The method of section difference height between the fast detecting chip stack structure
Technical field
The present invention relates to the semiconductor integrated circuit field, particularly relate to a kind of method that is used for section difference height between power device process exploitation fast detecting chip stack structure.
Background technology
In the power device product because its high withstand voltage characteristic is often introduced epitaxial loayer, buried regions, technologies such as deep trench isolation, and these technologies can cause many shoulder heights that are difficult to predict (step hei ght), if can not in time recognize section difference state actual in the chip (chip) in the process exploitation stage, bring influence can for the foundation of subsequent module condition.Directly cause the inefficacy of device on physical structure, influence the exploitation and the progress of integrated artistic.
Existing power device process exploitation mainly is the structure sheet experiment by some weak point flow processs, relies on some experiences and the in-problem processing step of some possibilities of theoretical heap, and module is carried out the shoulder height that destructive silicon chip fractograph analysis is confirmed silicon chip.This traditional method development cost height, and to research staff's experience, theoretical foundation has stronger dependence.
Summary of the invention
The technical problem to be solved in the present invention provides the method for section difference height between a kind of fast detecting chip stack structure, can effectively avoid making the device physics inefficacy by shoulder height in the power device process exploitation process.
For solving the problems of the technologies described above, the method for section difference height is to adopt following technical scheme to realize between fast detecting chip stack structure of the present invention:
Step 1, universal test mask plate of making; Set up one according to the size of the shape of resolution chart and CD (critical size) and can characterize the calibration system that concerns between CD and the shoulder height;
Step 2, with resolution chart with in batches or the combination mode, the rule and be positioned over uniformly in the universal test mask plate;
Step 3, on silicon chip, be coated with photoresist; Exposure, development form required resolution chart;
Step 4, the formed resolution chart critical size of step 3 measured or observes the variation of outward appearance;
Step 5, according to measuring or the result of observation contrasts calibration system and draws the shoulder height that exists in the power device technology.
The present invention directly utilizes the exposure of test mask plate, changes the shoulder height that characterizes each position in the chip according to the resolution chart CD on the mask plate and changes.Method of the present invention can measure by naked-eye observation and CD and realize making judgement accurately fast, changes and needn't test the shoulder height that obtains each position in the chip by destructive silicon chip section.Method of the present invention can not only direct detection actual silicon sheet situation, avoid causing the device physics inefficacy by shoulder height in the power device process exploitation process, and reduced development cost with respect to conventional method, and to research staff's experience, the degree of dependence of theoretical foundation.
Description of drawings
The present invention is further detailed explanation below in conjunction with accompanying drawing and embodiment:
Fig. 1 is a universal test mask plate structure chart;
Fig. 2 is an exposure area build-in test diagram form master drawing;
Fig. 3 is the focal length certification mark pattern card that is used to detect;
Fig. 4 is method one an embodiment control flow chart of the present invention.
Embodiment
In conjunction with shown in Figure 4, in one embodiment, the technological process that the method for section difference height is implemented between described fast detecting chip stack structure is as follows:
Step 1, universal test mask plate of making; Set up one according to the size of the shape of resolution chart and CD (critical size) and can characterize the calibration system that concerns between CD and the shoulder height.
Fig. 1 is one 6 inches standard universal test mask plates, has difform resolution chart in this mask plate.The exposure area size of described universal test mask plate can be adjusted according to the size (shot also can be regarded as die size) of exposing each time in the actual development technology; The scribe line width of mask plate must not be less than 300 μ m, to be applicable to all types photo-etching machine exposal baffle plate shading required precision; On the scribe line of mask plate ad-hoc location, make sign property mark, use to do the shot district office.
Described calibration system can be adopted in the following method and realize: select some figures relatively more responsive to the technique change reaction, in conjunction with shown in Figure 2, be generally long and narrow argyle design or lozenge diagram and other figure such as point-like [(or title island (dot), as the square among Fig. 2], the combination of strip [(or claim space (gap), as the rectangle among Fig. 2] is as resolution chart; Resolution chart is exposed under different focal (focus) by mask aligner, develop; The resolution chart that obtains is measured, and measurement is corresponding with focal length, promptly set up a calibration system.Described calibration system can be quantized the variation of resolution chart critical size and the relation between the shoulder height.For example, the resolution chart critical size 50nm that diminishes, corresponding shoulder height changes
The resolution chart critical size 80nm that diminishes, corresponding shoulder height changes
Deng.
Referring to shown in Figure 3, the focal length certification mark that is used for monitoring of tools (focus mark) that described resolution chart can adopt each mask aligner equipment vendors to be provided.For example in Fig. 3 (a), resolution chart is long and narrow rhombus, and this figure can obviously change along with the CD of its Y direction of slight variation of focal length (focus).Utilize the pattern of this class figure, the variation of CD can characterize the difference of the distance of the discharging of the coke significantly, and that the difference of focal length can be converted into the step section of true reactor stack architecture by the calibration system of having set up is poor.
Step 2, with resolution chart with in batches or the combination mode, the rule and be positioned over uniformly in the universal test mask plate.For example shown in Figure 2, the resolution chart of the different shape combination of in universal test mask plate exposure area, placing.
Step 3, on silicon chip, be coated with photoresist; Exposure, development form required resolution chart.Described " photoresist " can be the I-line that possesses the resolution chart analytic ability, KrF even short wavelength's photosensitizing chemical product material more.
Step 4, the formed resolution chart critical size of step 3 measured or observes the variation of outward appearance.The variation that is to say exposure back resolution chart critical size or outward appearance can adopt naked-eye observation and CD to measure two kinds of methods.For the ease of naked-eye observation, can place some on described resolution chart next door and indicate, so that the variation that naked eyes directly observe resolution chart produce.
Step 5, according to measuring or the result of observation contrasts calibration system and draws the shoulder height that exists in the power device technology.
Step 6, removal photoresist.After having detected between power device technology chips storehouse section difference height, only need just continuing flow behind the actual silicon chip stripping glue.
More than by specific embodiment the present invention is had been described in detail, but these are not to be construed as limiting the invention.Under the situation that does not break away from the principle of the invention, those skilled in the art also can make many distortion and improvement, and these also should be considered as protection scope of the present invention.