Testing apparatus and testing method thereof

A testing apparatus including a testing platform, a loading device, a testing-signal generating device, a sound sensing device, a control unit, and an unloading device is disclosed. The loading device is configured to load a plurality of under-test devices to the testing platform. The testing-signal generating device is configured to generate at least one testing signal. The plurality of under-test devices receives the at least one testing signal and produces at least one testing sound-according to the at least one testing signal. The sound sensing device is configured to receive the at least one testing sound. The control unit controls the unloading device to unload the plurality of under-test devices from the testing platform and controls the unloading device to categorize the plurality of under-test devices into a plurality of groups according to the at least one testing sound received by the sound sensing device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a testing apparatus and a testing method thereof, and more particularly, to a testing apparatus and a testing method thereof capable of increasing testing efficiency and quality.

2. Description of the Prior Art

MEMS sound transducers are typically manufactured in wafer form in a semiconductor manufacturing process. After the semiconductor manufacturing process, the wafer is separated into individual MEMS die in a singular/sawing process and then assembled into a protective package structure in a packaging process.

Test is the process of attempting to sort defective products from non-defective ones. Rapid and accurate acoustic testing of MEMS sound transducers is of continued interest to manufacturers. However, the MEMS sound transducers are normally tested manually, which can bring various challenges and costs time, money and effort. Manual testing would limit the number of MEMS sound transducers that could be tested at one time. During testing, the MEMS sound transducer is attached to a test board and placed next to a microphone inside an acoustical chamber. It is difficult to transport between a position outside the acoustical chamber in an exposed state and a second position inside the acoustical chamber in a shielded state stably and rapidly. Sound-proof problems exist in manual testing approach as well. The distance between the MEMS sound transducer and the microphone is calibrated/adjusted manually each time, which reduces accuracy.

Therefore, there is still room for improvement when it comes to acoustical testing of MEMS sound transducers.

SUMMARY OF THE INVENTION

It is therefore a primary objective of the present invention to provide a testing apparatus and a testing method thereof capable of increasing testing efficiency and quality.

An embodiment of the present invention provides a testing apparatus, comprising a testing platform; a loading device, configured to load a plurality of under-test devices to the testing platform; a testing-signal generating device, configured to generate at least one testing signal, wherein the plurality of under-test devices receives the at least one testing signal and produces at least one testing sound according to the at least one testing signal; a sound sensing device, configured to receive the at least one testing sound; a control unit; and an unloading device, wherein the control unit controls the unloading device to unload the plurality of under-test devices from the testing platform and controls the unloading device to categorize the plurality of under-test devices into a plurality of groups according to the at least one testing sound received by the sound sensing device.

Another embodiment of the present invention provides a testing method, comprising loading a plurality of under-test devices to the testing platform; generating at least one testing signal; the plurality of under-test devices receiving the at least one testing signal and producing at least one testing sound according to the at least one testing signal; and categorizing the plurality of under-test devices into a plurality of groups according to the at least one testing sound received by a sound sensing device.

Another embodiment of the present invention provides a testing method, comprising generating a plurality of testing signals, wherein the plurality of testing signals has a plurality of tones; delivering the plurality of testing signals with the plurality of tones to the plurality of under-test devices; the plurality of under-test devices producing a testing sound according to the plurality of testing signals; and categorizing the plurality of under-test devices into a plurality of groups according to a testing sound according to the plurality of testing signals with the plurality of tones.

DETAILED DESCRIPTION

A testing method disclosed in the present application makes use of the conventional semiconductor testing process for mass production to ensure high reliability and achieve high throughput. However, compared to the conventional semiconductor testing process, microphone(s) is/are disposed in a testing apparatus of the present application since the present application aims to perform (final) test on (semiconductor packaged) speakers. In addition, to improve testing quality, the testing apparatus of the present application further includes a sealing component to prevent air pressure changes of a back/second sub-chamber of a speaker from interfering with air pressure changes of a front/first sub-chamber of the speaker during testing.

FIG. 1is a schematic diagram of an acoustic testing system10according to an embodiment of the present invention. The acoustic testing system10includes under-test devices DUT1and a testing apparatus110. The testing apparatus110is similar to a conventional handler. As known by the art, the handler is usually used for final test on manufactured semiconductor devices for mass production. As a handler, the testing apparatus110may include sockets111, a testing platform112, a loading device113, a testing-signal generating device114, a tester116, an unloading device117, and a control unit119. High-volume testing is automated with the testing apparatus110.

Different from the traditional handler for final test of semiconductor devices which do not produce sound, the testing apparatus110, for acoustic testing, further comprises sound sensing device(s) (e.g., a sound sensing device315inFIG. 3), which is for final testing of sound producing devices manufactured by semiconductor process, especially for mass production.

The control unit119may be a controller or controlling circuit, which may be realized/implemented by processing circuit(s) (e.g., CPU (central processing unit), MCU (microcontroller unit) or a controller), logic or digital circuit(s), or ASIC (application specific integrated circuit), which is not limited thereto. As long as the control unit119can be programmed to execute certain controlling program, requirement of the control unit119is satisfied.

The loading device113is configured to move the under-test devices DUT1from a tray/carrier and load the under-test devices DUT1onto the testing platform112. The loading device113may be robotic arm(s) to perform automatic actions of picking and placing of the under-test devices DUT1, and thus may be implemented by a loader of the conventional semiconductor testing apparatus.

The testing-signal generating device114is configured to generate testing signal(s) (such as DC voltage(s) Vdc or input signal(s) Sn16inFIG. 16). After the under-test devices DUT1are placed within the testing platform112by the loading device113, each of the under-test devices DUT1may receive the testing signal(s) and then produce a testing sound (such as a testing sound TS16inFIG. 16) according to the testing signal(s).

The sound sensing device(s) mount on the testing platform112are configured to receive the testing sound(s). Each sound sensing device may be implemented by a microphone.

The unloading device117is configured to remove the under-test devices DUT1from the testing platform112. The unloading device117may be robotic arm(s), and thus may be implemented by an unloader of the conventional semiconductor testing apparatus.

The control unit119controls the unloading device117to unload the under-test devices DUT1from the testing platform112and controls the unloading device117to categorize the under-test devices DUT1into groups according to the testing sounds, which are produced from the under-test devices DUT1and received by the sound sensing device(s). For example, the testing sound may be analyzed (by the tester116) to determine the performance of the under-test device DUT1corresponding to the testing sound. The control unit119may then notify the unloading device117which bin/tray the under-test device DUT1would be assigned to according to the results of the test/analysis. If the testing sound satisfies certain requirement(s), the under-test device DUT1is categorized into a passing group or a first class group. Otherwise, the under-test device DUT1is categorized into a failed group or other class group.

In a word, the testing apparatus110makes use of the conventional semiconductor testing apparatus for mass production to ensure high reliability and achieve high throughput. In addition, the sound sensing device(s) of the testing apparatus110facilitates acoustic test on the under-test device DUT1.

The sockets111disposed (in a kit/socket board111bwith pogo pins) on the testing platform112of the testing apparatus110may be designed in a sophisticated approach according to the structure of the under-test device DUT1to improve testing quality and/or enhance the quality of the testing sound being generated.

Specifically, different from traditional sockets on the handler, the socket of the present application may further comprise a sealing component. The sealing component is configured to isolate a first chamber from a second chamber formed within the under-test device, so as to achieve better testing sound quality.

For example,FIG. 2is a schematic diagram of an under-test device DUT2according to an embodiment of the present invention.FIG. 3is a schematic diagram of a socket311, the sound sensing device315, and the under-test device DUT2shown inFIG. 2in an exploded view according to an embodiment of the present invention.FIG. 4is a schematic diagram illustrating the socket311, the sound sensing device315, and the under-test device DUT2when the socket311is open/exposed.FIG. 5is a schematic diagram illustrating the socket311, the sound sensing device315, and the under-test device DUT2when the socket311is closed/shielded.FIG. 6is a schematic diagram of the socket311and the sound sensing device315.

FIG. 2aillustrates a view of the under-test device DUT2.FIG. 2billustrates a cross-sectional view taken along a cross-sectional plane CSP2shown inFIG. 2a. As shown inFIG. 2, the under-test device DUT2may include a base210, a chip220, a cap230and a chamber CB. The under-test device DUT2may have a package structure similar to that disclosed in U.S. application Ser. No. 16/699,078, which is incorporated herein by reference.

The chip220may include a membrane222and an actuator224(which may be similar to that disclosed in U.S. application Ser. No. 16/920,384 or Ser. No. 16/699,078, which are incorporated herein by reference). The membrane222, which is configured to produce a testing sound (by, for example, generating air pulses), may partition the chamber CB into a front/first sub-chamber CB1and a back/second sub-chamber CB2. The front/first sub-chamber CB1is situated between the membrane222and the cap230; the back/second sub-chamber CB2is situated between the membrane222and the base210.

The cap230of the under-test device DUT2may have a sound outlet opening S02connected to the front/first sub-chamber CB1, such that the testing sound generated by the membrane222may propagate outwards through the sound outlet opening S02. The sound outlet opening S02may be situated on the upper side of the chip120and may face the membrane222(parallel to the upper side). Therefore, the under-test device DUT2may be classified into a top firing sound producing device. In other words, top firing refers to a package structure where the sound outlet opening is formed on a top structure/plate of the cap230, as shown inFIG. 2, and the top structure/plate of the cap230is (substantially) parallel to the membrane222.

The base210of the under-test device DUT2may have back opening(s) B02connected to the back/second sub-chamber CB2so as to, for example, allow air to flow in/out freely, and/or bonding pad(s) BP3disposed on the outermost side of the base210. The size of the back opening B02is less than or equal to the sound outlet opening S02. The bonding pad(s) BP3may be electrically connected to the chip220through trace(s)/wire(s), such that the actuator224of the chip220is able to receive signal(s) such as the testing signal(s) from outside.

FIG. 4andFIG. 5illustrate the operating principle of the socket311. The socket311may include a socket cover311C and a socket base311B. The socket base311B may be mounted/fixed on the testing platform112. After the loading device113takes the under-test device DUT2and puts the under-test device DUT2into the socket311as shown inFIG. 4, the socket cover311C may exert a moderate force downwards to the top of the under-test device DUT2and/or the top of the socket base311B to make the socket cover311C come into contact with the under-test device DUT2and/or the socket base311B as shown inFIG. 5. The under-test device DUT2may be thus inserted between the socket cover311C and the socket base311B for fast automated (final) test.

As shown inFIG. 3, the socket cover311C may include socket cover components311C1-311C3, (springy) pogo pins311PGP, and/or a printed circuit board311PCB. The socket cover components311C1-311C3are individual parts being assembled to fix/house the printed circuit board311PCB and the pogo pins311PGP.

During testing, the (open/exposed) socket base311B is closed/shielded with the socket cover311C as shown inFIG. 5. The bonding pad(s) BP3of the under-test device DUT2may connect to the printed circuit board311PCB through the pogo pins311PGP (or other pressure-type connector(s) in other embodiments), and the testing-signal generating device114may be connected to the printed circuit board311PCB. As a result, the testing signal(s) is transmitted from the testing-signal generating device114to the under-test device DUT2, and the under-test device DUT2may produce the testing sound downwards according to the testing signal(s).

To expel air from the back/second sub-chamber CB2to the outside, the socket cover components311C1-311C3and the printed circuit board311PCB have openings311C1h-311C3hand311PCBh respectively. As shown inFIG. 5, the openings311C1h-311C3hand311PCBh of the socket311are designed according to the distribution of the back opening(s) B02of the under-test device DUT2so as to, for example, allow air to flow in/out freely. Take the socket cover component311C3as an example: The area of the opening311C3his larger than or equal to the distribution area of the back opening(s) B02, which may be distributed in the central region of the base210of the under-test device DUT2. The opening311C3hoverlaps all the back opening(s) B02.

As shown inFIG. 3, the socket base311B may include socket base components311B1-311B2, a sealing component311SG, silicone bars311SB and/or a silicone ring311SG. The socket base components311B1-311B2and the socket board111bare individual parts being assembled to fix/house the sealing component311SG, the silicone bars311SB, the silicone ring311SG, and the sound sensing device315. For example, the area/perimeter/contour of an opening311B1hof the socket base component311B1is similar to (is the same as or matches) the area/perimeter/contour of the under-test device DUT2such that the under-test device DUT2may be fixed or stuck in the opening311B1h.

To transmit the testing sound from the sound outlet opening S02of the under-test device DUT2, the socket base component311B2and the sealing component311SG have openings311B2hand311SGh respectively. As shown inFIG. 5, the openings311B2hand311SGh of the socket311are designed according to the size of the sound outlet opening S02of the under-test device DUT2so as to, for example, output the testing sound to the sound sensing device315. Take the sealing component311SG as an example: The area of the opening311SGh is larger than or equal to the area of the sound outlet opening S02to avoid the sealing component311SG from blocking/covering the sound outlet opening S02. The opening311SGh overlaps the sound outlet opening S02. The geometric center of the sound outlet opening S02is roughly aligned to the geometric center of the opening311SGh of the sealing component311SG or the geometric center of a receiving surface315rof the sound sensing device315.

As shown inFIG. 5, the socket base components311B1-311B2, the sealing component311SG, and the silicone ring311SG erect barriers to prevent noises to seep through and confine the testing sound to a closed space enclosed by the socket base components311B1-311B2, the sealing component311SG, and the sound sensing device315.

More specifically, the sealing component311SG (serving as a sealing gasket) of the socket311is configured to isolate the front/first sub-chamber CB1of the under-test device DUT2from the back/second sub-chamber CB2of the under-test device DUT2as shown inFIG. 5when the under-test device DUT2, which has been shuttled into the testing platform112by the loading device113, produces the testing sound according to the testing signal(s). Hence, when the membrane222of the under-test device DUT2vibrates to cause slight changes in air pressure, air pressure changes of the back/second sub-chamber CB2would not interfere with those of the front/first sub-chamber CB1. The air pressure changes of the front/first sub-chamber CB1travel as waves through the openings311B1h-311B2hand311SGh of the socket base311B and are detected/measured by the sound sensing device315.

The sealing component311SG may be made from a material that is to some degree yielding such that the sealing component311SG is able to deform, to tightly fill the space which the sealing component311SG is designed for, and/or to seal the (slightly irregular) gap among the socket base components311B1-311B2and the under-test device DUT2. The sealing component311SG may be made from silicone; alternatively, the sealing component311SG may be made from paper, rubber, metal, cork, felt, neoprene, nitrile rubber, fiberglass, polytetrafluoroethylene (known as PTFE or Teflon) or a plastic polymer (such as polychlorotrifluoroethylene). The hardness of the sealing component311SG may be 20 N/mm2(newtons per square millimeter).

In a word, the socket base311B of the socket311has the openings311B1h-311B2hand311SGh for the testing sound from the under-test device DUT2to pass through and travel outwards to the sound sensing device315. The sealing component311SG (under compression) prevents air leakage from the back/second sub-chamber CB2and/or into the front/first sub-chamber CB1during testing, such that the air pressure changes of the back/second sub-chamber CB2would propagate across the openings311C1h-311C3hand311PCBh of the socket cover311C of the socket311without interfering with the air pressure changes of the front/first sub-chamber CB1. These improve testing quality and/or enhance the quality of the testing sound being generated.

The structure of the socket311may vary with the structure of the under-test device DUT2. For example,FIG. 7is a schematic diagram of an under-test device DUT7according to an embodiment of the present invention.FIG. 8is a schematic diagram of a socket811, the sound sensing device315, and the under-test device DUT7shown inFIG. 7in an exploded view according to an embodiment of the present invention.FIG. 9is a schematic diagram illustrating the socket811, the sound sensing device315, and the under-test device DUT7when the socket811is open/exposed.FIG. 10is a schematic diagram illustrating the socket811, the sound sensing device315, and the under-test device DUT7when the socket811is closed/shielded.FIG. 11-FIG. 13are schematic diagrams of the socket811and the sound sensing device315.

FIG. 7aillustrates a view of the under-test device DUT2.FIG. 7billustrates a cross-sectional view taken along a cross-sectional plane CSP7shown inFIG. 7a. Compared to the sound outlet opening S02of the cap230of the under-test device DUT2shown inFIG. 2, a sound outlet opening S07of a cap730of the under-test device DUT7shown inFIG. 7may be situated on the lateral side of the chip120(perpendicular to the membrane222of the chip220). Therefore, the under-test device DUT7may be classified into a side firing sound producing device. In other words, side firing refers to a package structure where the sound outlet opening is formed on a side wall of the cap730, as shown inFIG. 7, and the side wall of the cap730is (substantially) perpendicular to the membrane222. The under-test device DUT7may have a package structure similar to that disclosed in U.S. application Ser. No. 17/348,773, which is incorporated herein by reference.

As shown inFIG. 8, the socket811may include a socket cover811C and a socket base811B. Compared to the socket cover311C shown inFIG. 3, the socket cover811C shown inFIG. 8may include socket cover components811C1-811C4, and/or a sealing component811SG apart from the (springy) pogo pins311PGP, and/or the printed circuit board311PCB.

To expel air from the back/second sub-chamber CB2to the outside, the socket cover components811C1-811C3, the sealing component811SG, and the printed circuit board311PCB have openings811C1h-811C3h,811SGh and311PCBh respectively. As shown inFIG. 10, the openings811C1h-811C3h,811SGh and311PCBh of the socket811are designed according to the distribution of the back opening(s) B02of the under-test device DUT7so as to, for example, allow air to flow in/out freely. Take the sealing component811SG as an example: The area of the opening811SGh is larger than or equal to the distribution area of the back opening(s) B02. The opening811SGh overlaps all the back opening(s) B02.

Compared to the socket base311B shown inFIG. 3, the socket base811B shown inFIG. 7may include socket base components811B1-811B2apart from the silicone ring311SG. As shown inFIG. 12, which illustrates a bottom view of the socket base component811B1and the under-test device DUT7, the socket base component811B1has not only an opening811B1hbut also a groove811B1g. The area/perimeter/contour of the opening811B1hof the socket base component811B1is similar to the area/perimeter/contour of the under-test device DUT7to fix the under-test device DUT7to the socket base component811B1. The width Wig of the groove811B1gof the socket base component811B1is narrower than or equal to the width W1hof the opening811B1hof the socket base component811B17to prevent the under-test device DUT7from sliding out.

To transmit the testing sound from the sound outlet opening S07of the under-test device DUT7, the socket base component811B2has an opening811B2h. As shown inFIG. 11, the width Wig or the length L1gof the groove811B1gof the socket base component811B1is designed according to the size (for example, the width WW or the length LL) of the sound outlet opening S07of the under-test device DUT7so as to, for example, output the testing sound to the sound sensing device315. The width Wig or the length L1gof the groove811B1gof the socket base component811B1may be wider than or equal to the width WW or the length LL of the sound outlet opening S07of the under-test device DUT7. As shown inFIG. 10, the depth D2of the opening811B2hof the socket base component811B2is designed according to the depth D1gof the groove811B1gof the socket base component811B1so as to, for example, output the testing sound to the sound sensing device315. The opening811B2hoverlaps the groove811B1g. The geometric center of the sound outlet opening S07is roughly aligned to the geometric center of the groove811B1gof the socket base component811B1or the geometric center of the receiving surface315rof the sound sensing device315.

As shown inFIG. 10, the sealing component811SG of the socket811is configured to isolate the front/first sub-chamber CB1of the under-test device DUT7from the back/second sub-chamber CB2of the under-test device DUT7as shown inFIG. 10when the under-test device DUT7, which has been loaded to the testing platform112, produces the testing sound according to the testing signal(s). Hence, when the membrane222of the under-test device DUT7vibrates, air pressure changes of the back/second sub-chamber CB2would not interfere with those of the front/first sub-chamber CB1. The air pressure changes of the front/first sub-chamber CB1travel as waves through the groove811B1gand the opening811B2hof the socket base811B and are detected/measured by the sound sensing device315.

In a word, the socket base811B of the socket811has the groove811B1gand the opening811B2hfor the testing sound from the under-test device DUT7to pass through and travel outwards to the sound sensing device315. The sealing component811SG prevents air leakage from the back/second sub-chamber CB2and/or into the front/first sub-chamber CB1during testing, and the air pressure changes of the back/second sub-chamber CB2would propagate across the openings811C1h-811C3h,811SGh, and311PCBh of the socket cover811C of the socket811without interfering with the air pressure changes of the front/first sub-chamber CB1. These improve testing quality and/or enhance the quality of the testing sound being generated.

As shown inFIG. 10, the receiving surface315rof the sound sensing device315is parallel to the membrane222of the under-test device DUT7while the sound outlet opening S07is located on the lateral side (perpendicular to the membrane222) of the cap730of the under-test device DUT7. The structure of the socket base811B of the socket811is designed according to the arrangement/structure of the sound sensing device315and the under-test device DUT7.

The structure of the socket base may vary according to the arrangement/structure of the sound sensing device and/or the under-test device.FIG. 14is a schematic diagram of a socket1411, the sound sensing device315, and the under-test device DUT7according to an embodiment of the present invention. Compared to the socket base component811B2of the socket base811B shown inFIG. 10, a socket base component1411B2of a socket base1411B of the socket1411shown inFIG. 14is shaped so that the receiving surface315rof the sound sensing device315is perpendicular to the membrane222of the under-test device DUT7but parallel to the lateral side (on which the sound outlet opening S07is located) of the cap730of the under-test device DUT7.

Note that, inFIG. 8, the socket base811B of the socket811accommodates one sound sensing device315and one under-test device DUT7. Each sound sensing device315corresponds to one under-test device DUT7.

In another aspect, one sound sensing device315may correspond to more than one under-test devices.FIG. 15is a schematic diagram of an acoustic testing system15according to an embodiment of the present invention. The acoustic testing system15includes under-test devices DUT15a-DUT15dand a testing apparatus1510. The testing apparatus1510may include a sound sensing device1515, amplifiers1514m, apart from the sockets111, the testing platform112, the loading device113, the testing-signal generating device114, the tester116, the unloading device117, and/or the control unit119.

Compared to the acoustic testing system10, testing of the under-test devices DUT15a-DUT15dmay take place in parallel. The testing-signal generating device114may transmit testing signals Sn15a-Sn15d, which correspond to different frequencies/tones, to the under-test devices DUT15a-DUT15drespectively at a time. After receiving the testing signals Sn15a-Sn15drespectively at the same time, the under-test devices DUT15a-DUT15dmay produce testing sounds TS15a-TS15drespectively, the testing sounds TS15a-TS15dmay be superimposed to constitute a testing sound. The sound sensing device1515may detect testing sounds TS15a-TS15d, which correspond to frequencies different from each other, at a time. By providing the testing signals Sn15a-Sn15dof different frequencies/tones to the under-test devices DUT15a-DUT15d, the tester116can distinguish each of the testing sounds TS15a-TS15dbecause the testing sounds TS15a-TS15dproduced from the under-test devices DUT15a-DUT15dhave different frequencies respectively. In this way, audio performance of each of the under-test devices DUT15a-DUT15dcan be determined individually. The parallelization of testing the under-test devices DUT15a-DUT15dmay reduce the number of the sound sensing device(s) and the testing cost/space.

Each of the under-test devices DUT15a-DUT15dmay be a sound producing device such as a packaged under-test device, a (semiconductor packaged) speaker, a die on a wafer, or a sound producing die formed on a wafer before a singular/sawing process is performed.

The testing apparatus110/1510of the present invention may perform acoustic test as well as DC (direct current) test.FIG. 16is a schematic diagram of an acoustic testing system16according to an embodiment of the present invention. The acoustic testing system16may be implemented by the acoustic testing system10or15.

FIG. 16aillustrates the DC test. During the DC test, the testing-signal generating device114may input testing signal(s) such as DC voltage(s) Vdc to an under-test device DUT16, and circuit behavior(s) of the under-test device DUT16may then be electrically tested/measured by the tester116. The DC test typically includes tests for capacitance, leakage (on input pins and/or tri-state pins), opens and shorts, voltage levels, and/or standby current/active power dissipation. The DC test may verify that all bond wires are connected properly, check signal continuity to the under-test device DUT16, verify operational characteristics, and/or determine whether the under-test device DUT16functions according to standard requirements.

FIG. 16billustrates the acoustic test. During the acoustic test, the testing-signal generating device114inputs testing signal(s) such as input signal(s)/voltage(s) Sn16to the under-test device DUT16, the sound sensing device1615may then receive/detect the testing sound TS16generated by the under-test device DUT16. The tester116may analyze the output of a sound sensing device1615to verify acoustic functionality of the under-test device DUT16. The acoustic test may involve sound intensity, sound power, sound quality, or sound spectral measurement. For example, the testing apparatus110may measure the sound-pressure-level (SPL) or total-harmonic-distortion (THD) of the under-test device DUT16. The acoustic testing system16may check whether the sound-pressure-level of the testing sound TS16exceeds certain threshold, such as 55 decibel (dB). The acoustic testing system16may determine whether distortion is created or increased.

The testing apparatus110/1510may be dedicated to a final test. Basically, a semiconductor manufacturing process (by which a wafer is formed), wafer-level DC and acoustic test(s), a singular/sawing process, a packaging process (by which each separated die is packaged and/or by which each separated die is mounted in an enclosure), and a final test are performed and follow the sequence outlined above. The under-test device DUT16, which may be a micro electro mechanical system (MEMS), may be formed by the semiconductor manufacturing process. Defects such as contamination or metal shorts that may occur during the semiconductor manufacturing process are examined at the wafer-level DC and acoustic test(s). The wafer-level DC and acoustic test(s) is/are disclosed in U.S. application Ser. No. 17/009,789, which is incorporated herein by reference, and performed at wafer level. Defects such as wire shorts, lifted balls and bridging, which are created after the semiconductor manufacturing process, are screened at the final test. The final test may be performed on a packaged speaker (namely, the under-test device DUT16) by the testing apparatus110/1510and include the acoustic test and the DC test.

In summary, the present application makes use of the conventional semiconductor testing process for mass production to ensure high reliability and achieve high throughput. Moreover, microphone(s) is/are disposed in a testing apparatus of the present application since the present application aims to perform (final) test on (semiconductor packaged) speakers. In addition, to improve testing quality, the testing apparatus of the present application further includes a sealing component to prevent air pressure changes of a back/second sub-chamber of a speaker from interfering with air pressure changes of a front/first sub-chamber of the speaker during testing.