KR100446637B1 - Optical Scanner utilizing Anodic Bonding and Manufacturing Method thereof - Google Patents

Abstract

Disclosed are an optical scanner using anodic bonding and a method of manufacturing the same. An optical scanner using the disclosed anodic bonding includes a rectangular frame including at least one dielectric and a metal film formed between a substrate and a glass plate, the structure including the dielectric and the glass plate being anodized; A torsion bar positioned in the frame with an isolation area therebetween and extending from the frame; A rectangular scanning mirror in the center portion connected to the torsion bar; And a driving comb electrode formed on the bottom surface of the scanning mirror. The present invention enables the fabrication of an optical scanner capable of realizing stable performance by enabling anodic bonding of a dielectric material and a glass plate and anodic bonding of a dielectric material and a metal film in a structure in which a metal film and a dielectric are laminated between a substrate and a glass plate.

Description

Optical scanner utilizing anodic bonding and manufacturing method

The present invention relates to an optical scanner using anodic bonding and a method of manufacturing the same, and more particularly, to an optical scanner using an anode bonding of a dielectric and a glass plate or a dielectric and a metal film.

Anodic bonding is a technique for bonding a glass substrate with a similar thermal expansion coefficient to a silicon substrate which is widely used in micro sensor device fabrication. In general, Pyrex glass (Corning glass 7740) used in the anode bonding contains a certain amount of sodium (Na), potassium (K), etc. When heated to a temperature of 200 ℃ or more, the elements charge and move easily according to the voltage. When the silicon and the glass plate are aligned and a voltage of 600V or more is applied to both sides, the mobile charges move rapidly and strong charges occur at the interface between the silicon and the glass plate, thereby bonding the silicon substrate and the glass plate. Many microelectromechanical systems (MEMS) processes use anodic bonding methods, which enable stable silicon structures.

1 is a cross-sectional view showing a conventional bipolar junction structure. The substrate 13 is positioned on the base plate 11 and the glass plate 15 is installed on the substrate 13 to form a structure. The above-described heat is applied to the structure, the cathode is connected to the upper part of the glass plate 15, and the anode is connected to the lower part of the base plate 11, and the substrate 13 and the glass plate 15 are applied. Charged ions move between them, forming a strong anodic junction.

This anode bonding process is also used for the optical scanner manufacturing process. In the conventional optical scanner manufacturing method, since only the silicon substrate is used, it is difficult to execute the automated process, and the breakage increases and the yield decreases due to the unstable movement of the hinge. In order to make up for this drawback, silicon and glass plates are bonded to realize stable devices. However, since the hinge is difficult to drive safely, there has been an attempt to implement a stable performance of the hinge using a silicon on insulator (SOI) substrate. There is a difficulty in connection.

Accordingly, the technical problem to be achieved by the present invention is to improve the above-mentioned problems of the prior art, and implements an anode-bonded structure between a dielectric and a glass plate and a dielectric and a metal film, and uses the same in an optical scanner manufacturing method to produce an SOI substrate. It is to provide an optical scanner having stable performance by electrically connecting.

1 is a cross-sectional view showing a conventional bipolar junction structure,

Figure 2a is a cross-sectional view showing a bipolar junction structure according to a first embodiment of the present invention,

Figure 2b is a cross-sectional view showing a bipolar junction structure according to a second embodiment of the present invention,

Figure 2c is a cross-sectional view showing a bipolar junction structure according to a third embodiment of the present invention,

Figure 2d is a cross-sectional view showing a bipolar junction structure according to a fourth embodiment of the present invention,

Figure 3a is a SEM (Scanning Electron Microscopy) photograph of the bipolar junction structure according to the first embodiment of the present invention,

Figure 3b is a SEM (Scanning Electron Microscopy) photograph of the bipolar junction structure according to the second embodiment of the present invention,

Figure 4 is a cross-sectional view showing the structure of the optical scanner manufactured by the optical scanner manufacturing method according to an embodiment of the present invention,

5 is a perspective view of an optical scanner manufactured by the optical scanner manufacturing method according to the embodiment of the present invention.

6a to 6k are cross-sectional views showing a light scanner manufacturing method according to an embodiment of the present invention.

<Code Description of Main Parts of Drawing>

21, 31, 31 ', 41, 51, 51': metal film

22, 32, 32 ', 42, 42', 52, 52 '; dielectric

23, 33, 43, 53; Board

25, 35, 45, 55; Glass plate

61; Board 1 61 ': Torsion Bar

62; Dielectric 63; 2nd board

In order to achieve the above technical problem, the present invention is a rectangular frame including at least one dielectric and a metal film is formed between the substrate and the glass plate, the structure comprising the dielectric and the glass plate anodized;

A torsion bar positioned in the frame with an isolation area therebetween and extending from the frame;

A rectangular scanning mirror in the center portion connected to the torsion bar; And

An optical scanner using an anode junction including a driving comb electrode formed on a bottom surface of the scanning mirror is provided.

In the present invention, the at least one metal film comprises a first metal film and a second metal film, the at least one dielectric material comprises a first and a second dielectric, and the first metal between the substrate and the glass plate. The film, the first dielectric, the second metal film, and the second dielectric are arranged in order, and the second dielectric is anodically bonded to the glass plate.

In the present invention, the at least one dielectric includes a first dielectric and a second dielectric, wherein a first dielectric, a metal film, and a second dielectric are sequentially arranged between the substrate and the glass plate, and the second dielectric Anodized with the glass plate is characterized in that.

In the present invention, the rectangular frame and the separation region in the frame is located between, and formed on the torsion bar extending from the frame, the rectangular scanning mirror of the central portion connected to the torsion bar and the bottom surface of the scanning mirror. In the manufacturing method of the optical scanner having a driving comb electrode,

Stacking the first substrate, the dielectric layer, and the second substrate in order;

Performing a photo process on an upper surface of the second substrate to form a lower frame of the scanning mirror and the frame;

Forming a pinhole in the scanning mirror and the lower frame, and then depositing a metal film on an upper surface of the scanning mirror and the lower frame;

Depositing a dielectric on an upper surface of the metal film, and then anodic bonding the dielectric and a glass plate on the upper surface of the lower frame;

Polishing the first substrate and patterning the metal film to be applied only to an upper surface of the frame to be the upper frame; And

Etching the first substrate in a predetermined pattern to form a portion of the upper frame and a torsion bar by penetrating a portion corresponding to the separation region, and forming a driving comb electrode on a bottom surface of the scanning mirror; To provide.

In the present invention, the anodic bonding step is characterized in that for applying a heat of about 300 ℃ to 400 ℃, a pressure of about 800N to 1200N, and a voltage of about 800V to 2000V.

In the present invention, the first and second substrates are formed of silicon.

In the present invention, the dielectric is characterized in that formed of silicon dioxide.

In the present invention, the metal film is formed of Au or Cr.

The present invention enables the fabrication of various devices using a MEMS process by providing an anode junction structure of a dielectric and a glass plate and an anode junction of a dielectric and a metal film, and an optical scanner having stable performance by using this process in an optical scanner manufacturing method. Can be provided.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Hereinafter, embodiments of a bipolar junction structure and a method of manufacturing the same, used in an optical scanner according to the present invention will be described in detail with reference to the accompanying drawings.

2A to 2D are cross-sectional views illustrating anodic junction structures according to the first to fourth embodiments of the present invention. The anode bonding structure according to the first to third embodiments of the present invention is characterized in that the anode and the glass plate positioned at the top of the stack structure of the metal film and the dielectric provided between the substrate and the glass plate are anodic bonded.

Referring to FIG. 2A, a metal film 21 is deposited on an upper surface of the substrate 23, a dielectric 22 is formed on the metal film 21, and the dielectric 22 and the glass plate 25 are formed on the upper surface of the substrate 23. ), The anodic bonding structure according to the first embodiment of the present invention is formed.

Referring to FIG. 2B, a first metal film 31 is deposited on the top surface of the substrate 33, a first dielectric 32 is formed on the top surface of the first metal film 31, and then the first metal film 31 is formed. The second metal film 31 'is deposited on the upper surface of the dielectric 32, and the second dielectric 32' is formed on the upper surface of the second metal film 31 ', and then the second dielectric 32 ') And the glass plate 35 are anodic bonded to form an anodic bonded structure according to the second embodiment of the present invention.

Referring to FIG. 2C, a first dielectric 42 is formed on the top surface of the substrate 43, and a metal film 41 is deposited on the top surface of the first dielectric 42. A second dielectric material 42 'is formed on the upper surface to form a bipolar junction structure according to the third embodiment of the present invention.

Unlike the anodic bonding structure according to the first to third embodiments of the present invention, the anode bonding structure according to the fourth embodiment of the present invention is a second dielectric formed on the lower portion of the glass plate and a metal film arranged on the substrate. And the metal film located at the top of the laminated structure of the dielectric and the dielectric is anodic bonded to each other.

Referring to FIG. 2D, a second dielectric 52 ′ is formed in advance under the glass plate 55, a first metal film 51 is deposited on the substrate 53, and the first metal film ( The first dielectric 52 is formed on the upper portion of the 51, and the second metal film 51 ′ is deposited on the upper portion of the first dielectric 52. The two dielectrics 52 'are anodic bonded to produce a positive electrode bonded structure according to the third embodiment of the present invention.

In the step of anodic bonding, it is preferable to apply heat of about 300 ° C to 400 ° C, a pressure of about 800N to 1200N, and a voltage of about 800V to 2000V.

Hereinafter, the components of the bipolar junction structure according to the first to fourth embodiments of the present invention will be described in detail.

The substrates 23, 33, 43, and 53 may be mainly silicon substrates, but are not limited thereto. For example, a substrate such as gallium (Ga), a nitride compound, or arsenic (As) may be used. Accordingly, a structure in which two or more materials are stacked may be used.

The metal films 21, 31, 31 ′, 41, 51, and 51 ′ may be made of gold (Au), chromium (Cr), and the like, and may use any material that exhibits the properties of the metal. The metal films 21, 31, 31 ′, 41, 51, and 51 ′ may be deposited using physical vapor deposition such as sputtering or chemical vapor deposition such as chemical vapor deposition (CVD).

Dielectrics 22, 32, 32 ', 42, 42', 52, 52 'may use silicon oxide (SiO ₂ ) or nitride-based compounds and the like, and may be mainly formed by chemical vapor deposition such as CVD. .

In the anodic bonding structures according to the first to third embodiments of the present invention, an anodic bonding is formed between the dielectrics 22, 32, 32 ', 42 and 42' and the glass plates 25, 35, 45 and 55, and the present invention. In the anodic junction structure according to the fourth embodiment of the present invention, an anodic junction is formed between the dielectric 52 'and the metal film 51.

In order to manufacture such an anodic junction structure, the above-described metal films 21, 31, 31 ', 41, 51, 51' and dielectrics 22, 32, 32 ', 42, 42', 52, 52 'are needed. After sequentially depositing an appropriate number, heat is applied at about 350 ° C. to 400 ° C. to the formed structure, and at the same time, 800 to 200 V is applied to the substrates 23, 33, 43, and 53 and the glass plates 25, 35, 45, and 55. A dielectric constant 22, 32 ', 42' 52 'and the glass plates 25, 35, 45 are anodic-bonded or the dielectric 52' and the metal film 51 are anodic-bonded.

3A shows an SEM of an anodic junction structure according to a first embodiment of the present invention having a silicon substrate 23, a metal film 21, a dielectric 22 formed of silicon oxide (SiO ₂ ), and a glass plate 25. 3B illustrates a silicon substrate 33, a first metal film 31, a first dielectric 32 formed of silicon oxide (SiO ₂ ), a second metal film 31 ′, and silicon oxide (SiO ₂ ). SEM picture of the positive electrode junction structure according to the second embodiment of the present invention having a second dielectric 32 'and a glass plate 35. The conditions for the anodic bonding for producing such a structure are about 400 ° C temperature, about 1200N pressure, about -1500V cathode voltage and about 5 minutes of bonding time.

4 is a cross-sectional view showing the upper structure of the optical scanner manufactured by applying the above-described bipolar junction structure and its manufacturing method, Figure 5 is a perspective view thereof.

4 and 5, the upper structure of the optical scanner manufactured by the optical scanner manufacturing method according to the embodiment of the present invention includes a rectangular frame 80 and a separation region 73 in the frame 80. A torsion bar 61 'positioned between and extending from the frame 80, a rectangular scanning mirror 66 "in the center portion connected to the torsion bar 61', and a bottom surface 66" of the scanning mirror; Drive comb electrode 61 "

The frame 80 is divided into an upper frame 81 and a lower frame 83 around the torsion bar 61 '. The upper frame 81 is disposed on the bottom surface of the glass plate 68 and the glass plate 68 and is disposed on the bottom surface of the dielectric (SiO ₂ ) 67 and the bottom surface of the dielectric 67. Au or Cr) 66. Here, the anodic junction structure is an anodic junction structure according to the first embodiment of the present invention described above.

In the step of anodic bonding, it is preferable to apply heat of about 300 ° C to 400 ° C, a pressure of about 800N to 1200N, and a voltage of about 800V to 2000V.

The lower frame 83 is positioned on the upper surface of the first substrate (Si) 61 and the metal film (Au or Cr) 66 'deposited on the bottom surface of the first substrate 61 and the first substrate 61. And a second substrate (Si) 63 arranged on the top surface of the dielectric 62 and extending to the torsion bar 61 '.

The scanning mirror 66 ″ is formed by depositing a metal film (Au or Cr) 66 on the upper surface of the second substrate 63 and reflects light.

Pinholes are formed in two portions of the center portion of the frame 80 and the scanning mirror 66 ″ to penetrate the second substrate 63. The metal layer 66 is deposited inside the pinhole to form an upper metal layer ( 66 and the dielectric 62 are connected to allow the lower metal film 66 'to be electrically connected.

Here, the structures of the first substrate 61, the dielectric 62, and the second substrate 63 used are a silicon on insulator (SOI) wafer 60. The SOI wafer 60 enables stable driving of the scanning mirror 66 "to improve the performance of the optical scanner.

Hereinafter, a method of manufacturing a superstructure of an optical scanner according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

The optical scanner according to the embodiment of the present invention uses a bipolar junction structure in the first embodiment according to the embodiment of the present invention. In FIG. 6H, a metal film 66 is deposited on the second substrate 63 made of silicon, and a dielectric 67 is formed on the metal film 66. The dielectric 67 and the glass plate ( It can be seen that 68 is anodic bonded.

6A to 6K are views illustrating a method of manufacturing the light scanner shown in FIGS. 4 and 5.

As shown in FIG. 6A, a first substrate 61 made of a silicon wafer or the like having a thickness of about 500 μm is prepared, and then the surface is oxidized to form a dielectric 62 such as about 1 μm of silicon oxide. Then, a second substrate is formed of a silicon 63 wafer having a thickness of about 15 μm on the upper surface of the dielectric 62 to form an SOI wafer 60.

When the photoresist film 64 such as AZ7220 is applied on the top of the SOI wafer 60, then the mask is exposed, and the exposure and development are performed, the SOI wafer 60 having the photoresist film 64 patterned in the form as shown in FIG. 6B is formed. Is made.

The second substrate 63 is etched using an etching process such as ICPRIE (Inductively Coupled Plasma Reactive Ion Etch). The etch stops at the dielectric 62 made of silicon oxide on the bottom of 15 μm to form the portion to be the hinge 71 and the scanning mirror 66 ″ having a thickness of exactly 15 μm as shown in FIG. 6C. do.

As shown in FIG. 6D, the photosensitive film 65 is coated again, and a photo process is performed to perform hole patterning. As shown in FIG. 6E, the second substrate 63 is etched again through an etching process such as ICPRIE, and the silicon oxide (SiO 2) dielectric 62 is etched through Reactive Ion Etch (RIE) to form the SOI wafer 60. Penetrate

Referring to FIG. 6E, the pinhole penetrates through the center portion of the frame 80 to the surface of the first substrate 61 and is formed at the left side and the right side of the portion to be the scanning mirror 66 ″, respectively. Penetrates up to 61).

Next, as shown in FIG. 6F, Cr to be used as a reflective film is deposited on the upper surface of the frame 80 and the portion to be the scanning mirror 66 ″ to a thickness of about 300 μs, and Au is then deposited on the metal about 3000 μs. Forming the film 66 causes the top and bottom of the SOI wafer 60 to be electrically connected.

As shown in FIG. 6G, a silicon oxide dielectric 67 is deposited and patterned on the upper surface of the metal film 66 made of Au and Cr by a chemical vapor deposition method such as CVD by a thickness of about 5000 kPa, and then the structure Turn over to make anodization with a glass plate 68, for example a Pyrex glass plate, as shown in FIG. 6H.

As shown in FIG. 6I, a 500 μm-thick silicon substrate 61 is polished to about 100 μm using a chemical mechanical polishing (CMP) planarization process, and a metal film of Au and Cr to be used as a substructure and a melt bonding layer 66 ') Is deposited and then patterned.

As shown in FIG. 6J, the photosensitive film 69, such as AZ4620, is again coated and then patterned using a general photo process to form the comb 70 structure and the upper photosensitive pattern 69 of the metal film 66 ′. ).

When the first substrate 61 is etched by using an etching process such as ICPRIE, the separation region 72 of the frame 80 and the scanning mirror 66 '' penetrates and the torsion bar 61 extending from the second substrate 63. ') Is formed to complete the structure as shown in FIG. 6K.

Anodic bonding according to an embodiment of the present invention can perform anodic bonding between a glass plate, a dielectric, and a dielectric and a metal film, and thus it is possible to manufacture a new type of MEMs structure such as a capacitor, cantilever, sensor, and inductor, and also used in a packaging process. This is possible. In the method of manufacturing the upper structure of the optical scanner using the same, by electrically connecting the upper and lower parts of the SOI wafer using an anode bonding, it is possible to stably manufacture and drive the optical scanner and to improve the overall performance.

While many details are set forth in the foregoing description, they should be construed as illustrative of preferred embodiments, rather than to limit the scope of the invention.

For example, one of ordinary skill in the art to which the present invention pertains may implement various combinations of a dielectric and a metal film between a substrate and a glass plate according to the spirit of the present invention. Therefore, the scope of the present invention should not be defined by the described embodiments, but should be determined by the technical spirit described in the claims.

As described above, an advantage of the anode bonding structure according to the present invention and a method of manufacturing the same is that it enables the combination of various stacking structures of the metal film and the dielectric between the substrate and the dielectric to enable the implementation of new devices.

In addition, the optical scanner manufacturing method using the same can be improved by the overall performance of the optical scanner by electrically connecting the upper substrate and the lower substrate using a bipolar junction.

Claims (8)

At least one dielectric and a metal film formed between the substrate and the glass plate, the rectangular frame including a structure in which the dielectric and the glass plate are anodized; A torsion bar positioned in the frame with an isolation area therebetween and extending from the frame; A rectangular scanning mirror in the center portion connected to the torsion bar; And And a driving comb electrode formed on the bottom surface of the scanning mirror. The method of claim 1, The at least one metal film comprises a first metal film and a second metal film, and the at least one dielectric includes a first and a second dielectric, The first metal film, the first dielectric, the second metal film, and the second dielectric are sequentially arranged between the substrate and the glass plate, and the second dielectric is positively bonded to the glass plate. Optical scanner using junction. The method of claim 1, The at least one dielectric includes a first dielectric and a second dielectric, A first scanner, a metal film, and a second dielectric are arranged in sequence between the substrate and the glass plate, and the second dielectric is positively bonded to the glass plate. A rectangular frame, a torsion bar extending from the frame, a torsion bar extending from the frame, a rectangular scanning mirror in a central portion connected to the torsion bar, and a driving comb electrode formed on a bottom surface of the scanning mirror; In the manufacturing method of the optical scanner provided, Stacking the first substrate, the dielectric layer, and the second substrate in order; Performing a photo process on an upper surface of the second substrate to form a lower frame of the scanning mirror and the frame; Forming a pinhole in the scanning mirror and the lower frame, and then depositing a metal film on an upper surface of the scanning mirror and the lower frame; Depositing a dielectric on an upper surface of the metal film, and then anodic bonding the dielectric and a glass plate on the upper surface of the lower frame; Polishing the first substrate and patterning the metal film to be applied only to an upper surface of the frame to be the upper frame; And And etching the first substrate into a predetermined pattern to form a portion of the upper frame and the torsion bar by penetrating a portion corresponding to the separation region, and forming a driving comb electrode on a bottom surface of the scanning mirror. Optical scanner manufacturing method. The method of claim 4, wherein in the anodic bonding step, A method of manufacturing an optical scanner comprising applying a heat of about 300 ° C to 400 ° C, a pressure of about 800N to about 1200N, and a voltage of about 800V to about 2000V. The method of claim 4, wherein And the first and second substrates are formed of silicon. The method of claim 4, wherein And the dielectric is formed of silicon dioxide. The method of claim 4, wherein The metal film manufacturing method of the optical scanner, characterized in that formed of Au or Cr.