CN101121501A

CN101121501A - Method for separating chip containing micro-electromechanical system in wafer

Info

Publication number: CN101121501A
Application number: CNA2007100253274A
Authority: CN
Inventors: 朱健; 姜理利; 郁元卫; 王立峰
Original assignee: CETC 55 Research Institute
Current assignee: CETC 55 Research Institute
Priority date: 2007-07-24
Filing date: 2007-07-24
Publication date: 2008-02-13

Abstract

The present invention provides a method separating a chip containing a micro electromechanical system from a wafer. The steps are as following: (11). A protection ring is made around the movable structure of the micro electromechanical system of the wafer. (12). A film with an alterable stickiness is stuck on the chip of the wafer. (13). A support layer of an underlay of the wafer is scribed. (14). The stickiness of the film is lowered. (15). The chip stuck on the film is separated. The method provided by the present invention fixes the chip with the film of variable stickiness and scribes the wafer containing the chip on the base that the chip is fixed, which ensures that the damage on the chip can be reduced to be minimal in the scribing process. After the chip in the wafer is separated and the stickiness of the film of alterable stickiness is reduced, each independent chip can be separated from the film conveniently. All in all, adopting the traditional semiconductor scribing equipment, the present invention completes the separation of the MEMS chip with the movable structure, improving the finished product rate with a low cost.

Description

The method of separating the chip that contains MEMS in the disk

Technical field

The present invention relates to the manufacturing process of MEMS (MEMS) device, particularly separate the method for the chip that contains MEMS in the disk.

Background technology

The MEMS device that contains movable structure mainly contains two characteristics: the firstth, and the MEMS device has movable structure; Second multilayer device that forms by structure sheaf and supporting layer.In the process of scribing, the very easily contaminated or damage of movable member, this makes the separation of the chip that contains MEMS in the disk comparison difficulty that becomes.

A kind of method of prior art is; before scribing, MEMS movable structure layer is coated with polymer; protected movable structure, it is contaminated to make also in the scribing processes that structure is difficult for, but scribing intact after; need to increase operation chip is carried out follow-up cleaning treatment; in order to prevent the MEMS structure cohesion, generally adopt sublimed method or supercritical drying to carry out the MEMS structure and discharge, workload is big; yield rate is low, the cost height.Be coated with simultaneously and often make the structure distortion that is distorted behind the polymer, after removing polymer, the micro-structural of distortion also can't return to original state, and this performance and reliability effect to device is very big.

The another kind of method of prior art is that scribing, is carried out sliver after in the end release is finished and got sheet about supporting layer reservation 100um to certain depth before MEMS movable structure sacrifice layer discharges.It is to reduce the required external force of scribing by the method for cutting deep trouth in the position to be cut of disk earlier, though this method has been avoided the scribing damage bigger to movable structure, but in dispose procedure, improved requirement, also might damage whole wafer technology.

The another kind of method of prior art is, the MEMS sacrificial layer release process is put in after the scribing, so just having guaranteed does not have movable micro mechanical structure in the process of scribing, this method need independently be carried out micro-structural release in the unit to each, consumed huge technology cost, and yield rate, uniformity can not be guaranteed.

All said methods of prior art all have himself fatal defective, therefore wish to have a good method, it can be applied to the separation of the MEMS chip of band movable structure in the disk efficiently, the chip structure surface cleaning that separates, the damage of MEMS micro-structural is low, can improve yield rate, improve the Performance And Reliability of device, cost and production efficiency aspect also further are benefited.

Summary of the invention

At above-mentioned defective; the method of the chip that contains MEMS in the separation disk provided by the invention; by around the movable structure of MEMS chip, making protection ring; protection MEMS movable structure; scribe line is being set between the protection ring on the chip; scribe line can be made the scribe line that certain depth is arranged synchronously with semiconductor technology when making the MEMS structure; also can only on chip, keep somewhere slot pitch; with the variable film fixed chip of viscosity; on another side substrate supports laminar surface on the other side, make the scribing alignment mark with semiconductor technology; scribe line on the alignment mark another side structure sheaf relative with it is corresponding one by one; on the substrate supports layer from the scribing of scribing alignment mark; the disk that will contain the MEMS chip is cut apart, and the viscosity of film is reduced, and chip is separated with film.

Compared with prior art; the method of the chip that contains MEMS in the separation disk provided by the invention; by around the structure of MEMS chip, making protection ring; use the variable film fixed chip of viscosity; on the basis that described chip is fixed, the disk that contains chip is carried out scribing; thereby guaranteed in the scribing processes damage minimum to chip; treat that chip in the disk is by separated; the viscosity of the variable film of this viscosity is reduced, thus easily with each independently chip separate from film.

In the preferred version of the present invention, use deep ultraviolet (UV) film fixed chip, the UV film has higher viscosity after heating, and the viscosity of UV film has very significantly and to descend behind UV-irradiation, therefore, earlier the UV film is heated the damage minimum that can guarantee in the scribing processes chip, after the chip for the treatment of disk is separated, adopt UV-irradiation UV film, the viscosity of UV film is significantly descended, thereby finish more easily separating of chip and film.

In the preferred version of the present invention, be added with protection ring, can effectively prevent the pollution that in scribing processes, produces, keep the device surface cleaning at the MEMS of chip structure periphery.Simultaneously the existence of protection ring can be affixed on disk on the UV film securely, has avoided the pollution of the flushing of cooling water in the scribing processes to chip, has protected in the scribing processes particles such as slight disintegrating tablet, chip to the pollution and the damage of MEMS structure.When chip took off from film, protection ring had also been shared a part of adhesive force, can improve yield rate widely.

In the preferred version of the present invention; between the protection ring of the structure sheaf of each described chip, scribe line is set; at the another side of substrate supports layer with respect to the MEMS structure; be manufactured with the scribing mark with semiconductor technology; the scribing mark is corresponding one by one with the scribe line on its structure sheaf; improve the accuracy of scribing greatly, the scribing difficulty is reduced, prolonged the service life of scribing cutter.

Generally speaking, the present invention adopts traditional semiconductor dice equipment to finish the separation of MEMS chip of band movable structure, improves the yield rate of product under situation cheaply, prolongs the service life of instrument.

Description of drawings

Fig. 1 is the front schematic view of disk.

Fig. 2 is the schematic diagram of segment chip in the disk.

Fig. 3 is the pad pasting and the chip structure schematic diagram of the embodiment of the invention.

Fig. 4 is the scribing schematic diagram of the embodiment of the invention.

The specific embodiment

Below be embodiment provided by the invention.

As shown in Figure 1, containing several chips that contains movable structure (101) in the disk (8), is the position at scribe line (2) place around this chip (101).

As shown in Figure 2; be manufactured with protection ring (3) around the movable structure (1) in this chip (101); scribe line (2) is set between each protection ring (3); the manufacturing process of making of this protection ring (3) and described chip (1) is synchronous; form structure sheaf, the apparent height of this protection ring (3) is not less than the height of movable structure in the described chip (1).

As shown in Figure 3, on the substrate supports layer of described disk (8), be manufactured with scribing mark (7), described scribing mark (7) position is corresponding to scribe line (2), disk (8) is placed on the horizontal table top of smooth cleaning, with facing up of described movable structure (1) place, above the adhesive one side of UV film (4) covered gently, do not apply local power, guarantee to contain the integrality of the chip (101) of movable structure (1), wait for 5～10 minutes, UV film (4) will be fitted with structural plane gradually.In general viscosity is strong more, and the damage during scribing is more little, therefore selects the bigger UV film of viscosity.Evenly heating is attached on the UV film (4) disk (8) securely then; guarantee that protection ring (3) and UV film (4) fit tightly; the vibration that produces when reducing scribing is to the influence of structure; prevent that simultaneously power and cooling water that cutter (6) is produced when rotation is cut at a high speed from impacting down, chip (101) breaks away from from UV film (4).

Select different cutters according to different material requires during scribing, can obtain scribing effect preferably like this.The disk that backing material is different with structural material as pottery, glass etc., is selected the thick resinoid bond cutting blade scribing of 150～300um for use; Identical with structural material or the similar disk of backing material, as silicon, SOI etc. select the thick metallic bond cutting blade scribing of 20～100um for use.

After loading onto suitable cutter, the disk that will post UV film (4) is loaded on the scribing machine, and cutter (6) is aimed at scribing mark (7), sets accurate scribing parameter, begins to cut apart disk.

As shown in Figure 4, with cutter (6) scribing to UV film (4) position contacting, each chip (101) is separated fully.

After cutting is finished, remove the cooling water on the chip, the MEMS micro-structural can not sustain damage, and finishes low damage MEMS disk division process, then prepares exposure and gets sheet.

The one side that to not paste the UV film of MEMS movable structure chip is placed on exposure under the ultraviolet source, and whether exposure fully directly has influence on the yield rate of scribing.Ultraviolet light sees through the adhesion glue-line that the photic zone of UV film is applied to it, and the energy density of ultraviolet source should be enough big, drops to enough low in the short period of time so that the UV film adheres to glue-line viscosity.If the light intensity of ultraviolet light a little less than, can make the top layer sex change and inner sex change is very slow, and after the surface layer adhesive sex change UV iris action is become big, can make follow-up assimilation time become quite long, when glued membrane is thick even can not remove viscosity fully, MEMS movable structure chip just is difficult to separate with the UV film, so the power of ultraviolet light should be in the scope of 50～300W.

Irradiation time length depends primarily on UV adhesive gel layer thickness, adheres to the UV energy density that glue-line receives.Irradiation time is long, and the device interior temperature rise is big, destroys glued membrane easily and chip is adversely affected, and security simultaneously also reduces.The time of irradiation is too short, and the energy of reception is less, and it is not thorough to expose, and the viscosity of UV film can not drop to a certain degree, and easy damaged structure when chip takes off influences the performance and the yield rate of device.Therefore irradiation time should be in 200s～500s scope.

Behind the end exposure, cooling UV film is to room temperature naturally, and it is minimum that its viscosity is dropped to, and begins to take off unit chip (101).Below chip layer placed, the UV film did not have one of viscosity to face up, and the adhesive gel of the UV film of this moment has almost lost viscosity.At the layout of concrete structure, apply power a little in a direction, chip will come off from the UV film, finishes low damage chip and gets sheet.

Generally speaking, the present invention adopts traditional semiconductor dice equipment to finish the separation of the chip of band movable structure, is improving the yield rate of product, the service life of prolongation instrument under the situation cheaply.

Claims

1. a method of separating the chip that contains MEMS in the disk is characterized in that, may further comprise the steps:

11) in described disk, make protection ring around the movable structure of MEMS;

12) on the chip of described disk, paste the variable film of viscosity;

13) the substrate supports layer at described disk carries out scribing;

14) viscosity of the variable film of described viscosity is reduced;

15) the described chip that will be bonded on the described film breaks away from.

2. the method for the chip that contains MEMS in the separation disk according to claim 1 is characterized in that described protection ring is made with semiconductor technology.

3. the method for the chip that contains MEMS in the separation disk according to claim 2 is characterized in that, the structure manufacturing process of the manufacturing of described protection ring and MEMS is synchronous.

4. the method for the chip that contains MEMS in the separation disk according to claim 1 is characterized in that, the variable film of described viscosity is the ultraviolet film, and this method further comprises the steps:

41) on the chip of described disk, paste described ultraviolet film;

42) evenly heat described ultraviolet film;

43) the substrate supports layer at described disk carries out scribing;

44) described ultraviolet film is carried out ultraviolet photoetching;

45) described chip is separated with described ultraviolet film.

5. the method for the chip that contains MEMS in the separation disk according to claim 1 is characterized in that the height of described protection ring is not less than the height of the structure of MEMS.

6. the method for the chip that contains MEMS in the separation disk according to claim 1 is characterized in that, between the protection ring of each described chip scribe line is set.

7. the method for the chip that contains MEMS in the separation disk according to claim 6 is characterized in that, corresponding to the position of described scribe line, makes the scribing mark with semiconductor technology on described substrate supports layer.

8. the method for the chip that contains MEMS in the separation disk according to claim 4, it is characterized in that, described step 44) comprise the steps: that specifically described dark purple adventitia is placed on light intensity to expose in the ultraviolet light between the 50W to 300W, the time of exposure is between 200 seconds to 500 seconds.