# US 7,078,690 B2 · Monitoring of contact hole production > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,078,690 B2 - Document ID: US7078690B2 - Status: Granted - Kind: B2 - Application number: 10/209,087 - Filed: 2002-07-30 - Published: 2003-08-07 - Granted: 2006-07-18 - Earliest claimed: 2002-02-04 - Assignees: Applied Materials Israel Ltd. - Inventors: Avi Simon; Alexander Kadyshevitch - Web page: https://patentgrep.com/patent/US7078690B2 ## CPC - H10P 74/277: {Circuits for electrically characterising or monitoring manufacturing processes, e.g. circuits in tested chips or circuits in testing wafers} - H10P 74/203: {Structural properties, e.g. testing or measuring thicknesses, line widths, warpage, bond strengths or physical defects} - H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10 ## Abstract A method for production testing includes receiving a wafer including a semiconductor substrate and a non-conducting layer formed over the substrate, following etching of contact openings through the non-conducting layer to the substrate, the contact openings including an array of the contact openings arranged in a predefined test pattern in a test area on the wafer. An electron beam is directed to irradiate the test area, a specimen current flowing through the substrate responsive to the electron beam is measured. The specimen current is analyzed so as to assess a dimension of the contact openings. ## Claims ### Claim 1 A method for production testing, comprising: receiving a wafer comprising a semiconductor substrate, a non-conducting layer formed over the substrate, and a photoresist layer overlying the non-conducting layer, following etching of contact openings through the non-conducting layer to the substrate, the photoresist layer having been used in etching the contact openings, wherein the contact openings comprising comprise an array of the contact openings arranged in a predefined test pattern in a test area on the wafer; directing an electron beam to irradiate the test area; measuring a specimen current flowing through the substrate responsive to the electron beam before removal of the photoresist layer; and analyzing the specimen current so as to assess a dimension of the contact openings. ### Claim 2 (depends on 1) A method according to claim 1, wherein the contact openings comprise contact holes. ### Claim 3 (depends on 1) A method according to claim 1, wherein the contact openings comprise trenches. ### Claim 4 (depends on 1) A method according to claim 1, wherein the test pattern is at least 10×10 μm in size. ### Claim 5 (depends on 4) A method according to claim 4, wherein the test pattern comprises at least 100 of the contact openings. ### Claim 6 (depends on 4) A method according to claim 4, wherein directing the electron beam comprises focusing the beam to an area approximately equal to the size of the test pattern. ### Claim 7 (depends on 1) A method according to claim 1, and further comprising, if the specimen current indicates that the dimension of the contact openings is below a predetermined limit, further etching the non-conducting layer using the photoresist layer so as to increase the dimension. ### Claim 8 (depends on 1) A method according to claim 1, wherein the wafer includes multiple microelectronic circuits thereon, wherein the circuits are separated by scribe lines, and the test area is located on one of the scribe lines. ### Claim 9 (depends on 1) A method according to claim 1, wherein the test area is one of a plurality of such test areas in different locations on the wafer, and wherein directing the electron beam comprises positioning at least one of the electron beam and the wafer so as to irradiate each of at least two of the test areas in turn. ### Claim 10 (depends on 1) A method according to claim 1, wherein directing the electron beam comprises operating the electron beam during a precharge period so as to precharge the test area, and then operating the electron beam during a test period following the pre charge period, while measuring the specimen current. ### Claim 11 (depends on 10) A method according to claim 10, wherein operating the electron beam during the precharge period comprises applying a negative charge to a surface of the test area. ### Claim 12 (depends on 11) A method according to claim 11, wherein operating the electron beam during the test period comprises setting an energy of the electron beam in a positive charging domain of the substrate. ### Claim 13 (depends on 1) A method according to claim 1, wherein measuring the specimen current comprises contacting a conductive contact pad fixed to the wafer adjacent to the test area, and measuring the current flowing through the contact pad. ### Claim 14 (depends on 1) A method according to claim 1, wherein directing the electron beam comprises pulsing the electron beam while irradiating the test area, and wherein measuring the specimen current comprises measuring the current by capacitive coupling to the wafer. ### Claim 15 (depends on 1) A method according to claim 1, wherein analyzing the specimen current comprises assessing at least one of a depth and a width of the contact openings. ### Claim 16 (depends on 1) A method according to claim 1, and comprising measuring a secondary electron current emitted from the substrate responsive to the electron beam, and analyzing the secondary electron current together with the specimen current. ### Claim 17 (depends on 1) A method according to claim 1, wherein analyzing the specimen current comprises detecting a residue within the contact openings, and comprising irradiating the wafer with the electron beam so as to remove the residue. ### Claim 18 A method for production testing, comprising: receiving a wafer comprising a semiconductor substrate and a non-conducting layer formed over the substrate, following etching of contact openings through the non-conducting layer to the substrate, the contact openings comprising an array of the contact openings arranged in a predefined test pattern in a test area on the wafer; directing an electron beam to irradiate the test area; measuring a specimen current flowing through the substrate responsive to the electron beam; detecting a residue within an least one contact opening of the contact openings by analyzing the specimen current so as to assess a dimension of the contact openings; and irradiating the wafer with the electron beam so as to remove the detected residue from the at least one contact opening. ### Claim 19 (depends on 18) A method according to claim 18, wherein the contact openings comprise contact holes. ### Claim 20 (depends on 18) A method according to claim 18, wherein the contact openings comprise trenches. ### Claim 21 (depends on 18) A method according to claim 18, wherein the test pattern is at least 10×10 μm in size. ### Claim 22 (depends on 21) A method according to claim 21, wherein the test pattern comprises at least 100 of the contact openings. ### Claim 23 (depends on 21) A method according to claim 21, wherein directing the electron beam comprises focusing the beam to an area approximately equal to the size of the test pattern. ### Claim 24 (depends on 18) A method according to claim 18, wherein the wafer includes multiple microelectronic circuits thereon, wherein the circuits are separated by scribe lines, and the test area is located on one of the scribe lines. ### Claim 25 (depends on 18) A method according to claim 18, wherein the test area is one of a plurality of such test areas in different locations on the wafer, and wherein directing the electron beam comprises positioning at least one of the electron beam and the wafer so as to irradiate each of at least two of the test areas in turn. ### Claim 26 (depends on 18) A method according to claim 18, wherein directing the electron beam comprises operating the electron beam during a precharge period so as to precharge the test area, and then operating the electron beam during a test period following the pre charge period, while measuring the specimen current. ### Claim 27 (depends on 26) A method according to claim 26, wherein operating the electron beam during the precharge period comprises applying a negative charge to a surface of the test area. ### Claim 28 (depends on 27) A method according to claim 27, wherein operating the electron beam during the test period comprises setting an energy of the electron beam in a positive charging domain of the substrate. ### Claim 29 (depends on 18) A method according to claim 18, wherein measuring the specimen current comprises contacting a conductive contact pad fixed to the wafer adjacent to the test area, and measuring the current flowing through the contact pad. ### Claim 30 (depends on 18) A method according to claim 18, wherein directing the electron beam comprises pulsing the electron beam while irradiating the test area, and wherein measuring the specimen current comprises measuring the current by capacitive coupling to the wafer. ### Claim 31 (depends on 18) A method according to claim 18, wherein analyzing the specimen current comprises assessing at least one of a depth and a width of the contact openings. ### Claim 32 (depends on 18) A method according to claim 18, and comprising measuring a secondary electron current emitted from the substrate responsive to the electron beam, and analyzing the secondary electron current together with the specimen current.