JP2009160677A - Mems and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve shock absorbing ability of a cover against a movable part such as a beam and a diaphragm and also to prevent the cover from sticking to the movable part. <P>SOLUTION: A MEMS comprises a movable element having the movable part and the cover having a ceiling for covering the movable part and a shock absorbing part protruding from the ceiling toward the movable part and made of resin, wherein a space is formed between the movable part and the shock absorbing part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a MEMS manufacturing method and a MEMS.

Conventionally, MEMS (Micro Electro Mechanical Systems) manufactured using a semiconductor manufacturing process are known. A space for deforming the movable part is formed around the movable part such as a minute beam or diaphragm made of silicon or the like provided in the MEMS. Such a space is covered with a cover so as not to be crushed by resin sealing and so as not to be deformed until the movable part is damaged (see Patent Documents 1 to 11). Such a cover is generally formed from a part (cover part) different from the main body part that becomes a plurality of movable elements by dicing. Since the cover part also has a function of preventing damage to movable parts such as beams in the dicing process, the cover part is joined to the main part in the wafer process before the dicing process.
JP 2004-255487 A JP 2005-285864 A JP 2006-88268 A JP 2007-42786 A JP 2007-134636 A JP 2003-270262 A JP 2004-233072 A JP 2006-153519 A JP 2006-208272 A JP 2006-317180 A JP 2006-317181 A

  However, when the cover is made of a hard inorganic solid material such as silicon, glass, metal, or ceramic, there is a problem that the movable part comes into contact with the cover and is damaged when an impact exceeding the rating is applied to the MEMS. Further, when the movable part is covered with the cover, sticking in which the movable part comes into contact with the cover and is directly fixed to the cover becomes a problem.

  The present invention has been created to solve these problems, and it is an object of the present invention to enhance the buffering capacity of a cover with respect to a movable part such as a beam or a diaphragm and prevent sticking between the cover and the movable part.

(1) A MEMS for achieving the above object includes a movable element including a movable part, a cover including a ceiling part covering the movable part, and a buffer part protruding from the ceiling part toward the movable part and made of resin. And a space is formed between the movable part and the buffer part.
According to the present invention, since the buffer portion protrudes from the ceiling portion of the cover toward the movable portion of the movable element, sticking between the movable portion and the cover is less likely to occur than in a configuration in which the flat ceiling portion contacts the movable portion. . In addition, according to the present invention, since the buffer portion is made of resin, the cover has a higher buffering capacity with respect to the movable portion than when the ceiling portion made of an inorganic solid material contacts the movable portion. Note that the movable element is a component that is a component of an electronic circuit and includes a movable part such as a beam and independently has a specific electrical function.

(2) In the MEMS for achieving the above object, the cover preferably protrudes from the ceiling portion and is joined to the movable element to support the ceiling portion and includes a support portion made of resin.
When the support part joined to the movable element and supporting the ceiling part on the movable part is also made of resin, the impact generated on the movable part of the movable element by colliding with the cover causes the cover support part to be made of an inorganic solid material. Smaller than the case.

(3) In the MEMS for achieving the above object, the ceiling part is preferably made of a resin.
When the ceiling part is also made of resin, the impact generated in the movable part of the movable element by colliding with the cover is smaller than when the ceiling part is made of an inorganic solid material.

(4) In the MEMS for achieving the above object, a plate that is harder than the ceiling part may be joined to the back surface of the surface from which the buffer part of the ceiling part protrudes.
By joining a plate that is harder than the cover to the ceiling, the rigidity and flatness of the ceiling can be increased.

(5) In the MEMS for achieving the above object, the buffer portion may be joined to a ceiling portion made of a material harder than the buffer portion.
When the ceiling part is made of a material harder than the buffer part, the ceiling part can be formed thin while ensuring the rigidity of the ceiling part as compared with the case where the ceiling part is made of the same material as the buffer part.

(6) As for MEMS for achieving the said objective, a buffer part may be a hump shape.
When the buffer portion is formed in a hump shape, the buffer portion has a higher buffering capacity than when the buffer portion is a rib shape.

(7) As for MEMS for achieving the said objective, a buffer part may be a rib shape.
When the buffer portion is formed in a rib shape, the rigidity of the cover can be increased by the rigidity of the buffer portion itself as compared with the case where the buffer portion is a hump shape.

  (8) In the MEMS manufacturing method for achieving the above object, a cover part including a plurality of ceiling parts covering the movable parts of the plurality of movable elements and a buffer part protruding from the ceiling parts and made of resin is formed, and each of them is movable. A cover part is joined to a main body part corresponding to a plurality of movable elements including a part in a state where a space is formed between the buffer part and the movable part, and the joined cover part and the main body part are joined to each movable element. It is divided into.

  According to the present invention, since the buffer portion is formed so as to protrude from the ceiling portion of the cover part divided by the cover toward the movable portion of the movable element, the cover portion that contacts the movable portion is formed flat. In comparison, it is possible to manufacture a MEMS in which sticking between the movable part and the cover hardly occurs. Further, by forming the buffer portion with resin, the buffer capacity of the cover with respect to the movable portion can be increased as compared with the case where the portion of the cover that contacts the movable portion is formed with an inorganic solid material.

(9) In the MEMS manufacturing method for achieving the above object, it is preferable to form the ceiling portion from a resin.
The impact generated in the movable part of the movable element by colliding with the cover is reduced by forming the ceiling part from resin as compared with the case where the ceiling part is formed from an inorganic solid material.

(10) In the MEMS manufacturing method for achieving the above-mentioned object, it is preferable that a support part that protrudes from the ceiling part and supports the ceiling part is formed from a resin on the cover part for each movable element, and the support part is joined to the main body part. .
When the support part that is joined to the movable element and supports the ceiling part on the movable part is also made of resin, the impact generated on the movable part of the movable element by colliding with the cover forms the support part of the cover from an inorganic solid material. It becomes smaller than the case.

(11) In the MEMS manufacturing method for achieving the above object, it is preferable to join the protruding end of the support portion to the main body component by thermocompression bonding.
By bonding the protruding end of the support portion made of resin to the main body component by thermocompression bonding, it is possible to prevent variations in the sensitivity of the MEMS caused by variations in the amount of adhesive used to bond the cover and the movable element.

(12) In the MEMS manufacturing method for achieving the above object, it is preferable to form the protruding end of the support portion on a convex curved surface.
By forming the protruding end of the support part into a convex curved surface, it becomes difficult to form a void when the protruding end of the support part is crushed by thermocompression bonding. In addition, the protrusion formed on the convex curved surface is more likely to be deformed by thermocompression than the protrusion formed on the flat surface. Therefore, the wiring pattern is not easily damaged even if the protruding end of the support portion is crimped to a region having unevenness corresponding to the wiring pattern, so that the miniaturization is facilitated.

(13) In the MEMS manufacturing method for achieving the above object, it is preferable to form the buffer portion by transferring the concave portion of the mold.
By forming the buffer portion using the mold, the manufacturing cost can be reduced and the reproducibility of the fine shape of the buffer portion can be increased.

  (14) In the MEMS manufacturing method for achieving the above object, a buffer portion made of a photosensitive resin may be formed by patterning a film made of a photosensitive resin using a multi-tone mask.

(15) In the MEMS manufacturing method for achieving the above object, it is preferable to integrally form the cover parts with resin.
Manufacturing costs can be reduced by integrally forming the cover parts with resin.

(16) In the MEMS manufacturing method for achieving the above object, an integral part in which a plate member harder than the cover part is joined to the back surface of the surface from which the support part of the ceiling part projects is formed, and the projecting end of the support part of the integral part Is preferably joined to the body part.
By joining a plate that is harder than the cover component to the cover component made of resin, it becomes easy to handle the flexible cover component.

  Note that the order of operations described in the claims is not limited to the order of description as long as there is no technical obstruction factor, and may be executed at the same time, may be executed in the reverse order of the description order, or may be continuous. It does not have to be executed in order.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.

1. First Embodiment Configuration of MEMS FIG. 13 is a schematic cross-sectional view showing an acceleration sensor 1 that is a first embodiment of a MEMS of the present invention. FIG. 14 is a schematic cross-sectional view corresponding to the cross section along line AA of FIG. The acceleration sensor 1 is a chip that includes a movable element 120, a cover 100 that covers a movable part 120 c built in the movable element 120, and a package 130.

  The package 130 includes a box-shaped package substrate 131 joined to a printed circuit board (not shown) and a package cover 135. The package substrate 131 includes an internal terminal 133 that is electrically connected to the element terminal 122 of the movable element 120 by a wire W, and an external terminal 134 that is electrically connected to wiring of a printed circuit board (not shown). Yes. The internal terminal 133 and the external terminal 134 are electrically connected by a contact plug 132. A wall 136 rises from the periphery of the package substrate 131. A package cover 135 is bonded to the protruding end surface of the wall 136 by an adhesive B. The movable element 120 and the cover 100 are accommodated in the internal space of the package 130.

  The movable element 120 is a die bonded to the package substrate 131 with a conductive paste P. The movable element 120 is made of, for example, a substrate 124 made of silicon or the like, an insulating film, a conductive film, a piezoelectric film, or a piezoresistor. An annular through hole 124 a is formed in a part of the substrate 124. An island-shaped portion of the substrate 124 surrounded by the through hole 124a constitutes a weight 120a joined to a beam 120b made of an insulating film and a piezoelectric film. The beam 120b and the weight 120a constitute a movable portion 120c of the movable element 120. A space covered by the ceiling portion 100b of the cover 100 is formed above the movable portion 120c. A space is formed below the movable portion 120c by a recess 131a formed in the package substrate 131. On the surface of the movable element 120, a plurality of element terminals 122 and a plurality of conducting wires 123 for outputting a voltage of a piezoelectric film or a resistance value of a piezoresistor are formed by a conductive film.

  The cover 100 is directly joined to the movable element 120 so as to cover the movable portion 120 c of the movable element 120. The cover 100 is an integral part made of a resin such as plastic. Since the joining region between the cover 100 and the movable element 120 is located at a portion inside the element terminal 122, the element terminal 122 is located outside the cover 100. Therefore, the cover 100 does not hinder the process of connecting the element terminal 122 and the internal terminal 133 with the wire W.

The cover 100 includes a plate-shaped ceiling portion 100b, a plurality of support portions 100a, and a plurality of bump-shaped buffer portions 100c, and is integrally formed of resin.
Each support part 100a protrudes in a columnar shape from the peripheral part of the ceiling part 100b. Therefore, the space between the cover 100 and the movable element 120 communicates with the space outside the cover 100 through the space between the plurality of support portions 100a.

  The plurality of buffer portions 100c are located above the movable portion 120c of the movable element 120. The buffer portion 100c is formed in an independent hump shape inside the plurality of support portions 100a, and protrudes from the ceiling portion 100b toward the movable portion 120c. The protruding end of the buffer portion 100c is a convex curved surface that tapers gently. Therefore, the buffer portion 100c is more easily deformed than the ceiling portion 100b, and has excellent buffer performance.

-Action of MEMS When the movable portion 120c of the movable element 120 is deformed, a voltage is generated in the piezoelectric film of the movable element 120 in the piezoelectric type, and the resistance value of the piezoresistance of the movable element 120 is changed in the piezoresistive type. As a result, a signal corresponding to the voltage of the piezoelectric film or the resistance value of the piezoresistor is output from the external terminal 134 through the element terminal 122, the wire W, the internal terminal 133, and the like.

  It is assumed that the impact exceeding the rating is applied to the acceleration sensor 1 and the movable part 120c collides with the cover 100 in the moving direction of the movable part 120c. At this time, the height of the space between the buffer portion 100c and the movable portion 120c is lower than the height of the space between the ceiling portion 100b and the movable portion 120c. Therefore, when the movable part 120c collides with the cover 100, it collides with the buffer part 100c having better buffer performance than the ceiling part 100b.

  Compared with the configuration in which the movable portion 120c is in contact with the flat ceiling portion 100b, the configuration in which the movable portion 120c is in contact with the buffer portion 100c reduces the contact area, so that sticking between the cover 100 and the movable portion 120c is less likely to occur. Become. Moreover, since the rigidity of the cover 100 can be increased by the buffer portion 100c, the ceiling portion 100b can be made thinner than in the case where the buffer portion 100c is not formed.

  Since the ceiling portion 100b of the cover 100 is made of resin, the impact applied to the movable portion 120c is further reduced as compared with the case where the movable portion 120c collides with the buffer portion 100c joined to the ceiling portion made of an inorganic solid material. Furthermore, since the cover 100 is an integrally formed part made of resin, including the support portion 100a, the impact generated by the collision between the movable portion 120c and the cover 100 is absorbed by the entire cover 100. Therefore, the impact applied to the movable part 120c is further reduced.

MEMS Manufacturing Method FIGS. 1 to 12 are schematic cross-sectional views for explaining a method of manufacturing the acceleration sensor 1 shown in FIGS. 13 and 14 except for FIG. 2B. FIG. 2B is a plan view for explaining a method of manufacturing the acceleration sensor 1. FIG. 2A corresponds to the cross section along line AA shown in FIG. 2B. 8 corresponds to the AA line cross section shown in FIG. 7, and FIG. 7 corresponds to the AA line cross section shown in FIG. The process shown in FIGS. 1 to 11 is a wafer process in which a large number of movable elements 120 are simultaneously formed on a substrate, but only the portion corresponding to one movable element 120 is shown.

  First, as shown in FIG. 1, a protective film R1 made of a photosensitive resin is formed on the surface of the substrate M, which is a mold material for forming the cover 100. The substrate M may be a transparent member such as quartz, soda lime glass, transparent crystallized glass, or sapphire, or may be an opaque member such as ceramic, resin, or metal. The thickness of the board | substrate M should just be the thickness which can ensure rigidity required as a mold, for example, shall be 2 mm. On the surface of the substrate M, a first mark M101 for alignment is formed in advance. The first mark M101 can be formed by forming a metal film such as chromium or an insulating film and patterning using a photolithography technique. The thickness of the first mark M101 is, for example, 0.1 μm.

  A plurality of recesses R101 corresponding to the support part 100a of the cover 100 and a plurality of recesses R102 corresponding to the buffer part 100c of the cover 100 are formed in the protective film R1. The concave portion R101 and the concave portion R102 formed by pre-baking, exposure, and development are all bowl-shaped concave curved surfaces that taper gently. The concave portion R101 and the concave portion R102 that do not penetrate the protective film R1 can be formed by adjusting the exposure amount of the protective film R1.

  Next, as shown in FIGS. 2A and 2B, the surface shape of the protective film R1 is transferred to the surface of the substrate M by anisotropically etching the substrate M together with the protective film R1. As a result, a mold M made of the substrate M is formed. At this time, if the etching selectivity between the protective film R1 and the substrate M is 1: 1, the concave portion R101 of the protective film R1 is transferred to the concave portion M102 of the substrate M as it is, and the concave portion R102 of the protective film R1 is as it is. Transferred to the recess M103 of the substrate M. Even if the etching selectivity between the protective film R1 and the substrate M is not 1: 1, the bowl-shaped concave portion M102 and the concave portion M103 that taper gently can be formed in the substrate M. Specifically, for example, reactive ion etching using CF <SUB> 4 </ SUB> as an etching gas is performed on the substrate M made of quartz and the protective film R1 made of photoresist.

Further, as a method of forming the tapered recess M102 and the recess M103 on the substrate M, there are other methods as follows, for example.
1. A through hole corresponding to the recess M102 and the recess M103 is formed in the protective film R1, and isotropic etching is performed using the protective film R1 as a mask (eg, etching the glass substrate M with hydrofluoric acid or buffered hydrofluoric acid). .
2. Through holes corresponding to the recesses M102 and M103 are formed in the protective film R1 made of silicon nitride, and crystal anisotropic etching is performed on the substrate M made of silicon using the protective film R1 as a mask. In this case, the concave portion M102 and the concave portion M103 are formed to be sharp because they have the shape of the side surface of the cone.
3. Through holes corresponding to the recesses M102 and M103 are formed in the protective film R1 made of a photosensitive resin, and the recesses M102 and M103 are formed in the substrate M by sandblasting using the protective film R1 as a mask.

  Next, as shown in FIG. 3, a resin film 100 </ b> W that is a material of the cover 100 is formed on the surface of the mold M (the surface having the concave portions M <b> 102 and M <b> 103). The thickness of the resin film 100W is set to 20 μm, for example. As a material of the resin film 100W, polyimide, block copolymerized polyimide, polybenzoxazole, benzocyclobutene, or the like can be used. The resin film 100W is formed, for example, by applying a photosensitive resin to the surface of the mold M and then pre-baking, and further heating a part or all of the photosensitive resin by a crosslinking reaction. As a result of the surface shape of the mold M having the recesses R102 and R103 being transferred to the resin film 100W, a plurality of plate-like ceiling portions 100b, a plurality of support portions 100a corresponding to the recesses M102 of the mold M, and the mold M A plurality of buffer portions 100c corresponding to the recesses M103 are formed of the resin film 100W. When polyimide is used as the material for the resin film 100W, after pre-baking, it may be cured by heating for 30 minutes in an oven or hot plate at 300 ° C., for example. It is desirable to apply a release agent to the surface of the mold M before forming the resin film 100W.

  Thus, when the resin film 100W which is a cover component which becomes the several cover 100 with which the ceiling part 100b and the support part 100a are each formed integrally, the ceiling part 100b, the support part 100a, and the buffer part 100c are separately independent. The manufacturing cost of the cover 100 can be reduced as compared with the case of forming in the process. If the cover 100 is manufactured using the reusable mold M, the manufacturing cost of the acceleration sensor 1 can be further reduced. Further, the distance between the movable portion 120c of the movable element 120 and the buffer portion 100c of the cover 100 can be set with good dimensional accuracy and good reproducibility by the concave portion M102 and the concave portion M103 of the mold M.

  It should be noted that a powder mainly composed of an inorganic solid material such as a metal such as silicon oxide, alumina, silicon nitride, copper, nickel, silver, gold, or ceramics may be mixed in the resin film 100W as a filler. Since these fillers have a lower coefficient of thermal expansion and moisture absorption than the resin, mixing such filler into the resin film 100W can lower the coefficient of thermal expansion and moisture absorption of the cover 100.

  Next, as shown in FIG. 4, a plate 110 for reinforcing the resin film 100W is bonded to the surface of the resin film 100W. The plate body 110 is desirably formed of a material harder than the resin film 100W. This facilitates the handling of the resin film 100W, which is a flexible cover component. As the plate body 110, for example, a silicon substrate having a thickness of 625 μm can be used. In addition, an SOI substrate, an alumina substrate, a silicon nitride substrate, a glass substrate, a quartz substrate, a glass ceramic substrate, a glass epoxy substrate, a polybenzoxazole substrate, a benzocyclobutene substrate, a metal substrate, an alloy substrate, or the like is used as the plate body 110. it can.

  A second mark 111 for aligning the movable element 120 and the resin film 100W is previously formed on the plate 110. The plate 110 and the mold M are aligned and joined using the first mark M101 and the second mark 111. Accordingly, it is possible to align the support portion 100a formed in the concave portion M102 of the mold M, the buffer portion 100c formed in the concave portion M103 of the mold M, and the movable element 120 using the second mark 111. When either the plate 110 or the mold M is a transparent member with respect to visible light or infrared light, the first mark M101 and the second mark 111 can be aligned through the transparent member. Even when both the plate 110 and the mold M are opaque members, the plate 110 and the mold M are respectively positioned by two microscopes positioned at positions distant from the joining position, and then the plate 110 and What is necessary is just to move and move the mold M to the joining position by a predetermined distance.

  Next, as shown in FIG. 5, the resin film 100 </ b> W is separated from the mold M together with the plate body 110 by peeling the resin film 100 </ b> W from the mold M. As a result, a support portion 100a having a convex surface with a gentle protrusion, a buffer portion 100c having a convex surface with a gentle protrusion, and a flat lower surface (a surface facing the movable portion 120c) of the ceiling portion 100b appear.

  Next, as shown in FIG. 6, the resin film 100 </ b> W that is an integral part of the plate body 110 and the main body part 120 </ b> W are aligned. The main body component 120 </ b> W is obtained by depositing thin films such as an insulating film, a piezoelectric film, and a conductive film on the substrate 124 and patterning each thin film into a predetermined shape corresponding to the plurality of movable elements 120. An element terminal 122 made of a conductive film, a conducting wire 123, and a third mark 121 are formed for each movable element 120 on the surface of the main body part 120W. The third mark 121 is a mark for aligning the main part 120 </ b> W and the integrated part composed of the resin film 100 </ b> W and the plate body 110 by aligning with the second mark 111. As the substrate 124 of the main body component 120W, an SOI substrate, a silicon substrate, an alumina substrate, a silicon nitride substrate, a glass substrate, a quartz substrate, a glass ceramic substrate, a glass epoxy substrate, a metal substrate, an alloy substrate, or the like can be used.

  Next, as shown in FIG. 7, the resin film 100W aligned with the main body part 120W is joined to the surface of the main body part 120W by thermocompression bonding. At this time, the plurality of support portions 100a corresponding to one movable element 120 are joined to the inner region of the plurality of element terminals 122 corresponding to one movable element 120 as shown in FIG. When the support portion 100a and the element terminal 122 have such a positional relationship, wire bonding can be performed on the element terminal 122. The resin film 100W and the main body part 120W are pressure-bonded by applying a force equivalent to 2 t in terms of a 6-inch wafer while being heated at 300 ° C. for 30 minutes, for example. At this time, since the protruding end of the support portion 100a of the resin film 100W is a convex curved surface that is not a flat surface, it is difficult for air bubbles to be trapped in the bonding region. In addition, if the thermocompression bonding between the resin film 100W and the main body part 120W is performed in a vacuum state, the generation of bubbles can be reliably prevented. Further, since the protruding end of the support part 100a is a convex curved surface that easily deforms according to the surface shape of the main body part 120W, the surface of the main body part 120W may be uneven in the joining region with the support part 100a. Therefore, you may join the support part 100a just above the conducting wire 123, as shown in FIG.7 and FIG.8. For this reason, it is easy to reduce the size of the acceleration sensor 1. Further, since no adhesive is used for joining the main body part 120W and the resin film 100W as the cover part, there is no variation in stress caused by variation in the amount of adhesive used, and no stress due to shrinkage of the adhesive.

  Next, as shown in FIG. 9, a through hole 124a is formed in the substrate 124 of the main body part 120W. As a result, a plurality of movable parts 120c are formed in the main body part 120W. The step of forming the movable part 120c on the main body part 120W may be performed before the step of bonding the resin film 100W to the main body part 120W.

  Next, as shown in FIG. 10, the plate 110 is separated from the resin film 100W bonded to the main body part 120W. The acceleration sensor 1 can be thinly formed by separating the plate body 110 from the resin film 100W. The plate 110 may be separated by peeling from the resin film 100W, but may be removed by etching.

  Next, the resin film 100W is divided using a laser or the like for each die constituting the movable element 120, and the cover 100 is completed as shown in FIG. Note that the cutting may be performed by mechanical cutting instead of the laser. Alternatively, a photosensitive resin may be used as the material of the resin film 100W, and the cover 100 may be completed by dividing the resin film 100W by exposure and development.

  Next, the main body part 120W is divided along the contour of the movable element 120 using a dicer or the like, and the movable element 120 is completed as shown in FIG. At this time, since the upper portion of the movable portion 120c of the movable element 120 is covered with the cover 100, fragments generated by dicing are unlikely to damage the movable portion 120c. Note that the step of dividing the main body part 120W may be performed before the step of dividing the resin film 100W. The third mark 121 may be cut off from the movable element 120 or may be left on the movable element 120. The main body part 120W may be divided by anisotropic etching such as Deep-RIE instead of mechanical cutting using a dicer or the like.

  Finally, the acceleration sensor 1 is completed by packaging the integrated part composed of the main body part 120W and the cover 100 as shown in FIGS. That is, the back surface of the main part 120W is bonded to the package substrate 131 integral with the wall 136 with the conductive paste P or the like, the element terminal 122 and the internal terminal 133 are connected by the wire W, and the end surface of the wall 136 is bonded to the end surface with an adhesive. When the package cover 135 is joined, the acceleration sensor 1 is completed.

2. Second Embodiment FIGS. 16 and 17 are schematic sectional views showing an acceleration sensor 2 according to a second embodiment of the present invention. FIG. 17 corresponds to the cross section along the line AA shown in FIG. FIG. 15 is a plan view showing a method for manufacturing the acceleration sensor 2.
As shown in FIGS. 16 and 17, the support portion 100 a of the cover 100 may be formed in an annular shape so as to surround the movable portion 120 c of the movable element 120. In this case, the space above the movable part 120 c is sealed by the cover 100. Further, the buffer portion 100c of the cover 100 may be formed in a rib shape. That is, for example, the buffer portion 100c may have a rib shape in which the cross section along the line AA shown in FIG. Even if the buffer part 100c is a rib shape, it is more easily deformed than the ceiling part 100b, and the buffer performance is improved. Moreover, since the buffer part 100c can further increase the rigidity of the cover 100 when the buffer part 100c has a rib shape, the ceiling part 100b can be further thinned. A plurality of rib-shaped buffer portions 100c that are independent from each other may be formed on the cover 100.

  In the process of manufacturing the acceleration sensor 2, in the process of the first embodiment corresponding to FIG. 2A and FIG. 2B, the recess M102 of the mold M corresponding to the support part 100a is formed in an annular shape as shown in FIG. The protective film R1 of the mold M may be exposed and developed so that the concave portions M103 of the mold M corresponding to 100c are formed in a lattice shape as shown in FIG.

3. Third Embodiment FIG. 21 is a schematic sectional view showing an acceleration sensor 3 according to a third embodiment of the present invention.
As shown in FIG. 21, the upper and lower spaces of the movable portion 120 c of the movable element 120 may be covered with two covers 100. The space above and below the movable portion 120 c may be sealed or released by the cover 100, or one of the top and bottom may be released and the other may be sealed by the cover 100. Further, when the support portions 100a of the upper and lower covers 100 are formed in an annular shape and the insides of the two covers 100 are sealed, the package of the acceleration sensor 3 may be a lead frame package. That is, the element terminal 122 of the movable element 120 may be electrically connected to the lead frame 141 with the wire W, and the movable element 120, the cover 100, and the lead frame 141 may be sealed with the resin 140.

  18 to 20 are schematic cross-sectional views illustrating a method for manufacturing the acceleration sensor 3. In the process of manufacturing the acceleration sensor 3, the resin film 100W is bonded to the upper and lower surfaces of the main body part 120W as shown in FIG. The movable part 120c of the main body part 120W is formed before at least one of the two resin films 100W is joined to the main body part 120W.

  Thereafter, as shown in FIG. 19, the two plate bodies 110 are separated from the respective resin films 100W. Then, after the resin film 100W and the main body part 120W are divided for each movable element 120 as shown in FIG. 20, one cover 100 is joined to the lead frame 141 with the conductive paste P and sealed with the resin 140, as shown in FIG. The acceleration sensor 3 is completed. When the main body part 120W is divided, the upper and lower sides of each movable portion 120c are covered with the cover 100, so that the movable portion 120c is further less likely to be damaged by debris generated during dicing. When the insides of the two covers 100 are sealed, the movable part 120c is not damaged by debris generated during dicing.

4). Fourth Embodiment As shown in FIG. 22, a sacrificial film M110 for mold release is formed on the surface of the mold M (the surface on which the concave portion M102 and the concave portion M103 are formed), and a resin film 100W is formed on the sacrificial film M110. It may be formed. In the step of separating the resin film 100W from the mold M, the sacrificial film M110 is removed by etching. As a material for the sacrificial film M110, for example, a metal or an alloy such as chromium, copper, tin, indium, gallium, or solder may be used, or a semiconductor compound such as silicon oxide or silicon nitride may be used. The sacrificial film M110 may have a multilayer structure. Sputtering, vapor deposition, electrolytic plating, electroless plating, or the like is used for forming the sacrificial film M110.

5. Fifth Embodiment Further, as shown in FIG. 23, a sacrificial film 112 for separating the plate body 110 from the resin film 100W may be formed on the surface of the plate body 110. In the step of separating the plate body 110 from the resin film 100W, the sacrificial film 112 is removed by etching.

6). Sixth Embodiment FIG. 27 is a schematic sectional view showing an acceleration sensor 6 according to a sixth embodiment of the present invention.
As shown in FIG. 27, the cover 100 may have a multilayer structure including a surface layer resin film 101W forming the support portion 100a and the buffer portion 100c and a base layer resin film 102W forming the ceiling portion 100b. . That is, the cover 100 may have a multilayer structure in which the material is different between the surface layer and the base layer. For example, the surface resin film 101W may be made of a softer resin than the base resin film 102W. By constituting the base layer resin film 102W with a resin harder than the surface layer resin film 101W, in other words, by constituting the surface layer resin film 101W with a softer resin than the base layer resin film 102W, the buffering capacity and cover for the movable portion 120c 100 rigidity can be increased. Specifically, positive photosensitive polybenzoxazole can be used for the surface layer resin film 101W, and polyimide can be used for the base layer resin film 102W. Further, the plate body 110 made of an inorganic solid material harder than the cover 100 may be joined to the back side of the surface of the cover 100 where the support portion 100a and the buffer portion 100c are formed, and may be incorporated as a part of the acceleration sensor 6. When the plate body 110 is made of an inorganic solid material such as silicon, alumina, silicon nitride, glass, quartz, glass ceramics, glass epoxy, metal, or alloy that is harder than the cover 100, the movable portion 120c of the movable element 120 is covered. It is also possible to make the acceleration sensor 6 thinner while keeping the rigidity of the member high. In addition, the flatness of the ceiling portion 100b can be increased. Further, even when the movable element 120 is sealed with resin, the cover 100 is not easily deformed.

  The acceleration sensor 6 in which the material of the surface resin film 101W and the material of the base resin film 102W are different can be formed as follows. That is, as shown in FIG. 24, a surface resin film 101W is formed on the surface of the mold M. Next, as shown in FIG. 25, the surface layer of the surface layer resin film 101W is removed to a depth at which the mold M is exposed so that the surface layer resin film 101W remains only in the recesses M102 and M103 of the mold M. As a result, the exposed mold A first mark M101 is formed on the surface of M. Further, a base resin film 102W is formed on the surface of the mold M and the surface of the surface resin film 101W. Thereafter, as shown in FIG. 26, the plate 110 may be bonded to the base resin film 102W, and the plate 110 may be divided into movable elements (movable elements 120) together with the surface resin film 101W and the base resin film 102W.

  When the surface layer of the surface layer resin film 101W is removed, the end point may be set to a depth at which the surface of the mold M is not exposed. That is, the resin film 100W may be formed so that the entire inner surface of the completed cover 100 (the surface facing the movable element 120) is configured by the surface resin film 101W. Alternatively, the surface resin film 101W may be made of a resin that has a higher bonding force by thermocompression bonding than the base resin film 102W. This increases the bonding strength between the cover 100 and the movable element 120. Further, the resin layers different from each other constituting the cover 100 may be three or more layers.

7). Seventh Embodiment A surface resin film 101W that becomes the support portion 100a and the buffer portion 100c may be formed by patterning. That is, as shown in FIG. 28, the surface resin film 101W is applied to the surface of the mold M and pre-baked, and then the surface resin film 101W is exposed and developed using a mask as shown in FIG. Thereafter, the base resin film 102W may be formed on the surface resin film 101W and the mold M.

8). Eighth Embodiment The cover 100 in which the material of the surface layer resin film 101W and the material of the base layer resin film 102W are different may be formed using a multi-tone mask. For example, as shown in FIG. 30, after a base layer resin film 102W made of polyimide is formed on the surface of the plate 110, and a surface layer resin film 101W made of positive photosensitive polybenzoxazole is formed on the surface of the base layer resin film 102W. The surface layer resin film 101W alone can be formed by exposing and developing with the halftone mask H. When the surface resin film 101W is exposed and developed using a multi-tone mask such as the halftone mask H, the support portion 100a and the buffer portion 100c whose end surfaces are convex curved surfaces can be formed with the remaining portions corresponding to the non-photosensitive portions.

9. Ninth Embodiment FIG. 31 is a schematic cross-sectional view showing a pressure sensor 9 according to a ninth embodiment of the present invention. The ceiling part 100b of the cover 100 may be formed of a material harder than the support part 100a and the buffer part 100c. That is, for example, as shown in FIG. 31, the support portion 100a and the buffer portion 100c are made of resin, and the ceiling portion 100b is made of an inorganic solid material such as alumina, silicon nitride, glass, quartz, glass ceramics, glass epoxy, metal, or alloy. The support part 100a and the buffer part 100c may be formed, and a material obtained by adding a photosensitive agent to photosensitive polyimide, block copolymerized polyimide, polybenzoxazole, or benzocyclobutene may be used. If the ceiling part 100b is formed of a material harder than the support part 100a and the buffer part 100c, the rigidity of the ceiling part 100b can be easily ensured even if the ceiling part 100b is thinned, so that the pressure sensor 9 can be thinned.

Further, as shown in FIG. 31, the movable part 120c is a thin film formed on the substrate 124 of the movable element 120, and is a diaphragm or a beam to which a weight is not joined. The movable portion 120c may be exposed from the rectangular through hole 124a. In such a case, the buffer portion 100c may be formed so as to protrude higher than the support portion 100a from the ceiling portion 100b of one cover 100 in order to make the heights of the upper and lower spaces of the movable portion 120c coincide.
The package 130 may be formed with a through hole 130a for balancing the pressure inside and outside the package 130.

  The pressure sensor 9 can be manufactured as follows, for example. That is, as described in the column of the seventh embodiment based on FIG. 29, a plate body 103W that becomes a plurality of ceiling portions 100b when it is divided after forming the support portion 100a and the buffer portion 100c is shown in FIG. Are joined to the support portion 100a and the buffer portion 100c. A fourth mark 103a for aligning the movable element 120 and the resin film 100W is previously formed on the plate 103W. The plate body 103W and the resin film 100W are bonded together by, for example, thermocompression bonding. The thermocompression bonding may be performed by applying a force equivalent to 2 t per 6 inch wafer to the plate body 103W at a temperature of 300 ° C., for example.

10. Other Embodiments The technical scope of the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made without departing from the scope of the present invention. For example, the configurations described in the above embodiments can be combined with each other. In addition, the materials, dimensions, film forming methods, and pattern transfer methods shown in the above embodiment are merely examples, and descriptions of addition and deletion of processes and replacement of the process order that are obvious to those skilled in the art are omitted. Yes. Needless to say, the present invention can be applied to other MEMS such as a microphone and an angular velocity sensor.

Sectional drawing concerning 1st embodiment of this invention. FIG. 2A is a sectional view according to the first embodiment of the present invention. FIG. 2B is a plan view according to the first embodiment of the present invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. Sectional drawing concerning 1st embodiment of this invention. The top view concerning 2nd embodiment of the present invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 2nd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 3rd embodiment of this invention. Sectional drawing concerning 4th embodiment of this invention. Sectional drawing concerning 5th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 6th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 7th embodiment of this invention. Sectional drawing concerning 8th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention. Sectional drawing concerning 9th embodiment of this invention.

Explanation of symbols

1: Acceleration sensor, 2: Acceleration sensor, 3: Acceleration sensor, 6: Acceleration sensor, 9: Pressure sensor, 100: Cover, 100W: Resin film, 100a: Support part, 100b: Ceiling part, 100c: Buffer part, 101W : Surface layer resin film, 102W: base layer resin film, 103W: plate body, 103a: fourth mark, 110: plate body, 111: second mark, 112: sacrificial film, 120: movable element, 120W: main body part, 120a: 120b: beam, 120c: movable part, 121: third mark, 122: element terminal, 123: conductor, 124: substrate, 124a: through hole, 130: package, 130a: through hole, 131: package substrate, 131a : Recess, 132: contact plug, 133: internal terminal, 134: external terminal, 135: package cover, 136: wall, 140: resin, 41: lead frame, B: adhesive, H: halftone mask, M: mold, M101: first mark, M102: recess, M103: recess, M110: sacrificial film, P: conductive paste, R1: protective film, R101 : Recess, R102: recess, W: wire

Claims (16)

A movable element comprising a movable part;
A cover provided with a ceiling part covering the movable part and a buffer part protruding from the ceiling part toward the movable part and made of resin;
With
A space is formed between the movable part and the buffer part,
MEMS. The cover protrudes from the ceiling and is joined to the movable element to support the ceiling and includes a support made of resin.
The MEMS according to claim 1. The ceiling part is made of resin,
The MEMS according to claim 1 or 2. A plate body harder than the ceiling part is joined to the back surface of the surface from which the buffer part of the ceiling part protrudes.
The MEMS according to claim 3. The buffer part is joined to the ceiling part made of a material harder than the buffer part,
The MEMS according to claim 1 or 2. The buffer portion has a hump shape,
The MEMS according to any one of claims 1 to 5. The buffer portion is rib-shaped,
The MEMS according to any one of claims 1 to 5. Forming a cover component including a plurality of ceiling portions covering the movable portions of the plurality of movable elements and a buffer portion protruding from the ceiling portion and made of resin;
Joining the cover part in a state where a space is formed between the buffer part and the movable part to the body part corresponding to a plurality of movable elements each having a movable part,
The cover part and the main body part that are joined to each other are divided for each movable element,
MEMS manufacturing method including the above. Forming the ceiling from resin;
The MEMS manufacturing method according to claim 8. A support part that protrudes from the ceiling part and supports the ceiling part is formed from resin on the cover component for each of the movable elements,
Joining the support to the body part;
The MEMS manufacturing method of Claim 8 or 9 including this. Bonding the protruding end of the support part to the main body component by thermocompression bonding;
The MEMS manufacturing method according to claim 10. Forming a protruding end of the support part into a convex curved surface;
The MEMS manufacturing method of Claim 11 containing this. The buffer portion is formed by transferring the concave portion of the mold.
The MEMS manufacturing method as described in any one of Claims 8-12 containing this. Forming the buffer portion made of the photosensitive resin by patterning a film made of the photosensitive resin using a multi-tone mask;
The MEMS manufacturing method as described in any one of Claims 8-12 containing this. The cover part is integrally formed of resin.
The MEMS manufacturing method as described in any one of Claims 8-14 containing this. Forming an integral part in which a plate member harder than the cover part is joined to the back surface of the surface of the ceiling part from which the support part protrudes;
Joining the protruding end of the support part of the integral part to the main body part;
The MEMS manufacturing method according to claim 15.

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