CN205720430U

CN205720430U - Quartz wafer grinds online Frequency Measurement System

Info

Publication number: CN205720430U
Application number: CN201620370210.4U
Authority: CN
Inventors: 郭彬; 潘凌锋; 陈浙泊; 陈信; 陈一信; 林斌
Original assignee: Research Institute of Zhejiang University Taizhou
Current assignee: Research Institute of Zhejiang University Taizhou
Priority date: 2016-04-28
Filing date: 2016-04-28
Publication date: 2016-11-23
Anticipated expiration: 2026-04-28

Abstract

The utility model discloses a kind of quartz wafer and grind online Frequency Measurement System, amplify filtration module, radio frequency amplitude detection module and touch screen module including power module, MCU control system module, DDS module, radio frequency power amplification module, π network interface circuit module, signal.This utility model enhances the anti-interference of system with π Network Maximum Transmission method Cleaning Principle based on DDS technology, the problem solving existing ALC system " in some frequency range generation frequency measurement value saltus step ".The all frequency ranges of this utility model use unified π network interface circuit, solve existing ALC system different frequency range and need to change the defect of detecting head, reduce radio-frequency joint and frequently plug the electrical failure risk caused, enhancing system job stability, it is possible to be obviously improved wafer grinding quality and product with stable quality.Hardware system scheme can not only cover all frequency ranges involved by the production of current wafer grinding, and has only to all cut types by the compatible quartz wafer of just energy of amendment on algorithm parameter.

Description

Quartz wafer grinds online Frequency Measurement System

Technical field

This utility model relates to test instrunment technical field, particularly relates to a kind of quartz wafer and grinds online Frequency Measurement System.

Background technology

Quartz wafer is the core component of crystal oscillator, and quartz oscillator (crystal oscillator) provides time base for electronic equipment Standard, has extremely important status in electronics and information industry.China is the manufacture big country of crystal oscillator, but product specification and the gross output value The most still there is bigger gap.

The manufacturing process of crystal oscillator can be largely classified into wafer manufacture and two stages of wafer package, and the former is mainly by cutting Cut, grind and quartz crystal bar is processed into the wafer of specific thicknesses and size by the operation such as corrosion；The latter is mainly by draping over one's shoulders silver, point Glue, finely tune and wafer package is the crystal oscillator of all size by the operation such as sealing.In the range of certain frequency, the thickness of quartz wafer Can be simplified to proportional relation with its resonant frequency, the frequency range of the most a large amount of crystal oscillators is in several million to tens megahertzs, corresponding thick Degree is hundreds of micron, just meets this relation.Technology involved by this utility model is mainly used in the wafer manufacture stage, should The productive target in stage is around the resonant frequency expansion of quartz wafer.

According to the demand of different phase in wafer production process flow process, frequency detecting technology can be divided into both direction.One Individual direction is flow process back segment " wafer electric parameter testing " technology, and the wafer substantially machined according to resonant frequency is by it Core parameter sorts, and mainly stresses the accuracy of measurement and the comprehensive of test parameter.Lot of domestic and international research institution is all It research and probe, corresponding product also comparative maturity have been carried out.Such as, 250A, 250B series net of U.S.'s Saunders company The frequency bandwidth of the E5100 series of network analyser of network analyser and Agilent company of the U.S. is respectively at 400 MHz and 200 MHz, within load resonant frequency certainty of measurement reaches 2 ppm, represents the static generation with quasistatic frequency measurement field of quartz wafer Boundary's top level.

Another direction of frequency detecting technology is exactly " online frequency measurement " technology that this utility model is paid close attention to, and mainly stresses The speed measured and real-time.Quartz crystal bar, by first becoming certain thickness quartz thin slice after cutting, next utilizes grinding Machine is thinned to wafer target frequency exactly.In whole process of lapping, wafer is all the time between the abrasive disk up and down of grinder The most relatively sliding, its thickness cannot directly be measured.Contactless chi if, with high accuracy (sub-micrometer scale) at present Very little measurement technology carries out measurement online to quartz wafer thickness, and difficulty is big and with high costs.Reach therefore, it is desirable to control wafer To target frequency, or repeatedly shutting down taking-up wafer carries out static frequency measurement, or uses online Technology of Frequency Measurement by Using.Obviously the former Being loaded down with trivial details and insecure, current all wafers production firm is required for grinding online Frequency Measurement System and online Technology of Frequency Measurement by Using.

In wafer grinding production process, abrasive disk is constantly to slide relative to wafer, is not to exist all the time under detecting head Wafer, resonance signal is to be interrupted；It addition, the radio-frequency (RF) excited watt level required for the wafer of different frequency is different, no Also it is different with the amplitude of frequency band resonance signal.Existing online Technology of Frequency Measurement by Using possesses extraction dynamic resonance under different frequency range The ability of signal, it is already possible to realize most basic online frequency measurement and grinder automatic hold function.

External many wafer fabrication provider all use the online frequency monitoring instrument (Auto of TRANSAT company of the U.S. Lapping Control system-ALC) the wafer frequency in process of lapping is carried out online monitoring method, this instrument can be real The basic function of the existing online frequency measurement of wafer, but core technology is monopolized by the said firm, it is possible to and the patented technology data of acquisition is very Limited.ALC-2000 type that domestic wafer fabrication provider many uses Beijing three Technology Co., Ltd. of standing grain Taida is on sale and ALC-2100 Type grinds frequency meter, and this instrument still uses core technology based on TRANSAT company of the U.S..Frequency measurement is ground with ALC-2100 type As a example by instrument, the frequency measurement scope of its nominal is at 1-95 MHz；Measuring accuracy is 0.1%；Current frequency is shown with two eight segment numeral pipes Rate and frequency scattered error；Possesses the function of " when quartz wafer reaches preset target frequency, instrument is automatically turned off grinder ".

Make wafer accurately achieve target frequency and avoid the overclocking production accident occurring overmastication to cause, be all crystalline substances The sheet manufacturer most basic demand to online frequency meter.But, along with quartz crystal oscillator product requirement is improved constantly by market, Quartz crystal oscillator industry technology makes rapid progress, and the function of original ALC system does not the most upgrade in time the replacement, goes out in production practices Show more and more problems that can not ignore and some other urgent application demand is urgently to be resolved hurrily.

First, the resonant frequency of quartz crystal oscillator product improves constantly, and the high band of volume production has reached 70 MHz, a lot Enterprise can run into such as " in some frequency range generation frequency measurement value saltus step " during actually used ALC and cannot effectively control to grind The defect of mill amount, has a strong impact on product quality and manufacturing schedule.This is owing to its hardware architecture is based on traditional phaselocked loop frequency sweep Technology and 51 series flush bonding processors, be easily subject to the electricity that noise of motor in the environment of plant, electrode contacts and abrasive sand introduce Learn noise jamming；

Second, the kind of quartz crystal oscillator product is continuously increased, and develops into more from the most single single corner AT cut type Come the most double cuts types, such as SC cut type and BT cut type.Double cuts type has the most steady at some specific temperature spots Qualitative, but its thickness and the functional relationship of frequency are but different with AT cut type.Through reality test, existing ALC system is i.e. Make can not meet the production requirement of online frequency measurement under automatic gain.

3rd, quartz crystal oscillator product has covered in 5 MHz-70 MHz range almost each frequency, existing In process of production, different frequency range needs to change different detecting heads ALC system.Plug radio-frequency devices causes interface continually Electrical failure probability rises significantly, and causing detecting head electrode fracture to damage also is often to occur.Some are difficult to the detecting head discovered Poor contact of contacts will cause unstable product quality, even cause the production accident of " overclocking ".This is owing to ALC system uses Radio-frequency coil carries out voltage amplification as input signal, and different frequency range needs to use different coils to cause.

Therefore, in conjunction with producing practical study and exploring the online Technology of Frequency Measurement by Using of wafer, existing ALC system architecture is broken away from, innovation The ground research and development online Frequency Measurement System of wafer grinding is the urgent needs of current quartz crystal oscillator Ge great production firm.Piezoquartz industry is near Develop very rapid over Nian, to the demand of the process equipment in quartz wafer production process and online high accuracy measuring and controlling equipment also It is being continuously increased.

Summary of the invention

The purpose of this utility model is to solve the online frequency monitoring instrument of tradition in current quartz wafer process of lapping to survey online Frequently the technical problem " in some frequency range generation frequency measurement value saltus step ".

For realizing above utility model purpose, this utility model provides a kind of quartz wafer to grind online Frequency Measurement System, bag Include power module, MCU control system module, DDS module, radio frequency power amplification module, π network interface circuit module, signal are put Big filtration module, radio frequency amplitude detection module and touch screen module；

Described power module is described MCU control system module, DDS module, radio frequency power amplification module, signal amplification filter Mode block, radio frequency amplitude detection module and touch screen module provide DC source；

The input of described DDS module is connected to described MCU control system module, and the outfan of DDS module is connected to institute State the input of radio frequency power amplification module；

The outfan of described radio frequency power amplification module is connected to the input of described π network interface circuit module, described π The outfan of network interface circuit module is connected to described signal and amplifies the input of filtration module；

The outfan of described signal amplification filtration module is connected to the input of described radio frequency amplitude detection module；

The outfan of described radio frequency amplitude detection module is connected to described MCU control system module；

Described touch screen module is two-way with described MCU control system module to be electrically connected.

Further, described MCU control system module includes MCU processor and permanent memory.

Further, described π network interface circuit module is directly connected in the top lap of grinder, is inserted on described and grinds In input electrode socket that mill is corresponding and output electrode socket.

Further, described π network interface circuit module includes some resistors, input electrode and output electrode, wherein Resistor R1=R6=159 Ω, R2=R5=66.2 Ω, R3=R4=14.2 Ω, described input electrode and output electrode all use 3 The fine copper banana plug of mm diameter.

Further, the maximum operating frequency of described DDS module is 300 MHz.

Compared with prior art, the beneficial effects of the utility model are:

This utility model the most innovatively maximum transmitted method detection scheme by piezoquartz is used for the grinding of quartz wafer Online Technology of Frequency Measurement by Using field, digitized based on DDS, high accuracy and the feature of high stability, and a kind of wide band radio-frequency amplitude Testing circuit, utilizes π Network Maximum Transmission method Cleaning Principle to greatly strengthen the anti-interference of system, solves existing ALC system The problem of " in some frequency range generation frequency measurement value saltus step ".The all frequency ranges of this utility model use unified π network interface circuit, solve Certainly existing ALC system different frequency range needs to change the defect of detecting head, significantly reduces radio-frequency joint and frequently plugs the electricity caused Failure risk, strengthens system job stability such that it is able to be obviously improved wafer grinding quality and product with stable quality.This reality The all frequency ranges involved by the production of current wafer grinding can not only be covered by novel hardware system scheme, and have only to lead to Crossing all cut types of the most compatible quartz wafer of amendment just energy on algorithm parameter, the scope of application is greatly expanded.

Accompanying drawing explanation

Fig. 1 is theory diagram of the present utility model；

Fig. 2 is mounting structure schematic diagram of the present utility model；

Fig. 3 is MCU control system module principle block diagram；

Fig. 4 is π network interface circuit figure；

Fig. 5 is that signal amplifies filtration module circuit theory diagrams；

Fig. 6 is radio frequency amplitude detection module circuit theory diagrams；

Fig. 7 is the typical resonance signal graph of quartz wafer maximum transmitted method.

Detailed description of the invention

The utility model is described in further detail with specific embodiment below in conjunction with the accompanying drawings.

Include as it is shown in figure 1, quartz wafer of the present utility model grinds online Frequency Measurement System: power module, MCU control system System module, DDS module, radio frequency power amplification module, π Network Interface Module, signal amplify filtration module, radio frequency amplitude detection mould Block and touch screen module；

Described power module is MCU control system module, DDS module, radio frequency power amplification module, signal amplification filtering mould Block, radio frequency amplitude detection module and touch screen module provide DC source.

Described touch screen module is two-way with described MCU control system module to be electrically connected；

Described DDS module produces designated frequency range, frequency sweep according to the frequency sweep order of the MCU control system module received Speed and the sinusoidal wave swept-frequency signal of radio frequency output amplitude；

MCU processor in described MCU control system module sends frequency sweep according to sweep parameters and instructs to DDS module；With In AD sampled data is carried out Treatment Analysis, calculate the statistical information such as wafer resonant frequency, grinding rate and scattered error；For root According to grinding control strategy, grinder switch, abrasive sand switch are controlled；Configuration information for monitoring touch screen in real time；Mould Permanent memory in block is used for storing grinding initial frequency and grinding target frequency, sweep parameters, waveform searching parameter and control Policing parameter processed；It is also used for storing each grinding process and repairing the associated statistical information of abrasive disk flow process；

Described radio frequency power amplification module improves the swept-frequency signal power of DDS module, and the swept-frequency signal after amplification is input to π Network interface circuit module；

Described signal amplifies filtration module and the wafer resonance signal obtained from the detection of π network interface circuit module is carried out width Value is amplified, and the interference signal filtered after amplification in radio frequency resonant signal；

Filtered wafer resonance signal is converted to only retain amplitude change information by described radio frequency amplitude detection module, sends out Give described MCU control system module and carry out AD sampling and calculating process；

Described touch screen module is mutual for system and user's, shows measurement statistical information and the system shape of quartz wafer State information；For arranging grinding initial frequency and grinding target frequency；For arranging parameter, including sweep parameters, statistical parameter, Waveform searching parameter and control strategy parameter；For arranging beginning and the emergent stopping of grinding process；

Described π Network Interface Module is as being directly connected to the standalone module of upper grinding plate in grinding machine, and quartz wafer grinds The main body of other module composition quartz wafers online frequency meter of grinding except π Network Interface Module in addition in online Frequency Measurement System.

Described quartz wafer grinds the online Frequency Measurement System typical mounting means such as Fig. 2 institute for quartz wafer grinder Show.Typical quartz wafer grinder is mainly by top lap, lower abrasive disk, grinding carrier, grinding motor, grinder switches set Become.π network interface circuit is inserted in input electrode socket corresponding to top lap and output electrode socket.Electrode socket is usually The copper post of hollow, Teflon sleeve pipe be tightly embedded intp in the through hole of top lap after being dielectrically separated from, electrode socket lower surface with Top lap surface is the most concordant, can directly and wafer surface contact in process of lapping.Should between input and output electrode socket Being spaced suitable distance, this utility model takes 15 mm.Online by 50 ohmages between frequency meter and π network interface circuit Radio-frequency cable connects, and grinds and is connected by the wire of 0.2 square between motor, grinder switch and online frequency meter.

220V civil power is converted to by power module ± 5V ,+12V and the DC source of+24V, wherein ± 5V power supply with based on The linear voltage stabilization chip of LM7805 and LM7905 realizes, and the 220V using rated power to be 10W turns double 9 V transformators, be used for Signal amplifies filtration module and radio frequency amplitude detection module is powered；Wherein+5V power supply be additionally operable to MCU control system module and DDS module is powered；Wherein+12V and+24V power supply use the bright big NET-35D Switching Power Supply in Taiwan, volume low-power 35W ,+12V It is 1A with+24V output-current rating；+ 12V power supply is for powering to radio frequency power amplification module, and+24V power supply touches for giving Touch panel module to power.

MCU control system module uses the STM32F439IIT6 processor of 32 kernels of ARM, 172 pins, 2GB flash memory Bin, LQFP encapsulates, and industrial work scope is-40 DEG C to+85 DEG C；Processor is integrated with FPU self adaptation simultaneously to accelerate in real time Degree device, operating frequency is up to 180 MHz；MCU control system module includes minimum system part and interactive portion；

The minimum system part of MCU control system module includes as shown in Figure 3: reset circuit is multiple to the input of MCU processor Bit level, processor work during low level.In the reset state powered on or in reseting procedure, reset circuit can control MCU, anti- Only MCU sends false command, performs faulty operation, it is also possible to improve Electro Magnetic Compatibility；BOOT circuit inputs to MCU processor Digital signal level, during low level, MCU processor starts program from internal storage, and during high level, MCU processor can be from outward Portion's memorizer starts program；Battery feed circuit can be that the power down memorizer of MCU processor is powered when outside dump, Use CR2032 normal cell can provide 3.0 V voltages；Crystal oscillating circuit provides clock reference for MCU processor, and this practicality is new The MCU processor that type uses has two groups of crystal oscillators.One group of master clock being used as 25 MHz, another group is used as the RTC of 32.768 kHz Real-time clock；JTAG emulation download circuit is that MCU control system module downloads and procedure simulation, and programmer can be facilitated to see Examine the change of MCU register data when system is run.

The interactive portion of MCU control system module includes: LED indicating circuit is used for indicating system mode, with the input of MCU Output port control LED bright secretly；AD sample circuit is responsible for inputting external analog signal the analog digital conversion end of MCU processor Mouthful, the data after digitized are analyzed and processed further by processor；SRAM circuit is as SRAM and MCU processor Carry out operational data mutual, for the second level cache of MCU processor；Eeprom circuit is as number after MCU processor power down According to the storage chip do not lost, for preserving the interaction data of user and equipment；Parallel port communication circuit is by the 20 of MCU processor Six input and output pins provide, the digital channel communicated with DDS as MCU control system module；Serial communication circuit Thered is provided by the serial ports input and output pin of MCU processor, the data interaction between MCU control system module and touch screen, The download for system program of the JTAG emulation download circuit can also be substituted；SD card circuit is provided corresponding SD by MCU processor Card storage pin, as external data memory of the present utility model.

The model that DDS module uses is AD9854, and maximum operating frequency is 300 MHz.Generally, clock frequency during DDS The 40% of rate is the highest frequency of Real output waveform, and therefore the highest frequency of AD9854 output waveform is up to 120 MHz, meets Demand of the present utility model；In order to provide the start reference of frequency sweep to MCU control system module, this utility model uses The Ramped FSK frequency sweep mode of AD9854, simultaneously can be according to demand signals real time modifying output amplitude；By DDS frequency sweep mode After being revised as Ramped FSK pattern, it is only necessary to beginning frequency, cut-off frequency, frequency sweep stepping, sweep velocity, frequency sweep amplitude are set After can start the frequency sweep from initial frequency to cut-off frequency, the single step frequency sweep time only needs 10 us；When frequency sweep starts every time, The data of AD9854 update pin and by low level, synchronous triggering signal are set to high level.

As a example by the generation of Ramped FSK pattern swept-frequency signal, illustrate the operating procedure of the AD9854 to DDS module: multiple 71st foot of position DDS, i.e. AD9854 keeps the positive pulse of more than 10 clock cycle；Write control register, arrange mode of operation, Data refresh mode, frequency multiplication of phase locked loop number, open and shield corresponding function；Write data register, the initial frequency of write frequency sweep Rate and termination frequency, arrange frequency sweep stepping and frequency sweep slope；After data are provided with, update pin generation rising edge in data and touch Sending out, chip starts frequency sweep, and constantly circulates in the way of whole frequency, just frequency, eventually frequency.

Radio frequency power amplification module uses MWLA-001080M20 low-noise amplifier, operating frequency range: 1 MHZ-80 MHz, gain: 20 dB, peak power output: 20 dBm.Power amplifier all uses SMA with DDS module and π network interface circuit module Radio frequency interface connects.

π network interface circuit module is as shown in Figure 4.Circuit is made up of resistor and input and output electrode, wherein resistor R1=R6=159 Ω, R2=R5=66.2 Ω, R3=R4=14.2 Ω.Input electrode and output electrode use the fine copper of 3 mm diameters Banana plug.

Signal amplifies filtration module circuit theory as it is shown in figure 5, the model of chip U1, U2 and U3 is all LMH6609, all ± 5 V are used to power, VCC=+5V, VSS=-5V in figure；The output signal of π network interface circuit module passes through SMA interface (S1) enter, input resistance R1=1 k Ω, R2=50 Ω be used for impedance matching, one end access U1 positive input (+), one end Connect signal ground；The resistance being connected with U1 reverse input end (-) is that another termination of R3=100 Ω is with reference to ground, the R4=1 k Ω other end Connect the outfan of U1, the voltage gain of structure tenfold；The outfan of U1 connects ac coupling capacitor C1=10 nF, is connected to R5 The reverse input end (-) of U2 is inputted after=100 Ω；R6=1 k Ω is connected across between reverse input end (-) and the outfan of U2, with The voltage gain of R5 structure tenfold, U1 and U2 amounts to the voltage gain constituting 100 times；R7=82 Ω is as compensating resistance one end Access U2 positive input (+), one termination signal ground；The two rank bars that outfan one cut-off frequency of connection is 1 MHz of U2 Special Butterworth high-pass filtering circuit, the outfan of wherein R8=930 Ω, R9=390 Ω, C2=390 pF, C3=180 pF, U3 with Reverse input end (-) is joined directly together, and outfan is connected to SMA interface (S2)；

As shown in Figure 6, all chips use ± 5 V to power to radio frequency amplitude detection module circuit theory, VCC=+5V in figure, VSS= -5V；Signal is amplified the output signal of filtration module and is entered by SMA interface (S1), and R1=50 Ω is used for impedance matching, One end access high-speed comparator OPA690(U1) positive input (+), one termination signal ground；High-speed comparator U1 is as buffering Device realizes impedance transformation, and outfan is joined directly together with reverse input end (-), input resistance R2=1 k Ω；Operational amplifier TL3016(U2) signal compared is the signal that measured signal and the end of oppisite phase (IN-) of in-phase end (IN+) feeds back, earth terminal GND and Enable Pin EN connect signal ground, and outfan Qout connects current-limiting resistance R3=820 Ω；What feedback circuit utilized is quick two Pole pipe IN4148(D1) and the RC charging and discharging circuit that is made up of R4=100 k Ω, C1=10 nF carry out detection, if measured signal Assignment more than diode D1 and RC detected amplitude, then comparator can export high level, at this moment diode D1 conducting to electric capacity Charging makes detected amplitude rise；If measured signal amplitude is less than diode D1 and RC detected amplitude, then comparator is the most defeated Going out low level, capacitor makes detected amplitude reduce by conductive discharge, final detection discharge and recharge balance；RC charging and discharging circuit connects Feedback operational amplifier TL081(U3) positive input (+), the outfan of U3 is joined directly together with reverse input end (-), current limliting Resistance R5=120 Ω, electric capacity R6=100 pF；Circuit measuring output valve enter operational amplifier TL081(U4) positive input (+), the outfan of U4 and reverse input end (-) are joined directly together composition follow circuit and export SMA interface (S2)；

Touch screen module uses the TPC7062Ti of the Kunlun on-state, leading between touch screen and MCU control system module Letter uses MODBUS agreement, and this communication protocol uses query response mechanism, can realize the reliable and stable transmission of data.MCU controls System module monitors the interface of touch screen in real time and redirects state, grinds whether button is pressed, whether urgent pause button is pressed, ground The information such as mill initial frequency and the whether amendment of target frequency, frequency measurement parameter.

The online measuring technique of quartz wafer resonant frequency is based on piezoelectric resonator principle: apply sinusoidal electricity in both sides of wafers , wafer will produce mechanical vibration, and the mechanical vibration of wafer simultaneously can produce again alternating electric field.In the ordinary course of things, wafer The amplitude of mechanical vibration and the amplitude of alternating electric field are the least, but the amplitude when the frequency of additional alternating voltage is a certain particular value Substantially strengthening, this frequency is exactly the resonant frequency of wafer.Therefore, the online Frequency Measurement System of quartz wafer must possess radiofrequency signal and sends out The raw function with frequency sweep.Direct digital frequency synthesis technology DDS(Direct Digital Synthesizer) it is a kind of novel Frequency synthesis technique, be better than with conventional phase locked loops (PLL) frequency sweep design signal generator.Its major advantage is easy to program Controlling, Phase Continuation, the spectral range width of output, output frequency degree of stability is high, and resolution is high, fast response time.This practicality is new The AD9854 DDS module that type is used can export the sine sweep signal of 1 MHz-120 MHz, peak power output 0 dBm。

The frequency of quartz wafer is ground in production process, and first wafer is arranged in grinding carrier, and wafer thickness is more than Grinding carrier thickness, upper lower millstone directly with contact wafers, is filled with the abrasive sand as abrasive media therebetween.Grinder starts While open the quartz wafer that relates to of this utility model and grind online Frequency Measurement System, when upper and lower abrasive disk relatively rotates, grind Carrier also can rotate and autobiography around motor driving shaft under the drive of lower abrasive disk Internal and external cycle gear, and wafer is by grinding up and down The slip relatively of dish is ground sand and constantly cuts thinning, and resonant frequency constantly rises until target frequency value.This utility model is real Time monitoring abrasive disk in the resonant frequency of wafer, accurately close down grinder when arriving target frequency point.Due to radio-frequency transmission line and Abrasive sand between input and output electrode can produce decay to the frequency sweep of DDS module, in order to ensure enough radio-frequency (RF) excited intensity, The radio frequency power amplification module that this utility model relates to can be by output raising 100 times to 20 dBm.

DDS module that this utility model relates to, radio frequency power amplification module, π network interface circuit, signal amplify filtered electrical Road and radio frequency amplitude testing circuit together constitute the quartz wafer involved by this utility model and grind online frequency measurement peak signal The hardware foundation of transmission method.When under input and output electrode corresponding during quartz wafer slides into π network interface circuit, DDS mould Block changes the frequency of input signal and is allowed to change to high frequency direction from low frequency, and radio frequency amplitude testing circuit will detect quartz wafer The voltage signal at two ends changes with the change of frequency, and the type signal of maximum transmitted method is as shown in Figure 7.Can from figure Arriving, when frequency swept signal is equal to Fr, there is maximum in voltage；And when frequency increases further, there is minima in voltage. Wherein Fr is the minimum impedance frequency of wafer, and when ignoring the mechanical loss of wafer, Fr may be considered the resonant frequency of wafer. Grind the stage in wafer frequency to be better than millesimal accuracy of detection (hundreds of PPM) and can meet actual demand, therefore this Being approximately of sample is entirely capable of being received.Finally, the MCU control system module that this utility model relates to can gather wafer resonance letter Number and draw the instantaneous value of Fr with appropriate algorithm, constantly compare until closing down grinder with target frequency.

In view of general wafer length dimension (about 10 mm), lap speed (per minute 10 circle), lap diameter and Spacing (15 mm) between input and output electrode, in process of lapping, wafer is about 100 ms through effective detection time of electrode Left and right.The sweep velocity of the DDS module that this utility model relates to and MCU control system resume module speed can reach 50 times often Second, frequency sweep and process 20 ms i.e. every time, it is sufficient to the demand of dynamic frequency measurement during meeting wafer grinding.

Owing to this utility model innovatively have employed maximum transmitted method grinding in online frequency measurement flow process of quartz wafer Principle, the most only just can cover all Frequency points with same π network interface circuit.Simultaneously for different cut types Wafer only need by change DDS module radio frequency power output just can realize effectively encouraging, meet different chips thickness and The functional relationship of frequency.Therefore native system can overcome the problems of the tradition online Frequency Measurement System of ALC, is being obviously improved system The customized function being badly in need of based on the brand-new more producer of MCU control system Development of Module while stability, compatibility, and can Mutual with the communication that realizes between each grinder station of grinding shop.

With above-mentioned according to desirable embodiment of the present utility model for enlightenment, by above-mentioned description, related work people Member can carry out various change and amendment completely in the range of without departing from this utility model technological thought.This reality The content being not limited in description by novel technical scope, it is necessary to determine its technology according to right Property scope.

Claims

1. quartz wafer grinds online Frequency Measurement System, it is characterised in that include power module, MCU control system module, DDS mould Block, radio frequency power amplification module, π network interface circuit module, signal amplify filtration module, radio frequency amplitude detection module and touch Panel module；

Described power module is described MCU control system module, DDS module, radio frequency power amplification module, signal amplification filtering mould Block, radio frequency amplitude detection module and touch screen module provide DC source；

The input of described DDS module is connected to described MCU control system module, the outfan of DDS module be connected to described in penetrate Frequently the input of power amplifier module；

The outfan of described radio frequency power amplification module is connected to the input of described π network interface circuit module, described π network The outfan of interface module is connected to described signal and amplifies the input of filtration module；

2. quartz wafer as claimed in claim 1 grinds online Frequency Measurement System, it is characterised in that described MCU control system mould Block includes MCU processor and permanent memory.

3. quartz wafer as claimed in claim 1 grinds online Frequency Measurement System, it is characterised in that described π network interface circuit Module is directly connected in the top lap of grinder, is inserted in input electrode socket corresponding to described top lap and output electrode is inserted In seat.

4. the quartz wafer as described in any one of claim 1-3 grinds online Frequency Measurement System, it is characterised in that described π network Interface module includes some resistors, input electrode and output electrode, wherein resistor R1=R6=159 Ω, R2=R5= 66.2 Ω, R3=R4=14.2 Ω, described input electrode and output electrode all use the fine copper banana plug of 3 mm diameters.

5. quartz wafer as claimed in claim 4 grinds online Frequency Measurement System, it is characterised in that described DDS module the highest Operating frequency is 300 MHz.