TWI232563B - Method and structure for packaging an optical chip by chip-on-film technique - Google Patents

Abstract

A method for packaging an optical chip by chip-on-film Technique is disclosed. A plurality of bumps of an optical chip are bonded on a film substrate. The film substrate has a window corresponding to a light active region. Then a thermosetting film is provided on backside of the optical chip. The thermosetting film is thermal-pressed to flow and cover backside, laterals of the optical chip and the film substrate, so as to be a sealing base combining the optical chip and the film substrate.

Description

1232563 V. Description of the invention (1) [Technical field to which the invention belongs] The present invention relates to a method for packaging a thin film substrate of an optical wafer, and in particular, to a method for packaging a thin film chip on an optical wafer completely sealed on a thin film substrate. '% [Prior art] I know that optical wafers have light-acting regions formed on the active surface of the wafer, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor.

Image sensor chip [complementary metal oxide semiconductor, CMOS] and other image sensor chips [i mage sensor ch ip], because the optical active area of the optical wafer is very sensitive, it needs to be appropriately packaged to protect the optical active area of the semiconductor optical wafer from dust Damaged by particles and moisture, common image sensor packaging methods use a lead frame [1 eadframe] or a hard printed circuit board as the carrier medium of the optical chip. During the packaging process, the lead frame is transmitted in individual plates or strips. Or a hard printed circuit board, and it is not easy to completely seal the optical chip by conveying the wafer with a thin film. Generally, the optical chip is still in a bare crystal form after packaging. The Republic of China Patent Bulletin No. 45 9355 discloses a packaging structure of an image sensor and a packaging method thereof, which is an image sensing chip flip-chip bonding to a light-transmitting layer (that is, transparent glass). The optical layer is provided with a signal input end and a signal output end connected to each other by wires and formed on different surfaces. After the image sensing chip and the signal input end of the light transmission layer are electrically connected, the light transmission layer can be The signal output end is connected to a printed circuit board with an opening, so the electrical transmission path is transmitted by the image sensing chip through light transmission.

Page 6 of 1232563 V. Description of the invention (2) When the layer is transmitted to the printed circuit board, the light-transmitting layer must have the functions of light transmission and double-sided electrical conduction, and it must be edited on the glass light-transmitting layer. It is difficult and costly to form a double-sided electrical conductive line. In addition, according to its packaging method, the f-sensor chip and the light-transmitting layer are electrically connected, and then an adhesive layer or an adhesive is provided to seal the periphery of the connection. However, the size of the image sensing wafer and the light-transmitting layer are approximately the same. After the electrical connection, when the light-transmitting layer does not have a sufficient bearing area, it is used for the application of the sealant layer or the adhesive. 2. The invention patent of the Republic of China Patent Bulletin No. 484237 discloses a tape-and-reel packaged optical device, which carries a photon sun-and-chip in a tape-and-reel flexible circuit substrate to achieve tape-and-reel optical packaging. The soft circuit substrate The metal circuit has pins extending into the window. The < empty in the window, using internal bonding [InnerLeadBJ; rL LB] technology, the pins are hot-compression-bonded with a compression head [c〇mpressi〇n]. The bump of the optical chip, the optical chip is only with the floating inner pin J: ί ΐ The latter two are not stable, especially the light action of the optical chip ^ L2 is very high. When the optical chip is filled with colloid Resulting package: tj in the package of the optical chip, in addition, the Hai image sensing supply / ΪΙί requires a base for housing the optical chip, so that external electronic components can be firmly connected after the ΐΐί in advance, the base In order to seal and fix the optical chip and the soft circuit substrate, the sentence "1 ..'_." Is not good. If the base is a rotary injection molding method measuring surface, and the bee Yuzhe sealant will cover the The shape of the optical chipο Hostage circuit board is susceptible to change by the injection pressure of the sealing compound

1232563

V. Description of the invention (3) [Summary of the invention] In the crystal packaging method of the present invention, the base of the flow chip of an optical wafer on the back of the sheet does not cover the crystal packaging structure of the present invention, and the side of the thermosetting adhesive is As a learning chip. According to the present invention, there is provided: a thin plate having a peripheral system on one side to form a flip-chip bonding optical wafer system surface and a connection end of a window substrate on the back side of a light-acting region film substrate. The main purpose is to provide a heat-set _The cover of the film substrate to the light 'achieves the purpose of the light of the complete wafer. One purpose is to seal the optical film with a thermosetting system by heat pressing. The heat-cured side optics of the wafer are provided for a thin film lamination step of an optical wafer provided on a pedestal base, and the bonding process is performed on the bonding adhesive. The optical crystal plane is used to seal the back and side of the optical wafer. A film of an optical wafer covers a back surface of the optical wafer, and a back surface of the optical wafer and a thin film chip-on-chip packaging method for completely sealing the optical wafer are provided. The method includes a film-on-chip package (COF) film substrate. The film has a lower surface and at least one window, wherein the mouth has a plurality of connection ends; at least one optical chip to the upper surface of the film substrate, which has a main A moving surface, a corresponding back surface, and a side surface between the main body, the active surface system includes a central position and a plurality of bumps, and the light-acting area corresponds to the thin surface. The bumps of the optical chip are electrically connected to the film. A thermosetting adhesive is provided on the back of the optical chip.

Page 81232563 V. Description of the invention (4) The thermosetting adhesive film is thermally laminated so that the thermosetting adhesive film flows and covers the back and sides of the optical chip, and the thermosetting adhesive film covers the film substrate more fluidly. A surface to seal the back and sides of the optical wafer; and an active surface of the optical wafer to seal, preferably, a transparent glass sheet is attached to the lower surface of the film substrate. [Embodiment] With reference to the drawings, the present invention will be described by the following embodiments. Please refer to FIG. 1. The method for mounting a thin film on a wafer of an optical wafer of the present invention mainly includes a step of “providing a thin film substrate”, a step of “bonding an optical wafer”, and a step of “providing a thermosetting film”. 3. Step 4 of "thermocompression of the thermosetting adhesive film" and step 5 of "sealing the optical wafer", which will be described in detail later. The thickness of the thin film substrate 10 is about 0.1 mm or thinner, which is a circuit substrate of a thin-film flip-chip package that can be rolled up and packaged with a tape and reel. The soft film of the thin film substrate 10 is electrically conductive. Insulation, such as polyimide

First, in step 1 of “Providing a thin film substrate”, please refer to FIG. 2A. A thin film substrate 10 [Chip-On-Film, COF] is provided. The thin film substrate 10 has an upper surface η The lower surface 12 and at least one window 13 ', wherein a plurality of connection terminals 14 are formed around the window 13 such as copper pads or metal wires. In this embodiment, the connection terminals j 4 are provided on the film. The upper surface of the substrate 1 丨 [also can be set on the lower surface 丨 2 or suspended in the window 13], and it is better to plate metal layers such as gold, tin, etc. 1232563 V. Description of the invention (5) ~ or Other materials. After 'perform step 2 of "bonding an optical chip", please refer to the figure "corresponding to each window 13 with fHp-chip bonding, inner lead bonding, and anisotropic conduction Attach at least one optical chip 20 to the upper surface of the thin film substrate 10 in a connection manner with a non-conductive adhesive (film). The optical chip 20 has an active surface 21, a corresponding back surface 22, and The side surface 23 between the active surface 21 and the back surface 22, the active surface 21 includes a central light actuating area 24 'for receiving or transmitting an image light source, and the active surface 21 includes a plurality of formations. The bump 25 on the periphery of the light actuating area 24 is used as the external electrical connection end of the optical chip 20. In this embodiment, the optical sun-dial 20 is an image sensor chip [i mage sensor ch ip], which is a flip-chip bonding method in which the bumps 2 5 of the optical wafer 20 are electrically connected to the connection end 14 of the film substrate 10, so that the light actuating region 24 corresponds to the film Window 1 3 of substrate 10; preferably, see section 2 c circle, after step 2 of the above-mentioned "bonding an optical wafer", a filling gel 30 can be formed around the window 13 of the film substrate 10, and the bumps 25 can be sealed with the filling gel 30. Then, perform step 3 of “Provide a thermosetting film”, please refer to FIG. 2D. 'Provide a thermosetting film 40 on the back surface 22 of the optical wafer 20. When the thermosetting film 40 is provided by Xin, it should be kept at a low temperature. With the thermosetting adhesive film 40 in a solid state, the thermosetting adhesive film 40 is placed on the back surface 22 of the optical wafer 20. In this embodiment, a thermally conductive mold 50 is provided above the thermosetting adhesive film 40. The mold 50 has a flat pressing surface 5 1. Should it be flat?

1232563 V. Description of the invention (6) The joint surface 51 is at least larger than the back surface 22 of the optical wafer 20 to facilitate the forming of the thermosetting film 40. Next, 'step 4 of the "thermocompression of the thermosetting adhesive film" is performed, referring to FIG. 2E, heating and moving the mold 50, and thermally pressing the thermosetting adhesive film 4 with the flat pressing surface 51 of the mold 50. So that the thermosetting adhesive film 40 has fluidity. The fluidity of the thermosetting adhesive film 40 flows from the back surface 22 of the optical wafer 20 and covers the side surface 23 of the optical wafer 20. Preferably, the The thermosetting adhesive film 40 covers the upper surface of the thin-film substrate 丨 0 in a fluid manner, so as to seal the back surface 22 and the side surface 2 3 of the 4 optical wafer 20. Since the flow of the thermosetting film 40 is mainly through the softening of the heating temperature, the pressing pressure is much smaller than the conventional injection molding pressure. In the above step 4, the upper surface 11 of the film substrate is slightly lower. On the active surface 21 of the optical wafer 20, and under the isolation of the window 13, the 'thermosetting adhesive film 40 can flow and stop between the bumps 25' and the excess thermosetting adhesive film 40 will be It flows to both sides of the upper surface 11 of the thin film substrate 10 and does not cover the light operating region 24 of the optical wafer 20. Preferably, in step 4 described above, another pre-baking process [PO lamp cure] 'is performed after the thermosetting film 40 has flowed and maintained to be heated to the thermosetting film 40 to form. At this time, the thermosetting film 〇 A partial curing cross-linking reaction has occurred to facilitate the detachment of the mold 50 [see Figure 2F]. Finally, please refer to FIG. 2G, perform the step of “sealing the optical wafer”, and seal the active surface 21 of the optical wafer 20, preferably, a transparent glass sheet 60 is attached with an adhesive 61 On the lower surface 12 of the thin film substrate 10, the area of the transparent glass sheet 60 is not larger than that of the thermosetting adhesive film 40. Alternatively, the active surface 21 of the optical chip 20 may be sealed with a transparent adhesive.

Page 111232563 V. Description of the invention (7) Therefore, the package structure, the backside 2 2, the side of the wafer 20, the base 20 of the wafer 20, the operating area 2 4, the surface 21 of the sealing film substrate, and the surface 2 1, the structure . In addition, for general wafers other substrates, the front's are first heated by the back of the plate base. The present invention shall prevail. For any work done in the surrounding area, please refer to its profit and the hot surface 23 ″ seat, and with a component, the fully sealed product trusts the invention of the board bearing plate, the invention of the press-fit and the protection of the package, and is familiar with this. In the second figure, "a solid adhesive is used to make the uncovered transparent glass to be thin and the optically high optical wafer has the characteristics of a thermosetting wafer. According to the present thermosetting film 40 series, it is thermosetting to the light glass sheet 60. Film substrate B The package of the film 20 on a general wafer is an adhesive film, and the above-mentioned square adhesive film 40 invented on the side is provided by thermal compression so that the adhesive film 40 can be used as a wafer 20 to actively act as the optical crystal for carrying and transportation. Backside 22, bare-film flip-chip packaging method carried by side tapes, and an optical wafer 20 formed by sealing a wafer so that the thermosetting 'as an effective junction method can be used to cover the optical sheet 20 of the optical seal and the optical surface 21 actively In the table, a thin surface 23 and active crystal packaging method should be applicable to the optical wafer or the film on the moving surface. It is defined as follows: 2 Artists ’belong to the protection scope of the invention without departing from the spirit, scope and modifications of the invention.

Page 12322563 Brief description of the drawings [Simplified illustration of the drawings] Figure 1: According to the present invention, the process flow of a thin-film flip-chip packaging method for an optical wafer is not intended, and Figures 2A to 2G: a specific implementation according to one of the present invention For example, a schematic diagram of a thin-film substrate wearing surface in the process steps of the thin-film flip-chip packaging method of the optical wafer. Brief description of component symbols: 1 Provide _ 丨 __ film substrate 2 bonding optical wafer 3 provide thermosetting film 4 thermocompression bonding the thermosetting film 5 seal the optical wafer 10 film substrate 11 on 13 windows U 14 even 20 optical chip 21 main 23 side 24 light 30 filled gel 40 heat 51 flat pressing surface 60 through

Surface 12 Lower surface Termination Moving surface 2 2 Back surface Operating area 2 5 Bump Solid film 5 0 Mould Clear glass piece 61 Adhesion ·

Page 13

Claims (1)

J232563 6. Scope of patent application [Scope of patent application] 1. A thin-film flip-chip packaging method for optical wafers, comprising the steps of: providing a thin-film substrate having an upper surface, a lower surface, and at least one window, of which The periphery of the window is formed with a plurality of connecting ends; and at least one optical chip is bonded to the upper surface of the thin film substrate. The optical chip has an active surface, a corresponding back surface, and a side surface between the active surface and the back surface. The active surface system includes a light actuation region and a plurality of bumps, the light actuation region corresponds to the opening of the film substrate, and the bumps of the optical wafer are electrically connected to the connection ends of the film substrate; Provide a thermocompression bonding of the optical chip 'if applying for special mounting method, and' if applying for special mounting method, its block, in the above 'if applying for special mounting method, its & film series flow' if applying for special mounting method , The side of its thermosetting film. The first range of the profit range includes the first range of the profit range. The first range of the optical range includes the thermal compression bonding in the first range to the first range of the optical range. The solid adhesive film is thermally bonded to the back of the optical wafer. ; And 'Make the thermosetting adhesive film flow and cover the optical wafer as described in the above-mentioned film-on-chip sealing of the optical wafer. Grab the active surface of the optical wafer. The film-on-chip encapsulation of the optical wafer as described in the above item forms a filling colloid to seal the convex bonding steps. The film-on-chip sealing of the optical wafer according to the item, in the step of the thermosetting film, the upper surface of the thermosetting film substrate. The film-on-chip encapsulation of the optical wafer as described in the item. In the step of the thermosetting film, it is based on Page 14 1232563 Scope of patent application A flat pressing surface of a high-temperature mold is pressed against the thermosetting film. 6: The thin film coating of the optical wafer as described in item 1 or 5 of the patent application, f. Packaging method, wherein in the step of thermocompression bonding the thermosetting film, heating is maintained to the thermosetting film after the far thermosetting film flows. Membrane set. 7. The thin-film encapsulation method for an optical wafer as described in item 丨 of the scope of the patent application, wherein in the step of thermocompression bonding the thermosetting film, the upper surface of the thin film substrate is lower than the active surface of the optical wafer. 8. The thin-film flip-chip packaging method for an optical wafer as described in item 2 of the scope of the patent application, wherein in the step of sealing the active surface of the optical wafer, a transparent glass sheet is attached to the lower surface of the thin-film substrate. . 9. The film-on-film encapsulation of the optical wafer as described in item 8 of the patent scope of the application, wherein, after the step of sealing the active surface of the optical wafer, the area of the transparent glass sheet is not larger than the thermosetting film. 1 〇 ^ ^ t 凊 The thin-film flip-chip 'method' of the optical wafer described in item 1 of the patent scope, wherein the connection ends are provided on the upper surface of the thin film substrate. 0 11 if 之Film-on-chip 'method' for optical wafers, wherein the connection ends are arranged below the film substrate and ο ′ 1 2. Two types of thin-film flip-chip packaging structures for optical wafers, including:: thin-film flip-chip package [⑽] thin-film substrate, the thin-film substrate is a field: the upper surface, the lower surface and at least one window, of which the window ° The edge system is formed with a plurality of connection ends; the optical chip is bonded to the film substrate Page 15 1232563 6. Application ^ Scope " " S ^ S ~ 1 8. The thin-film encapsulation structure of the optical chip as described in item 12 of the patent application scope, wherein the connection ends are provided at the Crystalline XS under the thin substrate) 〇1. A chip packaging method, comprising the steps of: providing a substrate, the substrate has an upper surface, a lower surface and at least one window, wherein the periphery of the window is formed with a plurality of Connecting ends; bonding at least one wafer to the upper surface of the substrate, the wafer having an active surface, a corresponding back surface, and a side surface between the active surface and the back surface, the active surface including a plurality of peripheral protrusions The bumps are electrically connected to the connection ends of the substrate; β provides a thermosetting adhesive film on the back of the wafer; and the thermosetting adhesive film is thermally pressed so that the thermosetting adhesive film flows and covers the wafer. Side; and you seal the active surface of the chip. 20. The chip packaging method as described in item 19 of the scope of patent application, further comprising: forming a filling gel to seal the bumps, after the wafer bonding step described above. 2 1. The chip packaging method according to item 19 of the scope of patent application, wherein in the step of thermocompression bonding the thermosetting film, the thermosetting film is fluidly covered on the upper surface of the substrate. 22. The chip packaging method as described in item 9 of the patent application scope, wherein in the step of thermocompression bonding the thermosetting adhesive film, it is pressed against the thermosetting adhesive film with a flat pressing surface of a high temperature mold. Page 17! 232563 VI. Patent application scope 23. The wafer packaging method as described in item 19 or 22 of the patent application scope, wherein in the step of thermocompression bonding the thermosetting film, heating is maintained after the thermosetting film flows. Until the thermosetting film is set. 24. The chip packaging method as described in item 19 of the scope of patent application, wherein in the step of sealing the active surface of the wafer, a transparent, glass sheet is attached to the lower surface of the substrate. 25. According to the wafer packaging method described in item 19 of the scope of application for patents, after the step of sealing the active surface of the wafer, the area of the edge-reading glass sheet is not larger than the thermosetting film.