CN105712286A - MEMS (Micro-electromechanical system) device manufacturing method - Google Patents
MEMS (Micro-electromechanical system) device manufacturing method Download PDFInfo
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- CN105712286A CN105712286A CN201410720429.8A CN201410720429A CN105712286A CN 105712286 A CN105712286 A CN 105712286A CN 201410720429 A CN201410720429 A CN 201410720429A CN 105712286 A CN105712286 A CN 105712286A
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Abstract
The present invention discloses a MEMS (micro-electromechanical system) device manufacturing method, and aims to solve the problem that a first film is deposited on the front side of a semiconductor substrate at high temperature, since the thermal expansion coefficient of the first film is greater than the thermal expansion coefficient of the semiconductor substrate, after cooling, two ends of the first film and the semiconductor substrate may cock toward the front side of the semiconductor substrate. The problem is solved in the following manner: a second film is continued to be formed on the back side of the semiconductor substrate, by laser heat treatment of the second film, the thermal expansion coefficient of the second film is greater than the thermal expansion coefficient of the semiconductor substrate, during the laser heat treatment, two ends of the semiconductor substrate and the second film at the front side of the semiconductor substrate may cock toward the back side of the semiconductor substrate, and the cocking trend of the second film offsets the cocking of the first film, so that after cooling, a flat semiconductor substrate, a flat first film and a flat second film can be obtained, after the flat first film is released, the flat first film is still in a flat state, and a movable member high sensing sensitivity MEMS device can be produced in a low cost manner.
Description
Technical field
The present invention relates to technical field of manufacturing semiconductors, particularly relate to the manufacture method of a kind of MEMS.
Background technology
From later 1980s, along with the development of MEMS (MicroElectroMechanicalSystem, MEMS) technology, some semiconductor device, such as various sensors achieve microminaturization, it is achieved that batch production, become the Main way of future development.
In MEMS, generally there is fixing parts and the movable member in the cavities that suspends, utilize MEMS local environment to change, for instance after motion, cause some electrical parameters between movable member and fixing parts, for instance electric capacity changes thus sensing.Above-mentioned movable member is generally thin film.
Practical study shows, above-mentioned MEMS is in manufacturing process, and owing to movable member thin film is high temperature deposition, thus after device cooling, this thin film, due to Stress Release reason, warpage, uneven phenomenon often occurs, and this will affect the sensing of MEMS.
For the problems referred to above, prior art also has some solutions.Such as: the material of exploitation low stress is as movable member, but this will result in the technique relating to movable member and need to change therewith, causes process window less, and cost increases, and on the other hand, for some low-stress material, its sensing sensitivity is relatively low.Again such as: the material adopting tensile stress contrary with compression stress both stress types replaces superposition and deposits to form movable thin film, and this will also result in process costs increases and movable member sensitivity step-down.
In view of this, the present invention provides the manufacture method of a kind of new MEMS, and cost is low and does not affect the sensing sensitivity of movable member.
Summary of the invention
The problem that this invention address that is the manufacture method how providing a kind of MEMS, and cost is low and does not affect the sensing sensitivity of movable member.
For solving the problems referred to above, the present invention provides the manufacture method of a kind of MEMS, including:
Thering is provided Semiconductor substrate, deposit the first film in described Semiconductor substrate front, the thermal coefficient of expansion of described the first film is more than the thermal coefficient of expansion of described Semiconductor substrate；
Continue to form the second thin film at the Semiconductor substrate back side, described second thin film is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion thermal coefficient of expansion more than described Semiconductor substrate；
After cooling, described the first film is carried out release and forms it into movable member.
Alternatively, the material of described Semiconductor substrate is silicon, and the material of described the first film is SiGe, copper or aluminum.
Alternatively, described the first film adopts furnace process to be formed, and temperature range is 300 DEG C～500 DEG C.
Alternatively, described second thin film carries out LASER HEAT TREATMENT makes its thermal coefficient of expansion make its density become big realization more than the thermal coefficient of expansion of described Semiconductor substrate by described second thin film carries out LASER HEAT TREATMENT.
Alternatively, described second thin film can absorb ultraviolet, and after described second thin film absorbs ultraviolet when LASER HEAT TREATMENT, density becomes big.
Alternatively, the material of described second thin film is SiGe or unformed silicon.
Alternatively, the LASER HEAT TREATMENT described second thin film carried out is Ultra-Violet Laser heat treatment.
Alternatively, the heat treated temperature of described Ultra-Violet Laser is more than 1000 DEG C.
Alternatively, the heat treated wave-length coverage of described Ultra-Violet Laser is: 100nm～400nm.
Alternatively, the heat treated energy of described Ultra-Violet Laser is less than 2J/cm2。
Alternatively, the described Ultra-Violet Laser heat treated time is less than 1 μ s.
Alternatively, described movable member is single armed beam or the movable sensitive thin film of two ends support.
Alternatively, described Semiconductor substrate is silicon substrate or SOI, and it is the silicon substrate by erosion removal subregion or SOI realization that the release of described the first film forms it into movable member.
Alternatively, described Semiconductor substrate has sacrifice layer, the release of described the first film is formed it into movable member and realizes by removing described sacrifice layer.
Compared with prior art, technical scheme has the advantage that 1) the first film is deposited in Semiconductor substrate front, above-mentioned deposition process adopts high temperature, owing to the thermal coefficient of expansion of the first film is more than the thermal coefficient of expansion of this Semiconductor substrate, thus the two ends of Semiconductor substrate and the first film there will be the phenomenon tilted to Semiconductor substrate front, for solving the problems referred to above, continue to form the second thin film at the Semiconductor substrate back side, second thin film is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion thermal coefficient of expansion more than Semiconductor substrate, owing to the thermal coefficient of expansion of the second thin film after processing is high temperature more than the thermal coefficient of expansion of Semiconductor substrate and above-mentioned process, thus, during LASER HEAT TREATMENT, the second thin film two ends at Semiconductor substrate and the back side thereof tend to tilt to the Semiconductor substrate back side, the tilting of above-mentioned tilting trend and the first film is offset, thus after cooling, flat Semiconductor substrate can be obtained, the first film and the second thin film, and flat the first film through release after still in flat state, the MEMS that movable member sensing sensitivity is high is obtained thus making in the way of low cost.
2) in alternative, second thin film can absorb ultraviolet, after described second thin film absorbs ultraviolet when LASER HEAT TREATMENT, density becomes big, density becomes the thermal coefficient of expansion of the second big thin film and becomes big, in addition it is high temperature during heat treatment, need to lower the temperature for follow-up and can obtain non-warpage, flat the first film, density the second big thin film of change and Semiconductor substrate.
3), in alternative, there are two kinds to discharge flat the first film and form the mode of MEMS movable member: a) Semiconductor substrate is silicon substrate or SOI, and the silicon substrate of erosion removal subregion or SOI are to form the cavity of suspension the first film；B) Semiconductor substrate has sacrifice layer, remove described sacrifice layer to form the cavity of suspension the first film.
Accompanying drawing explanation
Fig. 1 to Fig. 7 is the structural representation in the different production phases of the MEMS in one embodiment of the invention.
Detailed description of the invention
As described in the background art, existing MEMS is after making, and movable member therein, due to Stress Release reason, warpage often occurs, and uneven phenomenon, this will affect the sensing of MEMS.For the problems referred to above, the present invention proposes: deposit the first film in Semiconductor substrate front, above-mentioned deposition process adopts high temperature, owing to the thermal coefficient of expansion of the first film is more than the thermal coefficient of expansion of this Semiconductor substrate, thus Semiconductor substrate and the first film there will be the phenomenon that two ends tilt to Semiconductor substrate front, the first film of such warpage will also result in movable member injustice after release forms movable member, for solving the problems referred to above, the present invention proposes to continue to form the second thin film at the Semiconductor substrate back side, second thin film is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion thermal coefficient of expansion more than Semiconductor substrate, owing to the thermal coefficient of expansion of the second thin film after processing is high temperature more than the thermal coefficient of expansion of Semiconductor substrate and above-mentioned process, thus, during LASER HEAT TREATMENT, the second thin film two ends at Semiconductor substrate and the back side thereof tend to tilt to the Semiconductor substrate back side, the tilting of above-mentioned tilting trend and the first film is offset, thus after cooling, flat Semiconductor substrate can be obtained, the first film and the second thin film, and flat the first film through release after still in flat state, the MEMS that movable member sensing sensitivity is high is obtained thus making in the way of low cost.
Understandable for enabling the above-mentioned purpose of the present invention, feature and advantage to become apparent from, below in conjunction with accompanying drawing, specific embodiments of the invention are described in detail.
Fig. 1 to Fig. 7 is the MEMS structural representation in the different production phases of one embodiment of the invention offer.Below in conjunction with, shown in Fig. 1 to Fig. 7, the manufacture method of MEMS being discussed in detail.
First, with reference to the top view shown in Fig. 1 and the sectional view of A-A straight line along Fig. 1 shown in Fig. 2, thering is provided Semiconductor substrate, described Semiconductor substrate front has the first film 12, and the thermal coefficient of expansion of described the first film 12 is more than the thermal coefficient of expansion of described Semiconductor substrate.
In the present embodiment, Semiconductor substrate is silicon substrate 10 or SOI, and the material of the first film 12 thereon is such as SiGe, for instance adopting furnace process to be formed, formation temperature is such as 300 DEG C～500 DEG C.In other embodiments, the material of this first film 12 can also be the metal such as copper or aluminum, adopts physical vapour deposition (PVD) or chemical vapour deposition (CVD) under high temperature to be formed.This first film 12 is subsequently used for forming movable member, and in the present embodiment, this movable member is the movable sensitive thin film that two ends support, and in other embodiments, this movable member can also be the single armed beam of single-ended support.Semiconductor substrate front has transistor, metal interconnection structure (not shown) etc., for to described movable member electric insulation, between this first film 12 and silicon substrate 10 or SOI, or the subregion between the first film 12 and metal interconnection structure has insulating barrier 11, this insulating barrier 11 is subsequently used for forming support end, owing to insulating barrier 11 is covered by the first film 12, thus the region of insulating barrier 11 be have employed shown in phantom by Fig. 1.The material of insulating barrier 11 is such as silicon dioxide or silicon nitride.
Due to for high temperature in above-mentioned deposition the first film 12 process, and the thermal coefficient of expansion of the first film 12 is more than the thermal coefficient of expansion of Semiconductor substrate, thus the stress deformation of the SiGe of the first film 12 is more than the stress deformation of the silicon of Semiconductor substrate, the first film 12 tractive silicon semiconductor substrate, after cooling, as shown in Figure 3, it may appear that the phenomenon of two ends upturned (to the front warpage of Semiconductor substrate).
For solving the problems referred to above, then, with reference to, shown in Fig. 4, continuing to be formed at the Semiconductor substrate back side the second thin film 13, with reference to shown in Fig. 5, described second thin film 13 is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion thermal coefficient of expansion more than described Semiconductor substrate.
Specifically, shown in Fig. 4, overturning described Semiconductor substrate so that it is the back side upward, forms the second thin film 13 on the back side, the material of this second thin film 13 is such as SiGe or unformed silicon.SiGe is formed at silicon substrate 10 or the SOI back side for example with furnace process or epitaxial growth method, and unformed silicon carries out Si ion implantation formation for example with to silicon substrate 10 or the SOI back side.
After SiGe or unformed silicon at high temperature absorb ultraviolet, density becomes big, and density becomes the thermal coefficient of expansion of the second thin film 13 ' (with reference to shown in Fig. 6) after greatly and becomes big, and more than the thermal coefficient of expansion of Semiconductor substrate.As shown in Figure 5, above-mentioned Ultra-Violet Laser heat treatment is high temperature, shown in Fig. 6, owing to the thermal coefficient of expansion of the second thin film 13 ' is more than the thermal coefficient of expansion of Semiconductor substrate, thus the stress deformation of the second thin film 13 ' is more than the stress deformation of the silicon of Semiconductor substrate, second thin film 13 ' tractive silicon semiconductor substrate, two ends can tend to downsagging (to the back side warpage of Semiconductor substrate).
It can be seen that the deformation tendency of the second thin film 13 ' obtained after above-mentioned process is contrary with the warpage of the first film 12, thus adopts and the second thin film 13 is carried out LASER HEAT TREATMENT, can offset with the warpage of the first film 12.After LASER HEAT TREATMENT, as shown in Figure 6, only need to lower the temperature and can obtain flat Semiconductor substrate, the first film 12 and the second thin film 13 '.
It should be noted that, based on absorbing the character that ultraviolet density becomes big under above-mentioned SiGe or unformed silicon high temperature, what carry out in the present embodiment is Ultra-Violet Laser heat treatment, in other embodiments, can also according to the character of the second thin film 13, the LASER HEAT TREATMENT selecting other wave band makes its density become big, and thermal coefficient of expansion becomes big to the thermal coefficient of expansion more than silicon substrate.
Research shows, material is to the first film 12 and second thin film 13 of SiGe, and in the Ultra-Violet Laser heat treatment carry out the second thin film 13, technological parameter is: temperature is more than 1000 DEG C, and wave-length coverage: 100nm～400nm, energy is less than 2J/cm2, when the time is less than 1 μ s, the density of the second thin film 13 is become big degree and thermal coefficient of expansion becomes big degree and can obtain non-warpage, flat the first film the 12, second thin film 13 ' and Semiconductor substrate.In addition, research shows, under above-mentioned technological parameter, the depth bounds closed on the second thin film 13 is that the temperature of Semiconductor substrate 10 μm interior is more than 100 DEG C, depth bounds be the temperature of Semiconductor substrate 10 μm outer less than 100 DEG C, for the wafer (725 μm) of standard, the temperature of the first film 12 in Semiconductor substrate front is less than 50 DEG C, thus Ultra-Violet Laser heat treatment is less on the impact of the first film 12 in Semiconductor substrate and its front, both will not be caused damage.
Afterwards, with reference to shown in Fig. 7, after cooling, described the first film 12 is carried out release and forms it into movable member.
Specifically, with reference to shown in Fig. 7, after cooling, overturn described Semiconductor substrate, make it face up, the first film 12 is formed patterned first mask layer (not shown), with described patterned first mask layer for the first film 12 described in mask dry etching, forms patterned the first film 12 '.Afterwards, patterned the first film 12 ' and Semiconductor substrate are formed patterned second mask layer (not shown), with described patterned second mask layer for Semiconductor substrate described in mask corrosion, in the present embodiment, for instance adopt the subregion in TMAH solution selective removal silicon substrate 10 or SOI, form groove, this groove serves as the cavity 20 of suspension the first film 12, so, the first film 12 has been discharged so that it is become movable member.
It is understood that in the present embodiment, the first film 12 of suspension is that two ends support, thus for the movable sensitive thin film that two ends support, in other embodiments, it is also possible to being etched by the first film 12 of above-mentioned suspension as one end support, namely movable member is single armed beam.
It should be noted that, in the present embodiment, cavity 20 is formed by etching silicon substrate 10 or SOI, in other embodiments, Semiconductor substrate can also have sacrifice layer (not shown), the first film 12 is formed on sacrifice layer, removes described sacrifice layer and can also form the cavity 20 of suspension the first film 12, so realizes the release of the first film 12 is formed it into movable member.The material of sacrifice layer can be silicon dioxide, for instance adopting HF acid to remove, the material of sacrifice layer can also be agraphitic carbon, for instance adopt ashing method to remove.
Above-mentioned manufacture method defines flat movable member, thus movable member sensing sensitivity is high, it addition, the formation of the second thin film 13 in such scheme and make the method that its thermal coefficient of expansion increases less costly, namely make, in low cost mode, the MEMS that movable member sensing sensitivity is high.
Although present disclosure is as above, but the present invention is not limited to this.Any those skilled in the art, without departing from the spirit and scope of the present invention, all can make various changes or modifications, and therefore protection scope of the present invention should be as the criterion with claim limited range.
Claims (14)
1. a manufacture method for MEMS, including:
Thering is provided Semiconductor substrate, deposit the first film in described Semiconductor substrate front, the thermal coefficient of expansion of described the first film is more than the thermal coefficient of expansion of described Semiconductor substrate；
It is characterized in that, continue to form the second thin film at the Semiconductor substrate back side, described second thin film is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion thermal coefficient of expansion more than described Semiconductor substrate；
After cooling, described the first film is carried out release and forms it into movable member.
2. manufacture method according to claim 1, it is characterised in that the material of described Semiconductor substrate is silicon, the material of described the first film is SiGe, copper or aluminum.
3. manufacture method according to claim 2, it is characterised in that described the first film adopts furnace process to be formed, and temperature range is 300 DEG C～500 DEG C.
4. manufacture method according to claim 2, it is characterized in that, described second thin film is carried out LASER HEAT TREATMENT and makes its thermal coefficient of expansion make its density become big realization more than the thermal coefficient of expansion of described Semiconductor substrate by described second thin film carries out LASER HEAT TREATMENT.
5. manufacture method according to claim 4, it is characterised in that described second thin film can absorb ultraviolet, after described second thin film absorbs ultraviolet when LASER HEAT TREATMENT, density becomes big.
6. manufacture method according to claim 5, it is characterised in that the material of described second thin film is SiGe or unformed silicon.
7. manufacture method according to claim 6, it is characterised in that the LASER HEAT TREATMENT that described second thin film is carried out is Ultra-Violet Laser heat treatment.
8. manufacture method according to claim 7, it is characterised in that the heat treated temperature of described Ultra-Violet Laser is more than 1000 DEG C.
9. manufacture method according to claim 7, it is characterised in that the heat treated wave-length coverage of described Ultra-Violet Laser is: 100nm～400nm.
10. manufacture method according to claim 7, it is characterised in that the heat treated energy of described Ultra-Violet Laser is less than 2J/cm2。
11. manufacture method according to claim 10, it is characterised in that the described Ultra-Violet Laser heat treated time is less than 1 μ s.
12. manufacture method according to claim 1, it is characterised in that described movable member is single armed beam or the movable sensitive thin film of two ends support.
13. manufacture method according to claim 1, it is characterised in that described Semiconductor substrate is silicon substrate or SOI, it is the silicon substrate by erosion removal subregion or SOI realization that the release of described the first film forms it into movable member.
14. manufacture method according to claim 1, it is characterised in that in described Semiconductor substrate, there is sacrifice layer, the release of described the first film is formed it into movable member and realizes by removing described sacrifice layer.
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| US5183783A (en) * | 1990-12-28 | 1993-02-02 | Shin-Etsu Handotai Co., Ltd | Method for production of dielectric-separation substrate |
| US6756285B1 (en) * | 1999-02-10 | 2004-06-29 | Commissariat A L'energie Atomique | Multilayer structure with controlled internal stresses and making same |
| CN102024783A (en) * | 2009-09-22 | 2011-04-20 | 中芯国际集成电路制造(上海)有限公司 | Semiconductor element for use in interconnection process and manufacturing method thereof |
| CN102420176A (en) * | 2011-06-15 | 2012-04-18 | 上海华力微电子有限公司 | Method for improving warping of semiconductor wafer |
| CN102598243A (en) * | 2009-10-30 | 2012-07-18 | 索泰克公司 | Method for controlling the distribution of stresses in a semiconductor-on-insulator type structure and corresponding structure |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5183783A (en) * | 1990-12-28 | 1993-02-02 | Shin-Etsu Handotai Co., Ltd | Method for production of dielectric-separation substrate |
| US6756285B1 (en) * | 1999-02-10 | 2004-06-29 | Commissariat A L'energie Atomique | Multilayer structure with controlled internal stresses and making same |
| CN102024783A (en) * | 2009-09-22 | 2011-04-20 | 中芯国际集成电路制造(上海)有限公司 | Semiconductor element for use in interconnection process and manufacturing method thereof |
| CN102598243A (en) * | 2009-10-30 | 2012-07-18 | 索泰克公司 | Method for controlling the distribution of stresses in a semiconductor-on-insulator type structure and corresponding structure |
| CN102420176A (en) * | 2011-06-15 | 2012-04-18 | 上海华力微电子有限公司 | Method for improving warping of semiconductor wafer |
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