CN104425301B

CN104425301B - Method for monitoring HMDS (Hexamethyldisilazane) abnormity of photoresist bonding layer

Info

Publication number: CN104425301B
Application number: CN201310398681.7A
Authority: CN
Inventors: 胡骏
Original assignee: CSMC Technologies Corp
Current assignee: CSMC Technologies Corp
Priority date: 2013-09-04
Filing date: 2013-09-04
Publication date: 2017-04-12
Anticipated expiration: 2033-09-04
Also published as: CN104425301A

Abstract

The invention discloses a method for monitoring HMDS (Hexamethyldisilazane) abnormity of a photoresist bonding layer. The method comprises the following steps: growing silicon oxide layers on two silicon chips respectively; measuring respective thicknesses of the silicon oxide layers to form silicon oxide wafers; coating the surface of one silicon oxide wafer with a layer of uniform HMDS coating; feeding the silicon oxide wafer provided with the HMDS coating and the other silicon oxide wafer into a wet process corrosion platform; performing corrosion by adopting the same time T; after corrosion, measuring the thicknesses of the two wafers; calculating respective corrosion rates A1 and A2 by dividing the thickness difference between the wafers before and after corrosion with the corrosion time T; judging the thickness and component abnormity situation of the HMDS coating according to the difference value between A1 and A2. The thickness or component abnormity of the HMDS coating is indirectly judged according to the corrosion rates, so that online monitoring of HMDS is realized, product defects and a large amount of discarding are avoided, and the cost is reduced.

Description

A kind of monitoring photoetching glue bonding layer HMDS abnormal method

Technical field

The present invention relates to a kind of semiconductor devices process technique, more particularly to a kind of monitoring photoetching glue bonding layer HMDS exceptions Method.

Background technology

The gate oxidation silicon of processing procedure high tension apparatus mainly includes thick grid oxygen（High pressure）With thin grid oxygen（Low pressure）Two kinds of device classes Type, can first grow thick grid oxygen in technological process（400 angstroms～600 angstroms）, then carry out photoetching and the wet method of low-pressure area thickness grid oxygen Corrosion, exposes silicon substrate, finally grows thin grid oxygen in surface of silicon（20 angstroms～40 angstroms）.Wherein lithography step include gluing, Exposure, development.Because in coating technique, the used photoresist overwhelming majority is hydrophobic, and the hydroxyl on the surface of chip 21 Hydrone with residual is hydrophilic, if in the direct gluing in the surface of chip 21, causing photoresist 22 and chip 21 Cohesive is poor, or even causes gap or the bubble of local, so as to affect lithographic results and development.In order to solve this problem, Introduce a kind of chemicals in coating technique, the silicon alkane of hexamethyl two, Full Name in English is Hexamethyldisilazane （HMDS）.This layer of HMDS23 will be substantially removed after the series of steps such as removing photoresist through development, as indicated with 1.

The problem of existing process is：When the HMDS thickness brushed is unstable, serious defect can be caused.If HMDS is blocked up, and can affect to develop the ability removed photoresist, and after removing photoresist, crystal column surface has HMDS or associated byproduct residue （As shown in Figure 2）, in silica wet etch step, because residue is covered in silicon oxide surface, hinder the corruption of silica Erosion, ultimately causes silica residual.If conversely, HMDS is excessively thin（As shown in Figure 3）, photoresist can be caused to bond loosely, cause The stripping of photoresist and drift.Both defects, can all have a strong impact on yields.

As can be seen here, the thickness of HMDS has important impact to the defect and yields of chip.But due to HMDS very It is thin, the thickness of only several molecular layers（<5nm), effective ways of the current industry without online, quick detection HMDS thickness, make The monitoring of HMDS thickness in pairs becomes highly difficult, that is, affect the efficiency and quality of chip processing procedure.

The content of the invention

It is an object of the present invention to provide a kind of monitoring photoetching glue bonding layer HMDS abnormal method, using the method, Ke Yi Whether line is monitored extremely to HMDS, it is ensured that the yields of chip, reduces production cost.

To reach above-mentioned purpose, the technical solution used in the present invention is：A kind of monitoring photoetching glue bonding layer HMDS exceptions Method, distinguishes growing silicon oxide layer on two silicon chips, forms oxidation Silicon Wafer, and measures respective thickness, by one of oxygen SiClx crystal column surface applies the uniform HMDS coatings of last layer, then by the oxidation Silicon Wafer for being provided with HMDS coatings with another not The oxidation Silicon Wafer for arranging HMDS coatings is sent in the lump in wet etching board, is corroded using identical etching time T, rotten The thickness of two wafers is measured after erosion, and the thickness difference D/ etching time T by wafer before and after corrosion calculate respective corruption Erosion speed A1 and A2, the thickness abnormity or composition abnormal conditions of HMDS coatings are judged using the difference between A1 and A2, work as A1- After the difference over range of A2, judge that the thickness of HMDS coatings is blocked up or excessively thin, or the composition exception of HMDS coatings.

Wherein in an embodiment, the silicon oxide layer that the silicon chip surface is arranged is using the method for boiler tube thermal oxide in silicon chip Surface deposits to be formed, and the thickness of silicon oxide layer is at 400 angstroms～600 angstroms.

Wherein in an embodiment, in the wet etching course, corrosive liquid is using the oxide mixed with surfactant Etch buffer liquid BOE solution, etching time T is between 40 seconds～80 seconds.

To reach above-mentioned purpose, the technical solution used in the present invention is：It is a kind of using described monitoring photoetching glue bonding layer The high-voltage device grate silica manufacturing method thereof that HMDS abnormal method is realized, daily using described monitoring photoetching glue bonding layer HMDS abnormal method detects a HMDS coating, if there is the difference over range of A1-A2, shows that HMDS coatings are different Often, stop ray examination, the difference for measuring A1-A2 to be checked meets after rated range, continue gate oxidation silicon processing procedure.

Because above-mentioned technical proposal is used, the present invention has compared with prior art following advantages：

1. the present invention is provided with the corrosion of HMDS coatings and two oxidation Silicon Wafers for being not provided with HMDS coatings by detection Speed A1, A2, calculates both differences, judges the difference whether in rated range, exception occurs beyond as HMDS coatings, Profit is indirectly online in such a way to measure HMDS coating layer thicknesses, it is to avoid affect chip because of HMDS coating layer thicknesses or composition exception Yields, reduces production cost；

2., due to being detected by wet etching mode, not only HMDS coating layer thicknesses are monitored, at the same when HMDS into When distribution is raw abnormal, corrosion rate also can be affected, thus can be prevented effectively from because of HMDS coating layer thicknesses using the method or Composition is abnormal and causes product defects and scrap in a large number；

3. pair HMDS coating thickness monitors are on-line checking once a day, do not affect normal scheduling of production, and when HMDS is applied When layer occurs abnormal, can in time stop ray examination, the defective products for preventing to be caused because HMDS coatings are bad is produced.

Description of the drawings

Fig. 1 is the processing flow figure of background technology mesohigh device grids silica；

Fig. 2 is the defective products process schematic in background technology produced by HMDS overweight coatings；

Fig. 3 is the defective products process schematic in background technology produced by HMDS cover lights；

Fig. 4 is the detection method process schematic of the embodiment of the present invention one.

Wherein：11st, silicon chip；12nd, silicon oxide layer；13rd, HMDS coatings；21st, chip；22nd, photoresist；23、HMDS.

Specific embodiment

Below in conjunction with the accompanying drawings and embodiment the invention will be further described：

Embodiment one：A kind of method shown in Figure 4, monitoring photoetching glue bonding layer HMDS abnormal, in two silicon chips 11 Upper growing silicon oxide layer 12 respectively, and respective thickness is measured, one of oxidation silicon wafer surface is coated into one layer uniformly HMDS coatings 13, are then not provided with the silica of HMDS coatings 13 by the oxidation Silicon Wafer for being provided with HMDS coatings 13 with another Wafer is sent in the lump in wet etching board, is corroded using identical time T, and the thickness of two wafers is measured after corrosion, The thickness that measures before thickness value and corrosion is compared respectively, obtains change value of thickness D, and calculated each by D/T Corrosion rate A1 and A2, judged using the difference between A1 and A2 HMDS coatings 13 thickness abnormity or composition exception feelings Condition, after the difference over range of A1-A2, judges that HMDS coatings 13 are abnormal, i.e., HMDS coatings 13 exist thickness it is blocked up or Person is excessively thin, or the problem that the composition of HMDS coatings 13 is abnormal.

If as shown in figure 4, set difference rated range asDo not having figuratum two silicon The surface of piece 11 is respectively adopted the silica that the method for boiler tube thermal oxide deposits thick layer, measures its thickness and is 500 angstroms.Then by Photoetching equipment aoxidizes silicon wafer surface and coats one layer of uniform HMDS coating 13 at one（One production thickness）.There to be HMDS to apply Layer 13 and the oxidation Silicon Wafer without HMDS coatings 13 all send into wet etching board, and corrosive liquid is adopted mixed with surfactant Oxide etching buffer B OE solution（Main component HF and NH₄F）, corroded within 60 seconds using the set time, measure after corrosion Two panels aoxidizes the thickness of Silicon Wafer, measures：Without HMDS coatings oxidation Silicon Wafer corrosion rate beHave The oxidation Silicon Wafer of HMDS coatings 13, corrosive liquid can first dissolve HMDS coatings 13, then corrosion oxidation silicon, therefore the silica for obtaining Corrosion rate isBoth difference 20 isExactly loss of the corrosive liquid on HMDS is processed, meets volume Determine scope, show that the thickness and composition of HMDS coatings 13 is normal.The processing procedure of the gate oxidation silicon of high tension apparatus can be carried out.

Contrary, if the corrosion rate for measuring the oxidation Silicon Wafer without HMDS coatings 13 is 100And have HMDS Coating 13 oxidation Silicon Wafer corrosion rate beBoth difference isSo then show HMDS Coating 13 is blocked up, because the thickness of HMDS coatings 13 is thicker, loss of the corrosive liquid when HMDS is removed is more, actual corrosion oxidation The time of silicon is fewer, and the corrosion rate of silica is also lower.If there is the corrosion rate of the oxidation Silicon Wafer of HMDS coatings 13 For 90Both difference isSo then show that HMDS coatings 13 are excessively thin.Or HMDS compositions itself or There is exception in person's board, will also be detected improper difference, just needs to stop ray examination if detection, it is to avoid the product of defective products Go out.

In the gate oxidation silicon processing procedure of high tension apparatus, this detection operation is tested once daily, on-line checking, therefore is detected It is convenient, accomplish monitoring whether is normally carried out to the thickness of HMDS coatings 13 and composition, pinpointing the problems to prevent in time, without the need for HMDS Coating 13 thickness of itself is measured, and is judged indirectly with corrosion rate, after exception is detected, stops ray examination, until data Production is started again at after normal, the quantity of defective products, reduces cost is reduced.

In sum embodiment only expresses the concentration embodiment of the present invention, and its description is more concrete and detailed, but and Therefore the restriction to the scope of the claims of the present invention can not be interpreted as.It should be noted that for one of ordinary skill in the art comes Say, on the premise of present inventive concept is not tied down, some deformations and improvement can also be made, these are all belonging to the guarantor of the present invention Shield scope.Therefore, the protection domain of patent of the present invention should be defined by claim.

Claims

It is 1. a kind of to monitor the abnormal methods of photoetching glue bonding layer HMDS, it is characterised in that：The growth oxidation respectively on two silicon chips Silicon layer, forms oxidation Silicon Wafer, and measures respective thickness, and one of oxidation silicon wafer surface is coated into one layer of uniform HMDS Coating, then in the lump send the oxidation Silicon Wafer that the oxidation Silicon Wafer for being provided with HMDS coatings is not provided with HMDS coatings with another Enter in wet etching board, corroded using identical etching time T, the thickness of two wafers is measured after corrosion, and pass through The thickness difference D/ etching time T of wafer calculate respective corrosion rate A1 and A2 before and after corrosion, using between A1 and A2 Difference after the difference over range of A1-A2, is judged judging the thickness abnormity or composition abnormal conditions of HMDS coatings The thickness of HMDS coatings is blocked up or excessively thin, or the composition exception of HMDS coatings.
It is 2. according to claim 1 to monitor the abnormal methods of photoetching glue bonding layer HMDS, it is characterised in that：The silicon chip table The silicon oxide layer that face is arranged deposits to be formed using the method for boiler tube thermal oxide in silicon chip surface, and the thickness of silicon oxide layer is at 400 angstroms ～600 angstroms.
It is 3. according to claim 1 to monitor the abnormal methods of photoetching glue bonding layer HMDS, it is characterised in that：The wet method is rotten During erosion, corrosive liquid using mixed with surfactant oxide etching buffer B OE solution, etching time T 40 seconds～ Between 80 seconds.
4. a kind of usage right requires the high-voltage device grate that the method for the monitoring photoetching glue bonding layer HMDS exceptions described in 1 is realized Silica manufacturing method thereof, it is characterised in that：Daily using the method detection one that described monitoring photoetching glue bonding layer HMDS is abnormal Secondary HMDS coatings, if there is the difference over range of A1-A2, show HMDS coating exceptions, stop ray examination, to be checked to measure The difference of A1-A2 meets after rated range, continues gate oxidation silicon processing procedure.