CN104347443B

CN104347443B - Testing method for sudden change in horizontal direction of wafer alignment

Info

Publication number: CN104347443B
Application number: CN201310340596.5A
Authority: CN
Inventors: 李玉华; 姚振海
Original assignee: CSMC Technologies Corp
Current assignee: CSMC Technologies Corp
Priority date: 2013-08-07
Filing date: 2013-08-07
Publication date: 2017-02-08
Anticipated expiration: 2033-08-07
Also published as: CN104347443A

Abstract

The invention discloses a testing method for sudden change in the horizontal direction of wafer alignment, which is applied to a wafer photoetching platform. The method comprises the following steps: 1, making an alignment standard sheet, wherein the standard sheet is provided with a plurality of alignment points; 2, before treatment of the standard sheet, performing alignment once to obtain first alignment data; 3, feeding the standard sheet into a checking platform for wafer alignment treatment, and recording the position of a wafer gap relative to the platform; 4, aligning the standard sheet treated by the checking platform once again to obtain second alignment data; 5, comparing the first alignment data with the second alignment data, wherein local sudden change in the horizontal direction of a wafer is determined if a difference value is greater than 0.03/microns. The testing method has the advantages of accurate testing, high speed, high accuracy, freeness from loss and avoidance of the loss of product sheets.

Description

A kind of method of testing of the horizontal direction mutation of wafer alignment

Technical field

The present invention relates to the manufacture of wafer, particularly a kind of method for testing precision of wafer photolithography machine.

Background technology

Wafer（Wafer）Refer to the silicon used by silicon semiconductor production of integrated circuits.Wafer is processed through multiple light shield, its In step each time include photosensitizer coating, exposure, development, burn into infiltration or steam and write etc., make with multilayer line with The IC wafer of element, then transfer to the test of back segment, cutting, encapsulation factory, to make the integrated circuit finished product of entity.

Evaluate wafer manufacture level, particularly large scale wafer manufacture level when, yields is most important index. In the deep submicron process that wafer manufactures, alignment precision has vital impact to product yield, in wafer-process process In, the abnormal machines of some process steps（Litho machine）The alignment mutation of wafer local can be caused.

The method of existing investigation exception board, generally adopts the product of the normal batch of alignment（lot）With abnormal lot pair Than, but, if abnormal lot data leads to investigation result not accurate enough compared with I haven't seen you for ages.Checking can also be gone to make by testing burst Industry board whether there is extremely, needs to go operation on potential abnormal board with product, risk is larger.

Content of the invention

The present invention is exactly to overcome the abnormal detection of the existing alignment for wafer photolithography machine described in background technology The defect of method, the survey of abnormal sudden change in the horizontal direction of wafer alignment that invention is a kind of quickly, simple, risk is little, loss is little Method for testing.

The method of testing of the horizontal direction mutation of this wafer alignment, for wafer photolithography board, step is：

Step 1, makes alignment standard film, standard film has multiple loci；

Step 2, standard film before processing does a para-position, obtains first time para-position data；

Step 3, standard film enters needs the board of investigation to do the process of wafer alignment, relative to board at record notched wafer Position；

Step 4, standard film, after the process of wafer alignment, is cooked para-position again, obtains second para-position data；

Step 5, will para-position Data Comparison twice, difference ＞ 0.03/um is considered as wafer level direction abrupt local.

Described alignment standard film have loci, loci is fixed up through fine etching, remove unnecessary The wafer of photoresistance.

Preferably loci has X-direction and two reference patterns of Y-direction, is further preferred that two is in 90 ° of straight line.

Another preferred：Para-position data in step 2 or step 4 is loci physical location and ideal position on wafer Difference value, with/um as unit.

The present invention devises a set of testing tool with specific alignment standard film as core, using contrast difference's twice Mode carries out the precision to photoetching equipment（Especially it is horizontally oriented）Sudden Anomalies detection, be that one kind is applied to litho machine and crystalline substance The particular technology means of circle alignment special process, can obtain more accurate data.And, the speed of whole method is fast, accurate Exactness height, no consumption, the loss without product piece.

Brief description

Fig. 1 is the embodiment of the figure of the alignment mark of the standard film of the present invention.

Fig. 2 is in the embodiment of the present invention, the Data Comparison schematic diagram of one of coordinate.

Specific embodiment

The present invention is a kind of method of testing of the mutation of horizontal direction of the litho machine being applied to wafer alignment it is intended to find Go out the hardware part not up to standard of litho machine, the final yields improving wafer alignment.

With reference to an embodiment, whole method is described in detail：

The first step, makes alignment standard film

First, according to wafer（wafer）Procedure of processing, do zero in a wafer（zero）Level photolithographic reticle, obtains Photoresistance, then selects each 5 of 10 loci of different location arrangements, wherein X-direction and Y-direction, and specific loci is as schemed 1, it is strip, being mutually perpendicular to of the alignment mark of X-direction and Y-direction.Then figure is fixed up by fine etching, removes many Remaining photoresistance, makes alignment standard film.Being chosen at of specific loci discloses below in association with para-position data.

Second step, the first time of wafer standard film before processing, to bit test, obtains first time para-position data

Because litho machine is to walking in Barebone, exposure process and camera lens is not perfect, therefore loci is in wafer Upper physical location can't overlap with ideal position.It is to take alignment mark real on wafer to the purpose of bit test before wafer-process Border position and a difference of ideal position, the data of acquirement is as shown in table 1 below：

Table 1：

3rd step, standard wafer is placed into and treats that investigation machine is processed, relative to the position of board at record notched wafer.

4th step, carries out after wafer-process, to bit test, obtaining second para-position data, concrete data such as table 2 below again Shown：

Table 2：

Step 5, will para-position data twice（The difference value of Tables 1 and 2）Contrast, difference ＞ 0.03/um is considered as wafer water Square to abrupt local.Visible in the present embodiment, X（2,0）And Y（2,0）The data of two points has respectively reached 0.070 He 0.100, exceeded set difference range it is possible to judge this two points level mutation exceeded.

Thus, compare this two points position go check litho machine hardware device whether in need repair or debugging May, to improve the yields of product wafer.

It was found that adopting the method for the present invention, comparing with by the way of burst test, reaching the standard grade without product, and mark The manufacturing process of quasi- piece is special, and reliability is higher than product, as long as standard film does not damage, can be used for multiple times.And the present invention High precision（The alignment mark of diverse location and quantity can be selected）, speed fast, more conform to the actual state of production scene.

Claims

1. a kind of method of testing of the horizontal direction mutation of wafer alignment, for wafer photolithography board, is characterized in that：Including following Step,

Step 1, makes alignment standard film, standard film has multiple loci；

Step 3, standard film enters needs the board of investigation to do the process of wafer alignment, relative to the position of board at record notched wafer Put；

2. a kind of method of testing of the horizontal direction mutation of wafer alignment according to claim 1, is characterized in that：Described Alignment standard film is that have loci, the wafer of the unnecessary photoresistance that loci is fixed up, removes through fine etching.

3. a kind of method of testing of the horizontal direction mutation of wafer alignment according to claim 1, is characterized in that：Described Para-position data in step 2 or step 4 is the difference value of loci physical location and ideal position on wafer.

4. a kind of method of testing of the horizontal direction mutation of wafer alignment according to claim 2, is characterized in that：Described Loci has X-direction and two reference patterns of Y-direction.