jaw 12 is attached thereto, then high frequency charger 10 is linked to each other with worktable 6.Select according to different test requests during measurement, PZT worktable 10.1 is mainly used under precision, the small strain rate condition and tests, and electromagnetic exciter 10.2 is mainly used in the high-cycle fatigue test experiments of sample.

Small six fatigue tester control system comprise analog-and digital-two parts, mainly are to finish the accurate control to worktable, collection and storage, treatment of picture and the demonstration etc. of force signal.This patent adopts controlling schemes as shown in Figure 5, and control system realizes control and data acquisition to six Shaft and NC Machining Test worktable and six force cells by computing machine 28, digital signal processor (DSP).CPU carries out communication by serial ports and DSP1, controls two Nutec controllers that model is Micromatic-5, realizes the driving to above-mentioned 5 worktable, comprises X, Y, Rx, Ry, Rz; Communicate by letter with DSP2, DSP3 by two 16 I/O ports, controlling model respectively is the Acs linear electric motors controller of SB214, drive Z to linear electric motors, and realize data acquisition to the six-axis force sensor of JR3 company; Utilize the closed-loop control of parallel port EPP pattern realization, realize accurate the loading the PZT worktable; The process that transmits control signal D/A conversion 31 and gauge tap circuit 30 are realized the break-make of electromagnetic exciter, obtain periodic motion with signal generator input same frequency, its frequency can be adjustable continuously between 10-500Hz, amplitude ± 5mm is adjustable continuously, realizes that high frequency loads; Need adopt 9 pairs of sample distortion of optics anti-phase scattering deformation measuring system directly to measure for the accurate measurement of sample distortion.

Below be the performance parameter of these above-mentioned small six fatigue testers:

● X, Y are to two rectilinear motion parameters

Stroke: 100mm

Displacement resolution: 0.1 μ m

Translational speed: 0.25mm/s

Repetitive positioning accuracy: 1 μ m

Hysteresis error: 3.5 μ m

● Rx, Ry, three rotational motion parameters of Rz

Corner resolution: 0.001 °

● Z is to the rectilinear motion parameter

Stroke: 100mm

Driving force: 32N

Maximum movement speed: 1.5m/s

Peak acceleration: 10g

Bearing accuracy: 0.1 μ m

● six-axis force sensor

Range: Fx, Fy:18N, Fz:10N, Mx, My, Mz:1.4Nm

Power resolution: Fx, Fy:6mN, Fz:10mN, Mx, My:0.3mNm, Mz:0.4mNm

● the heating box temperature

Temperature range: 25～250 ℃

Temperature control precision: 1 ℃

● the PZT worktable

Stroke: 50 μ m

Displacement resolution: 5nm

Closed loop response frequency: 20Hz

Open-loop response frequency: 100Hz

● electromagnetic exciter

Amplitude: 0～± 5mm

Frequency 10～500Hz

● 3D transform optics back scattering phase method

Detection resolution 5-100nm

Sensing range: 100 μ m

● computer control system: Pentium III 933MHz, Windows98 system, Visual C++6.0

Adopt above-mentioned testing machine that tiny sampler is carried out experimental test, at first make tiny sampler 13 according to the standard model size, then with the sample clamping on jaw 11,12.By six movable workbench of reading FEEDBACK CONTROL 1,2,3,4,5,6 of six-axis force sensor 7, to eliminate the predeformation of sample clamping.Then, the mechanical characteristic experiment that just can be correlated with to tiny sampler is as stretching, compression, lax, creep, fatigue, CYCLIC LOADING, reversing and shearing experiment.In the experimentation, the motion of Control work platform can realize that the single shaft of six direction, multiaxis load simultaneously, magnitude of load is write down in the output that utilizes computing machine 28 to gather six-axis force sensor (7), the distortion of sample can obtain by dual mode: for the test of general precision, come the distortion of secondary indication sample by the displacement of worktable; For precision measurement, when the rigidity error of worktable can not be ignored, by the distortion of optics anti-phase scattering deformation measuring system 9 direct measuring samples, to eliminate the error that the worktable stiff problem causes.For experiments such as fatigure failures, in order to improve testing efficiency, can use 10 pairs of samples of high frequency charger to carry out CYCLIC LOADING, can realize the epipodium testing fatigue of 10-500Hz, wherein 10.2 high-cycle fatigues that are mainly used in sample are tested, and 10.1 are used for the accurate Experimental Mechanics characteristic test of tiny sampler.

Claims (6)

1, a kind of six mechanical property measurement mechanisms that are used for tiny sampler, comprise computing machine, six Shaft and NC Machining Test worktable, six force cells, heating box and jaw, it is characterized in that: described six Shaft and NC Machining Test worktable (1,2,3,4,5,6) drive by a permanent-magnet linear motor and 5 direct current generators, wherein, be assemblied in Z on worktable (3) around the Ry worktable (5) that Y-axis is rotated, Rz worktable (6) around the rotation of Z axle is fixed on the Ry worktable (5) by counter flange (14), Y is assemblied in X to worktable (2) by flange (15) and goes up the formation two-dimentional work bench to worktable (1), X is fixed on the base plate (17) to worktable (1), be fixed on Y on worktable (2) around the Rx worktable (4) that X-axis is rotated, six force cells (7) flanges (16) are installed on the Rx worktable (4), and Z links to each other with base plate (17) by accurate line slideway (18) to worktable (3); One end of left and right jaw (11,12) makes multidiameter shape flange, link to each other with six force cells (7) and Rz worktable (6) respectively, its other end is positioned at heating box (8), be used for fixing tested tiny sampler, the temperature of heating box (8) is by computing machine (28) control, and six Shaft and NC Machining Test worktable (1,2,3,4,5,6) and six force cells (7) link to each other with computing machine (28) by digital signal processor (33.1,33.2,33.3) respectively.

2, measurement mechanism according to claim 1, it is characterized in that: this measurement mechanism is provided with optics anti-phase scattering deformation measuring system (9), its structure is: laser instrument (23) emitted laser is through beam collimation device (24) and Transflective spectroscope (25), be radiated at the sample surface, its reflected light is to fourier transform lens (26), the focus place of these lens (26) is provided with ccd array sensor (27), and computing machine (28) links to each other with ccd array sensor (27) by image card (34).

3, measurement mechanism according to claim 1 and 2 is characterized in that: this measurement mechanism also comprises high frequency charger (10), and it is positioned between right jaw (12) and the Rz worktable (6), is controlled by computing machine (28).

4, measurement mechanism according to claim 3 is characterized in that: high frequency charger (10) is a piezoelectric ceramics worktable (10.1), and it links to each other with computing machine (28) by the parallel port.

5, measurement mechanism according to claim 3, it is characterized in that: high frequency charger (10) is an electromagnetic exciter (10.2), the control signal that computing machine (28) sends is through the break-make of D/A conversion (31) and gauge tap circuit (30) control electromagnetic exciter (10.2), signal generator (29) input signal is given electromagnetic exciter (10.2), realizes that high frequency loads.

6, measurement mechanism according to claim 3 is characterized in that: high frequency charger (10) comprises piezoelectric ceramics worktable (10.1) and electromagnetic exciter (10.2); Piezoelectric ceramics worktable (10.1) links to each other with computing machine (28) by the parallel port; The control signal that computing machine (28) sends is through the break-make of D/A conversion (31) and gauge tap circuit (30) control electromagnetic exciter (10.2), and signal generator (29) input signal is given electromagnetic exciter (10.2), realizes that high frequency loads.

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