CN2666074Y - Chip with high sensitivity used for silicon micro-capacitance microphone - Google Patents
Chip with high sensitivity used for silicon micro-capacitance microphone Download PDFInfo
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- CN2666074Y CN2666074Y CN 200320129759 CN200320129759U CN2666074Y CN 2666074 Y CN2666074 Y CN 2666074Y CN 200320129759 CN200320129759 CN 200320129759 CN 200320129759 U CN200320129759 U CN 200320129759U CN 2666074 Y CN2666074 Y CN 2666074Y
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Abstract
The utility model relates to a chip of a silicon condenser microphone, comprising an n-model silicon substrate on the front of which a p plus model doping layer is formed by boron diffusion. Silica is deposited on the surface of the p plus model doping layer to be etched into an isolation layer which is covered with a vibration film layer. A metal aluminum film is deposited on the vibration film layer to be photolithograph and etched into a round aluminum film and a square aluminum electrode. The back of the silicon substrate is provided with a silicon nitride protective film while a trapeze cut is etched on the bottom of the silicon substrate. The trapeze cut reaches the p plus model doping layer and is vertical to the p plus model doping layer and etches an acoustic hole to form a perforation backplane. An air gap is between the perforation backplane and the vibration film layer which is made of silicon nitride. The utility model is made into the round air gap layer, the round vibration film layer, the ring isolation layer and round micro-perforations which are uniform distributed on the edges of the vibration film layer so as to reduce the stress of the vibration film layer; enhance the sensitivity of the vibration film layer greatly and prevent rapture of ageing.
Description
Technical field
The utility model relates to the silicon micro capacitor microphone field, and particularly a kind of have a highly sensitive chip that is used for silicon micro capacitor microphone.
Background technology
Silicon micro capacitor microphone is grouped into by silicon part that forms silicon micro capacitor and peripheral circuit portion, wherein silicon partly by silicon chip and on perforation (acoustic holes) backboard, air-gap, separator, vibrating membrane, metal film and metal electrode form.Common silicon micro capacitor microphone is owing to be subjected to the restriction of production method, general air-gap, separator, vibrating membrane are square, as Micro Electro Mechanical Systems (MEMS), 1998 IEEE11th International Workshop p580-585, by P.-C.Hsu, C.H.Mastrangelo, described in " A HIGH SENSITIVITY POLYSILICON DIAPHRAGM CONDENSERMICROPHONE " literary composition that andK.D.Wise showed.When making this silicon micro capacitor microphone, can only produce square backboard from the body etching at the silicon chip back side, corrode with hydrofluoric acid afterwards, hydrofluoric acid is by the less acoustic holes corrode silicon dioxide layer of geometric scale on this square backboard, the sacrifice layer that carries out silicon dioxide discharges, silicon dioxide is simultaneously as sacrifice layer and square separator, and the sacrifice layer of the centre that erodes partly forms air-gap, and the rest parts silicon dioxide layer is as square separator behind the releasing sacrificial layer.Under the slower situation of hydrofluoric acid corrode silicon dioxide, may erode away circular air-gap zone hardly, and cross long corrosion and will cause the silicon nitride vibrating membrane destroyed.Like this, under the situation that sacrifice layer and separator are square, the stress of vibrating membrane is bigger, and especially the stress at sharp corner is bigger, produces stress and concentrates, and then cause the sensitivity decline and even the season cracking of microphone.Adopt above-mentioned manufacture craft, even make Round Membranes, also inevitable air-gap zone with irregular (non-circular) forms the wedge angle that stress is concentrated, and complete vibrating membrane also makes stress keep higher level simultaneously.
Summary of the invention
The purpose of this utility model is: it is bigger at the stress of sharp corner to overcome the square vibrating membrane that existing manufacture craft makes, therefore cause the sensitivity decline of microphone and even the defective of season cracking, thus providing a kind of has annular separator and circular air-gap, on the vibrating membrane edge, be furnished with simultaneously uniform circular micropunch, have a highly sensitive chip that is used for silicon micro capacitor microphone.
The purpose of this utility model is achieved in that
The utility model provides a kind ofly has a highly sensitive chip that is used for silicon micro capacitor microphone, comprise a n-type silicon chip 1, positive diffused with boron at silicon chip 1 forms p+ type doped layer 3, deposition of silica on p+ type doped layer 3, photoetching, corrode into separator 4, adhere to the vibration rete 6 that one deck silicon nitride is done on the separator 4, plated metal aluminium film on the vibration rete 6, and through photoetching, the circular aluminium film of corrosion and square aluminum electrode 9 (shown in Fig. 4,5); One deck silicon nitride diaphragm 11 is arranged at the back side of silicon chip 1, erode away a trapeze cut from the bottom surface of silicon chip 1, the degree of depth of this trapeze cut is to p+ type doped layer 3, on direction, erode away acoustic holes 7 and form the perforation backboard, be air-gap 8 between the vibration rete 6 that perforation backboard and silicon nitride are done perpendicular to p+ type doped layer 3; It is characterized in that: described vibration rete 6 and on the aluminium film of deposition on photoetching, the circular aluminium film edge of corrosion, be furnished with uniform circular micropunch 10; 1～20 micron of described circular micropunch 10 diameter, its center of circle is positioned on 70～98% the concentric circles that diameter is circular aluminium film diameter, and the central angle that the center of circle of adjacent two micropunch forms is micropunch and 1～10 times of the central angle of crossing 2 formation of concentric circles.
Described separator 4 is circular; Its thickness is 0.5～6 micron, and internal diameter is 500～3000 microns, and radial width is 50～150 microns.
Described air-gap 8 is circular, and its thickness is 0.6～7 micron, and diameter is 500～3000 microns.
Described vibration rete 6 is circular, and its thickness is 0.1～1 micron, 600～3300 microns of diameters.
The hole that erodes away on the described perforation backboard is arranged and is array, and the position is a p+ type doped layer 3 except that the hole, and boron diffusion depth is 3～20 microns.
The diameter of the circular auxiliary sacrifice layer of described zinc oxide is 500～3000 microns, thickness is 0.1～1 micron, the diameter of described silicon nitride Round Membranes (equaling the diameter of circular low temperature silicon dioxide layer) is 600～3300 microns, and its diameter is bigger 100～300 microns than the diameter of circular auxiliary sacrifice layer; The thickness of annular low temperature silicon dioxide layer is 0.5～6 micron;
Adopt more corrosion-prone zinc oxide as auxiliary sacrifice layer, form sacrifice layer jointly with the low temperature silicon dioxide of difficult corrosion; Therefore air-gap that actual air-gap forms after being corroded by potassium hydroxide by the auxiliary sacrifice layer of circular zinc oxide and the circular low temperature silicon dioxide layer that is positioned on the zinc oxide are formed jointly by the air-gap that hydrofluoric acid corrosion back forms.Potassium hydroxide rapidly removes by the zinc-oxide film of perforation with circle after the body etching, thereby forms circular air-gap zone; When hydrofluoric acid corroded circular low temperature silicon dioxide sacrificial layer afterwards, the hydrofluoric acid corrosive liquid can corrode vertically upward with whole border circular areas plane.Because the geometric scale (about 1～6 micron) of sacrifice layer vertical direction is much smaller than geometric scale (at interval half of adjacent perforated of horizontal direction, about 20～40 microns), the low temperature silicon dioxide sacrificial layer can be corroded with the speed about ten times, keep simultaneously and the auxiliary identical shape of sacrifice layer of zinc oxide, hydrofluoric acid can keep circular shape when discharging silicon dioxide sacrificial layer.
Advantage of the present utility model is:
The utility model provides has the highly sensitive chip that is used for silicon micro capacitor microphone, adopt a kind of new process, made air gap layer, separator and the vibrating membrane of circular configuration, reduced the stress of vibrating membrane, improve the sensitivity of vibrating membrane greatly, avoided season cracking; Simultaneously, because the corrosion position of silicon dioxide sacrificial layer silicon dioxide is not the bigger horizontal direction of yardstick in the past, but the less vertical direction of yardstick, the speed that is corroded is very fast, the corrosion stronger to silicon nitride vibrating membrane when having reduced hydrofluoric acid releasing sacrificial layer in the past.
The chip that the utility model provides described vibration rete 6 and on the aluminium film of deposition on photoetching, the circular aluminium film edge of corrosion, be furnished with uniform circular micropunch, this circle micropunch can make the stress of silicon nitride Round Membranes obtain to a certain degree release, Chuan Kong diameter is enough little simultaneously, to keep bigger acoustic resistance, improve the sensitivity of vibrating membrane greatly, avoided season cracking.
The drawing explanation
Fig. 1 is that preparation method of the present utility model carries out the generalized section that deep boron diffusion back forms in the silicon chip front
Fig. 2 is deposit, photoetching among the preparation method of the present utility model, erode away circular auxiliary sacrifice layer, low temperature silicon dioxide, deposit, photoetching, etch Round Membranes, etch annular separator and circular sacrifice layer under the Round Membranes, photoetching, etch the generalized section that forms behind the mask of square silicon body etching at the back side
Fig. 3 is that auxiliary sacrifice layer of body etching silicon chip among the preparation method of the present utility model, corrosion and releasing sacrificial layer form the generalized section that forms after the circular air gap layer
Fig. 4 is deposit, makes circular metal aluminium film by lithography that photoetching also etches circular micropunch, finishes the generalized section of the chip in the utility model silicon micro capacitor microphone
Fig. 5 is the vertical view that the utility model is used for the chip of silicon micro capacitor microphone
Fig. 6 is the upward view that the utility model is used for the chip of silicon micro capacitor microphone
Fig. 7 is the flow chart of the utility model method for fabricating chip of microphone
The accompanying drawing sign:
1, n-(100) silicon chip 2, high temperature silica 3, p+ type doped layer
4, low temperature silicon dioxide layer 5, auxiliary sacrifice layer (zinc oxide) 6, vibration rete (silicon nitride)
7, acoustic holes 8, air-gap (forming behind the releasing sacrificial layer)
9, aluminium film and electrode 10, circular micropunch 11, diaphragm
1 n
-(100) Si 2 high temperature SiO
23p
+Doping Si 4 low temperature SiO
25 zinc oxide, 6,11 silicon nitrides, 9 aluminium film and electrodes
Embodiment
In conjunction with preparation method of the present utility model, will be described in detail microphone chip concrete structure of the present utility model with reference to accompanying drawing
A kind of the utility model that present embodiment provides is used for the chip of silicon micro capacitor microphone, referring to accompanying drawing 4-6; This chip comprises a n-type silicon chip 1, and in the positive diffused with boron formation p+ type doped layer 3 of silicon chip 1, its thickness is 3 or 20 microns; In p+ type doped layer 3 deposition of silica and photoetching, corrode into annular separator 4, the internal diameter of this annular separator 4 is 500 or 3000 microns, radial width is 50 or 150 microns; Adhere to the Round Membranes layer 6 that one deck silicon nitride is done on separator 4, deposition and photoetching, the circular aluminium film of corrosion and square-shaped electrode 9 are furnished with uniform circular micropunch 10 on the vibration rete 6 on vibrating membrane and circular aluminium film edge; These circle micropunch 10 diameters are 1～20 micron; Its center of circle is positioned on 70～98% the concentric circles that diameter is circular aluminium film diameter, and the central angle that the center of circle of adjacent two micropunch forms is micropunch and 1～10 times of the central angle of crossing 2 formation of concentric circles.Reverse side at silicon chip 1 has one deck silicon nitride diaphragm 11, erode away a trapeze cut from the bottom surface of silicon chip 1, the degree of depth of this trapeze cut is to p+ type doped layer 3, erode away acoustic holes 7 perpendicular to p+ type doped layer 3 and form the perforation backboard, be air-gap 8 between the vibration rete 6 that perforation backboard and silicon nitride are done; Described air-gap 8 is circular, and its thickness is 0.6 or 7 micron, and diameter is 500 or 3000 microns.The hole that erodes away on the perforation backboard is arranged and is array, and acoustic holes 7 length of sides are 30 microns, are spaced apart 30 microns.Vibration rete 6 thickness are 0.1 or 1 micron.
Embodiment 2
In conjunction with the accompanying drawings 7 and concrete preparation method chip of the present utility model is elaborated:
[1] getting a n-type silicon chip 1 is 1.5 microns silicon dioxide through the high-temperature oxydation thickness of growing, utilize hydrofluoric acid corrosion high temperature silica to make mask 2 after the photoetching, and carry out the deep boron diffusion in silicon chip 1 front, form in the perforation backboard p+ type doped layer 3 at position except that the pore size distribution position, boron diffusion depth is 10 microns;
[2] after hydrofluoric acid is removed the high temperature silica mask, at the auxiliary sacrifice layer of the zinc oxide of silicon chip front magnetron sputtering 0.5 micron thickness, photoetching, phosphoric acid corrosion go out circular auxiliary sacrifice layer 5, and the diameter of the circular auxiliary sacrifice layer of this zinc oxide is 1000 microns, and thickness is 0.5 micron; Utilizing plasma enhanced CVD equipment (PECVD) deposition thickness in silicon chip 1 front is 3 microns low temperature silicon dioxide 4; Be 0.5 micron silicon nitride at two-sided low-pressure chemical vapor phase deposition equipment (LPCVD) deposition thickness that utilizes of silicon chip 1 again, after its positive photoetching, silicon nitride is etched into Round Membranes 6 by plasma etching machine (ICP), low temperature silicon dioxide under the silicon nitride is that (this circular diameter is greater than the auxiliary sacrifice layer of circular zinc oxide for same circle by the ICP etching also, the part of the auxiliary sacrifice layer of wherein corresponding circular zinc oxide is as sacrifice layer, all the other annular parts are as separator 4, its thickness is 3 microns, internal diameter is 1500 microns, radial width is 75 microns), silicon nitride is etched into the mask of square silicon body etching after its back side photoetching by ICP; The diameter of this silicon nitride Round Membranes 6 (equaling the diameter of circular low temperature silicon dioxide layer) is 1500 microns, and its diameter is bigger 500 microns than the diameter of circular auxiliary sacrifice layer; The diameter of the circular auxiliary sacrifice layer of wherein said zinc oxide is 1500 microns, and thickness is 0.6 micron; The diameter of described silicon nitride Round Membranes (equaling the diameter of circular low temperature silicon dioxide layer) is 2600 microns, and its diameter is bigger 150 microns than the diameter of circular auxiliary sacrifice layer; The thickness of annular low temperature silicon dioxide layer is 3 microns;
[3] carry out silicon body etching from the silicon chip back side to silicon chip 1 usefulness potassium hydroxide, when potassium hydroxide erodes to p+ type doped layer 3, because potassium hydroxide is to the corrosion rate of the punched areas of the boron diffusion not perforation backplane region far above the deep boron diffusion, perforation back plate aperture distribution position is eroded very soon, on perpendicular to the perforation backboard, form acoustic holes 7, the acoustic holes 7 that erodes away on this perforation backboard is array arranges, and these acoustic holes 7 length of sides are 50 microns, are spaced apart 50 microns; Then, potassium hydroxide arrives the auxiliary sacrifice layer 5 of circular zinc oxide by perforation, will be corroded formation one and the auxiliary identical air-gap 8 of sacrifice layer 5 shapes of circular zinc oxide by the auxiliary sacrifice layer 5 that zinc oxide constitutes; Afterwards, with hydrofluoric acid circular low temperature silicon dioxide sacrificial layer (being the part that is positioned in the silicon dioxide layer on the auxiliary sacrifice layer of circular zinc oxide) corrosion is discharged and forms air-gap, thereby assists the circular air-gap 8 of the identical air-gap mutual group of sacrifice layer 5 shapes with aforesaid and circular zinc oxide; Wherein air-gap 8 is circular, and its thickness is the thickness sum of annular separator 4 and the zinc oxide film that is corroded, and is 4 microns, and diameter is 2000 microns;
[4] at silicon chip 1 front evaporation thickness be 0.1 micron aluminium film, and photoetching, phosphoric acid corrosion go out circular aluminium film and square-shaped electrode 9.After getting rid of photoresist, photoetching, phosphoric acid corrosion go out the circular micropunch on the circular aluminium film, again the silicon nitride Round Membranes under the aluminium film are etched circular micropunch.2 microns of circular micropunch 10 diameters, its center of circle are positioned on 95% the concentric circles that diameter is circular aluminium film diameter, and the central angle that the center of circle of adjacent two micropunch forms is micropunch and 3 times of the central angle of crossing 2 formation of concentric circles.
Claims (6)
1. one kind has the highly sensitive chip that is used for silicon micro capacitor microphone; Comprise a n-type silicon chip (1), positive diffused with boron at silicon chip (1) forms p+ type doped layer (3), on p+ type doped layer (3) by deposition of silica with photoetching, corrode into separator (4), adhere to the vibration rete (6) that one deck silicon nitride is done thereon, deposit also photoetching on the vibration rete (6), corrode circular aluminium film (9) and square metal aluminium electrode (9); At the back side of silicon chip (1) one deck silicon nitride diaphragm (11) is arranged, erode away a trapeze cut from the bottom surface of silicon chip (1), the degree of depth of this trapeze cut is to p+ type doped layer (3), and on perpendicular to p+ type doped layer (3), erode away acoustic holes (7) formation one perforation backboard, be air-gap (8) between perforation backboard and the vibration rete (6); It is characterized in that: described vibration rete 6 and on the aluminium film of deposition on photoetching, the circular aluminium film edge of corrosion, be furnished with uniform circular micropunch 10; 1～20 micron of these circle micropunch 10 diameter, its center of circle are positioned on 70～98% the concentric circles that diameter is circular aluminium film diameter, and the central angle that the center of circle of adjacent two micropunch forms is micropunch and 1～10 times of the central angle of crossing 2 formation of concentric circles.
2. have a highly sensitive chip that is used for silicon micro capacitor microphone by claim 1 is described, it is characterized in that: described separator (4) is for circular; Its thickness is 0.5～6 micron, and internal diameter is 500～3000 microns, and radial width is 50～150 microns.
3. has a highly sensitive chip that is used for silicon micro capacitor microphone by claim 1 is described, it is characterized in that: described air-gap 8 is for circular, its thickness is the thickness sum of annular separator (4) and the zinc oxide film that is corroded, is 0.6～7 micron, and diameter is 500～3000 microns.
4. have a highly sensitive chip that is used for silicon micro capacitor microphone by claim 1 is described, it is characterized in that: described vibration rete 6 is for circular, and its thickness is 0.1～1 micron, 500～3300 microns of diameters.
5. has a highly sensitive chip that is used for silicon micro capacitor microphone by claim 1 is described, it is characterized in that: the acoustic holes (7) that erodes away on the described perforation backboard is arranged and is array, the position is a p+ type doped layer 3 except that the hole, and boron diffusion depth is 3～20 microns.
6. describedly have a highly sensitive chip that is used for silicon micro capacitor microphone by claim 1 or 5, it is characterized in that: described acoustic holes (7) length of side is 30～80 microns, is spaced apart 30～80 microns.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200320129759 CN2666074Y (en) | 2003-12-23 | 2003-12-23 | Chip with high sensitivity used for silicon micro-capacitance microphone |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200320129759 CN2666074Y (en) | 2003-12-23 | 2003-12-23 | Chip with high sensitivity used for silicon micro-capacitance microphone |
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| CN2666074Y true CN2666074Y (en) | 2004-12-22 |
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| CN 200320129759 Expired - Fee Related CN2666074Y (en) | 2003-12-23 | 2003-12-23 | Chip with high sensitivity used for silicon micro-capacitance microphone |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100499877C (en) * | 2003-12-17 | 2009-06-10 | 中国科学院声学研究所 | Chip having high sensitivity for silicon micro-capacitor microphone and preparation method thereof |
| CN101098569B (en) * | 2006-06-28 | 2011-06-29 | 歌尔声学股份有限公司 | Semiconductor microphone chip |
| CN104581570A (en) * | 2014-12-31 | 2015-04-29 | 苏州恒听电子有限公司 | Telephone receiver provided with improved vibration film |
-
2003
- 2003-12-23 CN CN 200320129759 patent/CN2666074Y/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100499877C (en) * | 2003-12-17 | 2009-06-10 | 中国科学院声学研究所 | Chip having high sensitivity for silicon micro-capacitor microphone and preparation method thereof |
| CN101098569B (en) * | 2006-06-28 | 2011-06-29 | 歌尔声学股份有限公司 | Semiconductor microphone chip |
| CN104581570A (en) * | 2014-12-31 | 2015-04-29 | 苏州恒听电子有限公司 | Telephone receiver provided with improved vibration film |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |