CN102082101B

CN102082101B - Packaging process method of photosensitive element

Info

Publication number: CN102082101B
Application number: CN2010102170009A
Authority: CN
Inventors: 陈吉; 谢禹钧; 刘峰; 蒋应田
Original assignee: Liaoning Shihua University
Current assignee: Liaoning Shihua University
Priority date: 2010-07-02
Filing date: 2010-07-02
Publication date: 2012-07-11
Anticipated expiration: 2030-07-02
Also published as: CN102082101A

Abstract

The invention relates to a packaging process of a photosensitive element, in particular to a packaging process method of a photosensitive element, which comprises the steps of: directly mounting a photosensitive bare chip on a PCB (Printed Circuit Board), then adding a packaging plate and finally adhering an MASK. The method in the invention has the advantages of lowering the packaging difficulty, reducing the process procedures, realizing that the packaging structure of the photosensitive element is simplified, saving cost, shortening the production time, improving the production efficiency, increasing the size accuracy of the photosensitive element to a certain degree, meeting the requirement for the GAP accuracy, and being remarkably superior to the traditional packaging method of the photosensitive element. The method can be popularized to other packaging procedures related to the chip elements.

Description

A kind of packaging process of light-sensitive device

One, technical field

The present invention relates to the method for packing of the packaging technology of chip device, particularly light-sensitive device.

Two, background technology

The light-sensitive device kind is varied, is widely used in the every field of national economy such as civilian, aviation, national defence.The operation principle of normal optical sensing device is: light-sensitive device is encapsulated on the printed circuit board (PCB) (PCB); Led light source sees through code-disc grating irradiates light sensing device, and the surperficial photoetching of light-sensitive device is covered worn-out layer (MASK) and is engaged in receiver surface formation grating Moire fringe with moving grating.Wherein photoreceptor photomask surface masking layer (MASK) is to the distance of code-disc grating; The sensitiveness of just so-called gap parameter (GAP) appreciable impact rotation code-disc Moire fringe projection on light-sensitive device is an important parameter of light-sensitive device production technology and quality control.The packaging technology of light-sensitive device should guarantee the precision of GAP distance, guarantees parallel between code-disc and the light-sensitive device surface again, and it is more little good more to require to mount between PCB, light-sensitive device receiver, the MASK error.

The light-sensitive device method for packing is that packaged chip is welded on the PCB surface through surface mounting technology (SMT) with the encapsulation in advance of photosensitive bare chip mostly at present.Be about to be welded on the PCB surface through the SMT mode again after photosensitive bare chip encapsulates with encapsulation lower plate, encapsulation upper plate and encapsulation cover plate.The structure of encapsulation back light-sensitive device is followed successively by:

1. solder thickness a

2. encapsulate plate thickness b down

3. encapsulate upper and lower plates intermediate gelatine layer thickness c

4. encapsulate the upper plate thickness d

5. encapsulate the middle bondline thickness e of upper plate and encapsulation cover plate

6. encapsulation cover plate f

7. the bondline thickness g in the middle of encapsulation cover plate and the MASK

8. MASK thickness h

Then final receiving device thickness K1=a+b+c+d+e+f+g+h

In practical set technology, all by accumulative total, cumulative errors are the error of each thickness: Δ K1.

Light-sensitive device through after this technology encapsulation has eight layers of structure, and the encapsulation precision of each layer structure is strict, technology controlling and process very complicated, waste great amount of time and material; Each layer glue and package board technology all produce error simultaneously, and cumulative errors are bigger, finally influence the control precision of GAP.The existing defective of current light-sensitive device method for packing directly influences the quality of light-sensitive device.

Three, summary of the invention

The packaging process that the purpose of this invention is to provide a kind of light-sensitive device adopts this process, can reduce light-sensitive device encapsulation back error, reduces technological process and saves material, and the precision of raising GAP is to reach the requirement of instrument to light-sensitive device.

The inventive method will not mount on the PCB through SMT after the encapsulation by the electronics bare chip in advance again, but photosensitive bare chip is directly mounted on the PCB, adds package board then, pastes MASK again.This technology has reduced encapsulation difficulty, has reduced technological process, has realized that the light-sensitive device encapsulating structure simplifies most.Light-sensitive device structure after the encapsulation is followed successively by:

1. PCB and package board intermediate gelatine layer thickness a

2. package board thickness b

3. package board and MASK intermediate gelatine layer thickness c

4. MASK thickness d

Encapsulating concrete processing step is: at first photosensitive bare chip is sticked with glue on the PCB, package board is sticked with glue on the PCB around the photosensitive bare chip again, on package board, paste MASK at last.The final receiving device thickness K2=a+b+c+d in its encapsulation back

In practical set technology, all by accumulative total, cumulative errors are the error of each thickness: Δ K2.

In sum, the cumulative errors of the inventive method are far smaller than the cumulative errors of conventional method, i.e. Δ K2＜Δ K1.Traditional handicraft is difficult to satisfy the high requirement of GAP to precision, and technological process of the present invention is simple, and encapsulation back light-sensitive device only has four-layer structure, and cumulative errors are less, have obvious superiority, can satisfy the degree of precision requirement of GAP size.

The direct mounting method of photosensitive bare chip of the present invention has been simplified light-sensitive device packaging technology flow process significantly, has reduced process complexity, practices thrift cost, has reduced the production time, enhances productivity; And improved the dimensional accuracy of light-sensitive device to a certain extent, satisfied the requirement of GAP precision, obviously be superior to traditional light-sensitive device encapsulation scheme.The method can be generalized to other encapsulation processs that relates to chip device.

Four, description of drawings

Fig. 1 is a light-sensitive device operation principle sketch map;

Fig. 2 is traditional light-sensitive device packaging technology sketch map;

Fig. 3 is the structural representation after traditional light-sensitive device encapsulation;

Fig. 4 is a light-sensitive device packaging technology sketch map of the present invention;

The structural representation of Fig. 5 after for light-sensitive device of the present invention encapsulation.

Five, embodiment

The operation principle of light-sensitive device is that photoreceiver 9 is encapsulated on the pcb board 1; The surface of photoreceiver 9 has photoetching to cover worn-out layer MASK6; The code-disc grating 8 of rotation is set in the MASK6 front; The led light source 7 in code-disc grating 8 outsides sees through code-disc grating 8 irradiation MASK6, and the code-disc grating 8 of MASK6 and rotation is engaged in photoreceiver 9 surfaces and forms the grating Moire fringe.

Tradition light-sensitive device packaging technology is that photosensitive bare chip 2 usefulness encapsulation lower plate 12 is packaged together through viscose glue 13 with encapsulation upper plate 14; Encapsulation lower plate 12 is solid flat board; Pass through empty in the middle of the encapsulation upper plate 14; Again empty encapsulation cover plate 16 usefulness glue 15 are passed through in the centre and stick on and encapsulate on the upper plate 14, more packaged chip 10 usefulness scolding tin 11 are welded on the PCB1, at last on encapsulation cover plate 16 with glue 5 bonding MASK6.

Concrete encapsulation step of the present invention is: at first photosensitive bare chip 2 is sticked with glue on the PCB 1, again package board 3 usefulness glue 4 is sticked on the PCB1 around the photosensitive bare chip 2, at last on package board 3 with glue 5 stickup MASK6.Said package board 3 is that empty whole plate is passed through in a centre; The area that the vacancy is greater than photosensitive bare chip 2 is passed through in the centre of package board 3; The thickness of package board 2 is greater than the thickness of photosensitive bare chip 2; Photosensitive bare chip 2 packed plates 3 are trapped among it and pass through the vacancy when encapsulation, and MASK6 sticks on above the package board 3, and photosensitive bare chip 2 is covered.

The auxiliary lead circuit that adapts with photosensitive bare chip 2 is arranged on PCB1, and this auxiliary lead circuit directly is printed on the circuit board PCB1 upper surface, need not extra encapsulating lead.

SMT among the present invention (surface mount technology surface mounting technology) is a kind of circuit assembly technology; Originate from the eighties in 20th century; Be with electronic component; Be installed on the surface-mounted integrated circuit (Print Circuit Board) like resistance, electric capacity, transistor, integrated circuit or the like, and form electric connection through soldering.

GAP refer in particular to encoder make in distance between code-disc and the anti-dazzling screen.

MASK is that worn-out layer (also claim anti-dazzling screen or be quiet grating) is covered in the photoetching on light-sensitive device surface, refers in particular to during encoder makes, and is engaged in the thin slice that the receiver surface forms the grating Moire fringe (thin slice of being made up of printing opacity and light tight striped) with moving grating.

Claims

1. the packaging process of a light-sensitive device, it is characterized in that: it is that photosensitive bare chip (2) is directly mounted on the PCB (1), package board (3) is sticked on photosensitive bare chip (2) PCB (1) all around again, on package board (3), pastes MASK (6) at last; Package board (3) is that empty whole plate is passed through in a centre; The area that the vacancy is greater than photosensitive bare chip (2) is passed through in the centre of package board (3); The thickness of package board (3) is greater than the thickness of photosensitive bare chip (2); The packed plate of photosensitive bare chip (2) (3) is trapped among it and passes through the vacancy when encapsulation, and MASK (6) sticks on above the package board (3), and photosensitive bare chip (2) is covered.

2. the packaging process of light-sensitive device according to claim 1 is characterized in that: on PCB (1), have the auxiliary lead circuit that adapts with photosensitive bare chip (2), this auxiliary lead circuit directly to be printed on circuit board PCB (1) surface.