LIGHT SCANNER PACKAGE AND METHOD FOR MANUFACTURING SAME
20230127991 · 2023-04-27
Inventors
- Jonghyun LEE (Gwangju, KR)
- Seunghwan MOON (Gwangju, KR)
- Jinhong CHOI (Gwangju, KR)
- Kyoungwoo JO (Gwangju, KR)
Cpc classification
B81C2201/0132
PERFORMING OPERATIONS; TRANSPORTING
B81B2203/058
PERFORMING OPERATIONS; TRANSPORTING
G02B19/0028
PHYSICS
B81C1/00198
PERFORMING OPERATIONS; TRANSPORTING
G02B26/101
PHYSICS
B81C2201/0118
PERFORMING OPERATIONS; TRANSPORTING
G02B26/0841
PHYSICS
B81B7/02
PERFORMING OPERATIONS; TRANSPORTING
B81B2207/11
PERFORMING OPERATIONS; TRANSPORTING
B81B7/0067
PERFORMING OPERATIONS; TRANSPORTING
B81B7/00
PERFORMING OPERATIONS; TRANSPORTING
International classification
B81B7/02
PERFORMING OPERATIONS; TRANSPORTING
B81C1/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The present disclosure relates to an optical scanner package comprising a scanner element, a lower substrate having an inner space, and a semi-spherical transmissive window. The semi-spherical transmissive window has different inclinations in an incident position thereof and in an emission position thereof, and interference caused by sub-reflection can thus be reduced. Since the incident angle α and the maximum emission angle β are small, anti-reflection coating design is easy, and light loss can be reduced. There is an advantage in that, even when the optical scanning angle (OSA) γ of a laser is large, the maximum emission angle β is small, and emitted laser light thus has a small change in characteristics. In addition, since there are curvatures on both sides of two axes, there is little restriction regarding the incident direction even in the case of two-axis driving.
Claims
1. An optical scanner package including: a MEMS scanner element including a mirror, a spring, a driver, and a fixed body; a lower substrate positioned at a lower portion of the MEMS scanner element and supporting the MEMS scanner element in a form bonded to the MEMS scanner element; and a transmissive window having a shell shape corresponding to a portion of a semi-sphere or ellipsoid in outward appearance, and having a bonding surface continuously connected to the lower portion, wherein the transmissive window has a structure having curvatures in two axes.
2. The optical scanner package of claim 1, further including a lens or an optical element in a partial region of the transmissive window through which incident light and emission light pass.
3. The optical scanner package of claim 2, wherein the lens is formed integrally with the transmissive window.
4. (canceled)
5. The optical scanner package of claim 1, wherein the lower substrate is made of a glass material, and an inner space is formed at an upper portion of the lower substrate.
6. The optical scanner package of claim 5, further including a via metal filled in an up-down direction of the lower substrate.
7. The optical scanner package of claim 1, wherein an opaque blocking film is formed in a region excluding incident light and emission light regions in the transmissive window.
8. The optical scanner package of claim 1, further including: an inner space having an inclined plane angle of 54.7 degrees present on an upper portion of the lower substrate made of a crystalline silicon material; a silicon electrode formed in a trench structure outside a scanner for electrode separation on an upper substrate; an unbroken silicon barrier on an outside of the trench structure; an insulating film formed over the silicon barrier; and two types of metal electrodes formed over the silicon electrode and the insulating film, wherein there is the transmissive window sealed over a metal electrode of the silicon barrier.
9. (canceled)
10. The optical scanner package of claim 8, further including a separate silicon substrate or circuit board for sealing the lower substrate through which the inner space is perforated downward.
11. The optical scanner package of claim 8, further including: an insulating film filling the trench structure and formed over the barrier; and a metal circuit pattern formed over the insulating film, wherein there is the transmissive window sealed over the metal circuit pattern.
12. The optical scanner package of claim 1, further including: an inner space having cross-sectional shape that becomes wider or keeps same toward a lower portion of the lower substrate; a metal reflective film formed in a lower portion of the mirror; and a circuit board, as a base layer, sealed with a solder in a state where an up-down position of the scanner element and the lower substrate are changed.
13. The optical scanner package of claim 12, further including: a silicon substrate having an inner space glued to an electrode of the scanner element with a solder and a barrier with a glass sealing material.
14. (canceled)
15. The optical scanner package of claim 1, further including a chip carrier attached to an underside of the lower substrate.
16. The optical scanner package of claim 15, wherein the lower portion of the transmissive window has a square or rectangular shape.
17. The optical scanner package of claim 15, wherein, when an inner shape of the chip carrier is a quadrangle, a metal substrate having a large circular hole opened in a center portion is additionally used.
18-20. (canceled)
21. A method for manufacturing an optical scanner package, the method including: forming a cavity on a glass wafer using wet etching (a1); forming a via-hole on the glass wafer using DRIE or sand blast for electrical connection with a scanner element (a2); forming a metal pattern (seed layer) on a separate Si wafer, aligned with the position of the via-hole (a3); anodic bonding the glass wafer and the Si wafer (a4); filling the via-hole with a conductive material (a5); lowering the height of the top of the Si wafer by CMP processing (a6); forming a metal pattern over a mirror surface, an electric wiring and a pad (a7); forming an element structure and an electrode on the top of the Si wafer by DRIE process (a8); and bonding a semi-spherical or ellipsoidal transmissive window over an external structure (a9).
22. (canceled)
23. A method for manufacturing an optical scanner package, the method including: forming an inner space on a Si wafer using wet etching or DRIE (b1); lowering height of top of the Si wafer by CMP after performing fusion bonding with a separate Si wafer on which an oxide film (BOX: buried oxide) is formed (b2); forming an insulating film in an outermost barrier region of a scanner element (b3); depositing a metal at corresponding positions of a mirror surface, wiring and barrier (b4); forming Si electrode for scanner driving and sensing on an inside of the top of the Si wafer by DRIE process, and simultaneously forming a separate barrier separated by an inner electrode and a trench on an outer edge of a chip (b5); performing wiring between the inner electrode and an outer barrier (b6); and performing sealing by adhering a semi-spherical or ellipsoidal transmissive window in a vacuum atmosphere over an external structure (b7).
24. The method of claim 23, wherein in the formation of the inner space (b1), instead of the Si wafer, a glass wafer having a cavity is anodically bonded.
25. The method of claim 23, wherein in the forming the separate barrier (b5), the barrier is directly connected to the inner electrode without a trench to prevent electrical floating.
26. The method of claim 23, wherein in the performing sealing by adhering the transmissive window (b7), a plurality of holes or dimples are formed over the metal to strengthen adhesion of the transmissive window.
27-32. (canceled)
33. A method for manufacturing an optical scanner package, the method including: preparing a Si wafer, and lowering height of top of the Si wafer by CMP after performing fusion bonding with a separate Si wafer on which an oxide film (BOX: buried oxide) is formed (d1); depositing a metal at a corresponding position of wiring and a barrier (d2); forming Si electrode for scanner driving and sensing on an inside of the top of the Si wafer by DRIE process, and simultaneously forming a separate barrier separated by an inner electrode and a trench on an outer edge of a chip (d3); forming a through-hole in a (100) Si lower substrate using crystalline wet etching (d4); coating a metal to use inside of a mirror as a reflective surface of the scanner (d5); bonding a transmissive window to an upper surface of the Si lower substrate (d6); soldering to the top of the Si wafer (d7); and preparing a separate circuit board having a metal line formed thereon and having a cavity therein, and attaching the separate circuit board to the Si wafer having a scanner element by flip-chip bonding after turning over the Si wafer (d8).
34-35. (canceled)
Description
DESCRIPTION OF DRAWINGS
[0054] The accompany drawings, which are included to provide a further understanding of the present disclosure and are incorporated on and constitute a part of this specification illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure.
[0055]
[0056]
[0057]
[0058]
[0059]
[0060]
[0061]
[0062]
[0063]
[0064]
[0065]
[0066]
[0067]
[0068]
[0069]
[0070]
[0071]
[0072]
[0073]
[0074]
[0075]
[0076]
[0077]
[0078]
[0079]
[0080]
[0081]
[0082]
[0083]
MODE FOR DISCLOSURE
[0084]
[0085] In an embodiment of
[0086]
[0087] The semi-spherical structure exhibits compressive stress when there is an external pressure, and even the stress is not concentrated. Glass is strong in compressive stress, so it may be safely used even when produced as thin as 0.4 to 0.8 mm thick at 1 atmosphere. In general, the scanner parts are protected by a system housing, so a direct impact is rarely applied. Even in the case of an indirect impact due to an acceleration of several tens of G, the influence on the stress is 1/10 or less of the external pressure, so it may be neglected.
[0088]
[0089] When the transmissive window has a semi-spherical shape, the incident angle and the emission angle are always perpendicular, so that the cross-sectional profile of the laser beam does not change significantly, but there is a problem that the height of the transmissive window is somewhat increased. In order to lower this height, a portion of an ellipsoid or a shallow semi-spherical shape having a ratio of the height (h) to the lower diameter (D) of the transmissive window in the range of 0.3 to 0.4 may be used. In this connection, a spherical lens or an aspherical optical element for compensating for the shape of the laser beam may be included in a partial region of the transmissive window through which the incident light and the emission light pass so that the change in the cross-sectional profile of the laser beam is minimized.
[0090] The driving angle of the mirror is greatly affected by air resistance (air squeeze damping). As the size of the mirror decreases, the air resistance also decreases, so that the driving angle may be increased or the possible driving frequency may be increased. When the driving angle or driving frequency is maintained the same, a portion of the driver (for example, a comb electrode) may be utilized as an integrated sensor for measuring the driving angle. The lens may be produced to be integrated with the transmissive window, and as a result, an optical system such as LiDAR may be produced small by using an integrated lens and integrated sensor. The transmissive window with the integrated lens may be produced by injection molding, and may be combined with an aspherical lens and a concave lens when needed.
[0091]
[0092] a1) An inner space (cavity) 311 is formed on a glass wafer by wet etching.
[0093] a2) A via-hole is formed on the glass wafer using DRIE or sand blast for electrical connection with a Si scanner element.
[0094] a3) A seed layer 211 of metal pattern is formed on a separate Si wafer, aligned with the position of the via-hole.
[0095] a4) The glass wafer and the Si wafer are anodically bonded.
[0096] a5) The via-hole is filled with a conductive material. For example, a conductive material may be filled in the via-hole by electroplating. When filled with a metal, it is referred to as a via metal 212.
[0097] a6) The height of the top Si is adjusted by CMP. The height of Si is set to approximately 30-90 um.
[0098] a7) A metal pattern is made over a mirror surface, an electric wiring and a pad.
[0099] a8) An element structure and an electrode are made on the top Si by a DRIE process. In this connection, since there is an inner space, there is no need for a release process.
[0100] a9) A semi-spherical transmissive window 52 is bonded over an external structure using vacuum epoxy, frit glass, or anodic bonding.
[0101] After process a9) above, it may be adhered to a printed circuit board (PCB) using a surface mounting technology.
[0102] In the above manufacturing process, process a5) may be performed after process a9).
[0103] Although a via metal process of a glass substrate is added, since surface mounting technology (SMT) may be applied, the process is simple and the product size may be reduced.
[0104] When the transmissive glass window is anodically bonded on Si at wafer-level in process a9), the scanner element is protected, so that chip dicing becomes to be easy.
[0105] When the bonding process of process a9) is performed in a vacuum, vacuum packaging of the scanner is possible.
[0106] Si used in an embodiment of the present disclosure is crystalline Si, which has better reproducibility of properties than conventional polysilicon (poly-Si), and has a yield-stress three times higher than that of polysilicon, resulting in a longer life time.
[0107] When the glass transmissive window is independently made and diced, it may be used for chip-level packaging.
[0108]
[0109] However, when vacuum packaging is required to increase a driving angle, this trench may be a cause of serious leakage.
[0110] In an embodiment of the present disclosure, trench leakage and wiring issues are solved by the following manufacturing method. The manufacturing method is described with reference to
[0111] b1) An inner space 311 is formed on a Si wafer using wet etching or DRIE.
[0112] b2) After performing fusion bonding with a separate Si wafer on which an oxide film (BOX: buried oxide) is formed, the height of top Si is adjusted to approximately 30-90 μm by CMP.
[0113] b3) An insulating film is formed in an outermost barrier 142 region of the element.
[0114] b4) A metal is deposited at corresponding positions of a mirror surface, wiring and barrier.
[0115] b5) Si electrode for scanner driving and sensing is formed on inside of the top Si by a DRIE process, and simultaneously a separate barrier 142 separated by an inner electrode 145 and the trench 140 is formed on an outer edge of a chip.
[0116] b6) Wiring is performed between the inner electrode 145 and an outer barrier 142.
[0117] b7) Sealing is performed by adhering the transmissive window 51 in a vacuum atmosphere over an external structure using vacuum epoxy or frit glass.
[0118] b8) Additional wiring is performed outside the transmissive window 51.
[0119] In process b1) above, instead of the Si wafer, a glass wafer having a cavity may be anodically bonded.
[0120] The barrier 142 in process b5) may be directly connected to the inner electrode 145 without a trench to prevent floating.
[0121] In process b7), a plurality of holes or dimples may be formed over the metal to strengthen the adhesion of the transmissive window.
[0122]
[0123] In addition, as illustrated in
[0124]
[0125]
[0126]
[0127] c1) An inner space is formed on a Si wafer using wet etching or DRIE.
[0128] c2) After performing fusion bonding with a separate Si wafer on which an oxide film (BOX: buried oxide) is formed, the height of top Si is adjusted to approximately 30-90 μm by CMP.
[0129] c3) A trench is made between an inner electrode and a barrier on the top Si by DRIE process.
[0130] c4) The insulator 141 fills the trench 140 and is deposited to above the barrier.
[0131] c5) A metal is deposited for electrical connection between the inner electrode and the barrier and for formation of a mirror reflective surface.
[0132] c6) After passivating the metal, a scanner element pattern is formed by DRIE.
[0133] c7) Sealing is performed by adhering the transmissive window in a vacuum atmosphere over an external structure using vacuum epoxy or frit glass.
[0134] In process c1) above, a getter (reference numeral 312 in
[0135] In the manufacturing process of
[0136] When the transmissive window is attached as illustrated in
[0137] In order to smoothly perform the adhesion of the transmissive window in process c7), a planarization process may be performed after process c4).
[0138] As described above, when the structure of
[0139]
[0140] d1) a Si wafer is prepared.
[0141] d2) After performing fusion bonding with a separate Si wafer on which an oxide film (BOX: buried oxide) is formed, the height of top Si is adjusted to approximately 30-90 μm by CMP.
[0142] d3) A metal is deposited at a corresponding position of wiring.
[0143] d4) Si electrode for scanner driving and sensing is formed on inside of the top Si by a DRIE process, and simultaneously a separate barrier separated by an inner electrode and a trench is formed on an outer edge of a chip.
[0144] d5) A through-hole is formed in a (100) Si lower substrate 113 using crystalline wet etching.
[0145] d6) The metal is coated to use an inside of a mirror as a reflective surface of the scanner.
[0146] d7) An insulating film pattern is formed on a separate Si wafer (see reference numeral 40).
[0147] d8) A metal line is formed on the separate Si wafer and then an inner space (cavity) is formed in a passivated state.
[0148] d9) After turning over a wafer having a scanner element, the separate Si wafer is attached by flip-chip bonding. In this connection, the inner electrode may be adhered by conductive welding and the outer barrier may be adhered with an insulator.
[0149] The process d4) above may be performed after d5).
[0150] In the above production process, vacuum packaging is possible on a chip-level or wafer-level level.
[0151]
[0152] As illustrated in
[0153]
[0154]
[0155]
[0156] The above description is only illustrative of the technical idea of the present disclosure, and for those skilled in the technical field to which the present disclosure pertains, various modifications, changes, and substitutions will be possible without departing from the essential characteristics of the present disclosure. Accordingly, the present embodiment is not intended to limit the technical idea of the present disclosure, and the scope of the technical idea of the present disclosure is not limited by these embodiments. The scope of protection of the present disclosure should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as being included in the scope of right of the present disclosure.
DESCRIPTION OF REFERENCE NUMERALS
[0157] 100: SCANNER ELEMENT [0158] 11, 111: UPPER SUBSTRATE [0159] 12, 112: OXIDE FILM [0160] 13, 113: LOWER SUBSTRATE [0161] 113A: CIRCUIT BOARD [0162] 114: SOI WAFER [0163] 21, 121: FIXED BODY [0164] 22, 122: SPRING [0165] 25, 125: MIRROR [0166] 126: METAL REFLECTIVE FILM [0167] 31, 131: FIXED ELECTRODE [0168] 32, 132: DRIVING ELECTRODE [0169] 140: TRENCH [0170] 141: INSULATOR [0171] 142: BARRIER [0172] 145: INNER ELECTRODE [0173] 40: BASE LAYER [0174] 50, 51, 52: TRANSMISSIVE WINDOW [0175] 70: INCIDENT LIGHT [0176] 71, 71A, 71B, 171: MAIN REFLECTED LIGHT [0177] 72, 172: SUB-REFLECTED LIGHT [0178] 211: SEED LAYER [0179] 212: VIA METAL [0180] 221: BLOCKING FILM [0181] 222: LENS [0182] 311: INNER SPACE (CAVITY) [0183] 312: GETTER [0184] 321: CIRCUIT BOARD [0185] 322: CMOS SI CIRCUIT BOARD [0186] 352, 352A, 352B: SOLDER [0187] 353: THROUGH-HOLE [0188] 354: SOLDER PAD