U.S. patent application number 09/302225 was filed with the patent office on 2001-08-30 for micromechanical component and method for producing the micromechanical component.
Invention is credited to BUCHAN, NICHOLAS, FEHRENBACH, MICHAEL, SCHUBERT, DIETRICH.
Application Number | 20010017058 09/302225 |
Document ID | / |
Family ID | 7866365 |
Filed Date | 2001-08-30 |
United States Patent
Application |
20010017058 |
Kind Code |
A1 |
BUCHAN, NICHOLAS ; et
al. |
August 30, 2001 |
MICROMECHANICAL COMPONENT AND METHOD FOR PRODUCING THE
MICROMECHANICAL COMPONENT
Abstract
A method for producing a micromechanical component (e.g., a
capacitive acceleration sensor) having one or several electrical or
mechanical function variables dependent on at least one geometric
design parameter. The micromechanical component is produced by an
etching process via which a structure with bars and trenches is
formed. The structure is formed by drafting a design for the
micromechanical component in such a way that the geometric design
parameter within the local area of the micromechanical component is
subject to a predetermined process-related regularity. The design
parameter is essentially constant in relation to function blocks in
particular, so that in the etching process, the process tolerance
of the design parameter within the micromechanical component
essentially shows no locus dependency.
Inventors: |
BUCHAN, NICHOLAS; (AALBORG,
DE) ; FEHRENBACH, MICHAEL; (ENINGEN, DE) ;
SCHUBERT, DIETRICH; (REUTLINGEN, DE) |
Correspondence
Address: |
KENYON & KENYON
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
7866365 |
Appl. No.: |
09/302225 |
Filed: |
April 29, 1999 |
Current U.S.
Class: |
73/514.32 ;
73/514.16 |
Current CPC
Class: |
G01P 2015/0814 20130101;
B81C 1/00626 20130101; G01P 15/125 20130101; B81C 99/006 20130101;
G01P 15/0802 20130101; B81B 2201/0235 20130101 |
Class at
Publication: |
73/514.32 ;
73/514.16 |
International
Class: |
G01F 023/30; G01P
015/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 30, 1998 |
DE |
1 98 19 458.7 |
Claims
What is claimed is:
1. A method for producing a micromechanical component, comprising
the steps of: providing at least one substantially constant
geometric design parameter to generate a design draft of the
micromechanical component, the at least one geometric design
parameter within a local area of the micromechanical component
being affected by a predetermined process-related regularity; and
etching a work piece to form the micromechanical component which
includes a particular structure having bars and trenches, the
micromechanical component having at least one function variable,
the at least one function variable including one of an electrical
function variable and a mechanical function variable, wherein the
at least one function variable depends from the at least one
geometric design parameter, and wherein the at least one geometric
design parameter includes a process tolerance parameter which is
provided for the micromechanical component, the process tolerance
parameter being substantially locus independent in the etching
step.
2. The method according to claim 1, further comprising the steps
of: determining a dependency of at least one function variable on
one of the process tolerance parameter and the at least one
geometric design parameter; deriving a relationship for the at
least one geometric design parameter to minimize the dependency;
and determining the at least one geometric design parameter to
complete the relationship using the process tolerance
parameter.
3. The method according to claim 2, wherein the micromechanical
component is a capacitive acceleration sensor which has: a seismic
mass device suspended on a torsion spring device, a movable
capacitor plate device attached to the seismic mass device, and a
fixed capacitor plate device cooperating with the movable capacitor
plate device, and wherein the at least one function variable
corresponds to a sensitivity of the capacitive acceleration sensor,
the at least one function variable being defined as: 9 S = C ( b m
- ) ( b f - ) 3 ( d + ) wherein: C is a predetermined constant,
.DELTA. is the process tolerance parameter, b.sub.m is a width of
the seismic mass device, b.sub.f is a width of torsion springs of
the torsion spring device, and d is a plate distance of at least
one of the movable and fixed capacitor plate devices in an
unaccelerated state.
4. The method according to claim 2, wherein the relationship is
determined by deriving the dependency as a function of the process
tolerance parameter.
5. The method according to claim 1, further comprising the step of:
providing the predetermined process-related regularity to maintain
an etching density within predetermined limits.
6. The method according to claim 1, wherein the micromechanical
component is a capacitive acceleration sensor.
7. The method according to claim 1, wherein the at least one
geometric design parameter is substantially constant with respect
to function blocks of the at least one function variable.
8. A micromechanical component having at least one function
variable, comprising: a structure having bars and trenches, the
structure being formed by an etching procedure; and a local area
portion in which at least one substantially constant geometric
design parameter is affected by a predetermined process-related
regularity wherein the at least one function variable depends from
the at least one geometric design parameter, the at least one
function variable being one of an electrical function variable and
a mechanical function variable, and wherein the at least one
geometric design parameter includes a process tolerance parameter
which is provided for the micromechanical component, the process
tolerance parameter being substantially locus independent in the
etching procedure.
9. The micromechanical component according to claim 8, wherein the
micromechanical component is a capacitive acceleration sensor, the
capacitive acceleration sensor including: a seismic mass device
suspended on a torsion spring device, a movable capacitor plate
device attached to the seismic mass device, and a fixed capacitor
plate device cooperating with the movable capacitor plate
device.
10. The micromechanical component according to claim 8, wherein the
local area portion includes at least one of a fill structure and a
further structure having further trenches, the further structure
being independent from the at least one function variable.
11. The micromechanical component according to claim 8, further
comprising: a functional element, wherein the at least one
geometric design parameter includes at least one of a bar width of
the functional element and a trench width of the functional
element.
12. The micromechanical component according to claim 8, wherein the
movable capacitor plate device includes capacitor plates which have
a dual-arm structure.
13. The micromechanical component according to claim 8, wherein the
micromechanical component is a capacitive acceleration sensor.
14. The micromechanical component according to claim 8, wherein the
at least one geometric design parameter is substantially constant
with respect to function blocks of the at least one function
variable.
15. A micromechanical component having at least one function
variable, comprising: a structure having bars and trenches, the
bars provided in an alternating manner with respect to the
trenches, the structure being formed by an etching procedure,
wherein a first width of the bars and a second width of the
trenches are maintained substantially uniform according to a
predetermined grid pattern which extends across the micromechanical
component, the structure including elements which have a
functionally larger overall width and which are at least partially
structured according to the predetermined grid pattern, wherein the
at least one function variable is one of an electrical function
variable and a mechanical function variable, and wherein the at
least one function variable depends from at least one geometric
design parameter.
16. The micromechanical component according to claim 15, wherein
the micromechanical component is a capacitive acceleration
sensor.
17. A capacitive acceleration sensor composed of polycrystalline
silicon and produced by a surface micromachining procedure,
comprising: a torsion spring device; a seismic mass device
suspended on the torsion spring device; a movable capacitor plate
device attached to the seismic mass device; and a fixed capacitor
plate device cooperating with the movable capacitor plate device,
wherein the seismic mass device and the movable capacitor plate
device attached to the seismic mass device are composed of bars
which are electrodes, the electrodes having a first
process-specific value range for a first width of a particular bar
of the bars, wherein the bars have a first process-specific value
range for a first distance which extends to solid electrodes of the
fixed capacitor plate device, wherein the first distance
corresponds to a second distance of the bars, and wherein a second
width of the torsion springs is within a second process-specific
value range.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to a micromechanical component
and to a method for producing the micromechanical component (e.g.,
a capacitive acceleration sensor) having one or several electrical
or mechanical function variables dependent on at least one
geometric design parameter. The micromechanical component is
produced by an etching process via which a structure with bars and
trenches is formed.
BACKGROUND INFORMATION
[0002] Using processes of surface micromachining technology, it is
possible to produce sensors, actuators and other miniaturized
components according to methods that are known from a production of
microelectronic components.
[0003] It is known that such processes used in surface
micromachining technology for producing mechanical and/or
electrical functional elements are subject to production process
tolerances. In this manner, the term production tolerance is
intended to designate the deviation from a setpoint which is
expediently selected as the process mean value. As a rule, these
production process tolerances result in high variations in the
characteristic data of the mechanical or electrical functional
elements in question, which must be provided for by balancing,
compensation or calibration.
[0004] Examples for this are the sensitivity and the resonance
frequency of the mentioned micromechanical capacitive acceleration
sensor as a function of the trench etching process. In this trench
etching process, the sensor is subdivided into a structure having
trenches and bars, which contains the necessary functional
elements, in this case, capacitor devices and spring devices.
[0005] Such production process tolerances, or process tolerances in
short, are known to arise in trench etching (e.g., dry etching) due
to varying process temperatures or process gas compositions or
process gas flow rates, etc.
[0006] In general, it is desirable to produce micromechanical
components with low characteristic data variation in order to avoid
time-consuming and costly calibration processes, balancing
processes or the like.
[0007] Consequently, one of the objects of the present invention is
to keep the characteristic data variations as a function of process
tolerances at a low level or to reduce them by a suitable
arrangement of certain geometric design parameters.
SUMMARY OF THE INVENTION
[0008] A method according to the present invention for producing a
micromechanical component, and the micromechanical component have
an advantage that, in a specified process tolerance range, a
dependency of the characteristic data on the present process
situation in the process tolerance range (e.g., 3.sigma. range) is
minimized; thus a compensation of the influences occurs
simultaneously.
[0009] For example, this compensation brings about an increase of
the wafer and product yield, a uniform reliability with low
balancing outlay (expenses for evaluation electronics are reduced)
as well as a smaller possible size of the component.
[0010] The present invention provides that the drafting of a design
for the micromechanical component proceeds in such a way that the
geometric design parameter within the local area of the
micromechanical component is subject to a predetermined
process-related regularity, the design parameter being essentially
constant in relation to function blocks in particular, so that in
the etching process, the process tolerance of the design parameter
within the micromechanical component shows essentially no locus
dependency.
[0011] According to another embodiment of the present invention, a
determination of an essential dependency of at least one of the
electrical or mechanical function variables of the component on the
process tolerance of the design parameter or design parameters in
question takes place in the etching process. Then, a relationship
for the design parameter or design parameters is derived in order
to minimize the dependency and finally, the design parameter is
determined in such a way that the derived relationship is fulfilled
with the expected process tolerance. This procedure is expedient
when several design parameters exert a substantial influence and
therefore cannot be selected independent of one another.
[0012] According to another embodiment of the present invention,
the micromechanical component is a capacitive acceleration sensor
having a seismic mass device suspended on a torsion spring device,
a movable capacitor plate device attached to the seismic mass
device and a fixed capacitor plate device interacts with the
movable capacitor plate device. In this embodiment, the function
variable is the sensitivity of the acceleration sensor, the
essential dependency being stated by the following equation: 1 S =
C ( b m - ) ( b f - ) 3 ( d + )
[0013] where C is a constant, .DELTA. is a process tolerance,
b.sub.m is a width of the seismic mass device, b.sub.f is a width
of the torsion springs of the torsion spring device, and d is a
plate distance of the particular capacitor plate device in the
unaccelerated state.
[0014] According to another embodiment of the present invention,
the relationship is formed by forming the derivation of the
dependency according to the process tolerance. This may occur
either numerically or, if possible, analytically.
[0015] According to an additional embodiment, the regularity is
specified in such a way that the etching density is held within
certain limits of a specified value.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1a shows a top view of a schematic representation of a
micromechanical capacitive acceleration sensor.
[0017] FIG. 1b shows a schematic representation of the
micromechanical capacitive acceleration sensor illustrated in FIG.
1a in a cross-section along line A-B.
[0018] FIG. 2 shows a schematic representation of a structure of
the micromechanical capacitive acceleration sensor which is not
produced by a method according to the present invention.
[0019] FIG. 3 shows a schematic representation of the structure of
the micromechanical capacitive acceleration sensor which is
produced by the method according to the present invention.
[0020] FIG. 4 shows a graphical representation of a sensitivity of
the sensors illustrated in FIGS. 2 and 3 as a function of a process
tolerance.
DETAILED DESCRIPTION
[0021] Although the present invention is applicable to any number
of micromechanical components, the present invention will be
explained below with reference to a micromechanical capacitive
acceleration sensor.
[0022] FIG. 1a shows a schematic representation of a
micromechanical capacitive acceleration sensor to explain the
present invention and the set of problems on which it is based.
[0023] FIGS. 1a and 1b show a seismic mass device 1, a first
torsion spring 2a having a width b.sub.f and a length l.sub.f, a
second torsion spring 2b having a width b.sub.f and a length
l.sub.f, a third torsion spring 3a having a width b.sub.f and a
length l.sub.f, a fourth torsion spring 3b having a width b.sub.f
and a length l.sub.f, a first movable capacitor plate 4 having a
width b.sub.m, a first fixed capacitor plate 4a, a second fixed
capacitor plate 4b, a second movable capacitor plate 5 having a
width b.sub.m, a third fixed capacitor plate 5a, and a fourth fixed
capacitor plate 5b.
[0024] Together with first movable capacitor plate 4 and second
movable capacitor plate 5, first fixed capacitor plate 4a and third
fixed capacitor plate 5a form a first plate capacitor device
10.
[0025] Together with first movable capacitor plate 4 and second
movable capacitor plate 5, second fixed capacitor plate 4b and
fourth fixed capacitor plate 5b form a second plate capacitor
device 20.
[0026] FIG. 1b shows a schematic representation of the
micromechanical capacitive acceleration sensor illustrated in FIG.
1a in cross-section along the line A-B. The deflection of seismic
mass device 1 from the center position corresponding to the
unaccelerated state is identified as x and the plate distance of
the two capacitor devices 10, 20 in the unaccelerated state is
identified as d.
[0027] The physical relationships on which the analysis of this
micromechanical capacitive acceleration sensor is based will be
explained in greater detail below.
[0028] Voltage output signal V.sub.out at the time of a deflection
x from the equilibrium position can be described as follows: 2 V
out = ( C1 - C2 ) ( C1 + C2 ) V ref ( 1 )
[0029] C1 being the capacitance of first plate capacitor device 10,
C2 being the capacitance of second plate capacitor device 20 and
V.sub.ref being a reference voltage applied from the outside to
plate capacitor devices 10, 20.
[0030] Furthermore: 3 ( C1 - C2 ) ( C1 + C2 ) = m a k d ( 2 )
[0031] m identifying the seismic mass of seismic mass device 1, a
identifying the instantaneous acceleration occurring at the time of
measurement and k identifying the flexural strength of torsion
springs 2a, 2b, 3a, 3b.
[0032] The following relationship applies to seismic mass m: 4 m =
h l m ( b m - ) ( 3 )
[0033] .rho. identifying the specific weight of the material used
(polysilicon in this case), h identifying the layer thickness,
l.sub.m identifying the length of seismic mass device 1, and
.DELTA. identifying the present process tolerance.
[0034] The following relationship applies to flexural strength k: 5
k = N E si h ( b f - ) 3 l f 3 ( 4 )
[0035] N identifying the number of bending elements, and E.sub.si
the modulus of elasticity of the material used (polysilicon in this
case).
[0036] If equations (3) and (4) are inserted into equation (2) and
the thus obtained equation (2) is inserted into equation (1), the
following is obtained: 6 V out = l f 3 h l m ( b m - ) a V ref N E
si h ( b f - ) 3 ( d + ) ( 5 )
[0037] In this connection, the etching process under consideration
influences the structure defined by the masking method. The plate
distance of plate capacitor devices 10, 20 in the equilibrium
position increases by the assumed present process tolerance
.DELTA., and width b.sub.m of seismic mass device 1 and widths
b.sub.f of torsion springs 2a, 2b, 3a, 3b decrease accordingly.
[0038] Combining the variables which are not subject to
fluctuations or only relatively insignificant ones into a constant
C results in the following: 7 V out = C ( b m - ) a ( b f - ) 3 ( d
+ ) ( 6 )
[0039] The electrical function variable of the acceleration sensor
that is of primary interest is its sensitivity S which is precisely
the derivation of the output voltage with regard to the
instantaneous acceleration a to be recorded; thus 8 S = C ( b m - )
( b f - ) 3 ( d + ) ( 7 )
[0040] It is possible to select variables b.sub.m, b.sub.f and d of
such a size that the relative influence of the process tolerance is
reduced. However, this may result in an unfavorable characteristic
data field of the sensor, specifically due to the reduction of the
capacitance of capacitor devices 10, 20 and the associated
reduction of the sensitivity.
[0041] From equation (7), variables b.sub.m, b.sub.f and d should
not be freely selected in a design intended to satisfy the set
requirement for reduction or suppression of the influence of
process tolerances but rather should fulfill a certain
relationship.
[0042] In particular, the derivation of equation (7) according to
process tolerance .DELTA. should be equal to zero; thus
dS/d.DELTA.=0. In the case described above, this results in the
relationship for variables b.sub.m, b.sub.f and d for the creation
of a design satisfying the set requirement for reduction or
suppression of the influence of process tolerances.
[0043] Moreover, care must be taken that the process tolerance is
locally constant within the local area of an individual component
on a wafer, i.e., it does not show any locus dependency, since
otherwise the above assumptions no longer apply. This can be
assured by compliance with certain layout rules which will be
explained in greater detail below.
[0044] In the etching process, the design should ensure that the
material removed by etching from the structural elements is
essentially equal. This is primarily achieved by keeping the
specified etching density, i.e., the desired amount of material
removed by etching per unit of surface area, within certain limits
of a specified value.
[0045] FIG. 2 shows a schematic representation of the structure of
a micromechanical capacitive acceleration sensor which is not
produced of the method according to the present invention.
[0046] In particular, FIG. 2 shows a seismic mass device 1' with
movable capacitor plates 30, a first comb structure 40 with
corresponding first fixed capacitor plates, a second comb structure
50 with corresponding second fixed capacitor plates, a torsion
spring device 60, and a wide trench structure 70. The mode of
operation of this sensor according to FIG. 2 is analogous to that
of the sensor according to FIG. 1a. Various trench widths of the
etching trenches are identified as d, d', d", d'".
[0047] The following values are selected independent of each other
for the variables b.sub.m, b.sub.f and d:
[0048] b.sub.f=3.0 .mu.m
[0049] b.sub.m=5.0 .mu.m
[0050] d=2.0 .mu.m
[0051] Furthermore, constant C from equation (6) is 0.333*10.sup.18
V/g and the sensor is designed for a sensitivity of 35 g with a
surface area of 0.5 mm.sup.2.
[0052] The above-described design does not meet the requirement for
low variation of the sensitivity of the sensor and caused great
fluctuations of characteristic data in sensitivity.
[0053] This is due to the fact that the critical trench widths and
bar widths of the essential functional elements and the
intermediate and/or marginal areas of the sensor are not matched.
In particular, in this design, there are different trench widths d,
d' in the area of capacitor plate structure 30, 40, 50; a large
trench width d" in area 70 and an additional trench width d'" in
the area of torsion spring device 60.
[0054] FIG. 3 shows a schematic representation of the structure of
a micromechanical capacitive acceleration sensor which is produced
by the method according to the present invention.
[0055] In particular, FIG. 3 shows a seismic mass device 1",
movable capacitor plates 300 with a dual-arm structure 301, 302
with cross bars 303, a first comb structure 400 with corresponding
first fixed capacitor plates, a second comb structure 500 with
corresponding second fixed capacitor plates, a torsion spring
device 600, a fill area 700, and an added structural area 800 with
trenches.
[0056] The mode of operation of this sensor shown in FIG. 3 is also
analogous to that of the sensor illustrated in FIG. 1a.
[0057] In contrast to the sensor shown in FIG. 2, it was ensured
for the sensor design illustrated in FIG. 3 provides that the
design parameter b.sub.m, b.sub.f, d within the local area of the
micromechanical component is formed essentially uniformly in
relation to function blocks. In other words, trench width d is
essentially equal in the capacitor devices, between the capacitor
devices and in torsion spring device 600. Fill area 700 and added
structural area 800 with trenches were provided in addition in
order to obtain the locally constant process tolerance A. The
greater trench width at the edge of the capacitor devices is
preferable to avoid interfering edge effects. It does not have an
interfering effect, since the fluctuations in length do not exert a
substantial influence on the sensitivity.
[0058] These design measures of the present invention bring it
about that with the trench etching process, the process tolerance
A, i.e., the bar width or the trench width within the sensor,
essentially shows no locus dependency.
[0059] The following values are selected independent of each other
in particular for the variables b.sub.m, b.sub.f and d:
[0060] b.sub.f=4.0 .mu.m
[0061] b.sub.m=2*3.0 .mu.m (dual-arm structure)
[0062] d=2.0 .mu.m
[0063] Furthermore, constant C from equation (6) was
1.175*10.sup.18 V/g and the sensor is likewise designed for a
sensitivity of 35 g with a surface area of 0.5 mm.sup.2.
[0064] For the selection of these variables, the derivation of the
sensitivity dS/d.DELTA. for the expected process tolerance is set
to equal zero. Then, d was set as the minimum design measure.
b.sub.m is specified according to an experience value and b.sub.f
is calculated from the determined relationship for
dS/D.DELTA.=0.
[0065] This design meets the requirement for less variation of the
sensitivity of the sensor.
[0066] FIG. 4 shows a representation of the sensitivity of the
sensors illustrated in FIGS. 2 and 3 as a function of the process
tolerance.
[0067] As shown in FIG. 4, the process tolerance is indicated in
arbitrary units on the x axis and the sensitivity is indicated on
the y axis in mV/g. Line SW identifies the process setpoint. The
result for the uncompensated sensor shown in FIG. 2 is reproduced
by curve UKS and the result for the compensated sensor shown in
FIG. 3 is reproduced by curve KS.
[0068] FIG. 4 illustrated that a curve KS shows no dependency on
the process tolerance while a curve UKS shows a drastic dependency
on the process tolerance.
[0069] With special reference to a capacitive acceleration sensor
made of polycrystalline silicon produced by surface micromachining
as shown in FIG. 1, 2 or 3, for example, the following may
apply.
[0070] Seismic mass device 1, 1' or 1" and the movable capacitor
plate device 4, 5 or 30 or 300 attached thereto are composed of
bars as electrodes which have a process-specific value range for
the bar width bm.
[0071] The bars of the movable capacitor plate device 4, 5 or 30 or
300 which are attached to the seismic mass device 1, 1' or 1" have
a process-specific value range for distance d to the solid
electrodes of fixed capacitor plate device 40, 400 or 50, 500.
[0072] The distance of the fixed electrodes corresponds to the
distance of the bars from which seismic mass device 1, 1' or 1" and
movable capacitor plate device 4, 5 or 30 or 300 attached thereto
are made up.
[0073] Finally, the width of torsion springs b.sub.f is set in a
possible range of values specific to the process.
[0074] The trench process for structuring the elements from
polycrystalline silicon causes the bars and springs to be narrower
and the distance of the electrodes to be greater.
[0075] The values for this loss of structure have a process-related
range of variation, e.g., 0.7+/-0.5 .mu.m.
[0076] In order to suppress the influence of variation of this loss
of structure on the variation of the sensitivity, the ratio
bm/bf=0.5 to 0.9 should be maintained for the ranges of design
values that are of practical interest, thus
[0077] 2.0 .mu.m.ltoreq.bm.ltoreq.4.0 .mu.m
[0078] 1.5 .mu.m.ltoreq.d.ltoreq.3.0 .mu.m
[0079] 3.0 .mu.m.ltoreq.bf.ltoreq.6.0 .mu.m
[0080] irrespective of the desired absolute value for
sensitivity.
[0081] If the range of values is limited to
[0082] 2.5 .mu.m.ltoreq.b.sub.m.ltoreq.3.5 .mu.m
[0083] 1.5 .mu.m.ltoreq.d.ltoreq.2.5 .mu.m
[0084] 3.9 .mu.m.ltoreq.b.sub.f.ltoreq.5.1 .mu.m
[0085] the ratio b.sub.m/b.sub.f=0.6 to 0.8 must be maintained
irrespective of the desired absolute value for sensitivity.
[0086] In order to obtain a sufficiently high mechanical stability
of the electrodes, it is advantageous to design the electrodes in
the form of two connected bars due to the limitations of electrode
width b.sub.m (FIG. 3).
1 Influence of b.sub.m d 1.5 1.5 1.5 1.5 1.5 b.sub.m 2.0 2.5 3.0
3.5 4.0 MAX-MIN b.sub.f 3.10 3.61 4.01 4.29 4.55 b.sub.f 1.45
b.sub.mb.sub.f 0.69 0.69 0.75 0.82 0.88 b.sub.m/b.sub.f 0.23 d 2.0
2.0 2.0 2.0 2.0 b.sub.m 2.0 2.5 3.0 3.5 4.0 MAX-MIN b.sub.f 3.29
3.87 4.35 4.73 4.93 b.sub.f 1.64 b.sub.mb.sub.f 0.61 0.65 0.69 0.74
0.81 b.sub.m/b.sub.f 0.20 d 2.5 2.5 2.5 2.5 2.5 b.sub.m 2.0 2.5 3.0
3.5 4.0 MAX-MIN b.sub.f 3.42 4.09 4.60 5.06 5.40 b.sub.f 1.98
b.sub.mb.sub.f 0.58 0.61 0.65 0.69 0.74 b.sub.m/b.sub.f 0.26 d 3.0
3.0 3.0 3.0 3.0 b.sub.m 2.0 2.5 3.0 3.5 4.0 MAX-MIN b.sub.f 3.54
4.26 4.85 5.35 5.78 b.sub.f 2.24 b.sub.mb.sub.f 0.56 0.59 0.62 0.65
0.69 b.sub.m/b.sub.f 0.13 Influence of d MAX-MIN bf 0.44 0.65 0.84
1.06 1.23 MAX-MIN 0.08 0.11 0.13 0.16 0.19 b.sub.m/b.sub.f
[0087] The above table shows exemplary values for bar distance d,
bar width b.sub.m, torsion spring width b.sub.f and the influence
of bar distance and bar width.
[0088] Although the present invention was described above using a
preferred exemplary embodiment, it is not limited to this
embodiment but rather can be modified in various ways.
[0089] In particular, the method of the present invention is not
limited to capacitive acceleration sensors and can also be
generalized to any micromechanical components.
* * * * *