JPH01199173A - Electrostatic capacity measuring type apparatus for inspecting board - Google Patents

Abstract

PURPOSE:To dispense with a resistance meter for discriminating an insulation fault between patterns from a fault due to a short circuit, by providing additionally a group of resistors connected in series and a switch element switching over the resistors in the group, between a probe coming into contact with a pattern and a capacitance meter. CONSTITUTION:A group 4 of resistors is connected in series between a probe 6 coming into contact with a metal wiring pattern 9 on a board 7 to be measured, and a capacitance meter 1. In addition, a switch division 5 selecting one of the resistors in the group 4 is provided. When inspection of the pattern 9 is conducted, a short-circuit wire 10 is selected by the switch division 5 and an electrostatic capacity between the pattern 9 and a reference potential plane 8 is measured. In the case when a measured value thus obtained is within the range of an allowable error of a theoretical value, the capacity is determined to be good, and when the measured value is smaller than the theoretical value, it is determined to be a fault due to a disconnection in the middle of the pattern. In the case when the measured value is larger than the theoretical value, one of the resistors in the group 4 is selected and inserted between the capacitance meter 1 and the probe 6. When a composite resistance found in this state is large sufficiently, it is determined as a fault due to a short circuit between patterns, while it is determined as an insulation fault when the resistance is small.

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明は静電容量測定式基板検査装置に関する。[Detailed description of the invention] [Industrial application field] The present invention relates to a capacitance measurement type board inspection device.

〔従来の技術〕[Conventional technology]

従来の静電容量測定式基板検査装置は、静電容量計と、
金属配線パターン（以下パターンとする）に接触するプ
ローブと、前記プローブの位置決め部と、前記静電容量
計、プローブ、位置決め部を制御する制御部とを含んで
構成される。Conventional capacitance measurement type board inspection equipment uses a capacitance meter,
The device includes a probe that contacts a metal wiring pattern (hereinafter referred to as a pattern), a positioning section for the probe, and a control section that controls the capacitance meter, the probe, and the positioning section.

この装置は、任意のパターンと設定した基準電位面との
間の静電容量を測定し、理論的に計算した値と比較する
ことＫよシ、パターンの不良を判定する。This device determines whether a pattern is defective by measuring the capacitance between an arbitrary pattern and a set reference potential plane, and comparing it with a theoretically calculated value.

一般的には、被測定パターンの等価回路は第２図のよう
に表される。配線が食品である場合、他のパターンとの
間の絶縁抵抗１２、および基準電位面との絶縁抵抗１４
は十分大きいので、測定値は、静電容量１１と違ったも
のとなる。Generally, the equivalent circuit of the pattern to be measured is expressed as shown in FIG. If the wiring is food, insulation resistance 12 with other patterns and insulation resistance 14 with the reference potential plane
is sufficiently large, so the measured value is different from the capacitance 11.

例えば、パターンが途中で断線している場合は、静電容
量１１よυ小さい測定値が得られ、パターンが他のパタ
ーン容量１１より大きい測定値となる。For example, if a pattern is broken in the middle, a measured value υ smaller than the capacitance 11 will be obtained, and a measured value of the pattern will be larger than other pattern capacitances 11.

このように、理論的に計算した静電容量値と測定値が一
定しベル以上異なる場合に不良と判定する。In this way, if the theoretically calculated capacitance value and the measured value are constant and differ by more than a bell, it is determined to be defective.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

上述した従来の静電容量測定式基板検査装置は、静電容
量測定値が理論値よシ大きいという不良を検出した場合
、その原因がパターン間の絶縁不良（抵抗１２が十分大
きくない）Ｋよるものか短絡（抵抗１２が零）によるも
のか区別できないという欠点があった。When the above-mentioned conventional capacitance measurement type board inspection device detects a defect in which the measured capacitance value is larger than the theoretical value, it is determined that the cause is poor insulation between the patterns (resistance 12 is not large enough). There was a drawback that it was not possible to distinguish whether the problem was due to an accident or a short circuit (resistance 12 was zero).

〔問題点を解決するための手段〕[Means for solving problems]

本発明の静電容量測定式基板検査装置は、被測定基板上
の金属配線パターンに接触するプローブと、前記金属配
線パターンと基準電位面との間の静電容量を測定する静
電容量計と、前記プローブと前記静電容量計との間に直
列に挿入された抵抗器群と、この抵抗器群のうちひとつ
の抵抗を選択するスイッチ部と、前記プローブの位置決
めを行う位置決め部と、前記静電容量計、スイッチ部。The capacitance measurement type board inspection device of the present invention includes a probe that contacts a metal wiring pattern on a board to be measured, and a capacitance meter that measures the capacitance between the metal wiring pattern and a reference potential surface. , a resistor group inserted in series between the probe and the capacitance meter, a switch section for selecting one of the resistors from the resistor group, a positioning section for positioning the probe; Capacitance meter, switch section.

位置決め部を制御する制御部とを含んで構成される。and a control section that controls the positioning section.

〔実施例〕〔Example〕

次に１本発明の実施例について、図面を参照しある。　
　□ 静電容量計の測定端子の一方は基準電位面８に接続され
、他方はスイッチ部５にょシ選択された短絡線１０また
は抵抗器４を経て、接触プローブ６に接続される。接触
プローブ６は位置決め部３によシ被測定基板７上の任意
の位置のパターン９に接触する。この状態で静電容量計
の測定値を制御部２に送り、理論的に計算した値と比較
することにより、不良判定を行う。Next, an embodiment of the present invention will be described with reference to the drawings.
□ One of the measurement terminals of the capacitance meter is connected to the reference potential plane 8, and the other is connected to the contact probe 6 via the switch section 5, a selected shorting wire 10, or the resistor 4. The contact probe 6 is brought into contact with the pattern 9 at an arbitrary position on the substrate 7 to be measured by the positioning section 3 . In this state, the measured value of the capacitance meter is sent to the control unit 2 and compared with a theoretically calculated value to determine whether it is defective.

次に測定実施例を示す。Next, a measurement example will be shown.

パターンの検査をする場合、まず、スイッチ５で短絡線
１０を選択し、パターンと基準電位面８、との間の静電
容量の測定を行う。測定値が理論値の許容誤差範囲にあ
る場合は良と判定し、他のパターンの検査に移る。測定
値が理論値よシ小さい場合は、パターン途中の断線によ
る不良と判定する。測定値が理論値より大きい場合は次
に述べる手順を取る。When inspecting a pattern, first, the shorting line 10 is selected with the switch 5, and the capacitance between the pattern and the reference potential surface 8 is measured. If the measured value is within the allowable error range of the theoretical value, it is determined to be good and the inspection moves on to other patterns. If the measured value is smaller than the theoretical value, it is determined that the defect is due to a disconnection in the middle of the pattern. If the measured value is greater than the theoretical value, take the following steps.

第２図の回路図を交流理論によ）全体としてひとつの合
成抵抗と静電容量の並列接続と見なす。(According to AC theory), the circuit diagram in Figure 2 is regarded as a parallel connection of a combined resistance and capacitance.

第３図はこの状態を示している。FIG. 3 shows this state.

第３図における合成抵抗１６はパターンの間の絶縁抵抗
１２．および１４の値を反映しているので、抵抗１６の
値を求めれば、抵抗１２．および１４の情報を得ること
ができる。The combined resistance 16 in FIG. 3 is the insulation resistance 12 between the patterns. and 14, so if we find the value of resistor 16, we can find the value of resistor 12. and 14 information can be obtained.

合成抵抗１６の値を求める一方法として次に述べる方法
をとる。第１図に示した抵抗器群４のうちひとつを選択
して静電容量計とプローブの間に挿入する。この状態で
静電容量計の出力端子から見た回路は第４図に示すよう
に第３図の回路に抵抗１７を直列に挿入したものとなる
。One method for determining the value of the combined resistance 16 is the method described below. One of the resistor groups 4 shown in FIG. 1 is selected and inserted between the capacitance meter and the probe. In this state, the circuit viewed from the output terminal of the capacitance meter, as shown in FIG. 4, is the circuit shown in FIG. 3 with a resistor 17 inserted in series.

この状態での静電容量測定値をＣ３とおくと、第３図に
おける静電容量測定値をＣｌｓ合成抵抗１６をＲ９挿入
した抵抗１７をＲ１および測定周波数をωで表せば、 Ｃ意＝Ｃｔ／（（１＋Ｒ１／Ｒ）”＋（ωＣＩＲＩ）”
）　　　（１）となる。（１）式を変形するとＲが求ま
る。Letting the capacitance measurement value in this state be C3, the capacitance measurement value in FIG. /((1+R1/R)”+(ωCIRI)”
) (1). R can be found by transforming equation (1).

Ｒ＝Ｒｔｙ＜ＪＥフ【Ｙ；１不−１）　　（２）求めた
Ｒが十分大きい場合は、絶縁不良でないので、パターン
の間の短絡による不良と判定する。R=Rty<JEfu [Y; 1 - 1] (2) If the calculated R is sufficiently large, there is no insulation defect, and it is determined that the defect is due to a short circuit between patterns.

Ｒが小さい場合は絶縁不良と判定する。If R is small, it is determined that the insulation is defective.

測定を制限する要因は、周波数ω、および挿入抵抗１７
である。（１）式よシωが大き過ぎて、分母の２つの項
の関係が（１＋Ｒ１／Ｒ）”＜＜（ωＣｔＲｔ）”とな
る場合、Ｃ鵞の僅に対するＲの寄与が微小になり事実上
Ｒが計算できなくなる。The factors that limit the measurement are the frequency ω and the insertion resistance 17
It is. According to equation (1), if ω is too large and the relationship between the two terms in the denominator becomes (1+R1/R)”<<(ωCtRt), then the contribution of R to the C ratio becomes infinitesimal, and in fact R cannot be calculated.

次に、Ｒ１の値の違いによるＲの計算精度について述べ
る。測定値ＣＩおよびＣ３は誤差をそれぞれΔＣ１ｚΔ
Ｃ２と表すと、真値ＣＩＯｚ　ｃ２ｏ　に対して、測定
値Ｃ，、Ｃ，は ｃ　ｔ　”　ｃ　ｔｏ十ΔＣｔ　　　　　　　　　　　
（３）Ｃ，＝Ｃ，＋ΔＣｔ　　　　　　　　　　　（４
）と表される。測定に起因する誤差による、Ｒの計（２
）′式に（３）　、　（４）式を代入しＣｍ１０ｓ。＝
に、Δａｔ／Ｃ，，＝ΔＸ、ΔＣｔ／Ｃｔｏ　＝Δｙと
おく。すると（２）′式の右辺は （１＋Δｘ）−１＝・（５） ここでＲ＞＞Ｒ１なる条件の成シ立つ場合を考える。ル
ートの項に対して、−次近似を用い、かつ１／に−（”
ＣｓＲ＋）”７中１を用い、２次の微小項を無視すると （５）式中（Ｆじ１＝τ；ｉコＩｔ）”−１）＋〔ΔＸ
−Δｙ／ｋ”−Δｘ　（ωｃｔＲｔ）”　）−（６）（
６）式で第１項はＲｔ／Ｈの真値であり、Ｒ＞＞Ｒ，で
あるから、１より十分小さい。従って、第２項で表され
た誤差項のＲの計算値への影響はＲ１／Ｈの真値が小さ
い程大きくなることがわかる。このことからＲ″＞＞Ｒ
ｓの条件での静電容量測定値に基ず〈Ｒの計算値は信頼
性が低い。Next, the calculation accuracy of R due to the difference in the value of R1 will be described. Measured values CI and C3 each have an error of ΔC1zΔ
When expressed as C2, for the true value CIOz c2o, the measured value C,,C, is c t ” c to +ΔCt
(3) C, = C, +ΔCt (4
). Due to the error caused by the measurement, the total of R (2
)' Substitute equations (3) and (4) into equation Cm10s. =
Let Δat/C, , = ΔX and ΔCt/Cto = Δy. Then, the right side of equation (2)' is (1+Δx)-1=.(5) Here, consider the case where the condition R>>R1 is satisfied. For the root term, use −(”
CsR+)" Using 1 in 7 and ignoring the second-order minute term, in formula (5) (Fji1=τ;
−Δy/k”−Δx (ωctRt)” )−(6)(
In equation 6), the first term is the true value of Rt/H, and since R>>R, it is sufficiently smaller than 1. Therefore, it can be seen that the influence of the error term expressed by the second term on the calculated value of R becomes larger as the true value of R1/H becomes smaller. From this, R″>>R
Based on capacitance measurements under conditions of s, the calculated value of R is unreliable.

次にＲ１＜＜Ｈの場合を考える。Ｒ１／Ｒ＞＞　１　　
となるので、（１）式よりＣｔ＜＜Ｃｔ　　となる。と
ころで測定に起因する誤差には、測定値の大小に関係せ
ず一定の値をもつものがある。（プローブと、静電容量
計を結ぶ配線の浮遊容量による誤差等）従りてＣ１の測
定値の絶対値が小さくなると、この測定値のうち前述の
測定値の大小に関係しない誤差の占める割合が大きくな
る。従ってＲ１＞＞Ｈの条件での静電容量測定値に基ず
くＲの計算値は信頼性が低い。Next, consider the case where R1<<H. R1/R>> 1
Therefore, from equation (1), Ct<<Ct. By the way, some errors caused by measurement have a constant value regardless of the magnitude of the measured value. (Errors due to stray capacitance of wiring connecting the probe and capacitance meter, etc.) Therefore, as the absolute value of the measured value of C1 becomes smaller, the proportion of this measured value that is accounted for by errors that are not related to the size of the measured value mentioned above. becomes larger. Therefore, the calculated value of R based on the capacitance measurement under the condition of R1>>H has low reliability.

結果として、ＲとＲ１が近い値である条件のもとに、静
電容量を測定するのが最も良い。ところがＲの値は未知
であるからできるだけＲに近い値で、Ｒ８を選択できる
よう第４図の抵抗１７を固定抵抗とせずに、抵抗器群４
を採用し、これを切換えるという動作を行う。As a result, it is best to measure capacitance under conditions where R and R1 are close values. However, since the value of R is unknown, in order to select a value as close to R as possible and R8, instead of using the resistor 17 in Fig. 4 as a fixed resistor, resistor group 4 is used.
, and performs the operation of switching between them.

〔発明の効果〕〔Effect of the invention〕

本発明の静電容量測定式基板検査装置は、パターンに接
触するプローブと静電容量計の間に直列に接続される抵
抗器群と、該抵抗器群を切換えるスイッチ部を追加する
ことにより、従来、パターン間の絶縁不良と短絡による
不良の区別のため。The capacitance measurement type board inspection device of the present invention adds a group of resistors connected in series between the probe that contacts the pattern and the capacitance meter, and a switch unit that switches the group of resistors. Conventionally, this is used to distinguish between insulation defects between patterns and defects due to short circuits.

別に抵抗計が必要であったものを、省略できるという効
果がある。This has the effect of eliminating the need for a separate resistance meter.

【図面の簡単な説明】[Brief explanation of the drawing]

第１図は本発明の一実施例を示すブロック図、第２図は
被測定パターンの等価回路図、第３図は第２図を簡単化
した等価回路図、第４図は第３図に測定用抵抗を附加し
た回路図である。 １・・・・・・静電容量計、２・・・・・・制御部、３
・・・・・・位置決め部、４・・・・・・抵抗器、５・
・・・・・スイッチ部、６・・・・・・接触用プローブ
、７・・・・・・被測定基板、８・・・・・・基準電位
面、９・・・・・・パターン、１０−・・・・・短絡線
、１１・・・・・・被測定パターン単体の容量、１２・
・・・・・被測定パターンとは別の配線との間の絶縁抵
抗、１３・−・・・・被測定パターンとは別のパターン
の容量、１４・・・・・・電位基準面との間の絶縁抵抗
、１５−・・・・・被測定パターンの合成容量、１６・
・・・・・被測定パターンの合成抵抗、エフ・・・・・
・抵抗器群よシ選択したひとつの抵抗。 代理人　弁理士　　内　原　　　背 形１　■ 第４１Figure 1 is a block diagram showing an embodiment of the present invention, Figure 2 is an equivalent circuit diagram of the pattern to be measured, Figure 3 is a simplified equivalent circuit diagram of Figure 2, and Figure 4 is the same as Figure 3. FIG. 3 is a circuit diagram with a measurement resistor added. 1...Capacitance meter, 2...Control unit, 3
...Positioning part, 4...Resistor, 5.
...Switch section, 6 ... Contact probe, 7 ... Board to be measured, 8 ... Reference potential surface, 9 ... Pattern, 10-... Short-circuit wire, 11... Capacity of single pattern to be measured, 12-...
...Insulation resistance between the pattern to be measured and wiring different from the pattern to be measured, 13...Capacitance of the pattern different from the pattern to be measured, 14......Insulation resistance between the pattern and the wiring different from the pattern to be measured, 14... Insulation resistance between, 15-... Composite capacitance of pattern to be measured, 16-
...Combined resistance of the pattern to be measured, F...
・One resistor selected from a group of resistors. Agent Patent Attorney Hara Uchigata 1 ■ No. 41

Claims (1)

【特許請求の範囲】[Claims] 　被測定基板上の金属配線パターンに接触するプローブ
と、前記金属配線パターンと基準電位面との間の静電容
量を測定する静電容量計と、前記プローブと前記静電容
量計との間に直列に挿入された抵抗器群と、この抵抗器
群のうちひとつの抵抗を選択するスイッチ部と、前記プ
ローグの位置決めを行う位置決め部と、前記静電容量計
、スイッチ部、位置決め部を制御する制御部とを含むこ
とを特徴とする静電容量測定式基板検査装置。a probe that contacts a metal wiring pattern on a board to be measured; a capacitance meter that measures the capacitance between the metal wiring pattern and a reference potential surface; and a capacitance meter that measures the capacitance between the probe and the capacitance meter. A group of resistors inserted in series, a switch section that selects one of the resistors from the group of resistors, a positioning section that positions the probe, and a control section that controls the capacitance meter, the switch section, and the positioning section. 1. A capacitance measurement type board inspection device, comprising: a control section.